vi international congress on experimental mechanics technical program

VI INTERNATIONAL CONGRESS ON EXPERIMENTAL MECHANICS TECHNICAL PROGRAM June 5-10,1988 Red Lion Inn/Jantzen Beach, Portland, OR

SUNDAY EVENING, JUNE 5

1. Annual Business Meeting

Chairman: Clarence A. Calder, SEM President. Oregon State University

All members are invited to attend the annual business meeting at which the 1988/89 SEM Executive Board will be elected.

MONDAY MORNING, JUNE 6

2. Plenary Speaker

Chairman: Clarence A. Calder. SEM President, Oregon State University

PLENARY SPEAKER Vagn Askegaord. Technical University of Denrnork

Testing of Structures and Structural Components

The relation between experiment and theory and the purpose of testing of structures and structural components are discussed. Examples from the civil engineering field are used to illustrate different aspects of the problem of predicting experimental accuracy and the limitations in using physical models.

3. Research in Progress

Sponsored by the Research Committee

Chairman: Hank R. Busby, Ohio State University Cochairman: Jon Epstein. EG&G Idaho. Inc.

This informal session will allow authors to present a few timely ideas about their current research. Speakers will be limited to a ten- minute talk followed by a five-minute question-and-answer period. No manuscripts will be printed. but abstracts will be available. Com- ments and ideas from the audience to aid the researcher in his or her work are encouraged.

4. Transducers in Biomechanics

Sponsored by the Transducer Division

Chairman: James R. Weidner. Measurements Group. Inc. Cochairman: Charles Umeagukwa. Georgia Institute of

Technology

Problems and Techniques of Using Nine Accelerometers in Head Impact Studies Guy Nusholtz. University oj Michigon

Mechanical Testing of Soft Tissue and Heart Cells B.R. Durig. L Teracio. TK. Borg and Walter H. Peters. University of South Carolina

A computer-based system which was designed to mechanically stretch soft tissue (bovine retina) and a thin silicon membrane with attached live rat heart cells is described. Force. displacement. and video image data which was obtained with this system are presented. The use of this system to calibrate a mechanical scotch yoke testing system is also presented.

Pressure and Force Transducers: Proper Selection for Various Applications Walt Jacobson. Sens-All Corporation

5. Structural Testing I

Chairman: B.M. Kwak University of Iowa Cochairman: to be announced

Effects of Flatness on the Contact Pressure Between Joint- ed Plates By Using Ultrasonic Techniques Yoshihisa Minakuchi. Toshikazu Shibuya and Takashi Koiturni. Yarnanashi University

The contact pressures in jointed plates are measured by using ultrasonic techniques, especially varying the flatness of jointed surfaces. The results are presented graphically and the effect of the flatness deviation on the contact pressure is investigated.

Non-Destructive Measurement of Residual Stress Using Magnetic Sensors Kenji Kashiwaya. Hiroshi Sakarnoto. and Yasuo Inoue. Roilway Technical Research Institute

Several applications of magnetic sensors to the non-destructive measurement of residual stress in steel products are discussed. The measuring method utilizes the phenomenon of the permeablility changing under the effect of stress.

A Study on the Dynamic Characteristics of Structures with Joints Jang Moo Lee, Ho Bin Kim. Sin Young Lee and Ki Ook Kim, Seoul National University

Dynamic modeling of a structure with joints was studied by using modal testing, the condensation method and sensitivity analysis. The validity of the modeling was checked through experiments. The dynamic characteristics of joint structures were experimentally investigated for the various conditions.

The Dimensional Similar Constant Method and the Simulated Test on the Dynamic Response of Railroad Track Shaowen Yang, Yihui Wu and Lixin Shoo. Shantou University

According to the variable properties of physical measuring units, the definition of the Dimensional Similar Constant is made. A simulated test model on the dynamics of railroad track was designed by means of the Dimensional Similar Constant Method.

6. Optical Methods I

Chairman: Don Matthys. Marquette University Cochairman: John Gilbert, University of Alabama-Huntsville

Computer-Oriented Analysis of the Stress-Strain-State in 3- DSolids by Means of Holographic Interferometry Karl-Hans Laermann. Bergrsche Universitat-GH Wuppertal

Based on the principles of the multiple-hologram-analysis, the total displacement field %pi- of the surface r of a simply connected three-dimensional solid is determined. and the analogous optical informations are transformed into digital ones by automatic image- processing. To solve the boundary value problem of the first kind, a reconstruction algorithm for numerical evaluation of the experimental data is derived.

Holographic NDT of Composite, Laminated and Bonded Structures J.F. Clarady, h t t & Whitney Aircraft

A holographic NDT technique has been developed that permits the rapid inspection of composite, laminated, and bonded structures. Previous holographic methods that used vibration stressing were time-consuming since the test piece was excited with a discrete frequency-vibratory excitation. The new method utilizing random- vibratory excitation represents a considerable time savings making it practical for use in high-volume production applications.

Two-Dimensional Strain Analysis by Moire Method Using Fourier Transform Yoshiharu Morimoto. Yasuyuki Seguchi. Osaka University; and Toshihiko Higashi. Kansai Electric Power Co. Inc.

Two-dimensional strain distribution is analyzed by using the Fourier Transform of an image of two families of model gratings. The analysis is completely automatized by introducting an image-processing system which is objective. fast and accurate.

Transient Stress Intensity Factors of Cracked Plates Under Moving Thermal Loads Eiichi Matsumoto. Kinki Uniuenity: Arkady S. Voloshin. Lehigh Uniuenity; Masanobu Taki. Uniuenity of Osaka Prefecture: and Pinchas Katz. Lehigh Uniuersity

Thermoelastic response of a coolant load moving along a cracked surface is investigated. Photoelastic pictures are analyzed reading the position data, fringe, and stress intensity factors.

7. Materials Testing I

Chairmar Mitsuo Obata. Tohoku University Cochairman: George Eggeman. Kansas State University

Determination of Frictional Coefficient for Sheet Metal Working and its Application to Stretch Forming Choong-Hong Lee. K-Mek Co.; Hyun-Bo Shim and Dong-Yo/ Yang. Korea Advanced fnstitute of Science and Technology

Normal pressure at the frictional interface is usually low in sheet- metal deformation and the Coulomb coefficient of friction is widely used in simulating the sheet-metal processes. A proper method of friction measurement is suggested in which the Coulomb coefficient of friction is measured by using the relation for wrapping friction during deformation of sheet-metal. By application of measured coefficient to simulation of stretch forming. the relevancy of the method is checked by comparing simulation results with those obtained from the experiments.

A Multiaxial. High-pressure Test Device for Large Con- crete Specimens R.H. Atkinson. Atkinson-Noland & Associates. fnc.: C.D. Norman. D.M. Smith and M.I. Hammons. U.S. Army Engineer Waterways Experiment Station

A unique test device loads concrete specimens 150mm x 150mm x 900mm in size using fluid cushion bladders to apply lateral confin- ingstresses to 200 MPa. The design permits the lateral stresses to be unequal for creation of a multiaxial stress state in the specimen. Examples of tests on rebar pull-out specimens under lateral confin- ing stresses and from tests on compressive multiaxial specimens are presented.

Elaborate Simulation of Ball Indentation Process by Elas- toplastic, Large Deformation Contact Analysis Byung Chai Lee, Byung Man Kwak. Korea Advanced fnstitute of Science and Technology: and Jin Won Joo. Korea Standards Research lnstitute

The ball indentation process in a Brinell hardness test has been numerically simulated. An equivalent minimization formulation corresponding to the incremental field equations is used. where elastoplastic, large deformation is incorporated. The method can generate complete information and is shown indispensable for detailed analysis.

A New Automated Fatigue Crack-Growth Test System /ZUN Nishikawa. Yoshio Miyoshi and Keiji Ogura. Osaka Uniuenit y

A real-time image-processing system capable of measuring the crack-growth rate is developed. A personal computer controls the CCD camera on a pulse stage to trace the current crack tip and calculates the crack-growth rate. K-controlled crack-growth tests are conducted to demonstrate the accuracy and versatility of the system.

8. Modal Analysis Seminar I

Sponsored by the Education Committee

Presented by: Kenneth G. McConnell. Iowa State Uniuenity

SO April lW

OBJECTIVE An introductory short course in exerimental modal analysis for engineers with little or no experience with the technique. The course covers the fundamentals of vibration theory, vibration measurements, digital frequency analysis. and an introduction to modal analysis and testing. It is expected that the participants have had a first course in elementary vibration analysis that includes one and two degrees of freedom analysis and familiarity with second order linear differential equations and Fourier Series.

Typical Measurement Systems and Transducer Charac- teristics

The electrical and mechanical characteristics of force and motion measurement systems are reviewed for use in modal-analysis type of applications.

1. The Overall Measurement Test System a. Modal Analysis Requirements b. What the Measurement System Gives You

2. The Mechanical Characteristics of the Transducers Com- monly Employed

a. Natural Frequency Characteristics b. Damping Characteristics

a. Voltage Followers b. Charge Amplifiers Piezoelectric-Type Sensors c. Built-in Voltage Followers d. Strain-Gage Type Sensors

a. Mechanical Response b. Electrical Response

a. Mass Line b. Strain c. Phase Shift Considerations

3. The Electrical Characteristics of the Transducers

4. Response to Transient Events

5. Modal Test System Calibration Techniques

MONDAY AFTERNOON, JUNE 6

9. Materials Testing I1

Chairman: Dan Dawson. Sandia National Laboratories Cochairman: to be announced

Cyclic Elastic Follow-up Behavior on 2.25Cr-lMo Steel at Elevated Temperature Ken-ichi Kobayasbi. Chiba University; Yasushi Saitoh. Torshiba Corporation: Teruyoshi Udoguchi. University of Tokyo

Analytical and experimental investigations on monotonic and cyclic elastic follow-up behavior of metals were conducted. Tests were made on uniaxial specimens of 2.25Cr-1Mo steel at 600°C. Sim- plified inelastic analyses for the elastic follow-up are proposed.

Degradation of Lightweight Concrete Subjected to High- Explosive Loading Gayle E. Albritton and Paul W. Graham. US. Army Engineer Waterways Experiment Station

The use of lightweight concrete as a possible construction material for hardened structures to resist the effects of nuclear environments was examined by conducting an experimental test of concrete block specimens subjected to high-explosive aihlast loading. The results of this experiment are presented, along with a method to reduce the degradation of lightweight concrete members when loaded dynamically.

Notched Tensile Strength and Plastically Deformed Zone of Type 304 Stainless Steel at 4 K Yutaka lino. Toyota Technological Institute: and Kenichi Suzuki. Toshiba Heavy Apparatus Engineering Lab

The notch-strength ratio of the double-edge notched plate was determined. It decreased linearly with decreasing temperature from 1.05 at 375K to - 0.57 at 4K. The recrystallization technique was extended to 4K. and the plastic zone with plastic strain above 0.02 can be clearly observed. The plastic zone size at the notched ultimate tensile strength at 4K is also small compared with those at 77K and 298K. indicating the decrease of ductility at 4K.

Relation Between Cyclic Creep and Pure Creep on

Hiromasa lshikawa and Shigeru Tadano. Hokkaido University Copper

The behavior of a pure copper subjected to pure creep and cyclic creep under imposed load IS examined at room temperature and at 200 C. 300 C, and 400 C to show the relation between these two kinds of phenomena

Mechanical Testing and Microscopic Analysis of Structure of Extruded Powder Aluminum T O Woods Donald G Berghaus Georgia Institute of Technology and H B Peacock, E I duPont de Nemours & Company

Extruded powder aluminum specimens were mechanically tested at elevated temperature in tension and compression and were then sectioned, polished. and viewed microscopically to examine changes in the powder metal. Quantitative metallography was used to show changes produced in the laminar powder structure. The void content of the material increased with greater axial elongation in the tension tests and decreased with increasing levels of compression.

Parameter of Creep Local Strain Distribution Near the Crack Tip of Al Alloy by Fine Grid Method Gyu Chang Lee. Mitsuo Obata. Tohoku Unruersity: ond Heihachi Shimada. Akita National College of Technology

Local creepstrain distribution near a crack tip in AI alloy could be written in terms of a single parameter by measurements of a computer-aided fine-grid method By using this parameter. the authors discuss creegcrack initiation.

Complex Mode Shape Identification of a Machine Tool Structure in the Comparative Viewpoint Dong Woo Cho, Pohang lnstitute of Science & Technology: and Sang Jo Lee, Yonsei Uniuersity

The newly-proposed Multy-Input model analysis using the Time Series (MITS) method was applied to investigate the dynamic behavior of a vertical milling machine. and the Single-Input Fre- quency Response Function (SIFRF) method was also used in parallel for comparison purposes. The identified complex mode shapes from both methods were animated and showed good consistancy.

10. Optical Methods I1 - Moire and Caustics

Chairman: to be announced Cochairman: T Dixon Dudderar. AT&T Bell Laboratories

Design and Calibration of a Multi-Lens caustic Camera R.J. Sanford. Uniuersity of Maryland: and J.S. Gerstein. NJG. Inc.

Irpcrirncnlal lhhniqww 41

In order to increase the amount of data obtained from a caustic experiment. a multi-lens view camera system has been developed. With this camera four caustics with increasing transverse diameters are recorded at the film plane. The design principles and calibration procedures for the camera will be presented.

Exact Interpretation and Analysis of Moire Measurements by Digital Imaging Alex C. Lee ond Terry G Richard. University of Wisconsin- Madison

Digital-imaging systems and numerical-spline techniques can be combined to produce reliable deformation measurements with relatively low moire grating-line densities. This presentation addresses the application of techniques to situations where few hinges are available near the diffraction limit of geometric moire. Particular attention is given to the influences of the imaging system on the experimental configuration and interpretation of results.

Effects of Non-Singular Stress Terms on Caustics in Bile- Mngent Plate Under Various Fracture M o d e Loadings Ouk6ub Lee. SungKyung Hong and M.K. Hon. lnho University

The effects of the non-singular stress terms on the shapes of initial curves and caustics in birefringent plates under various static loading conditions are investigated. Williams' stress function is

employed to generate various theoretical initial curves and caustics at the vicinity of plane crack tips. Some experimentally obtained double. caustics are compared to the theoretically generated double caustics.

A New Technique for the Determination of Stress Optical Constants Using the Shadow Spot Method N T: Younis ond Loren W. Zochory. Iowa Stote University

Current methods require the use of E andp of the material and both the transmitted and reflected caustics to determine either the reflected or transmitted stress optical constant. A new technique has been developed that does not require E andp. and the stress optical constants are determined directly from the corresponding caustic.

S:udy on the Applicability of Caustics to the Stress-Frozen Model Through the Analysis of the Values of the Optical Constants Koji Shimizu. ond Susumu Tokohoshi. Konto Gokuin University

Caustic pattern cannot be obtained in the stress-frozen model by the conventional technique of caustics. This phenomenon is studied through the analysis of the individual values of the optical constants by a simple method and some techniques were proposed to apply the caustics method for a stress-frozen model.

Digital Secondary Moire Pattern and Digital Moire Fringe Multiplication Qifeng Yu. Chongsho Institute of Technology

New techniques of constructing secondary moire patterns and mul- tiplying moire fringes from common moire patterns with digital moire image-processing systems are proposed. These techniques can increase the accuracy and range of the-moire technique.

Moire Interferometry for Simultaneous Measurement of u.v.w M. T: Cheung ond A. Asundi. University of Hong Kong

Moire interferometry is used to simultaneously measure all three components of displacement. Since the in-plane and out-of-plane displacement components are recorded separately, there is no need for post recording filtering to separate out the components. By pro-

per choice of specimen and reference grating. the experimental set- up is greatly simplified.

11. Structural Testing I1

Chairman: J.M. Lee, Seoul National University Cochairman: Lloyd Lazarus. Allied Signal

Measurement of Impulsive Force and Duration of Impact in Elastic-Plastic Impact of Bodies Mososhi Doimoruyo. Muroron Institute of Technology. Shinli Tonimuro. University of Osoko Relecture. and Shigeru Onozoki. Muroron Institute of Technology

A new method for measuring an impulsive force generated at the impact end of a body subjected to impact loading is presented. The dynamic behavior of metal bars in plastic impact. experimentally and theoretically. is examined.

Vibration Analysis of a One-Link Flexible Manipulator Sub- jected to Impulsive-Like Rotation YoungPil Pork. YoungKyun Ho ond SeungHo Kim. Yonsei University

Analytical and experimental investigations are made to the dynamic response of a uniform cantilever with a tip mass at its free end subjected to a sudden stop after finite impulsive-like rotation. Results are obtained using Galerkin's method for the vibration amplitude of the bee end with respect to system parameters

Structure-Driven Processing for Image Understanding and Its Application to Photoelastic Analysis Mosohisa Tokoshi. Yoshioki Toyodo. Shizuo Mowotori. Aoyomo University; Koichi Honor, ASAHl Gloss Co Ltd.: ond Kikuno Shimosoki. Bonk of Jopon

Taking the physical characteristics of interference fnnge patterns into account, a microcomputer system of the structure-driven processing for image understanding was developed in order to facilitate photoelastic stress analysis

Simulation of Three-Point Bending at Large Deflections by an Elastoplastic Contact Analysis Jin Won Joo. Koreo Stondords Reseorch Institute; andByung Mon Kwbk. Koreo Adoonced Institute of Science ond Technology

A three-point bending is simulated by an elaborated numerical pro. cedure including an elastoplastic. large deflection. contact analysis An optimization technique based on the finite-element approximation is adopted for the solution method. Expenmental results are presented. and comparisons are made with numerical results

An Experimental Study on the Motion Accuracy Analysis of Active (Robot) Mechanisms Ho- Ryong Kim. Yon Sei University

A prototype of 3 D . 0 F. active mechanism is fabricated to experimentally analyze the motion of industrial robots. The errors in the motion of the fabricated mechanism which are caused from the manufacturing and flexibility errors are compensated to improve the motion accuracy. The error-compensated motion is compared with the uncompensated motion of the mechanism.

The Use of Vibration Analysis for Detecting Corrosion Damage in Pipes Nosser Moshrefi. Michigon Technological University: W. 7: Springer ond H.A. Sreshto. University of Arkonsos

The feasibility of usingvibrational analysis as a non-destructive testing method for assessment of corrosion damage in pipes is inves-

42 A p r i l I S M

tigated. The pipe was modeled as a beam vibrating transversely. From monitoring modal frequencies, an attempt was made to obtain percent weight loss of the pipe.

A Three-Dimensional Deformation Analysis of Workpieces Grasped by Chucks Toshiyuki Sawa. Yarnanashi University: Furnito Nakagawa. Tokyo Metropolitan College of Aeronautical Engineering: and Kyoichi Yarnarnoto. Yarnanashi University

The deformation of workpieces grasped by chucks are measured by electric comparators. The stresses of workpieces are also measured by photoelastic experiments. These results are compared with the results obtained by the three-dimensional theory of elasticity.

12. Fracture I - Determination of Parameters

Chairman: Kiyoshi Takahashi. Kyushu University Cochairman: Richard E. Lnk. David Taylor Naval Ship Research

& Development Center

Ultrasonic SurfaceWave Method for Measuring J- Aa Curve in a Region of 77-423 K Tsuyoshi Mihara. Mitsuo Obata. Tohoku University: and Heihachi Shirnoda. Akita National College of Technology

The ultrasonic surface-wave method could be successfully applied to monitoring crack extension in the fracture toughness test in a region of 77-423 K. Measurement system, wave-guide units and the correction method of received echo drift. were investigated.

J-Integral Measurement Using Moire Interferometry M.S. Dadkhah. Albert S. Kobayashi. F.X. Wang and D.L Graesser. University of Washington

The moire interferometry technique was used to record both vertical and horizontal displacement fields simultaneously in a single frame. A procedure was developed for determining the J-integral value exactly within the confineof the constitutive relation. This procedure was used to determine the J-values associated with stable crack growth in biaxialy loaded. 2024-T3 aluminum, single-edge notched specimens.

Stress-Intensity Factor Measurement in Service Condition Using “K-Gage” Yoshiyuki Kondo. Mitsubishi Heauy Industries. Ltd.

A new portable instrument has been developed to measure the stress-intensity factor of a crack using a specially patterned strain gage. The wave counting of stress-intensity factor is done in real time for randomly varying service loading. These data can be used for the residual life prediction of fatigue-crack propagation.

J-Integral Evaluation Using HRR Singularity Solutions and Displacement Field Near Crack Tip: An Application of Computer Picture Processing Genki Yagawa. Naokt Soneda and Shinobu Yoshimura. University of Tokyo

A new experimental scheme to evaluate the J-integral, using HRR singularity solutions and the displacement field measured by the computer picture processing is described. The experiment is performed on the CT specimen. and the J-integral value obtained by the present method is compared with that by Markle-Corten’s formula.

Experimental Determination of KI and KII Mixed Mode Stress-Intensity Factors by Slab Analogy and Out-of-Plane Moire Measurement Sun-Ho Choi. Yeungnarn University; Hideo Kitagawa. Yokohama National University: In-Bo Suh. Yeungnarn Junior College: and Jai-Do Kwon. Yeungnarn University; JongJoo Kim. Yeungnarn Junior College; and Jai-Sug Hawong. Yeungnarn University

A new experimental method in which stress-intensity factors under mixed mode can be determined is developed by using slab analogy and out-of-plane moire measurement. The margin of deviation of experimental value obtained from this method is 5 to 12 percent in comparison with theoretical values.

Analysis of the Dynamic Stress-Intensity Factor for the Mixed Mode Crack Hitoshi Wada. Zenji Ando. Daido Institute of Technology; and Tohru Nishirnura. Meijo University

The strain-gage method and the dynamic finite-element method are applied to analyze the mixed-mode dynamic stress-intensity factor. Analyses are carried out for plates with an inclined edge crack subjected to three-point bending in the plane of the plate.

On the Direct Measurement of J With Electrical Resistance Strain Gages H. Nigam. University of Rhode Island: James W. Dally. University of Maryland; and Arun Shukla. University of Rhode Island

A new method for direct measurement of J and the size of the J- dominated zone by using a standard strain-gage technique has been developed. The use of the technique is demonstrated by experiments conducted on power law hardening materials where the HRR singularity strain distribution is assumed.

13. Fatigue I

Chairman: Masahiro Jono. Osaka University Cochairman: to be announced

Wave Propagation in Fluid-Saturated and Unsaturated Porous Media Arun Shukla and Vikas Prakash. University of Rhode Island

An experimental investigation is conducted using dynamic photoelasticity to study wave propagation due to blast loading in fluid-saturated and unsaturated porous media. The study focused on the effect of the geometric nature of porous structure on transient pulse propagation as well as the effect of moisture in the pores on wave propagation.

Propagation of Waves on the Surface of a Magnetic Fluid by a Traveling Magnetic Field Tatsuo Sawada. Hirashige Kikura and Takahiko Tanahashi. Keio University

Propagation of waves on the surface of a magnetic fluid are investigated experimentally. The surface velocity of a magnetic fluid depends on strength of a magnetic field, depth of a magnetic fluid and the difference of each conducting magnet. Influences of these parameters on the propagation of waves are examined.

Simple Finite-Difference Iterative Schemes for Hybrid Experimental Numerical Stress Analysis K.A. Jacob. Aeronautical Deoelopment Establishment

Finite-difference schemes are given for evaluating the interior stresses (or displacements) by using experimental data on the surface of a three-dimensional component. The harmonic nature of

Bxparlmentd Rchniqucs 53

stress invariant is used to de-couple the second order simultaneous equations. Typical applications of the method and accuracies are illustrated.

Prediction of the Residual Stress Relaxation During Fatigue Taking Into Account these Stesses in a Multiaxial Fatigue Criterion J. Lu. a n d J . F Flauenot. Centre Technique Des industries Mecaniques

A model of relaxation of residual stress during fatigue, using the finite-element method. is presented which relates residual stress distribution in the depth plane to (1) number of fatigue cycles. (2) the cyclic stress amplitude, (3) the ratio R i min/i max. (4) the loading direction, (5) the cyclic hardening behaviors of the material, and (6) the notch effect. The stabilized residual stresses measured or calculated after fatigue testing were introduced in a multiaxial fatigue criterion for the life predicition.

A Study of Residual Stress Effects on Fatiguecrack Growth Using Moire Stephen M. Graham a n d R.J. Sanford. University of Maryland

The moire method was used to observe displacements conespond- ing to the release of stored elastic strain energy in a self-equilibrating residual-stress field during growth of a crack through the field. Results indicate that current fatigue-life design methods d o not properly account for residual-stress field redistribution.

Influence of Residual Stresses on the Estimation of Frac- ture Parameters Cheer Gheer G o a n d C.H. Lo. National Chung Hsing Uniuersity

The estimations of KIC and CTOD were conducted using compact tension-tension specimens. The magnitude of residual stress at crack tip was determined by the hole-drilling method. CTOD is invarient for varied values of residual stress and may be a better fracture parameter when residual stress exists.

The Effect of Stress Biaxiality in SENB Specimens on Fatiguecrack Growth Threshold Yuren Cheng. Binglin Hu. Northern Jioatong Uniuersity: a n d Xiaobao Sun. Changsha Railway lnstitute

The value of AKth decreases with decrease of a/w. when a/w is less than 0.2 for single-edge-notched bend (SENB) specimen. The non- singular uniform transverse component of the crack tip field eg. the parameter of stress biaxiality (3. was calculated by the boundary- collocation method. KI and T both dominate the process zone and plastic zone, which have a large effect on fatigue crack growth.

14. Non-Linear Methods

Chairman: John B. Ligon. Michigan Technological University Cochairman: Wendell Kawahara. Sandia National Laboratories

Dynamic Stress Analysis of a Three-Dimensional Solid Body (Dynamic Stress Concentration Factor Around a Hemispherical Cavity in a Cylindrical Bar) Mosakatsu Sugiura and Zenji Ando. Daido Institute of Tech- nology

Dynamic stress analysis of a cylindrical bar with a finite diameter having a hemispherical cavity has been analyzed. The stress propagation and the dynamic stress concentration phenomena around a

hemispherical cavity in a cylindrical bar utilizing the strain gage method. dynamic-photoelastic method and the finite-element method are used.

Effective Nonlinear Numerical Modeling of Reinforced Concrete Structures W.K. Rule. Structural Dynamics Research Corporation and RE. Rowlands. Uniuersity of Wisconsin-Madison

Using strain-induced orthotropic material concepts. a new numerical constitutive model for reinforced concrete is developed and demonstrated. Only uniaxial compressive strength of concrete and yield stress of reinforcing steel are needed to predict both constitutive behavior and structural strength. The approach is simple. reliable and computationally efficient.

An Analytical-Experimental Investigation of Nonlinear Orthotropic Sheets Undergoing Large Cylindrical Deformations J.C. Suhling. Auburn Uniuersity

A general elastic-plate theory for anisotropic media has been developed which includes geometric and material nonlinearities. Manipulation of the theoretical equations has demonstrated that several simplifications result in the formulation for the case of cylindrical deformations. Theoretical results for paperboard have been compared with experimental displacement measurements obtained with shadow moire and speckle interferometry.

Elastic Buckling of Non-Prismatic Bars With Intermediate Loads James 6. Matthews a n d Meshulam Groper. Western Michigan Univenit y

The paper presents the results of analytical investigation of the buckling load of built-up and hinge-ended elastic non-pnsmatic bars loaded with intermediate forces A set of experiments conducted in order to verify the validity of the solutions obtained. is also presented

Determination of a Simple Nonlinear Viscoelastic Material Model for a Semi-Crystalline Polymer Thomas G Ebbott. The Goodyear Tire & Rubber Company. and Terry G Richard University of Wisconsin-Madison

A simple nonlinear viscoelastic material model is determined from uniaxial creep tests. The model's predictions for multiple-step and constant load-rate loading compare favorably with experimental results. Situations involving nonuniaxial stress states are investigated through the use of moire and finite-element methods.

On the Prediction of 3-D Nonlinear Mechanical Behavior by 1-D Experiment - The Decoupling Model Method Jen-Dau Lin a n d Ching-Piao Hu. National Taiwan University

The prediction of 3-D nonlinear mechanical behavior by 1-D experiment is described as the results of the decoupling model method developed. With the aid of this model, a rubber system and a composite-structure system suffering from large deformation are analyzed.

TUESDAY MORNING, JUNE 7

15. Plenary Speaker


44 April I 9 0

PLENARY SPEAKER Takuo Hayoshi. Osaka University

A Survey of Recent Experimental Mechanics in Japan

A selective review of experimental mechanics in Japan is presented with attention given to recent experimental works o n stress analysis. The microcomputer has become more widely utilized to aid in the automatic measurement of strain. For analysis of strain distribution. an image-processing method is employed.

Composite Deformation Using Moire Interferometry A. Asundi. University of Hong Kong

Moire interferometry is used to study the deformation of glass fiber- woven composites and carbon-epoxy composites with a view to evaluating the damage process in composites. Characteristics of damage are immediately obvious and can be quantified both inside and outside the damaged zones. Deformation non-unformities can also be enhanced by subtracting the uniform fringes. using the classical moire effect.

16. Modal Analysis Seminar I1 18. Bio-Mechanics and Sports

Sponsored by the Education Committee Presented By: Alfred L Wicks. Virginia Polytechnic

Institute a n d Stote University

Frequency Analysis Considerations

1.

2. 3.

4.

5. 6.

Discrete Fourier Series a. Periodic Functions b. Aperiodic Functions

The PSD Vs Fourier Spectra Digital Frequency Analyzers

a. Window Function and Digital Filter b. Aliasing Problems

a. Pure Tone with Complete Cycles b. Pure Tone with Extra Half Cycle

Leakage Due to Window Functions

Calculating T h e FRF Averaging Considerations

17. Composites I

Chairman: C.S. Hong. Korea Advanced Institute of Science and

Cochairman: David A. Dillard. Virginia Polytechnic Institute and Technology

State University

A Study on Damage Growth of Random Short Fiber SMC Composites - In The Case of Quasi-Static and Tensile Loading Megumu Suzuki. Kyoto Institute of Technology; a n d Gui-Qiong Jioo. Northwestern Polytechnicol University

The mechanisms of damage initiation and growth of random short fiber SMC specimens with a notch and the relationship between the damage zone size and acoustic emission parameters are studied on quasi-static loading states.

Composite Material Characterization at the Large Coupon Level Gory G. Cassatt. O.J. Aviks. Merlyn Tenclay. Boeing Military Air. plane Company

An Experimental and Analytical Evaluation of Three Com- pressive Test Methods for Unidirectional Graphite/Epoxy Composites R.L. Westberg and M.G. Abdollah. Hercules Aerospace Company

A combined experimental/analytical study was conducted to evaluate and compare (1) the modified ASTM D695; (2) a modified IITRI; and (3) the 4-point sandwich-beam compression-test methods using AS4/3501-6. 00 graphitelexpoxy material. The results of this evaluation indicated that each test method in its optimum form could produce comparable results. and that the measured strengths were strongly dependent on the test method used. the specimen dimensions. the tab material and geometry as well as the adhesive used to bond the tabs to the specimen

Chairman: David Windstein. OMC Research Cochairman: Peter J. Gutenberger. Cummins Engine Company

Determination of Lower Limb Failure Modes and Tissue Damage by Impact Loading Tyler A. Kress. J.F. Wassermon. J.N. Snider. University of Ten- nessee: and P.M. Fuller. University of Louisville

A recently constructed facility is being used to conduct research on the dynamic response of the human lower leg to impact loading such as when a pedestrian is struck by an automobile. The elastic motion resulting in fracture occurred before significant rigid body motion occurred. Although the data are preliminary, x-ray data and dissection indicate that the mechanism of fracture is a function of velocity of impact.

Statistical Evaluation of Mechanical Characteristics of Animal Bone Akihiro Misawa. Konagouro Institute of Technology: Masahiso Takashi. Aoyomo University; Takashi Ueno. Motsushito Electric Co. Ltd: a n d Mikihiro Kaneko. The Japan Racing Association

Statistical characteristics of mechanical properties of bone are investigated with their dependence on the test conditions and the preservation methods. Brittle complex mechanisms in compressive fracture of bone are clearly explained through the microscopic observation of structures.

Development of a System for the Measurement of Forces and Moments Created by Orthodontic Appliances M.G. Faulkner. A. Hoy. P Fuchshuber a n d D. Haberstock. Univer- sity of Alberta

A computer-driven system for the measurement of forces and moments produced by orthodontic appliances is described. The system measures the three-dimensional force system produced at one end of the applicance when it is activated by a known amount at the other end. Both the activation and the forces are automatically measured and stored in a computer.

AStudy on the Identification of Noise Sources of a Gasoline Engine by Using Acoustic Intensity Method Joe Eung Oh. Ho Park. Jeong Hyeog Hong and Sung Ha Yum. Hanyang University

The acoustic-intensity method is applied to a gasoline engine to identify the noise sources. The response characteristics of acoustic intensity is obtained by a one-third octave band filter at every center point of overall frequency range. Plotted are contour-line and three- dimensional figures of emission characteristics of acoustic intensity at both overall frequency range and the center frequency of maximum-intensity level.

Transient Analysis of a Tennis Racket Using PC-Based Finite Elements and Experimental Techniques Christopher H.M. Jenkins and Clarence A. Colder. Oregon State Universit y

Ixprrlmenlel khnlquer 46

A method has been developed to facilitate the fully-stressed design optimization of a tennis racket. The method consists of a PC-based finite-element model with expenmental verification, and transient analysis using experimentally determined dynamic loading.

19. Materials Testing I11

Chairman: lbrahim Miskioglu. Michigan Technological University Cochairman: to be announced

Local Stress Measurement of PMMA by a LineFocus-Beam Acoustic Microscope Mitsuo Obata. Tsuyoshi Mihara. Tohoku Uniuersitb a n d Heihachi Shimoda. Akita National College of Technology

An acoustic microscope with line-focus-beam lens was successfully applied to local stress measurement in polymenc material. PMMA. The method allowed independent measurement of two principal stresses and their directions in the region less than 0 5 x 0.5 mm.

X-Ray Stress Analysis of Ni Foils Adhered to Metal Plates Hiroshi Kato. Kazumi Kodama a n d Keiji Yoshikawa. Soitama University

Stresses in Ni foils were measured by diffracting the Cr-K a ray at the (220) plane in the foil. The X-ray stress constant was obtained a s -500 MPa/deg. Stresses were 140 and 0 MPa respectively for the foils adhered and not adhered to a metal plate.

Numerical Simulation of Acoustoelastic Effects Caused by Plastic Anisotropy Growth and Experimental Verification Michiaki Kobayashi. Uniuersity of California: a n d Takao Kayaba. Hachinohe lnstitute of Technology

Simulation examples of acoustoelastic effects caused by plastic anisotropy growth and the experimental data are presented. The good agreement between theoretical and experimental results indicates that the plastic anisotropy is closely related to the acoustoelastic effects through the vertex-like yield effects of the corner theory.

Development of Interactive Image-Processing System for Analyzing Three-Dimensional Structure of SEM Picture Hiroyuki Okamura. Shinsuke Sakai. Hideaki Morita a n d Tachio Takano. Uniuersify of Tokyo

This paper proposes a new algroithm to analyze the three- dimensional structure of the picture of the scanning electron microscope (SEM) by using a personal computer with the image- processing technique. The method was used on several typical fracture surfaces and results on accuracy and speed were obtained.

Strain Measurement by Magnetic Barkhausen Noise of Steel Plate Under Biaxial Stress Condition Yasubumi FUNYO. Tohoku University: Heihachi Shimada. Akita National College of Technology: and Yuichi /to. Tohoku Un iueni t y

Digital signal analysis is performed for the induced voltage and Barkhausen Noise (BHN) from the contact-type sensor o n the surface of the 0 13 percent carbon steel plate in biaxial stress conditions. Changing the biaxial load ratio PA/@ in various values. it is found that BHN generating power is closely related to the value of the difference in each principal strain (or stress) less than € 1 - €2

400x10-6 strain in the elastic condition. Based on this result, nondestructive estimation of stress state in the semicircle-notched plate is also attempted by the BHN sensor.

20. Optical Methods 111: Shearography and Interferometry

Chairman: Jeff Suhling. Auburn University Cochairman: Yuh J. Chao. University of South Carolina

Moire-Holographic Analysis on Reinforced Plate Models Giuseppe Di Chirico. Francesco Ginesu a n d Raffaele Rossi. Uniuersita di Cagliari

This paper deals with an extension of moire-holography for structural analysis on reinforced plate models. Unequal optical paths. caused by lack of,uniform thickness. are compensated for and d o not alter the moire fringe patterns. Moreover. a simple technique is described for engraving high sensitivity moire gratings on perspex models.

The Detection and Evaluation of Ultrasonic Waves Using Single Mode Optical Fiber Interferometry John A. Gilbert. Uniuersity of Alabama-Huntsville:. Christian P Burger, Texas A&M Uniuersity: T Dixon Dudderar. AT&T Bell Laboratories: James A. Smith. Texas A&M Uniuersify. and Bruce R. Peters. Uniuersity of Alabama-Huntsuille

An innovative approach to nondestructive evaluation employing a noncontacting optical fiber interferometer is used to sense Rayleigh waves traveling along a steel bar. Acousto-optic time-domain reflec- tometry is used to detect and locate a flaw and spectrum analysis is used to estimate its size. This approach has significant applications in the ultrasonic evaluation of surface flaws in complex structures.

Quantitative Measurement Using Holographic Inter- ferometry Katherine Creath. WYKO Corporation

Real-time holographic interferometry has been combined with phase-measurement techniques to quantitatively measure object displacements and deformations. Results will be shown. and the state-of-the-art discussed.

Strain Determination by Means of Holography in 3-D Surfaces Cesar A. Sciammarella a n d M.A. Ahmadshahi. Illinois lnstitute of Tech nology

Electronic Shearography for High-speed Nondestructive Inspection of Adhesive Bonds and Composites Michael Y Y Hung, Oakland Uniuenity

21. Strain Gages I

Chairman: Larry C. Shull. McDonnell Douglas Corporation Cochairman: to be announced

Measurement of Impact Force History by Deconvolution Method Hirotsugu Inoue. Toshikazu Shibuya. Takashi Koizumi and Ryuichi Watanabe. Tokyo Institute of Technology

A method is presented for measuring the time history of impact force produced by collision of elastic bodies with arbitrary shape. The technique of deconvolution by FFT is used for determining the impact force history A practical application of this method is shown.

Limits of Accuracy of a Microcomputer-Controlled Scan- ning System For Strain Gage Data Readings Paolo Cappa. Uniuersita di Romo

The accuracy of systems based on low-cost general purpose switch- control units, DVM and microcomputers was examined. The stability of the readings was tested. The results obtained in the first tests showed noticeable zero drift; the intervals of uncertainty were in the ranges of f 3 0 p m / m and +70pm/m.

An Application of Shear-Lag Analysis to Weldable Strain Gage Design Koichi Egawa and Hisao Fukunaga National Aerospace Laboratory

A shear-lag analysis is done on a model of weldable strain gage, and the strain distributions and the average strain in the model are found. Calculations and experiments are done on the two trial gages to get better strain transmission. The recommendations on the shape of the gage and the method of spot-welding are shown.

Accuracy of Normal and Shear Stress Measurements in Par- ticulate Media Vagn Askegaard. Technical University of Denmark

Results a re given from calibration tests with a normal and a shear- stress cell embedded in non-cohesive particulate materials. The accuracy that can be expected when cells are used in such materials. even when the loading history is unknown, are discussed.

A Basic Study on a Strain Gage Made of Nickel Foil Mosaichiro Seika a n d Kikuo Hosono. Nagoya University

A strain gage of nickel foil is devised for measuring the elastic surface stress of machine parts in operation. The nickel foil is stuck o n the surface of a specimen subjected to repeated loads, and the elastic stress is measured by observing slipbands in the foil resulting from repeated strains.

TUESDAY AFTERNOON, JUNE 7

22. Structural Testing I11

Chairman: to be announced Cochairman: to be announced

Studies on Assembly Stresses and Stress Distribution In Multiple Bolted Structural Joints M.K. Padmanobhan. M.V. Kannan. N.C. Bhat a n d B.R. Anan- damurthy. lndion Research Organization Satellite Center

A study of assembly stresses in multiple bolted, flattened tubular single-lap end joints using the photoelastic coating technique is presented. Both symmetric and unsymmetric bolt configurations have been considered. The stress distributions at the critical transition zone of tubular-to-flat portions are examined and its significance is analyzed.

Mechanical Behavior of Vee Clamps /on M. Allison. University of Surrey

Identification of a Loose Joint in a Bolt-Connected Assembly J.D. Rogers a n d J.R. Hollingshead. Sandia National Laboratories

A method for experimentally determining the existence of a loose bolted joint is proposed. An experimental study of the forced vibration response of an aluminum beam with several steel masses attached by bolted connections is described. The beam is soft- supported to simulate free-free boundary conditions and is excited by an electrodynamic shaker. The driving force and driving point

acceleration are measured. The effect of one or more loose joints is investigated in terms of the dynamic response of the structure.

23. Residual Stress I

Chairman: Michael James. Rockwell International Cochairman: Gil T. Blake, Wiss. Janney. Elstner. Associates

Some Experimental Studies on Residual Stresses Due to Forming and Machining High-Strength Aluminium Alloys M.K. Padmanabhan. M.V. Kannan. B.R. Ananda Murthy and J. Suryanarayana Murthy. Indian Space Research Organization Satellite Center

This paper deals with some experimental studies carned out using the stress-milling technique The residual stresses due to forming by different forming methods, and machining operations under varying cutting-force parameters are presented

Residual Stress Due to Flame-Straightening Procedure Adttya P Chakravarti. Arctec Canada Limited. Aly M Nawwar University of Kuwait. a n d D C Stringer Dominion Bridge Company

Misalignments often occur in structures during fabrication. Fre- quently. misalignments are rectified using flame-straightening procedures. A case study of a cylindrical column with bearings at both ends is presented. It is shown that although misalignments are minimized, high residual stress is introduced in the structure due to the flame-straightening operation.

TweDimensional Acoustic Elastic Analysis of Residual Stress in a Seam-Welded Plate Wu Kecheng. Jiang Liqiang and Wu Xingjing. Huazhony Uniuer- sity of Science and Technology

The residual stress in a seam-welded plate has been analyzed by using the improved 2-D acoustoelastic method for slightly orthotropic material. The effects of texture of material and plastic deformation on the measurement are discussed.

24. Photoelasticity I

Chairman: to be announced Cochairman: Robert Telischi, Pratt & Whitney

An Evaluation on Design and Application of Bolt-Jointed Fixture for Hydrostatic Test of Large Dome Structure Jong-Soo Lee. Yong- Wie Seo. Kyu-Juhn Lee and Yo-Hon Yoo. Daejon Machine Depot

Analysis of Photoelastic Data and Stress Concentration Factor Determination Jose LF. Freire. J o a o F.S. Gomes and Marco A.M. Cavaco. Catholic University of Rio de Janeiro

This paper presents a simple idea of function fitting of isochromatic data (in a minimum standard deviation sense) over certain regions of photoelastic models, in order to determine maximum isochromatic fringe orders or stress concentration factors.

Photoelastic Stress Analysis of Rotating Disk With Dovetail Joints Yasuo Nokamura and Susumu Takahashi. Kanto Gakuin Uniuersit y

Uxperirncnlal Ikhniqura 47

This paper deals with photoelastic analysis of rotating discs having dovetail jointed blades with special attention to stress distributions along the rotating blades and the stress-intensity factors KI andKll with three different cracks artificially introduced at the locations of comparatively high stress due to the joint.

25. Fracture I1


Fundamental Study on Rupture by Low-Cycle Fatigue of Polymers Applying Fine-Grid Method Akira Shimamoto. The Saitama Institute of Technology: Akiro Yokota. Tokyo Ohka Kogyo Co. Ltd.: Y Furuya and Susumu Takahashi. Kanto Gakuin Uniuersity

The fine-grid method has been applied to study the fatigue rupture of polymers, to examine changes in local strain at the root of the notch during the process of crack initiation, and local strain at the tip of crack during the process of crack propagation.

Determination of Mixed-Mode Stress-Intensity Factors Using Digital-Image Correlation B.R. Durig. S.R. McNeill. M.A Sutton and Walter H. Peters. Uniuer- sity of South Carolina

Digital-image correlation is used to determine KI and KII for several edge-crack geometries in finite rectangular plates. The u and v components of the displacement are obtained from a digtial-image correlation methodology which quantifies these displacements in the crack tip region. The experimental displacement components are then used to find KI and KII from a least-square error method which formulates the error between the measured displacement data and the displacement field from the series solution for a cracked infinite body.

Quantitative Determination of Dynamic Crack Response to Shear Waves In Glassy Polymers Kiyoshi Takahashi. Hiroki Kojoh and Kazuo Arakawa. Kyushu University

Ultrasonic fractography provides information on the detailed fracture velocity change and on a material state at the tip of the advanc- ing crack. The work includes determination of the absolute amplitude of the shear waves and of the ultrasonically modulated crack deflection magnitude.

WEDNESDAY MORNING, JUNE 8

26. Plenary Speaker

Chairman: Clarence A. Calder. SEM President. Oregon State University

PLENARY SPEAKER August J. Durelli. Uniuersity of Maryland

Complete Determination of the Stress Tensor in a Field Using Brittle Coatings

Brittle coatings, when used to stress analyze a loaded body. can give complete and direct information about the stress tensor in a whole field of the surface of the body. The method is unique in that it does not require the knowledge of boundary conditions. which is indis. pensable for the use of numerical methods. Some other typical characteristics are also discussed.

27. Thermoelastic Emissions I

Chairman: to be announced Cochairman: Barry C. Gasper. Central Electricity Generating

Board

Dynamic Stress Analysis of Gas Turbine Rotor Airfoils Using Thermoelastic Techniques Thomas E. fircell. Pratt & Whitney

This analysis demonstrates the practical application of the SPATE 8000 thermoelastic dynamic stress analyzer to high technology gas turbine rotor airfoils subjected to resonant loading. Three applications are discussed which illustrate high-frequency full-field dynamic stress analysis on complex components and presents a unique technique for optimizing strain-gage instrumentation locations for monitoring blade and vane vibratory stress during rig and engine testing.

Thermoelastic Investigation of Stress Concentration at Cir- cular Holes in Thin Cylinders Subjected to Torsion S. W.K. Chon, The Welding Institute: and P. Stanley. Uniuersity of Manchester

The thermoelastic stress-analysis technique has been used to determine the stress concentrating effects of a series of single and opposed pairs of circular holes in thin-walled cylinders subjected to torsional loading. The results are compared with independent theoretical. numerical and experimental results taken from the literature.

Thermoelastic Stress Analysis of Plastic Models John M. Madakacherry and Jonathan E. Gunger. General Motors Corporation

Thermoelastic stress analysis of plastic models was successfully employed in the design and development of steel counter parts of an automobile. SPATE 8000 facilitated non-contact high- resolution stress measurements of cast and vacuum formed plastic models. The stress analysis of the model was used for predicting stresses on steel prototypes. Design sensivity analysis was performed on plastic models to evaluate different design iterations. Problem areas were identified before the design was committed to metal, thereby minimizing impact on cost and scheduling.

Determination of Individual Stress Components From SPATE Isopachics Only YM. Huong. M.H. Hamdi AbdelMohsen. University of Wisconsin- Madison; D. Lohr. Boeing Corporation; R.E. Rowlands. University of Wisconsin-Madison; and P. Stanley. Uniuersity of Manchester

Hybrid methods are developed and demonstrated for determining individual stresses from SPATE isopachics s= u, + uv. The approach is sensitive, non-contacting, local or full-field and usable at extreme environments. Many of the stress-separation techniques depend only on equilibrium and are independent of constitutive behavior, linearity or isotropy

28. Modal Analysis Seminar 111


Presented by: Larry D. Mitchell. Virginia Polytechnic Institute and State University

Putting It All Together to Make Meaningful Measure- ments I

Session 111 of this seminar will investigate the selection of forcing functions, force transducers, response transducers, and their effects on the measurement process. Selection of methods for acquiring sufficient frequency-response functions (FRFs) for modal analysis will be discussed. Topics include: roving transducers, spatial aliasing. establishing a forcing function, and completing a modal survey.

1. Selecting a Forcing Function a. Swept Sine or Step Sine b. Impulse c. Random d. Periodic Random

a. Displacement. Velocity, Acceleration b. Convenience c. Mass Loading Efiects d. FFTLeakage

a. Roving Force b. Roving Accelerometer

a. Griding the Structure (spacial aliasing, center vs outline grid, 1-.2-. 3-dimensional)

b. Establishing the Forcing Function (clipping, maximum energy spectral density, random excitation input power spectra - notches)

c. Modal Survey - Half the Job (determining all iatural Frequencies in band. the "best" response/forcing point, type of stationary transducer)

2. Selection of Response Transducers

3. Measuring Frequency Response Function

4. Measuring Modes of a Beam (a demonstration example)

29. Integration of Personal Computers With Experimental Mechanics

Spvnsored by the Applications Committee

Chairman: Terry G. Richard, University of Wisconsin-Madison Cochairman: Steven Shaler. Michigan Technological University

Rapid Real-Time Data Monitoring and Direct Data- Storage Techniques Kathleen M. Hutchison. Keithley Instruments. Inc.

Strip chart, oscillograph. FM tape, and other traditional methods of monitoring and storing data can now be implemented solely with the personal computer. However, graphics resolution and data- storage speed often limit real-time display and acquisition capability. This discussion centers on new hardware and software techniques which overcome these limitations.

Mobile Data-Acquisition Facilities for Field Applications Bradley R. Boyce. John Deere Horicon Works

A review of the uses and evolution of a 14-channel, medium speed, mobile data-acquisition system is presented. Primary uses include product functional and structural performance. Topics include radio telemetry, power supplies. transducer interfaces and installa- tion of equipment in a truck.

Remote Data Acquisition and Transducer Conditioning Steven Downing. Somat Corporation

A Comparison of Personal Computer Based Data- Acquisition Software Products Joseph E. Barbay. Southern Illinois University

Low cost personal computers coupled with data-acquisition products enable the use of computerized data-acquisition techniques by

an ever-expanding group of researchers. The key to successful a p plication of this technology is an understanding of the data- acquisition hardware and software. This paper touches upon the selection of data-acquisition hardware and compares available software products from a variety of vendors.

30. Short Cracks I

Sponsored by the Research Committee and the Fracture Division

Chairman: Mamidala Ramulu. University of Washington Cochairman: Frank D. Adams. US Air Force Wright

Aeronautical Laboratories

The Significance of Small-Crack Effects for Design-Life Calculations J.C. Newman. Jr. and E.P. Phillips. NASA Langley Research Center

This paper examines the significance of small-crack effects for design-life calculations in aerospace structures using the small- and large-crack data bases for an aluminum alloy Particular attention is given to the feasibility of using durability analyses based solely on crack-growth calculations. The influence of large-crack thresholds and small-crack effects on fatigue life of notched members are studied under constant-amplitude and under various aircraft load spectra (FALSTAFF and a Gaussian-type loading).

Stable Growth of Short Fatigue Cracks in Ceramics and Ceramic Composites S Suresh. Brown University

This paper examines the mechanics and mechanisms of crack initiation and short fatigue-crack growth in notched plates of single- phase ceramics, transforming ceramics and ceramic composites subjected to fully compressive far-field cyclic loads at room temperature. Some important applications of short-crack growth under cyclic compression to the fracture testing of brittle materials are discussed.

Microstructural Effects on the Growth of Long and Small Fatigue Cracks in Steel and Aluminum Alloys R.O. Ritchie. J.-K. Shang. K.7: Venkateswara Rao and W.Yu. University of California-Berkeley

The fatigue-crack growth behavior of microstructurally small (2 to 1000 pm) surface cracks is compared with that of long (25 mm) through-thickness cracks in a series of microstructures chosen to vary the primary sources of crack deflection and closure. namely duplex femtic/martensitic steels. 2000 and 7000 aluminum alloys. and aluminum-lithium alloys. Microstructural modification can lead to dramatic improvements in long crack-growth properties, while the effect on small-crack behavior can be quite different.

Short and Long Fatigue Crack Propagation in AL-Li

Farzad Zafari and Mamidala Ramulu. University of Washington Alloys

An experimental investigation was conducted to study the crack- propagation behavior in Aluminum-Lithium alloys under cyclic loading conditions. Crack opening displacements (COD) and crack lengths were measured by using Laser Instrumented Strain Gages (LISG) and traveling microscopes respectively. in SEN specimens The results obtained were used to correlate the behavior of short and long cracks with the COD.

Hxperimen#al lkrhniqum 49

31. Residual Stress I1

Chairman: CYNS Kano. Teledyne Engineering Services Cochairman: Hiroshi Kato, Saitama University

Residual Stress in Thermoplastic Resin Beam Due to Ther- moviscoelastic Behavior Yosushi Miyano. Minoru Shimbo. Konazawa lnstitute o/ Technol- ogy; Suguru Sugimori. Kanazowa Technical College; and Takeshi Kunio. Keio University

This paper discusses the deformation and residual stress in a thermoplastic resin beam produced by rapid cooling. A beam made of PMMA is initially held at a uniform temperature and free of traction on all surfaces, then drastically cooled from both sides to a lower temperature below the glass transition temperature of that resin. The deformation and residual stresses are calculated from the ther- moviscoelastic theory and measured experimentally.

Measurement of Welding Residual Stresses by Acous- toelastic Technique (Evaluation of Principal Direction of Material Anisotropy) Yoshio Arai. Hideo Kobayashi. and Hiromichi Suzuki. Tokyo Institute of Technology

The influences of the material anisotropu on acoustoelastic effects are evaluated. The residual stresses of the welded plate of carbon steel are measured. The influence of the material anisotropu on acoustoelastic effect is significant for the welded plate. The sign of the velocity difference in the weld metal is opposite to that of the base metal.

Creep in 1020L Steel at Low Temperatures Bernard Teper. Ontario Hydro

A Simplified Optical Method for Measuring Residual Stress in Two-Dimensional Photoviscoelastic Body Suguru Sugimori. Konazawa Technicol College: Yasushi Miyano. Kanazawa Institute of Technology; and Takeshi Kunio. Keio Univenit y

A simplified optical method is discussed for measuring the residual stress in a two-dimensional photovlscoelastic body generated by cooling. The fundamental equation for a two-dimensional photoviscoelastic body was derived using the linear photoviscoelastic theory. The effectiveness of this method can be assessed experimentally.

32. Strain Gages I1

Chairman: H. R. Kim. Yonsei University Cochairman: to be announced

The Strength of Combination Joints of Adhesive With Bolts Toshiyuki Sow0 and Takashi Kobayoshi. Yomanashi University

The strength of adhesion- and bolt-combined joints is treated both theoretically and experimentally. This paper shows that the strength of the combination joint is greater than that of the adhesive joint and is in fairly good agreement with the estimated value.

Measurement of Local Contact Pressure in Tool/Workpiece Interface in Cold Forging Niels Bay. Technicol Unioenity of Denmark

In cold-forging tools very large local pressures exist in the tool/ workpiece interface. A new technique for measuring the local pres-

sure is presented. The technique is based on measurement of the plastic deformation of a sensor with rough surface asperities in contact with the harder. smooth tool surface.

On-Line Measuring System Using High-Temperature Strain Gages and Application to the Steam Turbine Casing Toyokazu Fushimi. Katsuhiro Onda. Chubu Electric Power Co.. Inc.; Masamitsu Muramotsu. Fumihoru Ishii. Kazushige Kimura and Kazunari Fujiyoma. Toshiba Corporation

Operating conditions of temperature and stress to make accurate life assessments of high-temperature turbine components. on-line monitoring systems using weldable high-temperature strain gages have been developed. An example of the application of this system to in-service turbine casing is presented.

Vibration Mode Measuring Using Strain Gage Yukio Sugawora. Kitami lnstiture o/ 'lechnology

A procedure to determine the vibration mode of a cantilever beam subjected to a mechanical shock at the free end using a strain gage is discussed.

WEDNESDAY AFERNOON, JUNE8

33. William M. Murray Lecture


Murray Lecturer: Dr. Mosotaka Nisida. Emeritus Rincipal Scientist. The Institute of Physical and Chemical Research

34. Modal Analysis Seminar IV


Presented by: Lorry D. Mitchell. Virginia Polytechnic Institute and State Unioersity

Putting It All Together To Make Meaningful Measure- ments I1

Session IV of this seminar will discuss the measurement of quality frequency-response functions (FRFs). The topics include: "window- ing." averaging, and coherence (useful or useless?). Once FRFs are obtained, modal characterization follows. Modal extraction topics to be covered are peak picking, circle fit. multi-mode and fits. Modal display topics include structural geometry. connectivity. and viewing angle.

5. Measure a Column or Row of the Mobility Matrix a. "Window" the Data b. Averaging Considerations c. FRFs and Coherence d. Causes of Poor Coherence e. Poor Coherence but Good Data!

(1/0 noise, leakage. nonlinearity) 6. Acquire the Data

a. FRFs b. Mode Characterization

(peak pick, circle fit. multi mode, time-domain) 7. Displaying the Modes

a. Structural Geometry b. Structural Connectivity

c. Viewing Angle d. Complex or Real Modal Model

8. Other Modal Properties

35. Image Processing

Sponsored by the Applications Committee

Chairman: Donald G. Berghaus. Georgia Institute of

Cochairman: Jaime F. Cardenas-Garcia. Colorado State Technology

University

New Approaches to Optical Methods in Experimental Solid Mechanics Through Digital-Image Processing Christian P. Burger. Texas A&M University

Resarch Usage of PC-Based Image Processing John P. Kennealy. Mission Research Corporation; and R.A. Gonsalues. Tufts University

Advanced research on image enhancement/restoration applications can now be conducted on “image workstations” employing a PC coupled to an appropriate image acquisition and display system. In this presentation. examples of PC-based hardware systems and software development will be described in some detail, with emphasis on the strengths and limitations of such approaches.

Edge-Matching Techniques for Motion Analysis and Fringe Boundary Location William F. Ransan. University of South Carolina

A personal computer vision system is described for use in motion detection and fringe-boundary location. The theory of edge matching is based on a filter which is found to be the second derivative of a Gaussian. Correlation of edge-only information is inherently more accurate than intensity correlations and requires less computation time. Examples of large-strain measurements are described to illustrate the concepts of edge-only information for motion detection.

Computer-Sided FringePattern Analysis Cesar A. Sciammarella. lllinois Institute of Technology

The functional basics of analog and digital fringe-pattern processing will be presented. The different techniques that are currently applied will be introduced in a common framework of reference, stressing the fact that these techniques are basically variations of the same basic principle. Currently available hardware will be described, relationships between operations of fringe-pattern processing and hardware will be given.

A PC-based ImageProcessing System for Automatic Deduction of Holographically Recorded Displacements Michael YY Hung. Oakland University

36. Time Dependent Properties of Composites

Sponsored by the Composite Materials Division

Chairman: Gary L Cloud, Michigan State University Cochairman: Mohamed G. Abdallah, Hercules Inc. Aerospace

Division

Physical Aging and Creep of a Unidirectional Fiber/ Thermosetting Resin Composite John L Sullivan. Ford Motor Company

One expects that the physical aging phenomenon observed in polymer glasses also influences the viscoelastic properties of composites. The creep properties of a continuous-fiber reinforced composite and its corresponding resin are discussed The effect of physical aging on their creep behavior is covered in detail

A Comparison of the Viscoelastic Behavior of Graphite- Epoxy in Tension and Compression K.M. Gerdes and Mark E. Tuttle. University of Washington

The viscoelastic behavior of unidirectional graphite-epoxy laminates under tensile and compressive creep loadings was measured and compared. All measurements were obtained for dry conditions at 82°C (180 ‘F). The presentation will include a description of the test frame and loading fixtures used. and a summary of results obtained.

Creep of Thermoplastic Composites Xiao Xinran. University o/ Brussels: Clement Hiel. NASA Ames Research Center: and A.H. Cordon. Uniuersity of Brussels

The viscoelastic behavior of peek/apc-2 composites was studied. using creep and creeprecovery experiments. Test specimens were loaded transverse to the fiber direction and in shear The latter experiment was accomplished using a 10-degree off-axis test. Results of dynamic mechanical charaterization tests. using a 3-point bend test will also be presented.

Physical Aging in PEEK Composites A.A. Ogak and S.F. Henry Wang. Clemsen University

This study deals with physical aging effects in a polymer in its pure form as compared with those in its composite form. The polymer under investigation is a high-performance thermoplastic. polyetheretherketone (PEEK). and the composite is a short-carbon fiber-reinforced grade of PEEK.

Nonlinear Viscoelastic Response of KV49/3501-6 Unidirectional Composite Materials David E. Walrath. University of Wyoming

The viscoelastic response of unidirectional DuPont Kevlar KV49/ Hercules 3501-6 expoxy was measured. Measurement of the through-the-thickness or interlaminar shear viscoelastic response required development of a new test methodology. The losipescu shearatest method wasselected for this purpose. Theapplicability of the Schapery single-integral nonlinear viscoelastic constitutive model to describe time-dependent mechanical behavior of laminated composite materials containing two viscoelastic phases was explored. An automated data reduction scheme was developed to facilitate description of viscoelastic properties using the Schapery single-integral approach.

Matrix Dominated Creep and Fatigue in Composites K. Sriniuasan and S.S. Sternstein. Rensselaer Polytechnic lnstitute

Out-of-plane deformation of composite laminates is primarily dependent on the matrix response. The creep and stress relaxation of several thermoplastic matrix composites and neat resins subjected to three-point bending is considered. Time temperature superposition and linear viscoelastic behavior is obtained at low stresses. Mode II delamination fatigue crack-initiation data is also presented using a newly developed clamped-edge flawed-cantilever geometry. Scanning electron microscopy is used to distinguish several mechanisms of critical-flaw initiation.

Kxperlmenlal Ikhniquem 51

37. Experimental Mechanics in High- Temperature Environments

Sponsored by the Research Committee

Chairman: Frank D. Adams. U.S. Air Force Wright Aeronautical

Cochairman: Jon G. Epstein. Georgia Institute of Technology Laboratory

Crack Measurement Techniques for HighTemperature Applications Ted E. Kirchner. Foster-Miller. Inc.; Aruind Nagar. U.S. Air force Wright Aeronautical Laboratory: Larry Domash. Foster-Miller. Inc.; and Paul Berstein. Skiametrics Inc.

Both laser and x-ray technology were investigated for high- temperature measurement of fatigue-crack growth. Experimental data is provided on both approaches and an automated system con- ceptual design is presented for the most promising approach.

A Microcircuit-Grid Technique for Crack Measurement at Elevated Temperatures Arvind Nagar. U.S Air Force Wright Aeronautical Laboratory. Keuin Stuffle. Cerametec. Inc.; Dinesh K. Shetty. Anil V. Virkar. University of Utah; and Raymond A. Cutler. Ceramatec. Inc.

A microcircuit-grid technique previously used for measuring crack growth in ceramics was applied to fatigue-crack growth in metals. This technique requires no quantitative calibration of output voltage, has crack-length resolution of 5pm. can be used over a wide temperature range, and retains the capability for automated data acquisition.

NDE Methods for High-Temperature Materials and Environments Basial A. Barna. D.M. Tow. J.A. Johnson. R.7: Allemeier. NM. Carlson, J.G. Rodriguez and C.L. Shull. INEL EG&G Idaho

High-temperature environments and materials generally require innovative, noncontacting sensing methods for probing. Several unique sensing technologies specifically designed for these situations are discussed. Acousto-optic measurements of surface displacement and dynamics. and laser generation of ultrasound in molten materials are described. Applications of real-time imaging of high-temperature surfaces that are generally obscured by their own self luminance are also discussed.

Elevated Temperature Static and Fatigue Testing Techniques A S. Garrett. David M. Harmon, McDonnell Douglas Company; and S.D. Antolouich. Georgia Institute of Technology

Aircraft of the future, such as an aerospace vehicle or an advanced fighter. will have expanded operating envelopes and therefore, will be subject to extreme environmental conditions. Due to the com- plexity of full-scale testing with combined thermal and mechanical loads, subcomponent and coupon testing play an extremely important role in the verificaiton of the structural integrity of the plane. Testing facilities designed for elevated temperature testing of coupon specimens will be described. A method is also outlined for developing realistic thermal and mechanical load profiles for advanced aircraft.

Strain Measurement Techniques for High-Temperature Applications Joseph G Burns. Christopher J. Mazur. U.S. Air Force Wright Aeronautical Laboratory; Randy R. Nielsen. Terra Tek, Inc.: and Adel Sarrafzadeh. American Research Corporation of Virginia

Future Air Force aircraft will reach hypersonic velocities and be subject to high-temperature loads up to 5000 'F in key locations. To characterize materials for these applications. high-temperature strain-measurement techniques must be developed. Two high- temperature strain-measurement techniques include: (a) using a laser-speckle interferometric sensor approach. and (b) a high- temperature coating reference mark approach.

38. Fracture 111

Chairman: Daniel C. Drucker, University of Florida Cochainnan: Ken P. Chong. The University of Wyoming

Constrained Elastic-Plastic and Fully Plastic Bimetallic Structural Interface Crack Displacement Fields Using Moire Interferometry Jonathan G. Epstein. S.A. Chauez and Walter G. Reuter. Idaho National Engineering Laboratory. EG&G Idaho. Inc.

A Criterion For Crack Branching in Epoxy Kazuo Arakawa and Kiyoshi Takahashi. Kyushu Uniuersity

Conditions for crack branching in epoxy were examined. N o characteristic critical values could be defined for crack extension resistance or crack velocity at the onset of crack branching. Instead. it is found that dissipated energy per unit crack front and unit time. becomes constant with the crack branching.

Analyzing Crack-Tip lsochromatic Fringe Patterns Ravi Chona. Texas A&M University: and R.J. Sanford. University of Maryland

Algorithms well-suited to the analysis of crack-tip stress-field data are presented. The discussion is illustrated using photoelastic fringe patterns as examplessince the non-linearity of the problem requires special attention. The subtleties associated with the practical implementation of such algorithms are addressed in some detail.

An Experimental and Analytical Description of the Strain Fields Near a Crack Tip in a Ductile Polymer TG. Ebbott The Goodyear Tire & Rubber Company and Terry G. Richard. University of Wisconsin-Madison

Crack growth in a ductile polymer is investigated under dead-weight loading. Near-tip strains obtained through the moire method are compared with theoretical predictions for linear and nonlinear material models. Good correlation is found with the HRR fields for a particular value of the hardening exponent.

A Study on the Stable Crack Growth Based on the Recrys- tallization Technique Kyu-Zong Cho. Chonnam National University: and Se-Hi Chung. Chon Buk National University

The recrystallization technique was used to visualize and analyze the plastically deformed fracture-process zone. Since the recrys- tallized fracture-process zones were a formalized uniform band. the plastic work done at the crack-tip process zone and the recrys- tallized band width could be the stable crack-growing criteria. The calculated stable crack-growing resistance. AWp/aa. was used as a stable crack-growing criteria during the analysis of the elastic-plastic finite-element method to justify the credit of the suggested criteria.

Plastic Strain Concentrations at Notch Tips C. Lee. Yuh-Jin Chao. Walter H . Peters and M.A. Sutton. Univer- sity of South Carolina

The effective strains within the plastic zone at a notch tip were obtained throuqh a vision svstem and the feature extraction tech-

niques. An exponential decay of the effective strain values from the notch tip was observed.

39. Fatigue I1

Chairman: O.S. Lee. Inha University Cochairman: to be announced

Evaluation of Low-Cycle Fatiguecrack Initiation Life Using Parameter of Local Strain Mstribution Young Chul Park, Kia Motors Company; and Heihachi Shimada. Akita National College oj Technology

Local strain distribution around the fatigue crack-tip is measured ac- curately by the computer-aided fine-grid method. From the singularity of the crack-tip strain, the authors have shown a new parameter, A(m.p) for several materials. Correlation between A(m,p) and fatigue-crack initiation life as well as its fracture toughness is also discussed.

Relationship Between Fatigue Life in the CreepFatigue Region and Stress-Strain Response Auraham Berkouits and Shmuel Nadiu, Technion-Israel Institute of Technology

Elevated temperature-fatigue lives were predicted for nickel-based super-alloys and for a stainless steel. by introducing stress-strain parameters into the Manson-Coffin Equation. Necessary parameters are the maximum stress achievable under entirely plastic and creep conditions, and corresponding inelastic strains, as well as two pairs of plasticity/creep interaction parameters.

Relation Between Fatiguecrack Growth Law and Revers- ible Plastic Zone Size in Fe396Si Alloy Hironobu Nisitani. Kyushu University; and Norio Kawagoishi, Kagoshima Uniuersity

It was verified that the fatigue-crack growth rate is proportional to the reversible plastic zone size at a crack tip by the etch-pit method using a Fe-3%Si alloy. Based on the result, two representative fatigue-crack growth laws, for both large and small cracks which formerly contradicted each other. were explained consistently.

In-Situ Observations of Growing Fatigue Crack by Field Emission Type Scanning Electron Microscope Masahiro Jono and Atsushi Sugeta. Osaka University

Fatigue-crack growth tests were performed on both grain-oriented and conventional 3 percent silicon irons in a high-resolution, field- emission type scanning electron microscope equipped with specially designed servo-hydraulic fatigue-testing instrument. In. situ observations of growing fatigue cracks were made and fatigue- crack growth mechanisms were investigated.

The Plastic-Zone Size and the Structure of a Fatiguecrack Tip of Polycarbonate Shunji Nagasaka. Kogakuin Uniuersity

The structure and size of fatigue-crack tip plastic zone of a polycarbonate sheet specimen were studied. The study was made by applying photoelasto-plastic effects and a micro-scale gtid. It was found that the plastic zone consisted of a two-phase structure and Irwin's plastic-zone formula is applicable.

An Application of Image Processing to Measurements for Two-Dimensional Distribution and Propagation Path of Surface Fatigue Cracks Akira Ishii. Shigemi K. Sasaki and Yasuo Ochi. University oj Electro-Communications

An image-processing technique using a personal computer system has been introduced to make observations for surface fatigue cracks initiating and propagating in ductile materials. Extracted crack paths and two-dimensional distribution were evaluated as causes of statistical scatters of fatigue lives and investigated from metallurgical standpoints.

40. Materials and Instrumentation for Photoelasticity

Sponsored by the Subdivision on Applied Photoelasticity

Chairman: Jan Cernosek, Photostrain. Inc.

Presentation by commercial companies: Lockheed-Missiles and Space Company, Inc.; Photolastic. Inc. Division of Measurements Group, Inc.; Photostrain. Inc.. (formerly Stress- Strain Laboratories)

The presentation will be followed by a panel discussion. The topic of the discussion will be:

Photoelasticity in Computer-Dominated Environment Moderated by Tom Corby of Photolastic Inc.

THURSDAY MORNING, JUNE 9

41. Plenary Speaker

Chairman: Clarence A. Calder, SEM President. Oregon State University

PLENARY SPEAKERS James E. Stan: Altauar. lnc.: James Dorsey. Measurements Group. Inc.: and Charles C. Perry. Consultan t

Fifty Years of the Bonded Resistance Strain Gage - An American Retrospective A historical account of the invention, refinements. and usage of the bonded strain gage in the United States, from initial development to present-day applications.

42. SPECIAL JUBILEE PROGRAM Beglnningr Strain Ga- Load Cello and Brittle Coatings - 1938 The

Sponsored by the Western Regional Strain Gage Committee and the Technical Committee on Strain Gages

Program Chahnaa: Lawrence C. Shull, McDonnell-Douglas

Cochairman: Charles P. Wright. TRW Space & Technology ktronautics Company (TCSG/WRSGC)

Group (WRSGC)

Welcomes and Opening Addresses Clarence A. Colder, Resident, SEM; Susan K. Foss, Resident- Elect, SEM Kenneth A. Golione, Managing Director. SEM; Earl Wilson, Chairman, TCSG; and James I? Wallace. Chairman, WRSGC

Self-introduction of WRSGC/TCSG Delegates, Guests and Registrants

Bxperlmrnlml1kch.hniqura 63

Background Session: Painting The 1938 Scene

The temperature at the point of interest is monitored with an infrared camera and W while the member is subjected to sinusoidal, constant frequency loading. The temperature amplitude vs. frequency output. when combined with the cyclic stress-strain response of the material, is used to determine the elastic and plastic strain components.

Algorithms for Smoothing Noisy Data With Spline Functions and Smoothing Parameter Selection Clark R. Dohrmann. Sandia National Laboratories; and Henry R. Busby, The Ohio State Uniuersity

Procedures for smoothing univariate data using spline functions and for selecting the smoothing parameter are described. The procedures are applicable to smoothing n distinct data points that are not necessarily equally weighted or equally spaced. Smoothing parameter selection is based upon the technique of generalized cross validation. Both procedures require order n operations and order n storage locations.

W e Load Cell Scene Frank E Hines. Chairman of the Board RdF Corporation

The Strain Gage Scene J. Hans Meier. Manager (Retired), IBM Corporation

The Brlttle Coating Scene Ferdi B. Stern. Jr.. Retired, Magnoflux Corporation; Consultanf, J. P Technologies

The Early Applications William 7: Bean, Consultant

The Inventors Tell Their Stories Arthur C. “Prof’ Ruge, in 1938, Professor, Massachusetts Institute of Technology - represented by uideotape

EdwardE. Simmons, Jr.. in 1938. MSEE, 1936, California Institute of Technology, selj-employed

Greer Ellis, in 1938. Graduate Student. Massachusetts Institute of Technology, MS Aeronautical Engineering, M17; 1938. Inventor o/ STRESSCOAT and TWSLAC brittle coatings (both Registered Trademarks).

Luncheon with Jubilee Ceremonies

Luncheon Keynote Speaker: Darrell R. Harting, Research and Deuelopment Integration Technology Manager;Boeing Aerospace Company

“Flfty Years of Strain - Some Pain, Much Gain”

43. Thennoelastic Emissions I1


A Computerized Toolbox for Imaging Transducers Bradley R. Boyce. John Deer Horicon Works; and Dauid E. Oliver, Ometron. Inc.

Full-field imaging technologies produce large three-dimensional data sets that allow the experimentalist to produce visual images of the measurand. A flexible. modular, computerized system was developed to meet the needs of the experimentalist. Examples are given of output images. operational features, and user access points to the system.

Internal Stress Measurements by Thennoelastic Emissions Jon Lesniak. University of Wisconsin

Vibration Pattern Imaging With SPATE Daoid E. Oliver. Ometron. Inc.

A unique instrument has been developed for full-field non-contact displacement measurement. The vibration imager is based on the Michelson Interferometer but unlike other optical techniques, such as holography. does not require a specialized laboratory and stable environment, and works over a much wider dynamic range.

Elastic-Plastic Strain Analysis Using Differential Infrared Thermography Neal E Enke and Bela I. Sandor. University of Wisconsin- Madison

44. Short Cracks I1

Sponsored by the Research Committee and the Fracture Division

Chairman: Frank D. Adams, U.S. Air Force Wright Aeronautical

Cochairman: Mamidala Ramulu. University of Washington

Experimental Determination of the Short-Crack Effect for Metals Christopher J. Mazur and James L Rudd. U.S. Air Force Wright Flight Dynamics Laboratory

Unconservative life predictions for aircraft structures may occur if the “Short-Crack Effect” exists. The objective of this study is to verify the existance of such an effect. This verification is accomplished through a comprehensive test program involving short- crack tests on 2024 aluminum and 2090 aluminum lithium. The experimental techniques used to monitor the growth of the short cracks and the results of the program will be discussed.

Laboratory

Significance of the Short-Crack Effect on Aerospace Structure James A. Harter, Christopher J. Mazur. Joseph P. Nalepka. U.S. Air Force Wright Flight Dynamics Laboratory; and Douglas R. Miller. U.S. Air Force Academy

Unconservative life predictions for fixed- and rotory-wing aircraft structures may be caused by the short-crack phenomena. The objective of this program was to determine the effects of the short crack on current durability and damage tolerance analyses. This was accomplished by an analytical comparison using short-and long-crack data, with experimental verification.

Microanalysis of Short Fatigue Cracks by Stereoimaging Nagaraja S. Iyyer and Norman E. Dowling. Virginia Polytechnic institute and State University

One technique to monitor the tip displacements of short cracks. and thus advance the understanding of their behavior, is the use of stereoimaging. This technique aids in measuring the in-plane displacements localized to the crack tip and hence the gradients of displacements. High quality pictures of the same region of interest namely the vicinity to the crack tip, under two different loading conditions are compared under a steroscope. The relative in-plane dip placements are observed as a third dimension, i.e., height in the stereoviewer. Quantification of this third dimension gives information about the whole field.

SmalCCrack Closure Measurements in Titanium Alloys J.M. Larsen and J.R. Jira. U.S. Air Force Wright Materials La boratory

An automated interferometric displacement gage was used to monitor crack-mouth-opening behavior of naturally initiated small surface cracks in a series of titanium alloys having a range of microstructures. Findings indicate that the transient development of crack closure plays a significant role in the early propagation of small fatigue cracks.

COD Measurements at Various Positions Along a Crack William N. Sharpe. Jr. and X. Su. The Johns Hopkins University

Load versus crack-opening displacement was measured at various positions along the border of a fatigue crack as it grew from a small surface crack on the edge of an aluminum specimen into a through- the-thickness crack Displacements were measured with a laser- based interferometric system with a gage length of 70pm and a resolution of 0.01fim.

45. Composites I1

Chairman: to be announced Cochairman: S.C. Yen, Southern Illinois University

Fatigue Crack Behaviors of SMC Related to Stiffness Diminution Under Cyclic Loading Satoshi Sorniya. Takeshi Kunio and Junichiro Takamiya. Keio University

To make clear the fatigue process of FRP (SMC) closely related to the fatigue life. the diminution of the stiffness due to cyclic loading was investigated. with special attention to the crack growth quantitatively given by crack density and the applied stress level.

Effects of Fatigue and Environment on Residual Strengths of Center-Cracked Graphite/Epoxy Buffer-Strip Panels C.A. Bigelow. NASA Langley Research Center

Graphite/epoxy buffer-strip panels were subjected to a fatigue- loading spectrum. moisture, and heat. The panels were then tested to determine their residual strengths. The buffer strips arrested the crack growth and increased the residual strengths significantly over those of laminates without buffer strips under all conditions, with one exception. For the S-glass buffer-strip panels with moisture conditioning, the residual strengths were only slightly above the strength of a plain laminate.

Influences of Fillers, Temperature and Frequency on the Fatigue Strength of Reinforced Nylon 6 and 66 Hideto Suzuki. Oyama National College of Technology: and Takeshi Kunio, Keio University

Fatigue tests were performed on short glass fiber-filled, glass bead- filled and smaller particulate inorganic-filled reinforced nylon 6 and 66 castings at room temperature and 100 C. especially focusing on influences of fillers. temperature and frequency on the fatigue strength.

Quantitative Assessment of Delamination Growth in Com- posites Using Ultrasonics Vasudeuan R. lyer and V.K. Kinra. Texas A&M University

Phase velocity and attenuation of leaky lamb waves have been measured with a view to assessing the growth of interior delaminations in fiber-reinfored composite materials. Results for several angle-ply as well as cross-ply graphite/epoxy laminates will be presented.

46. Photoelasticity I1

Chairman: Toshikazu Shibuya. Tokyo Institute of Technology Cochairman: to be announced

Photo-Viscoelasto Plastic Stress Analysis on Cellulose Acetate Shigeru Tadano. and Hiromasa lshikawa. Hokkaido University

A new method of photoplastic stress analysls considenng the effect of strain rate with a plane model of cellulose acetate is discussed This method is appplied to an elasto-plastic problem of a fininte plate with a circular hole under uniaxial tension

A Quantitative Evaluation of Ultrasonic Wave in Solid by Stroboscopic Photoelasticity Kazuhiro Date. Miyagi National College oj Technology. and Heihachi Shimado. Akita National College of Technology

This paper presents a new method for ultrasonic wave-stress measurement based on the synthesizing technique of photoelastic pictures. Some synthesized photographs are presented showing the scattering of ultrasonic wave by the defect.

Suitability of the Photoelastic Implementation of Polymers with Material Birefringence Sarneh Salah Issa. University 01 Kuwait

THURSDAY AFERNOON, JUNE 9

47. SPECIAL JUBILEE PROGRAM Strain Gages. Load Cells & Brittle Coatings - 1938 The Beginnings

Sponsored by the Western Regional Strain Gage Committee and the Technical Committee On Strain Gages

Program Chairman: Lawrence C. Shull. McDonnell-Douglas

cochairman: Charles P. Wright. TRW Space & Technology Astronautics Company (TCSG/WRSGC)

Group (WRSGC)

Old-Timers’ Session Brief historical vignettes by developers and pioneers. mostly from the first decade of strain gage. load cell and brittle coating history

In Memoriam Session Tributes to pioneers no longer with us. Brief presentations will be made on behalf (but not limited to): Frank Tatnall. A.V. DeForest. Denis Drew, Given A. Brewer. Wilfrid L. “Bill” Walsh. Arnold Huggenberger. and Fred Singdale. If you knew these pioneers. bring along stories.

Passing of the WRSGC Gavel Incoming Chairman: Company

Strain Relief Cocktail Reception

Udell V. Merritt. Garrett Turbine Engine

48. Composites 111

Chairman: John L. Sullivan. Ford Motor Company Cochairman: Shankar Mall. U.S. Air Force Institute of

Technology

Thennoelastic Technique Applied to St~ess Analysis of Carbon-Fiber Reinforced Composite Materials Kazuro Kageyoma. Ministry of International Fade a n d Industry; Kiyoshi Ueki. Too Nenryo Kogyo K.K.: a n d Masanori Kikuchi. Science University of Tokyo

The thennoelastic techique for experimental stress analysis is applied to the carbon-fiber composites which have extremely orthotropic properties of elasticity and thermal expansion. The applicability is examined by comparing the experimental results with the numerical result obtained by a finite-element method.

Dynamic Properties of AS4/3502 Composites Under Hos- tile Environmental Conditions Ajit K. Roy and Ran Y Kim. Uniuersity of Dayton Research Institute

The effect of environmental conditions (temperature and moisture) and stacking sequence on the the dynamic properties of a group of multi-directional laminates of AS4/3502. both in undamaged and damaged conditions. are studied. The tests on the measurement of damping are done by the band-width method. The temperature range -65°F to 250°F is chosen for the tests.

Frkcture Condition of Glass Cloth/Epoxy Laminates Con- taining Stress Concentrations Hiizu Hyakutake and Terutoshi Hagio. Fukuoka University; a n d Hironobu Nisitani. Kyushu University

Tension tests of notched plate for glass cloth/epoxy laminates have been carried out for a wide range of notch-tip radii. O n the basis of the concept of linear notch mechanics. the experimental results can be clearly explained. and the limiting condition for fracture is expressed.

Cyclic Delamination Growth Mechanism in Advanced Thermoset Composite at Elevated Temperature Shankar Mall, Air Force lnstitute of Technology; a n d Golam M. Newaz. Battelle Columbus Diuision

An investigation was undertaken to study the delamination growth characteristics in advanced thermoset composite (T300/976) under cyclic loading at elevated temperature (200°F). An important characterstic of cyclic delamination growth at elevated temperature was that of decreasing crack-growth rate followed by slow stable growth. It was found that neither the strain-energy release rate, G. nor the stress-intensity factor K are appropriate driving forces for cyclic delamination growth at elevated temperature as observed at room temperature.

An Advanced Method Measuring the Internal Damage in GFRP - Acoustic Emission and Soft X-Ray Yang Guangsong. Changsha Institute a n d Liu Pide. South Dynamic Company

Influences of Fiber Layups Upon Composite Joints Shoo Yi-Xing. Tongli University and Zhang ChangMing. Shanghai GRP Research Institute

49. Hybrid Methods in Experimental Mechanics

Sponsored by the Optics\ Methods D)id~)ion

Chaimaw. Robert E. Row\ands, University at Wisconsin-

Cochairman: Wil Jorgenson. Sandia National Laboratories Madison

Photoelasticity - A True Hybrid Method of Experimental Stress Analysis J a n Cernosek. Photostrain Inc.

The presentation reviews the numerical methods which are available to supplement the photoelastic measurement. The relative merit of these methods are assessed. The source of enors and the achievable accuracy is discussed.

Hybrid Methods in Experimental Mechanics YJ. Chao. Walter H. Peters. John L Turner a n d M.A. Sutton. University of South Carolina

Hybrid Techniques in Thermal Analysis Elizabeth A. Fuchs. Sandia National Laboratories: YM. Huang. Z Feng a n d Robert E. Rowlands. Uniuersity of Wisconsin-Madison

An effective experimental-numerical approach to solving practical static and transient heat-conduction problems is formulated and demonstrated. Actual temperatures are recorded full-field by infrared thermography. Measured data is smoothed and differen- tiated numerically.

Hybrid Stress-Analysis Techniques Combining the BoundaryElement Method and Photoelastic Experi- mental Data R. Eiland. TRW Corporation; D.A. Chambless. Jeffrey C. Suhling. W.F. Swinson. Auburn University: and John L. Turner. Uniuersity of South Carolina

Some advantages over purely experimental or numerical solutions are realized by using a hybrid approach where experimental data are input a s boundary conditions for the BEM scheme. This paper includes a discussion of some of the advantages and limitations of using a hybrid photoelastic - BEM method for plane stress. plane strain and general stress problems.

Determining Fracture Parameters With Full-Field Optical Methods Robert J. Sanford. Uniuersity of Maryland

The multi-point. least-squares method for extracting the stress- intensity factor and related parameters from full-field optical patterns will be reviewed. The general equations for photoelasticity. interferometry and moire, a s well as suggestions for implementation of the algorithms, will be presented

On the Advantage of Hybrid Techniques in Experimental Stress Analysis in Solid Mechanics Karl H. Laermann. Bergische Uniuenitat-GH Wuppertal

Recent developments in computer and measuring techniques as well as increasing theoretical knowledge must necessarily lead toward advanced experimental methods to control the measuring process. optimize data-acquisition and evaluation. improve accuracy, and open new fields of application. Hybrid techniques as a combination of computer-oriented numerical and experimental methods are derived to analyze geometrical and physical nonlinear. viscoelastic and three-dimensional problems.

50. Fracture IV

Chairman: Michael E. Foumey. University of California Cochaimrar KO) Sh\m\zu, Kanto Gakuin University

Correlation Between Strain-Hardening Exponents and Fatigue-Crack Propagation S.C. Kim. 0,s. Lee0ndD.M. Kang. lnha Uniuersity

Through the various systematic tests, such as AK controlled fatigue tests and fatigue tests followed by a single overload, it was found that the behaviors of fatigue-crack propagation may be closely related with strain-hardening exponents of various materials.

On the Formation of Surface Cracks by a Reflecting Com- pressive Stress Wave William H. Wilson and D.C. Holloway, University of Maryland

Crack Growth Behavior of Short Cracks in 2 1/4 Cr-1 Mo Steel Chang-Min Suh. Kyung-Pook National University; R.O. Ritchie. University of California; and Yong-Goo Kang, Kumho lnstitute of Technology

Fatigue tests by axial loading were camed out to investigate fatigue- crack growth behavior of short cracks in 2 1/4 Cr-1 Mo steel at room temperature by using unnotched smooth specimens and notched specimens with a small artificial pit.

Crack-Growth at Notch Root and Life Prediction in Low Cycle Fatigue Kenji Hatanaka and Tatsuro Fujimitsu. Yamaguchi University

The surface-crack growth rate was analyzed in terms of elastic- plastic fracture mechanics for notched specimen low-cycle fatigue lives of notched specimens and were successfully evaluated on the basis of the short-surface crack growth.

Fatiguecrack Growth Behavior of HT80 Steel Weldments Under Low Temperatures Yoshio Kitsunai and H. Yoshihisa. Notional Research Institute of Industrial Safety

Fatigue-crack growth behavior of HT80 steel weldments is evaluated at temperatures ranging from room temperature down to 93K. The crack-growth rate was closely correlated with the effective stress-intensity factor range which has taken into account the residual stresses independent of temperatures.

Hybrid Method of Photoelastic/Least Squares-Collocation Techniques in Fracture Mechanics Bai Bing-Son. Shenyang Polytechnic University

A hybrid method for determining the stress-intensity factors and whole-field stresses is proposed. The method combines both the classical photoelasticity and the modern method of weighted residuals. The boundary conditions obtained from the photoelastic experiments are used in solving the problems.

51. Fatigue 111

Chairman: Kenji Hatanaka. Yamaguchi University Cochairman: Laurence Costin. Sandia National Laboratories

Fatigue Test and Material Estimation for Fatigue Design of Crankcase Cover Made of Aluminum Casting Alloy, AC4A- T6 Hideto Suzuki and Tadashi Ueki. Oyomo National College of Technology; and Takeshi Kunio. Keio University

Model Analysis of Box Culverts Subjected to Highway Loading Gerald R. Frederick and K.M. Tarhini. University of Toledo

The strain distribution in. and the deflections of, reinforced concrete box culverts associated with highway loading are determined by

testing scale models. Two types of models are used - one-sixth size concrete models and a one-huenty- fourth size photoelastic model. The strain and deflection data observed from testing of models are compared with values from testing of prototypes.

Vibrational Aspects in Structural Fatigue Testing Soon-Bok Lee and Joe-Chull Lee. Korea Institute of Machinery & Metals

Structural-bending and torsional-fatigue testing machines were developed. The vibrational characteristics of the machines and components to be tested are investigated analytically. numerically and experimentally to obtain the safe region of structural fatigue- testing frequencies.

An Exact and an Approximate Solution for the Buckling Load of MultiplyLoaded Columns of Continuously Varying Cross Section Meshulom Groper. Western Michigan University

The paper presents the solution and an approximate solution for the buckling load of two types of columns of continuously varying flexural rigidity, loaded along the columns' axes with several compressive forces. Experimental results obtained in tests are also presented and are compared with the analytical solutions.

Development of a Failure Assessment Diagram for Fatigue JongHyung Lee. Kum-oh Institute of Technology: and Hideo Kobayashi. Tokyo Institute of Technology

An Experimental Analysis of Stresses at the Bottom of Notch Roots by Stretcher Strains Kiyoshi Taniuchi. Meiji University

Stretcher strains have the property of corresponding to the yield stress of steel. Accordingly. the stress found at the bottom of the notch when the strips with semicircular notches were subjected to tensile loading was determined by measuring stretcher strains.

52. Industrial Application of Photoelas- ticity, State-of-theArt and Future Outlook

Sponsored by the Subdivision on Applied Photoelasticity

Chairman: Jan Cernosek Photostrain. Inc.

Application of Photoelasticity for Analysis of Jet Engine Components Thomas S. Guzofski and L. Dietz. Ba t t & Whitney

Photoelastic Analysis of Jet Engine Rotating Parts Donald G. Salyards and H.J. Macke. General Electric Company

A Three-Dimensional Photoelastic Analysis of a Rotating Gas Turbine Compressor Disk R.J. Peters and J.J. Kowalski. AVCO Lycoming Textron

Three-Dimensional Photoelastic Analysis of AerctEngine Parts H. Aono and 7: Kawashima. Ishikowoshima-Harima Heavy Industries

Brpcrimenlml "erhniqu- 57

FRIDAY MORNING, JUNE 10

53. Plenary Speaker

Chairman: Clarence A. Calder. SEM President. Oregon State University

PLENARY SPEAKERS: Christof Rohrboch. Vice Resident (Retired). Federol Institute for Moterials Research & Testing: ond Stefan Keil. Hottinger Baldwin Messtechnik

Fifty Years of Strain Gages and Brittle Coatings: The German Point of View

The speakers will address: historic work by Ohm. Thomson and L n - deck: first results by Czerlinski: first semiconductor strain gages by Theis; research by Fink: cooperation by Hottinger and Baldwin; Hottinger a s manufacturer of strain gages; research work especially in the BAM. from historic to most modern strain-gage bridges and scanning systems; the first brittle coatings by Dietrich and Lehr. their further development and important applications: and outlook for the future.

54. SPECIAL JUBILEE PROGRAM Strain Gages, Load Cells & Brittle Coatings - 1988 States- Of-The-Art


Program Chairman: F. Michael Tovey, Tovey Engineering

Cochairman: Richard J. “Rick DeWitt. Boeing Aerospace (TCSG/WRSGC)

Company (WRSGC)

Sponsors’ Seminar: Sponsors of WRSGC Report on their Latest Developments: BLH Electronics: Eaton Corporation. Transducer Products: HBM, Inc.; HiTec Products, Inc.; Hottinger Baldwin Measurements, Inc.; Measurements Group, Inc.: Micro Engineering II; and Precision Foil Technology

The Impact of IMEKO on the History and State-of-theArt of Strain Gages and Load Cells Tornos Kemeny. Secretory-Generol Internotionof Measurement Confederotion (IMEKO)

Strain Gages and Brittle Coatings - State-of-theArt and Future Directions John Hall. Resident. Micro Engineering I/

Semiconductor Strain Sensors: Background State-of-the Art, and Future Developments Joseph R. Mollon. Jr.. President & Chief Operating Officer. Nouo Sensor

Optimal Cam Profile Extraction Considering Dynamic Characteristics of a Cam-Valve System Hyuck-Soo Jeon. KyungJo Pork ond Youn-Srk Pork. Korea Aduonced Institute of Science a n d Technology

An analytical method to design an optimum cam profile for an OHV-type valve-train system is suggested The valve-train dynamic characteristics were included in the optimization process to max- imize the valve-lift area and minimize the valve acceleration while satisfying the prescnbed constraints

A Torsional Impulse-Frequency Response Technique for Evaluating the Dynamic Mechanical Properties of Stmc- tural Materials Roju Manteno. Ronald E Gibson ond ‘I: Alan Place. University of Idaho

A previously developed impulse-frequency response technique for measurement of the complex modulus of structural materials was modified for torsional vibration. The apparatus was then used to measure the complex shear modulus of a structural epoxy and a Ni- Mo-Bo-Fe rapidly solidified alloy.

Complex Envelope of the Vibration Signature of Ball Bear- ing System and its Application to Fault Detection Yang-Ham Kim, Koreo lnstitute of Technology: Wan Sup Cheung. Koreo Stondards Research Institute. ond Yoon Keun Kwok. Korea Institute of Technology

A new algorithm for easy detection of types of defects of ball. bearing systems is demonstrated. The types of faults of the ball- bearing systems can be easily recognized through the complex envelope and it graphically demonstrates the contact mechanism between the defects and other elements.

Changes in Modal Parameters of a Bridge Span During a High Cycle Fatigue Test HoroldJ. Solane ondJomes W. Boldwin. Jr.. Uniuersity ofMissouri- Columbia

Effects of four million fatigue cycles on the mode shapes. stiffness and modal damping for a full-scale bridge span are examined in this study. An electrohydraulic actuator has been used to excite the span in bending and torsional modes at a loading equivalent to a 356 kN (80.000 Ib) truck.

Modal Analysis of Frequency-Dependent Parameter Systems C h o n g Won Lee. S e o n g Wook Hong a n d KyungRyul Chung. Koreo Advanced Institute of Science a n d Technology

The modal-analysis method is developed for frequency-dependent parameter systems. The frequency-dependent parameters are approximated by even order polynomials. considering the causality of the systems. The frequency-dependent parameter systems are transfomed into the equivalent constant-parameter systems which give rise to the identical frequency-response matrices.

Luncheon 56. Composites IV - Reinforced Materials

55. Dynamic Systems

Chairman: Y.P. Park, Yonsei University Cochairman: Y.S. Park. Korea Advanced Institute of Science

and Technolow

Chairman: Hideto Suzuki. Oyama National College of

Cochairman: Samuel H. Smith. Battelle. Technology

Columbus Division

Acoustic Emissions From Composites at Lowering Temperatures Ffyush K. Dutta and Dennis R. Farrell, U.S. Army Cold Regions Research and Engineering Laboratory

Test results of acoustic emissions from fiberglass-epoxy and graphite-epoxy composites at lowering temperatures are presented, including a brief discussion of experimental techniques. Acoustic emission increased, possibly due to development of microcracks. at lowering of temperatures. Influence of thermal cycling of the composite materials on the acoustic emissions is also discussed.

The Torsional Rigidity of MultiplpConnected and lnhomogeneous Risms M.G. Faulkner and A. Mioduchowski. University of Alberta

It is shown that the torsional rigidity of a square bar can be altered considerably by the addition of a second stiffer material in parts of the cross-section. The study concentrates on investigation of multiply-connected prisms of triangular, square, and hexagonal cross-sections which have a certain percentage of reinforcing material in the cross-section.

M o d e I Interlaminar Fracture of Unidirectionally Reinfor- ced Carbon/Nylon laminates Masanori Kikuchi, Takayuki Kobayashi and Noboru Yanagisawa. Science University of Tokyo; and Kazuro Kageyama MITI

Mode I interlaminar fracture toughness of CFPR is evaluted using DCB specimens. Unidirectionally reinforced carbon/nylon laminates were used for the test, and the fracture toughness, Gc. wasob- tained. Two kinds of thickness specimens, 2mm and 8mm thick, are used and the results are compared with each other.

Crack-Opening Mechanisms and Free Surface Effects in a Particulate Composite C.W. Smith, R. Czamek and M. Rezvani. Virginia Polytechnic Institute and State University

A coarse-grid method is used to obtain displacement fields in the neighborhood of the tips of cracks in “biaxial” specimens of a particulate composite, namely inert solid rocket propellant. Measurements were digitized and fed into a simple programmed algorithm for extracting singularity orders (or lowest eigenvalues) where the crack intersected the free surface at right angles. It was necessary to modify an existing algorithm to account for crack-tip blunting.

Interlaminar Fracture Toughness of Graphite/Epoxy Com- posite Under Mixed-Mode Deformations C.S. Hong and S.H. Yoon. Korea Aduanced Institute of Science and Technology

Interlaminar fracture is a primary damage mode in laminated composites and it is generally caused by mixed-mode type fracture. Finite-element stress analysis for the fracture specimen was carried out to evalute the validity of mode-I, mode-It and mixed-mode loading conditions. Finite correction factors of K, and K,, for the gaphite/epoxy specimens are also presented with various crack lengths. Finite correction factors are used to determine critical stress-intensity factors of graphite/epoxy fracture specimens.

57. Residual Stress I11

Chairman: Beth Pardue. Technology for Energy Corporation Cochairman: C.M. Suh. KyungPook National University

Measurement of Residual Stresses in Circular Tubes of Polymethylmethacrylate (PMMA) R.K. Mittal. Indian Institute of Technology and /.A. Khan. Aligarh Muslim University

Residual stresses in circular tubes of a transparent polymer like polymethylmethacrylate (PMMA) have been measured by means of a photoelastic technique which is non-destructive. easy to apply and yields reproducible results. This technique has other advantages as compared to the layer-removal method. Using this technique the influence of several thermal parameters on residual stresses has been determined.

Applications of the Incremental Hole-Drilling Method For Measurement of Residual-Stress Distribution J. Lu and J.F. Flavenot. Centre Technique des Industries Meca n iq ues

New developments have shown that the strain measured on the surface during incremental drilling can be related to the residual- stress distribution. Some special aspects of this technique. plasticity. drilling system. and stress gradient will be presented. including some applications on several different materials.

Residual-Stress Testing Used for Quality Control for Heat Treatment Processes George W. Eggeman. Kansas State Unioersify

Residual stresses have proved to be a problem in suction press rolls by increasing the mean stress level associated with corrosion fatigue. Residual stress tests taken during the manufacturing processes of three rolls allowed changes to be made in the heat treatment of following rolls. By taking steps to reduce residual stresses. a longer service life can be expected for an expensive item which requires a long manufacturing cycle time.

Optimum Model of a Hole-Gage Assembly for Measuring Biaxial Residual Stresses Zongxuan Qiao and Peizhong Zhang. Shantou University

An optimum model of a hole-gage assembly is presented. Experimental verification was performed Residual stresses measured can be calculated only by using radial relaxation coef- ficients from theoretical considerations without calibrations of any type if the optimum model of hole-gage assembly is used Experimental data of strains introduced by hole-drilling are presented.

58. Optical Methods IV - Speckle Metrology

Chairman: Robert Czarnek, Virginia Polytechnic Institute and

Cochairman: to be announced

Enhancing Sensitivity of the White-Light Speckle Method in Terrestrial Applications Edgar G. Conley. University o/ Alaska and Gary L Cloud. Michigan State University

White-light speckle is used to measure surface displacement in glaciers. Data are consistent with flow rates obtained by surveying. Limitations on applicability. resolution, and accuracy are imposed by weather, atmospheric turbidity. and camera motion Limiting sensitivity is calculated and measured. Methods to extend sensitivity are proposed.

State University

Rrpcrlnirn18l lh-hniquen 59

Determination of Deformations Using Digital-Image Cor- relation wlth Newton-Raphson Iterative Corrections H.A. Bruck, S.R. McNeill. M.A. Sutton, YJ. Chao and W.H. Peters University ojSouth Carolina

Newton-Raphson iterative corrections are used to improve com- putational time of digital-image correlation for determining object deformation. Accuracy of the new method is baselined for different deformations.

Non-Contact Speed Measurement on Bobbin and Running Thread Using Spatial Filter Hirohisa Morikawa. Masaru Nakazawa and Toshikazu Hayashi. Shinshu University

The spatial filtering method is applied to speed measurement of moving textile materials when distinguishable marks of small reflec- tors cannot be attached on the surface. Both the speed of the bobbin and running thread are measured using the spatial filter. Analysis of the information to select a particular spatial frequency is carried out.

Vibration Analysis Using Digital Correlation John A. Gilbert. University of Alabama-Huntsville: Donald R. Matthys. Marquette University: T Dixon Dudderor. AT&T Bell Laboratories; and David L Lehner, University of Alabamo Hun tsville

The influence of pattern regularity on numerical correlation is investigated for cases in which a projected pattern (of lines. dots or speckles) is used to determined nodal locations and vibrational amplitudes

Deflection Measurements Using Stereoscopic and Digital- Image Correlation Techniques on an Elliptical Ring Zella L. Kahn-Jetter and Tsu-Chin Chu. Polytechnic University

A pair of stereo images of a speckle pattern superimposed on the surface of a thin metal ring is correlated with a set of stereo images of the speckled surface after the ring is stretched From the geometry involved, the three-dimensional displacements of a point on the surface of the ring can be measured.

FRIDAY AFTERNOON, JUNE 10

59. SPECIAL JUBILEE PROGRAM Strain Gages and Brittle Coatings - 1988


Chairman: F. Michael Tovey. Tovey Engineering (TCSG/

Cochairman: Richard J. DeWitt, b e i n g Aerospace Company WRSGC)

(WRSGC)

High-Volume Manufacturing and Test of High-Performance Strain-Gage-Based Load Cells Stephen Patoray, Toledo Scale Company

Strain Gaging New Materials Lawrence C. Shull. McDonnell-Douglas Astronautics Company

Current Developments in High-Temperature Strain-Gage Technology Steven Wnuk, Resident, HiTec Products, lnc.

Workshopc State-of-the-Ar& Projects in Strain Gages, Load Cells, and Brittle Coatings Brief presentations of current work by session registrants - discussion of unsolved problems

Business Meeting - WRSGC/TCSG Election d otftcerr

60. Structural Testing IV chairman: to be announced Cochairman: Jim Alper. Naval Air Development Center

Lateral Vibration of Free Running Circular Saw and Emit- ted Whistling Noise Masaru Nakazawa. Shinshu University; Hirao Aono. Ishikawajima- Harima Heavy lndustries Co.. Ltd: Akira Shinohara. Hirohisa Morikawa and Hui Lin. Shinshu University

Lateral vibration frequencies and modes of a circular saw which emits whistling noise when the saw is running are discussed. The finite-element method is applied for the theoretical analysis, while the holography technique and capacitance method are employed for the experimental measurement.

Laboratory Simulation Tests of Military Track Bushings Glen R. Simula Michigan Technological University

This paper describes the design and development of a specially designed track bushing endurance simulation machine for military track bushings. This machine simulates the loads acting on the track bushing as it traverses the drive sprocket. Results of parametric studies will be presented.

The Structural Damping of a Metal-Matrix Composite Graeme G. Wren and Vikram K. Kinra. Texas A&M University

The structural damping of unidirectional and symmetric laminated gaphite/aluminum metal-matrix composite specimens at low- frequencies (+lo0 Hz) and low strain amplitudes (+60ue) is presented. The experimental apparatus is designed to measure damping by the logarithmic decrement method. The speed and automation of the data-acquisition system, and the low level of strain amplitudes at which damping measurements can be reliably made make this technique unique. A measure of structural d a m p ingwas obtained by reducing the data using a linearized logarithmic decrement technique.

An Experimental Research of Stress Wave in a Hollow Disk Under Central Impact Binglin Hu and Yuren Cheng. Northern Jioatong Uniuersity

A polycarbonate hollow disk with a central round hole (outer diameter D100mm. internal hole diameter dl0mm). was used to simulate a wheel which was supported at the internal hole and loaded on the outer edge. The results showed that there was an apparent difference of stress distribution of the hollow disk between dynamic and static stresses, especially between the points of both internal support and outer edge impacted.

61. Photoelasticity I11

Chairman: Jose Freire, Catholic University of Rio de Janeiro Cochairman: Michael Sutton. University of South Carolina

80 Aprll 1 9 0

Whole-Field Stress Analysis Using Digitized Photoelastic Data and Numerical Methods Hassan Mahfuz. Robert 0. Case and Tin-Lup Wong. Florida Atlan- tic University

A computerized technique is presented that calculates stress values from digitized photoelastic data (isochromatics and isoclinics) within the boundary of a photoelastic specimen. A user-input-grid mesh is superimposed inside the boundary to solve the Laplace equation and subsequently separate the principal stresses. Finally, initial nodal input values are improved from the digitized data to enhance the convergence of the solution.

Photoelastic Stress Analysis in Mitered Bend Under Inter- nal Pressure Yoshiaki Sawa. Science University of Tokyo

The states of stress distribution in mitered-bend pipes subjected to internal pressure was investigated by means of the photoelastic stress-freezing method. The maximum stress value is greatly affec- ted by bent-angle The relation between stress concentration factors and bent angles was also determined in detail.

Experimental Study of the Impact of a Surface With a Soft Layer Stephen A. Rizzi and James F Doyle, h r d u e University

Strain-gage signals recorded from the impact of a layered sheet are actively used in a spectral-analysis method to obtain the force history. Computation of the resulting photoelastic fringe patterns are subsequently compared to the dynamically recorded photographs. Of particular interest are the Rayleigh and Stoneley waves formed.

Automatic Stress Analysis of Photoelastic Experiment by Use of Image Processing and Numerical Analysis Eisaku Umezaki and Tamotsu Tamaki. Nippon Institute of Technology; and Susumu Takahashi. Kanto Gakuin University

A new approach for automatic stress analysis from the photoelastic fringes in the whole region of a two-dimensional model is described. This method is composed of extraction of fringe patterns, determination of their orders, calculation of stress components and draw- ing of stress trajectories, and is done on a personal computer system.

62. Residual Stress IV Chairman: Gary Schajer. Weyerhauser Company Cochairman: to be announced

Measurement of the Residual-Stress Gradients in MuC tilayer Material J. Lu and J.F. Nauenot. Centre Technique des Industries Meca n iq ues

The hole-drilling method is widely used for the measurement of residual stress in mechanical components. This paper describes a finite-element procedure which has been used to compute calibration constants for measurements of residual-stress variation-with- depth in multilayer components (electroplated metals, claddings. sprayed coatings).

Nondestructive Detection of Residual Stresses by Shearography YY Hung. J.D. Houanesion. X. Zhang and K. W. Long. Oakland University

Measurement of Stress in Textured and Plastically Deformed Bodies Based on a New Acoustoelastic Theory

Wei-Yang Lu and Chi-Sing Man. University of Kentucky

A new acoustoelastic theory suggests experimental techniques that circumvent two outstanding difficulties in nondestructive evaluation of stress by ultrasonics. The essentials of the theory will be outlined. and experimental results will be discussed.

A Direct Method for Measurement of Residual Stresses by Using the Blind Hole Ma Guang. Wang Zhu-Too and Znao De-ping. Shengyong Polytechnic University

The release law of residual stress around the blind hole is studied. The strains released are measured by using the rosette made of superimposed strain gages. and based on the superposition principal and recurrence method; a method for determining the residual stress directly without calibration is developed.

63. Fracture V Chairman: to be announced Cochairman: to be announced

Interaction of a Flexural Wave With a Lengthwise Crack In a Beam James F. Doyle, TN. Farris and H.M. Ledington. Purdue University

The structural dynamics is handled by way of the spectral-analysis approach where the cracked beam is considered to be made of separate beam sections connected at imaginary joints. This structural analysis is verified through the impact of a split aluminum beam monitored by strain gages. A model is being developed that converts this information into dynamic stress-intensity behavior by way of a dynamic J integral. The quality of the model is assessed by measuring the crack-tip stress field using ultra-high-speed photoelastic photographs.

Vibration Characteristics of CentrallyCracked Plates Under Tension Takashi Fujimoto and Seinosuke Sumi. Kyushu University

The vibration characteristics of centrally-cracked plates subjected to a uniaxial tension are analyzed using a finite-element method. The results. frequencies. and modes of vibration, are compared with those measured by using laser-holographic interferometry.

Crack-Closure Measurements and Fatigue Threshold in the Temperature Range Between -100 and 500 C Keiji Ogura. Yoshio Miyoshi and I Z U N Nishikawa. Osaka University

Experimental results on near threshold fatigue-crack growth and crack closure at low and elevated temperatures are presented in several structural alloys. The role of crack closure on the temperature dependence of fatigue threshold is discussed. The effect of oxide products on crack closure at elevated temperature is also discussed.

The Uniqueness of the Solution to the Equations Derived from Gauss-Newton Method in Photoelastic Fracture Yon Jun Sun and Qian Zhao. Northern Jiaotong University

In this paper. it is proved that the set of equations derived from the Gauss-Newton method (over-deterministic least-square method) in photoelastic fracture has an unique solution in the meaning of first. order approximation. A computing example is given to show the uniqueness of practical computing procedure.

vi international congress on experimental mechanics technical program

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