mmber(s) ;

tlature of'

Designation: D 4255D 4255M - 01

, if other Standard Test Method forIn- Plane Shear Properties of Polymer Matrix CompositeMaterials by the Rail Shear MethodIple.

statdard

statdard

This stadard is issued under the fixed designation D 4255/D 4255M; the number imediately following the designation indicates iheyear of original adoption or in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.

This standard ha been approved for use by agencies of the Department of Defense.

s tatdard

acceptedd as the

lrementsIt of data.

1. Scope

1. Ths test method determnes the in-plate shear proper-ties of high-modulus fiber-reinforced composite materials byeither of two proceciures. In Procedure A, lamnates clampedbetween two pais of loading riuls are tested. When loaded intension the rails introduce shear forces in the specimen. In

Procedure B , lamnates clamped on opposite edges with atensile or compressive load applied to a thd pai of rails in thecenter are tested.

1.2 ' Application of this test method is limted to contiuous-fiber or discontinuous-fiber-reinorced polymer matrx composites in the following material forms:

1.2.1 Lamnates composed only of unidiectional fibrouslamae, with the fiber diection oriented either parallel orperpendicular to the fixtue rais.

2 Lamnates composed only of woven fabric filamentarlamae with the war diection oriented either parallel orperpendicular to the fixture rails.

1.2.3 Lamnates of balanced and symmetrc constrction,. with the 0 diection oriented either parallel or perpendicular tothe fixtue rails.

1.2.4 Short-fiber-reinorced composites with a majority ofthe. fibers being. randomly distrbuted.

NOTE l-Additidrial test methods for detenng in-plane shear prop-ertes of polymer matr composites may be found ' in Test MethodsD 5379/D 5379M and D 5448/D5448M, and Practice D 3518/D 3518M.

1. This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory ' limitations prior io use.

1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. Within the text theinch-pounds units are shown in brackets. The values stated ineach' system are not exact equivalents; therefore, each system

I Ths test method' is under the jursdiction of ASTM Commttee ' D30 on

Composite Materials and is the diect responsibilty of Subcommttee D30.04 onLana and Lamnate Test Methods.

Curnt edition approved Oct 10, 2001. Published Februar 2()02. OriginallyPUblished as D 4255/D 4255M - 83 Last previous edition D 4255/D 4255M - 83(1994).1

must be used independently of the other. Combining valuesfrom the two systems may result in nonconformance with thestandard.

2. Referenced Documents1 ASTM Standards.

D 792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by Displacement

D 883 Termnology Relating to PlasticsD 2584 Test Method for Igltion Loss of Cured Reinforced

ResinsD 2734 Test Method for Void Content of Reinorced Plas-

ticsD 3171 Test Method for Constituent Content of Composite

MaterialsD 3518/D 3518M Practice for In-Plane Shear Stress-StrainResponse of Unidirectional Polymer Matrx CompositeMaterials by Tensile Test of :!45 Lamnate

D 3878 Termnology for Composite MaterialsD 5229/D 5229M Test Method for Moistue ' Absorption

Propertes and Equilbrium Conditioning of Polymer Ma-trx Composite Materials

D 5379/D 5379M Test Method for Shear Propertes of. Composite Materials by the V-Notched Beam' Method

D 5448/D 5448M Test Method for In-Plane Shear Proper-ties of Hoop Wound Polymer Matrx Composite Cylin-ders

E 4 Practices for Force Verification of Testing MachiesE 6 Termology Relatig to Methods of Mechancal Test-

ingE 111 Test Method for Young s Modulus, Tangent Modulus,

and Chord ModuluS5 'E 122 Practice for Choice of Sample Size to Estiate a

Measure of Qualty for a Lot or ProcessE 177 Practice for Use of the Terms Precision and Bias in

ASTM Test MethodsE 251 Test Methods for Performance Characteristics of

Annual Book of ASTM Standards Vol 08.01.Annual Book of ASTM Standards Vol 08.02.Annual Book of ASTM Standards Vol 15.03.

5 Annual Book of ASTM Standrds Vol 03.01.6 Annual Book of ASTM Standards Vol 14.02.

COPYright (g ASTM International , 100 Barr Harbor Drive, PO Box C700, West Conshohocken , PA 19428-2959, United States.

207

cO D 4255/D 4255M

Metallic Bonded Resistance Strain GagesE 456 Termnology Relating to Quality and StatisticsE 1237 Guide for Installng Bonded Resistance Strain

GagesE 1309 Guide for Identification of Composite Materials in

Computerized Material Property DatabasesE 1434 Guide for Development of Standard Data Recordsfor Computerization of Mechanical Test Data for High-

Modulus Fiber-Reinforced Composite MaterialsE 1471 Guide for Identification of Fibers, Filers , and Core

Materials in Computerized Material Property Databases2 ASTM Adjunct.

Adjunct No. ADJD4255, Rail Shear Fixtures Machining

Drawings 7

3. Terminology1 Termnology D 3878 defines terms relating to high-

modulus fibers and their composites. Termnology D 883

defines terms relating to plastics. Termnology E 6 defines

terms relating to mechanical testing. Termnology E 456 andPractice E 177 define terms relatig to statistics. In the event of

a conflict between terms , Termnology D 3878 shall have

precedence over the other termnology standards.

NOTE 2-If the term represents a physical quantity, its analytical

dimensions are stated immediately following the term (or letter symbol) infundamental dimension form, using the following ASTM stadard sym-

bology for fundamental dimensions, shown within square brackets: (M)for mass, (L) for length, (T) for time , (a) for thermodynamc temperatue

and (nd) for nondimensional quantities. Use of these symbols is restrctedto analytcal dimensions when used with square brackets

, as the symbols

may have other definitions when used without the brackets.

2 Definitions of Terms Specifc to This Standard.1 in-plane shear, n-shear associated with shear forces

applied to the edges of the lamnate so that the resulting sheardeformations occur in the plane of the lamnate rather than

though the thickness.2 offset shear stress (M/(LT

)),

the shear stress

associated with an offset of the shear chord modulus of

elasticity line along the strain axis (see 12.4).3 shear strength (M/(LT

)),

the shear stress caredby a material at faiure under a pure shear condition.

2.4 transition region, n-a strain region of a stress-strainor strain-strain curve over which a significant change in the

slope of the cure occurs within a small strain range.2.4. 1 Discussion-Many filamentar composite materials

exhibit a nonlinear response during loading, such as seen inplots of either longitudinal stress versus longitudinal strain ortransverse strai versus longitudinal strain. In certai cases , the

nonlinear response may be conveniently approximated by a

bilinear fit. There are several physical reasons for the existenceof a transition region. Common examples include matrixcracking under tensile loading and ply delamnation.

5 traveler, n-a small piece of the same material as, and

processed similarly to, the test specimen, used for example to

7 A copy of the detailed drawing for the constrction of the fixtures shown in

Figs. 1 and 2 is available at a nominal cost from ASTM Headquarers. Request

Adjunct No. ADJD4255.

measure moisture content as a result of conditioning. This also sometimes termed as a reference sample.

3 Symbols:

A = cross-sectional area of test specimen= percent bending of specimen

CV = coeffcient of variation statistic of a sample population

for a given property, %= offset shear stress , the value of the shear stress at the

intersection of the stress-strain plot with a line passing through

the offset strain value at zero stress and with a slope equal to

the shear chord modulus of elasticity= ultimate shear stress

G = shear modulus of elasticity= specimen thickness= specimen length , the dimension parallel to the rails in the

gage section= number of specimens

= load carred by test specimen at ith data pointmax = load caried by a test specimen that is the lesser of (1)

the maximum load before failure, (2) the load at 5 shear

strain, or (3) the load at the bending limit (see 11.8.= sample standard deviation

= measured or derived property for an individual specimen

from the sample population

X = sample mean (average)'Y = shear strainE = indicated normal strain from strain transducer

= 10- m/m (10- in./in.

Ti = shear stress at ith data point instnrosetl

4. Summary of Test Method oppo:

1 Procedure A: Two-Rail Shear Test- flat panel wiil 4.

holes along opposing edges is clamped, usually by throu junct

bolts , between two pairs of parallel steel loading rails , see Fig

1 and 2. When loaded in tension , this fixture introduces shea 5. Si:

forces in the specimen that produce failures across the panel 5.1

This test method is typical but not the only configurati prope

usable. The two-rail shear fixtures can also be compressi9! opme

loaded. The load may be applied to failure. " and

1 If load-strain data are required, the specimen may li mater

instrumented with strain gages. Two three-element strain specir

rosettes are installed at corresponding locations on both face testinjof the specimen. : tie

2 Procedure B: Three-Rail Shear Test- flat pan ment

clamped securely between pairs of rails on opposite edges lIetho

in its center, is loaded by supporting the side rails while loadi 5.1.

the centerrails. See Figs. 3-5. A load on the center rail of eitb

tension or compression produces a shear load in each section 5.

the specimen. The load may be applied to failure. 5.

1 The test fixture consists of three pairs of parallel ra trai:

usually bolted to the test specimen by through bolts. The iIg to

outside pairs of rails are attached to a base plate which restS

the test machine. A third pair (middle rails) is guided thro

a slot in the top of the base fixture. The unit is normally loa

in compression. It is also permssible to load the middle rais

tension, but this requires attaching the base fixture to the t

machine.2 If load-strain data are required, the specimen may

6. Inti

a perff

accept.

PUros

208

This is

pulation

ss at the

throughequal to

ils in the

,er of (1)

% shear

;peclmen

mel with, throughsee Figs.

ces shear

he panel.5.gurationnpression

n may be

rain gage

loth faces

at panel,

dges and

Ie loading1 of either

section of

:allel rails

. The twO

:h rests on

d through

lly loadedlIe rails in

to the test

:n may be

cO D 4255/D 4255M

SPECIMEN

STRAIN GAGE

RAILS

LOAD PLATE

TENSILE FIXTURE

FIG. 1 Procedure A Assembly Rail Shear Apparatus

instrmented with strai gages. Thee-element strain gagerosettes are to be instaled at corresponding locations onopposite faces of the specimen.

3 Detailed fixtue drawings are available as ASTM Ad-junct No. ADJD4255.

S. Signficance and Use1 These shear tests are designed to produce in-plane shear

propert data for material specifications, research and devel-opment , and design. ' Factors that influence ' the shear responseatdshould therefore be reported include: material, methods ofmaterial preparation and lay-up, specimen stackig sequencespecimen preparation . specimen conditioning, environment oftesting, specimen algnment and grpping, speed of testing,tie at temperatue, void content, and fiber volume reinforce-ment 'content. Propertes that may be measured by this testmethod include:

1.1 In-plane shear stress versus shear strain response1.2 In-plane shear chord modulus of elasticity,1.3 Offset shear stress , and

5.1.4 Maximum in-plane shear stress. In cases in which thestrain at faiure is greater than 5 % , tle shear stress correspond-ing to 5 % shear strain should be reported.

6. Interferences

1 . There are no standard test methods capable of producinga perfectly pure and uniform shear stress condition to failurefor every material, although some test niethodscan comeacceptably close for a specific material for a given engineeringPurose. The off-axis load of the two-rail method introduces a

comparatively small tensile load in the panel.2 Material and Specimen Preparation-Poor material

fabrication practices, lack of control of fiber alignment, anddamage induced by improper specimen machining are knowncauses of high material data scatter in composites.

6.3 Determination of Failure-Rail shear specimens, espe-cially th ones, can buckle durig load application. Bucklingcan be detected by measurng surace strais on opposite facesof the specimens with thee-element strain gage rosettes. Datameasured with the specimen in a buckled state are not

representative of the material shear properties. Modulus datamust be checked to confirm that buckling has not occurred intle modulus measurement range. Strength measurements mustbe checked to confirm that shear strength has not beeninfluenced by specimen buckling. Faiure by buckling shouldnot be interpreted as indicating the maximum shear strength.. 6.3. 1 Ply delamnation is another possible failure mode forlamnates contaig a large number of 45 plies. Ths failurereflects instabilty of. 45 plies loaded in compression as

contrasted to the overall buckling failure previously described.Differences in strain gage readings wil not be noticeable, butthe failure can be identified by delamated plies in contrast tofiber breakage.

6.4 Gripping-Failure though bolt holes indicates inad-equate gripping. Alternate gripping methods are discussed in

2.3.5 End Effects-This test method assumes a state of pure

shear throughout the length of the specimen gage section.However, the gage section ends have zero shear stress becauseno traction and no constraints are applied there. A stresstransition region exists between the ends and interior portionsof the gage section. The length of this transition regiondetermnes the error induced iri the material shear data.

7. Apparatus1 Micrometers-The micrometer(s) shall use a suitable

size diameter ball interface on iregular suraces such as thebag-side of a lamate and ' a flat anvil interface on machinededges or very-smooth tooled suraces. The accuracy of theinstrments shall be suitable for reading to withi 1 % of thesample length and thickness. For typical specimen geometresan instrment with an accuracy of :!2.5 !J (:!O.OOOI in.) isdesirable for thickness measurement, whie an instrment withan accuracy of :!25 !J (:!O.OOI in.) is desirable for lengthmeasurement.

2 Rail Shear Fixtures

Two-Rail Shear- two-rail shear fixture is shown inFigs. 1 and 2. Detailed fixtue drawings are available as ASTMAdjunct No. ADJD4255. The test fixtue consists of two paisof rails which can clamp the test specimen with through bolts.The rails are then attached to the test machine though pins, aload plate that also aligns the rails witl each other, and a clevisthat connects directly to the test machine. This equipment istypical but not the only configuration usable. The two-rail

8 A. K. Hussain and D. F. Adams

, '

The Wyoming-Modified Two-Rail Shear TestFixture for Composite Materials Journal of Composites Technology and ResearchVol 21 , No. , October 1999, pp. 215-223. .

209

4255/D 4255M

FIG. 2 Procedure A Partially Assembled Typical Test Fixture

CENTER RAILSLIDES THROUGH GUIDE

STRAINGAG E S

(91

0--- 0--

FIG. 3 Procedure B Assembly Rail Shear Fixture

shear fixtue can be compression loaded. Also see 7. 3 for railmodifications.

2 Three-Rail Shear- three-rail shear fixtue is .shownin Figs. 3-5. Detailed fixtue drawings are available as ASTMAdjunct ADJD4255. The test fixtue consists of thee pais ofrails that clamp the test specimen with though bolts. The twooutside pais of rails are attached to a base plate that rests onthe test machine. The thd (middle) pai of rails are guidedthough a slot in the top of the base fixtue. The unit shown isloaded in compression. The middle rails can be. tensile loaded

FIG. 4 Procedure B Assembled Typical Test Fixture

which requires fastening the base fixtue to the test macbiThs equipment is typical but not the only configuration thatlS

usable. Also see 7. 3 for rail modifications.3 Rail Modifcations-The following list is not inclusi

but is typical of methods used by varous laboratories to meet

210

acbi, thatis

clusi\,e

:0 mee!

4255/D 4255M

FIG 5 Procedure. B Disassembled Typical Test Fixture

the requirements of specific materials. Techniques that workfor one material may be unacceptable for another. If thesemodifications are to be used as par of a specification, the railgrip system shall be completely specified and these modifica-tions noted in the test report. These modifications have beenused to grip the following specimens:

2.3. 1 Abrasive paper or cloth bonded to the rails2 Machiing V grooves in the rails

3.3 Center punching rails in a randem pattern7.2.3.4 Changing the number of bolt holes from thee up to

eight per rail and using smaller holes,2.3.5 Soft metal shims

6 Tabbing specimens in rail areas , and7 Thermal spray surfaces.

3 Testing Machine-The testing , machine shall conformwith Practices E 4 and shall satisfy these requiements:

3.1 Testing Machine Heads-The testing machine shallhave two loading heads with at least one movable head alongthe testing axis.

: 7. Platens/Adapter-One of the te ting machine headsshal be capable of being attached to the lower half of thetWo-rail shear test fiture (described in 7. 1) or of supporting

I:ase of the thee-rai fixtue (described in 7. 2) using anadapter or platen interface as requIred. The other head shall becapab e of being attached to the upper half of the fixtue or of

oading the center rail of the fixture. If required, one of theterfaces may be capable of relieving minor misalignmentsetweenheads, such as with a universal or a hemispherical ball

joint.

3 Drive Mechanism-The testing machine drve mecha-!Usmshall be capable of imparing to the movable head apntrolled displacement rate with respect to the stationar

head. The displacement of the movable head shall be capable

of regulation as specified in 11.3.

3.4 Load Indicator-The testing machine load-sensingdevice shall be capable of indicating the total load applied tothe test specimen. This device shall be essentially free fromresponse lag at the specified testing rate and shall indicate theload with an accuracy over the load range(s) of interest ofwithn:! 1 % of the indicated value, as specified by PracticesE 4. The load range(s) of interest may be faily low formodulus evaluation or much higher for strength evaluation, orboth, as required.

NOTE 3-0btaining precision load data over a large range of interest inthe same test, such as when both elastic modulus and maxum load arebeing detennned, places extreme requirements on the load cell and itscalibration. For some equipment a special calbration may be required. Forsome combinations of material and load cell, simultaeous precisionmeasurement of both elastic moduius and maxum strength may not bepossible, and measurement of modulus and strength may have to beperformed in separate tests using a dierent load cell range for each test.

7.4 Strain-Indicating Device-Bonded resistance straingages shall be used to measure strain. A minimum of twothee-element strain gage rosettes are required, at correspond-ing locations on opposite faces of the specimen at the center ofthe gage section, as ilustrated in Fig. 1 , Fig. 3 , and Figs. 6-

7.4. 1 Bonded Resistance Strain , Gages:-Strai gage selec-tion is a compromise based on the type of material. An activegage length of 3 mm (0. 125 in.) is. recommem!-ed for mostmaterials, although larger gages may be more suitable for somewoven fabrics. The gage should not be so large that it lieswith four specimen thicknesses of a rail. Gage calibrationcertification shall comply with Test Methods E 251. Straingage rosettes with a minimum normal strain range of approxi-mately 3 % (measuring 6 % shear strai) are recommended.When testing woven fabric lamnates, gage selection should

211

cO D 4255/D 4255M

Location(s) forthree-elementstrain gagerosettes

Rosettesrequired atcorrespondi nglocations onopposite faces

1/1.3IAI

i I

6X011-B-

IAIBICI

FIG. 6 Procedure A, Two-Rail Shear Specimen, SI Units

Location( s) forthree-element

. strain gagerosettes

Rosettesrequired atcorrespondinglocations onopposite faces

1l/1.QIA

~~~

I..IO021CI 6 x 0 0.433 - 0.512

B- IAIBI

FIG. 7 Procedure A, Two-Rail Shear Specimen, Inch-Pound Units

consider the use of an active gage length that is at least as largeas the characteristic repeating unit of the weave. Some guide-lines on strain gage use on composites follow. Additionalgeneral information can be found in the literatue.

7.4. 1.1 Surface preparation of fiber-reinforced compositesin accordance with Guide E 1237 can penetrate the matrmaterial and cause damage to the reinforcing fibers, resultingin iiproper speciien failures. Reinforcing fibers should not beexposed or damaged during the surace preparation process.Consult the strain gage manufacturer regarding surface prepa-ration guidelines and recommended bonding agents for com-posites , pendig the development of a set of standard practices

9 M. E. Tuttle and H. F. Brison

, "

Resistace-Foil Strain Gage Technology asApplied to Composite Materials Experimental Mechanics 1984, Vol 24, No.

, pp.

54- , Errata noted in Vol. 26, No. , June 1986, pp. 153- 154.10 Manual on

Exerimental Methods of Mechanical Testing of Composites C. H.Jenkis , Ed. , second edition, Society for Experimenta Mechanics, Section n, StrainMeasurement, 1998, pp. 25-84.

for strain gage installation surface preparation of fiber..

reinforced composite materials.7.4. 1.2 Select gages having higher resistaces to reduce

heating effects on low-conductivity materials. ll Resistatces

350 0. or higher are preferred. Use the minium possible gageexcitation voltage consistent with the desired accuracy (1 to 2

V is recommended) to reduce the power consumed by the gagefuher. Heating of the specimen by the gage may affect the:;

performance of the material directly, or it may affect the,

indicated strain as a result of a difference between the gage:'

temperatue compensation factor and the coeffcient of therJexpansion of the specimen material.

. ;

7.4. 1.3 Temperatue compensation is recommended whentesting at Standard Laboratory Atmosphere. Temperatue COJ1

pensation is required when testing in nonambient temperatt

11 D. F. Adams and E. Q. Lewis

, "

Influence of Specimen Gage Length an:Loading Method on the Axal Compression Strengt of a Unidirectional CompOSl

Material Experimental Mechanics, Vol 31 , No. , 1991 , pp. 14-20.

212

, fiber-

reduceiIces of

lIe gage

(1 to 2

b.e gage

fect the

ect the

le gage

thermal

i when

:e COll-leratue

mgth and

:omposite

4255/D 4255M

Location(s) forthree-elementstrain gagerosettes

141 - 139

Rosettesrequired at

correspondinglocations onoppoite faces

1//13I!T I

FIG. 8 ProcedureS, Three-Rail Shear Specimen, Sl Units

9XI/11,-IAIBICI

lr

Location(s) forthree-elementstrain gagerosettes

Rosettesrequired atcorrespondinglocations onopposite faces

environments. When appropriate, use atraveler with identicallay-up and strain gage orientations for thermal strain compen-sation.

7.4. 1.4 Correct for strai gage transverse sensitivity whenthe error caused by strain gage transverse sensitivity is greaterthat 1 %. Strai measurements using strain gages moUnted tocomposite materials are susceptible to transverse sensitivityerrors because of the highly ortotropic behavior of composite

terials. Unidirectional composites are especialy susceptibleto strai gage transverse sensitivity errors.

7.4. 1.5 Strain gage rosettes are required on opposite faces ofthe test specimen to detect bucklng deformation. When thespecimen bends as a result of bucklg, strains on one face ofthe specimen exceed strains on the opposite face.

5 Conditioning Chambir-'When conditioning materialsin other than ambient laboratory environments, a temperatue/vapor-level-controlled environmental conditioning chamber isrequied that shall be capable of maintaing the required

5 - 5.

relative temperatue to with :!3 C (:!5 F) and the required

relative vapor level to with :!3 %. Chamber conditions shallbe monitored either on an automated continuous basis or on a

manual basis at regular intervals.6 Environmental Test Chamber-An environmental test

chamber is required for test environments other than ambienttesting laboratory conditions. Ths chamber shall be capable ofmaintainig the gage section of the test specimen with :!3(:!5 F) of the required test temperatue durng the mechancaltest. In addition, the chamber may have to be capable ofmaitaining environmental conditions such as fluid exposure orrelative humidity durig the test (see 11.4).

NOTE 4-If specimens are to undergo environmental conditionig toequilbrium, and are of such tye or geometr that the weight change ofthe material canot be properly measured by weighig the specimen itself(such as a tabbed mechancal specimen), then another traveler specimen(reference sample) ' of the same nominal thckness and appropriate size

(but without tabs) shal be used to ,determne when equilibrium has been

213

4255/D 4255M

reached for the specimens being conditioned.

8. Sampling and Test Specimens1 Sampling-Test at least five specimens per test condi-

tion unless valid results can be gained through the use of fewerspecimens, such as in the case of a designed experiment.Consult Practice E 122 to determne statistically appropriatesample sizes. The method of sampling shall be reported.

Geometry-The specimens are rectangular panels withrows of holes for rail clamping bolts to pass through. It isrecommended that laminates be 1.3 to 3.2 mm (0.050 to 0.in.) thick. Thin lamnates buckle at low loads while thickerlaminates can have shear strengths exceeding the rail-clampingcapacity. Thicker specimens are preferred for strength mea-surements because of their higher buckling stabilty. Howeverthicker specimens may not permt spacing of strain gagerosettes four specimen thicknesses from the rail edges, asspecified in 7.4. 1. The mandatory specimen requirements aredescribed in 8. 1 and 8.

1 Two-Rail Shear Procedure-The recommended testspecimen shall conform to the dimensions shown in Fig. 6 (SIunits) or Fig. 7 (inch-pound units) and ASTM AdjunctADJD4255. Specimen flatness is essential to minimize thelikelihood of buckling. Note that while the sample outerdimensions are uniform, many varations of hole patterns andtabbed edges have been used. See 8.3 and 8.4.

2 Three-Rail Shear Procedure-The t specimen shallconform to the dimensions shown in Fig. 8 (SI units) or Fig. 9(inch-pound units) and ASTM Adjunct ADJD4255. Specimenflatness is essential to minimize the likelihood of buckling.

3 Use of Tabs-Tabs are not required. The key factor inthe selection of specimen tolerances and gripping methods isthe successful introduction of load in the specimen and theprevention of premature failure as a result of slipping. There-fore, the need to use tabs and specification of tab designparameters shall be determned by the end result: acceptablefailure mode and location. If acceptable failure modes occurwith reasonable frequency, then there is no reason to change agiven gripping method.

8.3. 1 Tab Geometry-Tab thickness may var, but is com-monly 1.5 mm (0.06 in.) The selection of a tab configurationthat can successfully produce a gage section failure withoutslipping is dependent upon the specimen material, specimenply orientation, and the type of grips being used. For alignmentpurposes it is essential that the tabs be of matched thcknessesand the tab surfaces be parallel.

2 Friction Tabs-Tabs need not always be bonded to thematerial under test to be effective in introducing the load intothe specimen. Friction tabs, essentially nonbonded tabs held inplace by the pressure of the grip, and often used with emerycloth or some other light abrasive between the tab and thespecimen, have been successfully used in some applications. Inspecific cases , lightly serrated wedge grips have been success-fully used with only emery cloth as the interface between thegrip and the specimen. However, the abrasive used must beable to withstand significant compressive loads. Some types ofemery cloth have been found ineffective in this application asa result of disintegration of the abrasive.

8.3.3 Tab Material-When tabs are used, the most com-

monly used materials are steel and continuous E-glass fiber.reinforced polymer matrix materials (woven or unwoven),

ina(0/90)ns laminate configuration.

4 Adhesive Material-Any high-elongation (tough) ad.

hesive system that meets the environmental requirements mar

be used when bonding tabs to the material under test. Auniform bondline of minimum thickness is desirable to reduceundesirable stresses in the assembly.

8.4 Bolt Holes- larger number of smaller holes may used in each rail pair to improve specimen clamping. Up eight holes have been used successfully. The holes as shoWlare oversize to the bolts, although press-fit bolts have beenused with success , particularly with tabbed specimens.

5 Specimen Preparation:1 Panel Fabrication-Control of fiber alignment

important. Improper fiber alignment wil reduce the measuredproperties. Improper fiber alignment will also increase thecoeffcient of variation. Suggested methods of maintainigfiber alignment have been discussedY The panel preparationmethod used shall be reported.

2 Machining-The straight edges of the specimen mayhave coarse tool marks from the machining operation. How.ever, the holes should be drilled and reamed if minor delam.nation occurs.

3 Labeling-Label the specimens so that they wil distinct from each other and traceable back to the raw materialand in a manner that wil both be unaffected by the test and notinfluence the test.

ill

9. Calibration

1 The accuracy of all measuring equipment shall havecertified calibrations that are current at the time of use of the

equipment.

10. Conditioning

10. 1 Standard Conditioning Procedure-Unless a differentenvironment is specified as part of the experiment, conditionthe test specimens in accordance with Procedure C of Test

Method D 5229/D 5229M and store and test at standarlaboratory atmosphere (23 :! 3 C (73.4 :! 5.4 F) and 50 :t10 % relative humidity).

11. Procedure11. 1 Parameters to Be Specifed Before Test:11. 1 The shear specimen sampling method, specimen type

and geometry, and conditioning travelers (if required).11. 2 The shear properties and data reporting format de-

sired.

NOTE 5-Determine specific material property, accuracy, and reporting requirements before test for proper selection of instrumentanOnand data recording equipment Estimate operating stress and strain eIs

to aid in transducer selection , calibration of equipment, and detennnanonof equipment settings.

11. 3 The environmental conditioning test parameters.11. 4 If performed, the sampling method, specime geoJI

etry, and test parameters used to determne densIty anreinforcement volume.

11.2 General Instructions:11. 1 Report any deviations from this test method, wheth

214

4255/D 4255M

l aintentional or inadvertent.

11. 2 If specific gravity, density, reinforcement volume, orvoid volume are to be reported , then obtai these samples fromthe same panels as the test samples. Specific gravity anddensity may be evaluated by means of Test Methods D 792.Volume percent of the constituents may be evaluated by one ofthe matrix digestion procedures of Test Method D 3171 , or, forcertain reinforcement materials such as glass and ceramcs, bythe matr bur-off technque of Test Method D 2584. Voidcontent may be evaluated from the equations of Test MethodD 2734 and are applicable to both Test Methods D 2584 andD3171.

11.2.3 Condition the specimens, either before or afer straingaging, as required.

NOTE 6-Gaging before conditionig may impede moistue absorptionlocaly underneath the strai gage, or the conditioning environment maydegrade the strain gage adhesive, or both. On the other hand , gaging

conditioning may not be possible for other reasons, or the gaging activityitself may cause loss of conditioning equilibrium. The timing on when togage specimens is left to the individual application and shal be reported.

II-

11.2.4 Following final specimen machinig and any condi-tionig, but before the shear testing, measW'e specimen length1, the specimen dimension parallel to the rails; and thcknessto the accuracy in 7. , at thee locations in the gage section.Record the average values of the length and thckness mea-surements in units of rnlimetres (inches). Verify that the holepositions and sizes satisfy the specified tolerances.

11.2.5 Apply strai gages to the specimen (see 7.4) asshown in Figs. 6-9.

11.3 Rate of Testing-Set the rate of testing to effect anearly constant strain rate in the gage section. If strain control

is not available on the testing machie, this may be approxi-mated by repeated monitorig and adjusting the displacementrate to maintain a nearly constant strain rate, as measured bythe strai transducer. Select a strai rate to produce failurewithn 1 to 10 min from the beginnng of load application. Ifthe maximum strai of the material canot be reasonablyestimated, conduct initial trals using standatd rates until themaxmum strain of the material and the, compliance of thesystem are known, and the strain rate can be adjusted. Thesuggested standard rates are as follows:

11.3. 1 Strain- Controlled Tests-"A standard strain rate of01 min11.3.2 Constant Head-Speed Tests--A standard crosshead

displacement of 1.5mmlmi (0.05 in./mi).NOTE 7-Compliant tab materials can result in specimen strain rates

substatialy lower than apparent from crosshead speed. In some cases,actual strain rates 10 to 50 ties lower than estiated by crosshead speedshave been observed.

11.4 Test Environment-Condition the specimen to the de-sired moistue profile and,

if possible, test under the sameconditioning fluid exposure level. However, cases such aselevated temperatue testing of a moist specimen place unre-alstic requirements on the capabilties of common testingmachie environmental chambers. In such cases , the mechani-cal test environment may need to be modified, for example, bytesting at elevated temperatue with no fluid exposure controlbut with a specified limit on

tie to failure from withdrawal

from the conditionig chamber. Record modifications to thetest environment.

. "

11.4. 1 Store the specimen in the conditioned environmentuntil test tie, if the testing area environment is different thanthe conditioning environment.

11.4.2 Moistue loss durng mechancal testing may occur ifthe test environment is different from the conditioning envi-ronment. This loss can be minimized by reducing exposuretime in the test chamber although care should be taken toensure that the specimen temperatue. is at equilbrium. Fix-tues may be preheated, the temperatue may be ramped upquickly, and the hold time at temperatue may be minizedprior to testing. Environmentally conditioned travelers may beused to measure moistue loss during exposure to the testenvironment. Weigh a traveler before testing and place it in thetest chamber at the same time as the specimen. Remove thetraveler immediately after fractue and reweigh it to determemoisture loss.

11.4.3 Monitor the test temperature by placing an appropri-ate thermocouple within 25 mm (1.0 in.) of the specimen gagesection. Maintain the temperatue of the specimen, and thetraveler, if one is being used, for thermal strain compensationor moisture loss evaluation, withn :!3 C (:!5 F) of therequired condition. Taping thermocouple(s) to the test speci-men (and the traveler) is an effective measurement method.

11.5 Fixture Installation:

NOTE 8-The following procedure is intended for vertcal testingmachies.

11.5. 1 Two-Rail Test Procedure:11.5. 1.1 Inspect the fixtue. Examne the fixtue for signs of

wear on the rails, bolt holes, load plate, tensile head, andconnecting pins.

11.5. 1.2 Attach the tensile heads to the upper and lower testmachie heads.

11.5.2 Three-Rail Test Procedure:11. 1 Inspect the fixtue. Examne the fixtue for signs of

wear on the rails, bolt holes, and center rai guide hole.11.5. 2 Mount the base on the lower test frame head.

Mount hardware required for pressing on the center rail withtht: upper tesfmachine head. ,

11.6 Specimen Insertion:11.6. 1 Two-Rail Test Procedure:1 1.6. 1 Place the specimen between the pais of rails. Align

pais of rails ' with each other by inserting the connecting pins.Insert lO-nu (%-in.) socket head cap screws through the railsand specimen holes and put on high-strength nuts loosely.Place a 12. mI (V2-in.) spacer between opposite pairs of rails.Align the rails with the specimen. Ensure that there is' nobearng contact in the direction of loading between the screwsand the specimen holes. Tighten the nuts fingertight. Torque thebolts to 7 to 70 N-m (5 to 50 Ibf-ft) (Note 9). Then torque eachbolt to 100 N-m pOlbf-ft). Use of a fixture to position the railsand sample is helpful.

NOTE 9-Tightening the bolts or screws is yery important; actual torquevalues may var with materials or rail guides, or both. The most importantfactor is to tighten the rails uniormy. Overtghtening must also beprevented. It is recommended that a fixed pattern of tightening beestablished and that the bolts be torqued in thee stages: fingertght, then

215

4255/D 4255M

one quarer the final torque, then tighten to the final torque. An additionalcheck of each bolt is advisable to see that all the bolts are at the establishedtorque.

11.6. 1.2 Mount the clamped specimen and rails between theloading heads and check for alignment of the test fixtue in a

vertical plane though the axis of load application.

11.6. 1.3 Attach the strai recording instrmentation to thestrai gages on the specimen.

11.6.2 Three-Rail Test Procedure:11. 1 Place the specimen between the pais of rails on the

base. Insert lO-mm (3f-in.) socket head cap screws through thefront rails, specimen, and into the rear rails. Ensure that thereis no bearng contact in the direction of loading between the

screws and the specimen holes. Torque each screw to 7 to 70N-m (5 to 50 IbMt) (Note 9). Torque each screw to 100 N-m(70 Ibf-ft). Insert the rear center rail though the guide hole.

Place the front center rail on the other side of the specimen andfasten them together with socket head cap screws as for theside rails previously stated.

11. 2 Place the test fixtue with specimen in the testingmachine takng care to align the center rail with the movable

member of the machine. Algnment can be improved by usinga spherical seat between the load head and center rail ifcompression loading is used.

11.6.3 Attach the strain recording instrentation to the

strain gages on the specimen.11.7 Loading:11. 1 Preload-Preload the specimen and fixtue (less than

5 % of failure load) and release to align the heads and rails andzero the strain gages.

11.7.2 Load the specimen at the specified rate until failure,while recording data.

11.8 Data Recording-Record load versus strai continu-

ously or at frequent regular intervals. If a transition region orinitial ply faiures are noted, record the load, strain, and mode

of damage at such points. If the specimen is to be faied, record

the maxmum load, the failure load, and the strain (or trans-ducer displacement) at, or as near as possible to; the moment offailure. Termnate the test at 5 % shear strain.

NOTE 10-0ther valuable data that can be useful in understadingtesting anomales and grpping or specimen slipping problems includesload versus head displacement data and load versus time data.

11.8. 1 A difference in the stress-strai or load-strain slopefrom opposite faces of the specimen indicates bending in thespecimen. For the elastic property test results to be consideredvald, percent bending shall be less . than 10 % as determned byEq 1. Determne percent bending at the midpoint of the strainrange used for chord modulus calculations (see 12.4. 1). The

same requirement shall be met at failure strai for the strengthand strain-to-faiure data to be considered valid. This require-ment shall be met for all specimens requirng back-to-back

strain measurement. If possible, a plot of percent bendingversus average strain should be recorded to aid in the determ-nation of failure mode.

) -Ex 100 :S 10 E)

where:

percent bending in specimenindicated strain from Gage 1indicated strain from Gage 2 , and

ave = average strain (E ) + E )12 at the data point closest tothe strain checkpoint for bending.

11. 2 Rapid divergence of the strain readings on the

opposite faces of the specimen or rapid increase in percent

bending is indicative of the onset of instability. For shear

property calculations discard all data for loads higher than thebuckling load at or immediately prior to failure.

11.9 Record the mode of failure.

12. Calculation

12. 1 Before calculating material properties, examine the

strain data to confirm that an acceptable state of shear strain

was induced in the specimen and to determine if buckling

occurred. The strains in the zero-degree direction as shown in

Figs. 6-9 should remain small compared to the magnitudes the :!45 strains. If the zero degree strain magnitudes are

greater than 10 % of the :!45 strain magnitudes material

properties , calculations should be based on calculated values ofmaximum shear strains. Also report the values and directions

of principal extensional strains. Strain transformation equa-

tions are available in many stress analysis textbooks , for

example , Footnote 11.12.2 Ultimate Shear Stress/Shear Stress:

12. 1 Two-Rail Shear Procedure-Calculate the ultimate

in-plane shear stress as the lesser of the maximum shear stress

before failure and the shear stress at 5 % shear strain. Use 2 and report the results to three significant digits. If the shear

modulus is to be calculated, determine the shear stress at each

required data point using Eq 3.

F' pmax

i = PiA

(2)

(3)

where:

maxultimate shear stress , MPa (psi);

= load carred by a test specimen that is the lesser of

(1) the maximum load before failure , (2) the load at

5 % shear strain, or (3) the load at the bending limit(see 11. 1), N (lbf);shear stress at the ith data point, MPa (psi);

= load at ith data point, N (lbf); andcross-sectional area at test section calculated as the

product of the average length and average

thickness, 2 (in.

12. 2 Three-Rail Shear Procedure-Calculate the ultimate

in-plane shear stress as the lesser of the maximum shear streSS

before failure and the shear stress at 5 % shear strain. Use 4 and report the results to three significant digits. If the shear

modulus is to be calculated, determine the shear stress at each

required data point using Eq 5.

'T '

F' max/2A

(4)

(5)

(1)i = P/2A

where:ultimate shear stress strength , MPa (psi);

216

Jsest to

on thepercentIr shear

than the

tine the

IT strain

mckling10wn intudes ofIdes are

materialalues ofrectionsn equa-

)ks, for

ultimatear stress

Use Eq

1e shear

at each

(2)

(3)

sser of

load at19 limit

:I as the

lverage

ultimatear stress

Use Eq

he shear

: at each

4255/D 4255M

= load cared by a test specimen that is the lesser of(1) the maximum load before failure, (2) the load at5 % shearstrain, or (3) the load at the bending limit(see 11.8.1), N (lbf1;shear stress at the ith data point, MPa (psi);

= load at ith data point, N (lbf1; andcross-sectional area at test section calculated as theproduct of the average length I, and average

thickness h, 2 (in?).

12.3 Shear Strain/ltimate Shear Strain-If shear modulusr ultimate shear strain is to be calculated, determe the shearstrai at each required data point from the indicated normalstrains at +45 and - at each required data point using Eq 6.Report the results to thee significant digits.

1'.

"Ii = IE +45 1 + IE-45

where:

"Ii

+45

shear strain at ith data point, /lE= normal strain in the +45 direction at ith data point

/lE, andE-45 = normal strain in the -45 direction at ith data point

/lE.12.4 . Shear Modulus of Elasticity:

12A. Chord Shear Modulus of Elasticity-Calculate thechord shear modulus of elasticity using Eq 8 , applied over a4000:! 200-/lE shear strain range, staring with the lower strainpoint in the range from 1500 to 2500 /lE, inclusive. Report theshear chord modulus of elasticity to thee significant digits.Also report the strain range used in the calculation. A graphicalexample of chord shear modulus is shown in Fig. 10.

12. 1 A different strain range must be used for materialsthat fai or exhbit a transition region (a significant change inthe slope of the stress-strai curve) at strain less than 6000 /lE.In such cases , the upper strain range value for the samplepopulation shall be determned after testing; defined as 90 % ofthe average value of the upper limit of the essentially linearregion, rounded downward to the nearest 500 /lE. Any presence

.2 20

(4)

(5)

10000 , 2000

of a transition region shall be reported, along with the strairange used.

Gchord = 6:r/I1'Y (7)

where:GchordLlT

(6)

= chord modulus of elasticity, GPa (psi),difference in applied shear stress between the twostrain points, MPa (psi), anddifference between the two shear strain points(nominally 0.004).

12A.2 Shear Modulus of Elasticity (Other Definitions)-Other definitions of elastic modulus may be evaluated andreported at the user s discretion. If such data are generated andreported, report also the definition used, the shear strain rangeused, and the results to thee significant digits. Test MethodE 111 provides additional guidance in the' determation ofmodulus of elasticity.

NOTE ll-An example of another modulus definition isthe secondarchord modulus of elasticity for materials that exhbit essentialy bilearstress-strain behavior. An example of secondar chord modulus is shownin Fig. 10.

12.5 Offset Shear Strength-If desired, an offset shear stressmay be determned from the shear stress versus shear-straincure. Translate the shear chord modulus of elasticity linealong the strain axis from the origin by a fixed strai value, andextend this line until, it intersects the stress-strain curve.Determne the shear stress that corresponds to the intersectionpoint and report ths value, to thee significant digits, as theoffset shear strength, along with the value of the offset strain.Fig. 10 shows a graphical example of offset shear stress where

(0.2 % offset) = 28 MPa.

Ll'Y

NOTE 12-In the absence of evidence suggestig the use of a moreappropriate value , an offset strain value: of 0.2 % is recommended.

12.6 Statistics-For each series of tests, calculate the aver-age value, standard deviation, and coeffcient of varation (inpercent) for each property determed:

Maximum

3000 40000

Shear Strain (PE)

FIG. 10 Ilustration of Modulus and Offset Strength Determination

217

4255/D 4255M

13 . 1.16 Relative humidity and temperature of the testing

laboratory.13 . 1.17 Environment of the test machine

environmental

chamber (if used) and soak time at environment.13. 1.18 Number of specimens tested.13. 1.9 Speed of testing.

13 . 1.20 Transducer placement on the specimen, transducer

type, and calibration data for each transducer used.13. 1.21 The strain gage type, resistance, size, gage factor

temperature compensation method, transverse sensitivity, lead-

wire resistance, and any correction factors employed.13. 1.22 Load-displacement and stress-strain curves for each

specimen.13. 1.23 Tabulated data of stress versus strain for each

specimen.13. 1.24 Individual strengths and average value, standard

deviation, and coeffcient of varation (in percent) for the

population. Note if the failure load was less than the maximumload prior to failure.

13 . 1.25 Individual strains at failure and the average valuestandard deviation, and coeffcient of varation (in percent) for

the population.13. 1.26 Strain range used for chord shear modulus determ-

X = ( xJln1=1

(8)

l = (L xT n (xi)/(n - I)i=l

cv= 100 x -/X (10)

where:= sample mean (average);

= sample standard deviation;= sample coeffcient of varation, %;= number of specimens; and= measured or derived propert.

13. Report

13. 1 All testing shall be reported in accordance with GuidesE 1434 and E 1309. The following information applies to theuse of these guides for reporting data from Test Method

D 4255/D 4255M. Report the following information, or refer-ences pointing to other documentation containing ths infor-mation, to the maximum extent applicable. (Reportg of items

beyond the control of a given testig laboratory, such as might

occur with material details of panel fabrication parameters,

shall be the responsibilty of the requestor):

13. 1 The revision level or date of issue of this test method.13. 1.2 The date(s) and location(s) of the test method.13. 1.3 The name(s) of the test operator(s).13. 1.4 Any varations to ths test method, anomalies noticed

durg testig, or equipment problems occurng durng testing.

13. 1.5 Identification of the material tested including: mate-rial specification, material type, material designation, manufac-

tuer, manufactuer s lot or batch number, source (if not from

the manufactuer), date of certification, expiration of certfica-

tion, filament diameter, tow or yar filament count and twist

sizing, form or weave, fiber areal weight, matrx type, prepreg

matr content, and prepreg volatiles content.13. 1.6 Description of the fabrication steps used to prepare

the lamnate including: fabrication star date, fabrication end

date, process specification, cure cycle, consolidation method,and a description of the equipment used.

13. 1.7 Ply orientation stackig sequence of the lamnate.13. 1.8 If requested, report density, reinforcement volume

fraction, and void content test methods, specimen samplingmethod and geometres, test parameters, and test data.

13. 1.9 Average ply thckness of the material.13. 1.10 Results of any nondestrctive evaluation tests.

13. 11 Method of preparng the test specimens, includig

specimen labeling scheme and method, specimen geometr,

sampling method, specimen cutting method, identification of

tab geometr, tab material, and tab adhesive used.

13. 1.12 Calibration dates and methods for all measurementand test equipment.

13. 1.3 Type of test machine, algnment data, and data

acquisition sampling rate and equipment type.13. 1.14 Dimensions of each test specimen.13. 1.15 Conditioning parameters and results, use of travel-

ers and traveler geometr, and the procedure used if other thanthat specified in this test method.

(9)

nation.13. 1.27 If another definition of modulus of elasticity is used

in addition to chord modulus , describe the method used, the

resulting correlation coeffcient (if applicable), and the strai

range used for the evaluation.13. 1.28 Individual values of shear chord modulus of elas-

ticity, and the average value, standard deviation , and coeffcient

of varation (in percent) for the population.

13 . 1.29 Individual values of offset shear strength with thevalue of the offset strain, along with the average

, standard

deviation, and coeffcient of varation (in percent) values for

the population.

13 . 1.30 Individual maximum shear stresses, and the aver-

age, standard deviation, and coeffcient of varation (in percent)

values for the population. Note any test in which the failure

load was less than the maximum load before failure.13. 1.31 Individual maximum shear strains and the average,

standard deviation, and coeffcient of varation (in percent)

values for the population. Note any test that was truncated 5 % shear strain.

13. 1.32 If transition strain is determned, the method of

linear fit (if used) and the strain ranges over which the linear fit

or chord lines were determned.13. 1.33 Individual values of transition strain (if applicabl

and the average value , standard deviation, and coeffcient of

varation (in percent) for the population.

13. 1.34 Failure mode and location of failure for each

specimen.13.2 The data reported with this test method include me-

chanical testing data, material identification data, and fib r, .

filler and core material identification data, and shall be

acco dance with Guides E 1434 , E 1309 , and E 1471 , respec-

tively. Each data item discussed is identified as belonging to

one of the following categories: (VT) required for reporting a valid test result, (VM) required for valid material traceability,

218

:ting

ntal

lucer

lctorlead-

each

each

1dardr the

mum

raluet) for

enn-

; used

, thestrain

, elas-licient

th the

mdardes for

aver-rcent)failure

rerage

rcent)lted to

lOd ofIlear fit

cable),ient of

reach

de me-

d fiber,I be inrespec-ging torting of

abil 1),

4255/D 4255M

(RT) recommended for maximum test method traceability, 13. 1.6 H32/K58, Progressive Damage

(R) recommended for maxmum material traceability, or (0) response shal be " 2 % offset strength.for optional data items. At a mium, the report shall includeal (VT) category items from Guide E 1434.

13. 1 Clarifcation of Guide E 1434 Responses for This

Standard:13. 1. Field AI, Test Method-The response shall be

either "D 4255-95" or "D 4255M-95," as appropriate.13. 1.2 Field A5, Type of Test-The response shall be

in-plane shear.13. 1.3 Field B2, Specimen Orientation-The response

shall be "13. 1.4 Block E, Transducer Block-Used twice; once foreach transducer.

13. 1.5 Block F, Specimen Geometry Block-F6 (reinorce-ment volume) may be actual values, or they may be thenomial or average value for the sample. F9 (area) is the actualarea.

Parameter-The

14. Precision and Bias

14. 1 Precision-The ASTM round-robin data indicates thatthe interlaboratory repeatabilty of an earlier version of the railshear test procedure was IOW. 12 However, round-robin data onths more detailed procedure are not yet available.

14.2 Bias-Bias canot be determned for ths test methodas no acceptable reference stadard exists.

15. Keywords

15. 1 composite materials; shear modulus of elasticity; shearproperties; shear strength

12 P. A. Lockwood

, "

Resulis of the ASTM Round Robin on the Rail Shear Testfor Composites, Composites Technology Review VoI3 No. 2, 1981, pp. 83-86.

ASTM International takes. no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such. rights, are entirely their own responsibilty

This standard is subject to revision at any time by the responsible technical commitee .and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments wil receive careful consideration at meeting of theresponsible technical commitee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Commitee on Standards, at the. address shown below.

This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTMat the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or service astm.org (e-mail); or through the ASTM . website(ww.astm. org).

219