rotorcraft acoustics and dynamics group activities design and testing 3. ... presentation outline....

SPENN TATE1 8 5 5

Center for Acoustics and Vibration

Rotorcraft Acoustics and Dynamics

Group Activities

Edward C. Smith, ProfessorDirector, Penn State Vertical Lift Research Center

CAV Group Leader

Steve Conlon, Res Associate, PSU ARLAssistant Professor, Aerospace Engineering Dept

Assoc. Director, Vertical Lift Research Center

2011 CAV Workshop

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Interaction with Other PSU Research Centers

Vertical Lift Research Center

of Excellence

National Centerfor Advanced

Drivetrain Technology

ARL

Condition BasedMaintenance Dept.

Centerfor Acoustics

andVibration

Institutefor

ComputationalScience Composites

ManufacturingTechnology

Center

ARL

ARLiMAST

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Vertical Lift Center Tech Base

31Faculty

60 +GraduateStudents

100 Undergraduate

Students(Freshman Sem, AHS Chapter,Senior Class, Design projects)

40 ContinuingEducationStudents

(Short course)

5Res Assoc

Penn State ARLNRTC CRI

SBIR Programs

apply & transition

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VLRCOE Research Portfolio: 2011

1. ROTOR AEROMECHANICS & DYNAMICS

2. AIRFOIL DESIGN and TESTING

3. COMPUTATIONAL FLUID DYNAMICS

4. ACOUSTICS

9. FLIGHT CONTROLS and SIMULATION

8. PROPULSION and DRIVE SYSTEMS

5. STRUCTURES, MATERIALS, and MANUFACTURING

7. ICE PROTECTION

6. CONDITION-BASED MAINTENANCE

10. DUCTED FAN AIR VEHICLES11. VARIABLE SPEED (RPM) & COMPOUND ROTORCRAFT

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Group Highlights (5 min)

Preparation and Submission of 2011-2016 VLRCOE Renewal Proposal

Individual Project Highlights

- Multi-State Damper: Design and Test (5 min)- Ultrasonic Anti-Icing: Recent progress (5 min)

- Airframe Structural Health Monitoring (15 min)(Prof. Steve Conlon)

Presentation Outline

SPENN TATE1 8 5 5

VLRCOE Renewal Proposal (aka 5 year storm)

25 Separate Tasks31 PIs (PSU, PSU ARL, Michigan (1), UT Austin (1))40 Graduate Students5 years (20011-2016)$25M Total (12.5M from sponsor: NRTC = Army + Navy + NASA)

Partners (proposal cost share)LORD Corp SikorskyGoodrich BellTimken Aerospace GyrodyneMagCanica Inc Penn State University

Group Highlights

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Aeromechanics: More Speed, More fuel efficiency, all weatherUnsteady Airfoil Design MethodsRotor Hub Flows > Drag reductionNew Rotorcraft Airfoil Design ConceptsIcing Physics, Modeling, Detection

Structures: Lower weight, more reliability, safetyNanotailored Composites> Improved Toughness and Thermal

ConductivityNovel SMA Based Energy AbsorbersInterfacial Fracture and Functional Grading > Ultrasonic DeicingFrequency Selective Rotor Lag Damping

Flight Dynamics & control: autonomy, safety, new configsAutonomous Multi-Lift SystemsLoad Limiting Flight Controls for Co-axial Rotors

Group Highlights: VLRCOE Renewal tasks

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Design Concepts: Speed, range, altitudeMorphing Rotor Blades and WingsAeroelastically Tailored wing extensions and Winglets

> Large Civil TiltrotorsControl Redundancy> Perf, HQ, and SurvivabilityReduced Actuation Reqs and HQ of Swashplateless Rotors

Vibration & Noise Control: active rotors, variable rotors, speedFund Physics of Active Rotors > Perf and AcousticsMulti-functional Trailing edge FlapsTunable Fluidlastic Structures > Vib control & energy harvestMultifunctional Fluidlastic Picth Links> active rotors, energy harvest, loads

control


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Propulsion and Drive Systems: weight, reliability, interior noise reduction

Comprehensive Anal of Gearbox Loss of LubeGearbox Health Monitoring and Loads Management via Piezo-

magneto-elastic control systemsMultifunctional Radial Isolator > bearing HUMS and Noise Red

Affordability: condition-based maintenance, SHM, etcHealth Monitoring for Joints in Composite StructuresStructural Tailoring for High Sens Robust Damage Detection

Maritime Operations: shipboard ops, dynamic interface, slung loads, etc

Advanced Response Types and Cueing Systems for Naval Ops

Autonomous Shipboard Take-Off and Landing


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Group Highlights


- Multi-State Damper: Design and Test- Ultrasonic Anti-Icing: Recent progress

- Airframe Structural Health Monitoring(Prof. Steve Conlon)


SPENN TATE1 8 5 5

Multi-State Lead-Lag Damper Development and Validation

Conor Marr, PhD Candidate, Penn StateZach Fuhrer, Senior Engineer, LORD Corporation

Edward C. Smith, Professor, Penn StateGeorge A. Lesieutre, Professor, Penn State

AHS International 67th Annual Forum and Technology DisplayTest and Evaluation ITuesday, May 3, 2011

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Objectives

Design, construct, and experimentally validate a first generation prototype of a passive or semi-active LORD Fluidlastic bypass damper that greatly reduces damper forces when damping is not required

An adaptable lag damper could greatly reduce the forces seen both by the damper and the blade and hub attachment points.

Longer damper life, smaller lower drag parts, lighter dampers

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Approach: Experiment

Design damper to meet damping requirements for a generic light helicopter

Reduce damper force by at least 50% via a bypass feature

Conduct a series of experimental bench tests to evaluate the damper performance with bypass channels open and closed

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Approach: Analysis

Predict damper behavior using basic analytical fluid flow equations

Develop a CFD model of the bypass damper

Validate models with experimental data

Use findings to work towards ultimate goal of developing a first-principles model that incorporates CFD correction factors

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Experimental Prototype

Parameter English MetricPiston

Diameter 2.74 in 0.07 m

Bypass Diameter 3 x 0.4 in 3 x 0.01 m

Adjustable number of orifices (max of 2) and orifice diameter

Bypass channels able to be open or closed

Adjustable number of bypass channels (max of 3)

Bypass inlet diameter alterable up to 0.4 inches in diameter

Closed state meets light helicopter damper requirements

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CFD Model

Bypass Channel

Annular Gap

PistonRestrictive

Orifice

Ansys Workbench meshing utility used to create geometry and mesh

Full 3 dimensional model

Fluent used to calculate fluid flow

Transient flow and dynamic meshing utilized

Carreau equation for shear thinning captures nonlinear fluid behavior:

( ) ( )( )

++=

2

12

inf0inf 1n

act

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CFD Results: Bypass Closed

Velocity Magnitude pictured over a single cycle for 2.5 Hz at 0.06 dynamic displacement

Closed bypass channel case

2D cross section of 3D calculation

Flow is almost exclusively through the orifice

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CFD Results: Bypass open

Velocity vectors at orifice and bypass entrance/exit

Flow is split between bypass channel and orifice

3 bypass channels with a diameter of 0.1 inches reduce damper force by approximately 50%

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Results: Comparison with CFD

4 Hz at 0.06 Bypass Closed

CFD Model: 10% error for Peak Force, 15% error for Loss Stiffness

Analytical Model: 45% error for Peak Force, 82% error for Loss Stiffness

-1500

-1000

-500

0

500

1000

1500

-0.08 -0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08

Position (in)

Forc

e (lb

f) Experiment

CFD

Analytical

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2.5 Hz at 0.06 Bypass Open

-300

-200

-100

0

100

200

300

-0.08 -0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08

Position (in)

Forc

e (lb

f) Experiment

CFD

Analytical

Both CFD and Analytical models predict a near elimination of damping when three 0.4 diameter bypass channels are opened

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2.5 Hz at 0.06 Bypass Open

-300

-200

-100

0

100

200

300

-0.08 -0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08

Position (in)

Forc

e (lb

f) Experiment

CFD

Analytical

Main source of error due to lack of damping from the elastomerin the CFD and analytical models

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Ultrasonic De-Icing Concept

CF

DragIce

Leading Edge Protection Cap

Piezoelectric actuators used to create ultrasonic waves which generate transverse shear stresses at the ice interface

a

a

SPENN TATE1 8 5 5

Ultrasonic De-Icing Concept

CF

DragIce

Leading Edge Protection Cap

Piezoelectric actuators used to create ultrasonic waves which generate transverse shear stresses at the ice interface

a

Leading Edge Mass (10 20% Weight of the Blade)

a

1

Substitute with Active Piezoelectric Material

2

aa

SPENN TATE1 8 5 5

Ultrasonic De-Icing Issues

Issue Proposed SolutionLimited control of matching ultrasonic modes

Actuator Cracking Failure

Actuator Debonding

PZT Actuation Controller

Drive Actuators in Compression

Optimal Thickness Actuators

SPENN TATE1 8 5 5

PZT Actuation Controller Design

Design Goal: Develop a program to autonomously check the ultrasonic modes of a PZT actuator and drive the actuator at the optimum ultrasonic mode

Variations in Ultrasonic Modes due to:

Loading ConditionsAmbient TemperatureActuator TemperatureBoundary Conditions

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Thickness Reduction

Predicted thinner actuators would not delaminate due to lower inertia forces

Modeled 0.10 vs. 0.05 Thick Disk Actuators to compare transverse shear stresses at the PZT/Glue interface

EP 21 Adhesive- 0.01 Thick=1078 kg/m3E=2240 MPa, =0.3

PZT-4 Disk 1.5 Diameter

Ti Plate 6x6x0.04

70 V

140 VApplied Voltage

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Thickness Reduction

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Rotational Test Setup

~NACA 0024, 6 Chord

Outer Airfoil: NACA 0015, 16 Chord

23.5

12

5

Test Specimen

Taper Section

Grip Attachment

Test Specimen: 12 Span, 16 Chord, NACA 0015 AirfoilInterchange leading edge cap/actuation systems

Ultrasonic Deicing System Tested on Representative Leading Edge Erosion Cap

Thin PZT-4 Disk1.5 Diameter, 0.05 Thickness (x12)Total Volume = 1.07 in2Radial Mode Frequency = 65-66 kHz

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Ice Accretion (2mm)

NACA 0015 Ti Leading Edge Erosion Cap

10.6 cm

Finite Element Model Setup

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Finite Element Results

Transverse shear stresses at the ice interface exceed published results for the adhesion strength of Ice-Ti (250kPa-875kPa)

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Rotational Test Matrix

A total of 4 Impact Icing Test Conducted

Tested at 2 Temperatures (-12 C, -18 C)

Constants RPM: 320 MVD: ~25 m LWC: ~3.5 g/m3

Total icing time dictated by the rotor imbalance load limitations

The Ice Thickness measured on Blade without ultrasonic deicing system

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Rotational Test Matrix

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Sample Results: Case 4

Icing ConditionsTemp: -18.2 CMVD: ~25 mLWC: ~3.5 g/m3RPM: 320

No Ultrasonic De-Icing System Ice Thickness: 0.431

Ultrasonic De-Icing SystemPower: 1.48 W/in2Deicing Time : 139 s

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Sample Results: Case 4

Icing ConditionsTemp: -18.2 CMVD: ~25 mLWC: ~3.5 g/m3RPM: 320

No Ultrasonic De-Icing System Ultrasonic De-Icing SystemPower: 1.48 W/in2Deicing Time : 139 s

Heaters to Prevent Ice Bridging to Test Section

SPENN TATE1 8 5 5

Group Highlights

Preparation and Submission of 2011-2016 VLRCOE Renewal Proposal


- Multi-State Damper: Design and Test- Ultrasonic Anti-Icing: Recent progress

- Airframe Structural Health Monitoring(Prof. Steve Conlon)


ARLPenn State

1

Overview of Recent Rotorcraft Structural Health Monitoring

/ Damage Detection Research Activity

9 May 2011

Center for Acoustics & Vibration

20th Annual Spring Workshop

Penn State Vertical Lift Research Center of Excellence

Stephen C. ConlonResearch Associate Applied Research Laboratory

Associate Director Vertical Lift Research Center of Excellence814-863-9894

[email protected]

ARLPenn State

2

Recent & OngoingSHM / CBM Projects

6.1 (SHM / Damage Detection)Rotor blade damage detection (CRI, 3 yrs)SI based damage detection (CRI, 2 yrs)

6.2 (SHM / Damage Detection)Intensity based airframe SHM (AATD, 2 yr)

6.2+ (SHM)OH-58D Tailboom damage detection study (PEO, 6 mo)

ARLPenn State

3

Recent SHM Developments

Airframe SHM Technology Development Overview:

1. Airframe Intensity Based Structural Health Monitoring, Aviation Applied Technology Directorate (AATD) U. S. Army Research, Development and Engineering Command Ft. Eustis, Virginia

2. OH-58 Tailboom Damage Detection Study, PEO US Army Aviation & Missile Command, SFAE-AV-ASH-KW, Redstone Arsenal

ARLPenn State

4

3f

Nonlinear Vibration Based Damage Detection

2 f 3 f

f

Considering a cracked rod subjected to an external dynamic axial load:

52

f32

f2f

Subharmonics and Ultra-subharmonics

The Subharmonics components are characterized by a threshold behavior, - they are not generated below a certain amplitude of the external driving force.

f

F. Semperlotti, K.W. Wang, E. C. Smith, Identification of the location of a breathing crack using super-harmonic response signals due to system nonlinearity, AIAA J., 47 (9), (2009).

ARLPenn State

5

Structural Intensity Based Damage Detection

Point source

Point sink

dB (r

e 1

Wat

t/N)

SI maps of plate driven at resonance frequencies

Frequency sweep from 135 Hz to 695 Hz, color bar indicated SI magnitude in dB, unit vectors indicate SI direction

(Damaged Structure)

For SHM implementation local sensors / sensor arrays will detect damaged induced changes to SI magnitude and direction

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Damage source

Point sink

Damage source

Point sink

Source due to harmonic distortion in drive / actuator system

xxxx

Frequency

Nonlinear Structural Intensity Based Damage Detection

Damaged Structure: Sub-harmonic vs Super-harmonic Vibration

The resonance growth of the modes is affected by the amplitude and frequency hysteresis & instability

Contact Acoustic Nonlinearity (CAN)Excitation Frequency

2f

F. Semperlotti and S.C. Conlon, Structural damage identification in plates via Nonlinear Structural Intensity maps, Journal of the Acoustical Society of America 127(2), EL48-EL53, 2010.

F. Semperlotti and S. C. Conlon, Nonlinear structural surface intensity: an application of contact acoustic nonlinearity to power flow based damage detection, Appl. Phys. Lett., 97, (2010)

ARLPenn State

7

Intensity Based Structural Health MonitoringTechnology Discussion

Issue:Rotorcraft airframe elements can experience critical fatigue loading during their usage life. The development and implementation of enhanced structural diagnostics techniques will directly support the Army Aviation S&T Mission

Objectives:Structural intensity based SHM approach for airframe structural damage detection was investigated

Program Solution:Study the fundamental energy flow mechanisms of vibrating structures

Develop simulation & experimental techniques to determine sensitivities for detecting and localizing structural damage

Apply techniques to representative rotorcraft airframe structure / typical damage flaws for detection performance validation

ARLPenn State

8

Structural Intensity BasedSHM System Overview

ARLPenn State

9

Why Airframe Structural Health Monitoring?

Goal of SHM development:

Develop technologies to provide critical actionable information, enabling a shift to airframe CBM

UH-60 Corrosion & Crack Locations Airframe and propulsion are

largest cost drivers

Inspection Activities

ARLPenn State

10

UH-60 Transmission Frame Primary Structural Element Cracking

Typical application of interest for Intensity Based SHM

Damage precursors fastener (rivets) loosening / damage, load / stress redistribution

Structure (frame strap) fatigue crack initiation & growth

Transmission Support and Attachment Structure

Region of interest: FS360 / BL 16.5

FS360

Fwd

(J.Cycon , SHM Activities and Needs for Sikorsky Products,PSU SHM Center of Excellence Meeting , Nov 2007)

ARLPenn State

11

Development and Verification / Validation Test Beds

d)

c)

a&b)

Incr

easi

ng C

ompl

exity

Plate & stiffened plate Study/insight SI for healthy &

damaged structures Discrete sensor development

/ implementation Algorithm development Detection performance V&V

Transmission frame joint mock-up

Technology transition to more complex substructure

Detection performance V&V

UH-60 upper cabin structure

Technology transition to airframe complex structure


Structural Complexity

Homogeneous plate

Plate + stiffener

I-beam frame structure

Joint strap w/ fasteners

Real aircraft structure Skin Stiffeners / ribs Riveted joints

ARLPenn State

12

Verification and Validation Test Beds: Transmission Frame Mock-up


Example - critical region of interest: FS360 / BL 16.5

FS360Electrodynamic shaker (out-of-plane excitation)

PZT actuator (in-plane excitation)

Straps loose fastener progression and strap crack progression for damage detection measurements

ARLPenn State

13

Verification and Validation Test Beds: UH-60 Upper Cabin Structure


Example - critical region of interest: FS360 / BL 16.5

Fwd

(~ 8 ft)



ARLPenn State

14

xxxx

Frequency

UH-60 Roof Section:Nonlinear Structural Surface Intensity

Active InterrogationNSSI exploits the nonlinear response characteristics of certain types of defects such as fatigue cracks and loose riveted joints.

Damage

Interrogation Signal

(Shaker)

Nonlinear Harmonics

The interrogation signal (single tone continuous excitation) triggers the damage nonlinear dynamic response at subharmonic frequencies.

ARLPenn State

15

Structural Intensity Based SHM System: Application Results

Transmission Frame Test Structure UH-60 Upper Cabin Test Structure

Damage detection at all 4 corner joints on frame using single SSI sensor location, drive frequency approx. 2.48 kHz

x x x x

xx

Damage detection loose fasteners, BW 1.75 to 1.85 kHz

Damage discrimination, loose fastener vs crack, BW 5.5 to 5.8 kHz

Sensor to damage distance:Upper left < 6 inchUpper right = 33 inchLower right = 66 inch (path)

NSSI Feature

(Condition Indicator)

12 dB

16 dB10 dB

25 dB

F. Semperlotti, S. Conlon, and A. Barnard, Airframe Structural Damage Detection: A Nonlinear Structural Surface Intensity basedtechnique, Journal of the Acoustical Society of America 129(4), EL121-EL127, 2011.

ARLPenn State

16

OH58 Tailboom Damage Detection StudyTechnology Discussion

Issue:Fleet OH-58s are experiencing tailboom cracking / damage which requires inspections every 10 hrs

Objectives:Nonlinear intensity based SHM approach for airframestructural damage detection is being investigated

Program Solution:Transition / enhance NSSI techniques developed under 6.2 AATD effort

Apply & adapt experimental techniques to laboratory test beds for demonstrating detection capability (NSSI sensors & actuators)

Assess (1) use of current HUMS sensors/locations for damage detection use, (2) in-flight passive SHM

Define system technology transition plan / aircraft integration requirements for 6.3 Phase II effort

(Phase II) Deploy techniques to OH58 airframe structure / typical damage flaws for detection performance validation and system flight qualification

ARLPenn State

17

Tailboom SHM Testbeds

ARLPenn State

18

Damage grouped around several hot spots - hanger bearing mounts, tailboom mounts, gearbox mount

Crack

Working Rivet/Hardware

Golden Rivet

Maintenance/Damage

Other

OH58 Tailboom Damage Data Base Review

Inspection area is one inch either side and

3 inches above and below golden rivet

Designated inspection

area captures 10% of cracks

ARLPenn State

19

OH-58D HUMS

ACC 12HB #6

ACC 11HB #5

ACC 10HB #4

ACC 9HB #3 ACC 8

HB #2 ACC 7HB #1

ACC 5Tail GBX Axial

TAC 2Tail Rotor

ACC 4Tail GBX Radial

Honeywell CBM for KW has 15 Accelerometers and 5 Tachometers covering all

the rotating drive train components

ACC 1Fore/Aft

ACC 2Vertical

ACC 18Input Quill

TAC 3NR

TAC 1Main RotorACC 17XMSN

Mast Bearing

ACC 13Engine

Compress

TAC 5NGTAC 4

NP

ACC 14Engine GB

ACC 15Engine Turbine

Existing HUMS accelerometers potential for use / integration with embedded Tailboom SHM system

ARLPenn State

20

SHM Technology Development and Verification / Validation Test Beds

Plates & Connected Plates

Discrete sensor & algorithm development / implementation

Fatigue crack detection performance

OH-58 Tailboom Structures


Algorithm development Detection performance V&V

Structural Complexity

Homogeneous plate

Plate + lap joint / fastener line

Real aircraft structure Skin, conical

shell Stiffeners / ribs Riveted joints

Incr

easi

ng C

ompl

exity

ARLPenn State

21

Structural Intensity Based SHM System Damage Detection: APPLICATION RESULTS

OH-58D Test Structure Aluminum Skin (Fatigue Crack) Test Structures

Damage detection, exposed and hidden small fatigue cracks

Detection with actuator position both local & remote (through lap-joint)

High damage detection sensitivity - loose HB bracket: NSSI (bulkhead sensors), NLS (skin mounted), NLA (HUMS accels at brackets)

Good vibration response from skin & bulkhead mounted PZT actuators

Crack (hidden by joint)

Fastener line / lap joint

30 dB

20 dB

20 dB

ARLPenn State

22

Penn StateSHM Team

S. Conlon (ARL/Aero Eng), E. Smith (Aero Eng), J. Banks (ARL), S. Evans (Aero Eng)

F. Semperlotti (Ph.D., UMich), P. Romano (M.S., Bell), W. Schmidt (M.S., Sikorsky), B. Grisso (Post Doc, NSWC

Carderock), K. Brennan (M.S.)

M. Shepherd (ARL), J. Hines (ARL), A. Barnard (ARL), K. Reichard (ARL/Acoustics), S. Hambric (ARL/Acoustics)

J. Cote (B.S., Pratt & Whitney), P. DiBiase (B.S., NAVAIR Pax River), Justin Long (B.S.)

CAVWorkshop11_newSlide Number 1Interaction with Other PSU Research CentersVertical Lift Center Tech BaseSlide Number 4Slide Number 5Slide Number 6Slide Number 7Slide Number 8Slide Number 9Slide Number 10Slide Number 11Slide Number 12Slide Number 13Slide Number 14Slide Number 15Slide Number 16Slide Number 17Slide Number 18Slide Number 19Slide Number 20Slide Number 21Ultrasonic De-Icing ConceptUltrasonic De-Icing ConceptUltrasonic De-Icing IssuesPZT Actuation Controller DesignThickness ReductionThickness ReductionThickness ReductionRotational Test SetupFinite Element Model SetupFinite Element ResultsFinite Element ResultsRotational Test MatrixRotational Test MatrixSample Results: Case 4Sample Results: Case 4Slide Number 37

CAV_rotrcraft_SHM_2011_scc_postSlide Number 1Recent & OngoingSHM / CBM Projects Recent SHM DevelopmentsNonlinear Vibration Based Damage DetectionStructural Intensity Based Damage DetectionNonlinear Structural Intensity Based Damage DetectionIntensity Based Structural Health MonitoringTechnology DiscussionStructural Intensity BasedSHM System OverviewWhy Airframe Structural Health Monitoring?UH-60 Transmission Frame Primary Structural Element CrackingDevelopment and Verification / Validation Test BedsVerification and Validation Test Beds: Transmission Frame Mock-upVerification and Validation Test Beds: UH-60 Upper Cabin StructureSlide Number 14Structural Intensity Based SHM System: Application ResultsOH58 Tailboom Damage Detection StudyTechnology DiscussionTailboom SHM TestbedsSlide Number 18OH-58D HUMSSHM Technology Development and Verification / Validation Test BedsStructural Intensity Based SHM System Damage Detection: APPLICATION RESULTS Penn StateSHM Team

rotorcraft acoustics and dynamics group activities design and testing 3. ... presentation outline....

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