Composite NDT and SHM for Spacecraft and Aircraft, Using ... Airworthiness Composites 2012.pdf ·...

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Airworthiness 2012 Slide 1 Copyright © 2012 JENTEK Sensors All Rights Reserved. Composite NDT and SHM for Spacecraft and Aircraft, Using MWM-Arrays Neil Goldfine, Andrew Washabaugh, David Jablonski, Zachary Thomas, and Christopher Martin JENTEK Sensors, Inc. 110-1 Clematis Avenue , Waltham MA 02453 Phone: 781-642-9666; Email: [email protected] www.jenteksensors.com April 5, 2012 2012 Aircraft Airworthiness & Sustainment (AA&S) Conference Baltimore, MD, April 2-5, 2012 MWM sensors and MWM-Arrays covered by issued and pending patents, including, but not limited to: 8,050,883; 7,994,781; 7,876,094; 7,812,601; 7,188,532; 7,183,764; 7,161,351; 7,161,350; 7,106,055; 7,095,224; 7,049,811; 6,995,557; 6,992,482; 6,952,095; 6,798,198; 6,784,662; 6,781,387; 6,727,691; 6,657,429; 6,486,673; 6,420,876; 6,380,747; 6,377,039; 6,351,120; 6,198,279; 6,188,218; 6,144,206; 5,966,011; 5,793,206; RE39,206 E.

Transcript of Composite NDT and SHM for Spacecraft and Aircraft, Using ... Airworthiness Composites 2012.pdf ·...

Airworthiness 2012 Slide 1Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Composite NDT and SHM for Spacecraft and Aircraft,

Using MWM-ArraysNeil Goldfine, Andrew Washabaugh, David Jablonski,

Zachary Thomas, and Christopher Martin

JENTEK Sensors, Inc. 110-1 Clematis Avenue , Waltham MA 02453

Phone: 781-642-9666; Email: [email protected]

April 5, 2012

2012 Aircraft Airworthiness & Sustainment (AA&S) ConferenceBaltimore, MD, April 2-5, 2012

MWM sensors and MWM-Arrays covered by issued and pending patents, including, but not limited to:8,050,883; 7,994,781; 7,876,094; 7,812,601; 7,188,532; 7,183,764; 7,161,351; 7,161,350; 7,106,055; 7,095,224; 7,049,811; 6,995,557; 6,992,482; 6,952,095; 6,798,198; 6,784,662; 6,781,387; 6,727,691; 6,657,429; 6,486,673; 6,420,876; 6,380,747;

6,377,039; 6,351,120; 6,198,279; 6,188,218; 6,144,206; 5,966,011; 5,793,206; RE39,206 E.

Airworthiness 2012 Slide 2Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Goals, Technical Approach and Funding

Goal is to develop: - High resolution damage and condition imaging for carbon fiber composite NDT- Volumetric stress sensing magnetic stress gages for composites

The MWM-Array is a linear drive eddy current sensor array construct - Can induce eddy currents in the linear fibers of carbon fiber composites- Use winding geometry changes to alter penetration depth and characterize damage

Detection/characterization of impact and other damage and monitoring of strain/stress as a function of depth and fiber orientation is accomplished by modeling the fiber properties/orientation/density/contact. Simplified models are being used now with advanced models still under development.

Funding- NASA for micromechanical model development and application to composite overwrapped pressure vessels (COPVs)

- Army for rotorblade NDT- Navy for NDT of aircraft composites

Airworthiness 2012 Slide 3Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Linear Drive Eddy Current Sensors

MWM® and MWM®-ArraysFA28 MWM-Array FA24 MWM-Array

(similar to FA26)

Parallel Architecture Instruments: GS-Durable and GS-HandHeld

Airworthiness 2012 Slide 4Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Micromechanical Model: Eddy Current Extension(Model under development in NASA Phase II SBIR)

Linear drive MWM-Array sensing of composite with conducting fibers and insulating matrix Model uses a composite cylinder assemblage

– Solve for field around a single fiber and extend to fiber bundle– Effective complex permeability and conductivity depend upon orientation

with respect to fiber axis, fiber density and fiber contact Focus on Carbon Fiber/Epoxy composites

perp

Fiber par

perp

Radius a

perp

par

perp

* *par perp o par f fv 0perp

Airworthiness 2012 Slide 5Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Uniaxial/Biaxial Specimens: Orientation Varied

Single element MWM sensor; 10 MHz– Air/shunt calibration– Sensor response highly directional– Highest response when fibers when

sensor drive oriented parallel to fibers

+45ºfibers

-45ºfibers

Uniaxial fibers

For the uniaxial specimen, both the magnitude and phase of the sensor response are significant every 180º

Signal Variation During Rotational Scan

Graphite fiber epoxy composite samples provided by Boeing

Uniaxial specimens

Biaxial (±45°) specimens

FS33 drive perpendicular to

uniaxial fibers

Airworthiness 2012 Slide 6Copyright © 2012 JENTEK Sensors

All Rights Reserved.

10 kHz 1 MHz

Example Grids for the MWM FS35 Sensor and Aluminum

Measurement Grids for Simplified Model

Airworthiness 2012 Slide 7Copyright © 2012 JENTEK Sensors

All Rights Reserved.

MWM Sensor Selection

Skin depth:1f

increasing

0.1

2

3

4

56789

1

2

3

4

5678

Pen

etra

tion

Dep

th (m

m)

103 104 105 106 107 108 109

Frequency (Hz)

4

5678910

2

3

4

56789100

2

3

Penetration D

epth (mils)

FA28

FA24/FA26(based on drive width)

Electrical Conductivity(kS/m)

10

100

1

0.1

MWM-Array

FA24/FA26(based on sense position)

Magnetic field decays exponentially with distance away from sensor– Decay rate determined by skin depth at high freq. and sensor dimensions at

low frequency High frequencies needed to induce significant eddy currents Large dimensions needed for thick composites

Airworthiness 2012 Slide 8Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Quasi-isotropic Composite Panel Stackup

Stackup for bending test panel– Uniaxial properties for each layer

MWM-Array sensitive to composite layers with fibers oriented parallel to drive windings Composite layer considered insulating if fibers NOT

within 5º of sensor orientation This visualization indicates that each sensor

orientation is only sensitive to a subset of plies at varying depths within the composite.

MWM-Arrayh

0 DEGREES45 DEGREES90 DEGREES-45 DEGREES

eff

eff

eff

eff

eff

eff

eff

eff

MWM-Arrayh

MWM-Arrayh

eff

eff

eff

eff

eff

eff

eff

eff

eff

effeff

eff

effeff

eff

eff

eff

eff

eff

effeff

eff

eff

eff

MWM-Arrayh

MWM-Arrayh

MWM-Arrayh

MWM-Arrayh

MWM-Arrayh

MWM-Arrayh

0º orientation 45º orientation 90º orientation -45º orientation

Airworthiness 2012 Slide 9Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Simplified Grids for Quasi-isotropic Stackup

90º

-45º

45º

Std half-space

FS36/BD-MSG

90º-45º

45º

Std half-space

FS33

IncreasingLift-off

IncreasingConductivity

IncreasingLift-off

IncreasingConductivity

Grid size illustrates the effect of fiber orientation and distance from the sensor

The plots compare standard infinite half space grid to parameterized grids for each sensor orientation Sensitivity to a subset of plies causes a shift in effective property estimates compared to standard grids Smaller effective conductivities; effective lift-off can be high, lower, even negative, depending upon orientation

Airworthiness 2012 Slide 10Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Example COPV Stackup

Stackup for COPV and COPV ring specimen MWM-Array sensitive to composite

layers with fibers oriented parallel to drive windings This indicates that the sensor

orientation is important for assessing the fiber properties.

non-fiber orientationAl liner

MWM-Array

h

Al liner

MWM-Array

h

eff/2

eff/2

eff/2

±17º or ±18º orientationAl liner

MWM-Array

h

Al liner

MWM-Array

h

eff

eff

±90º orientationAl liner

MWM-Array

h

Al liner

MWM-Array

h

eff/2

±60º orientationAl liner

MWM-Array

h

Al liner

MWM-Array

h

Airworthiness 2012 Slide 11Copyright © 2012 JENTEK Sensors

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JENTEK Grids for MWM-Array on COPV Samples

72º

90º

Air

22º

Std half-space

FA24

IncreasingLift-off

IncreasingConductivity

72º

90º

Air

22º

Std half-space

IncreasingLift-off

IncreasingConductivity

FA28

Representative grids for a composite overwrapped pressure vessel (COPV) Models account for layered geometry and orientation effects on properties

within each layer

Airworthiness 2012 Slide 12Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Segmented Field Magnetometry

Different sensor geometries provide different penetration depths Segmented field sensors such as FA41 can provide two depths in a single scan Depth of sensitivity variation needed to characterize damage variation with depth Frequency variation alone is not sufficient

Skin depth:1f

0.1

2

3

4

56789

1

2

3

4

5678

Pen

etra

tion

Dep

th (

mm

)

103 104 105 106 107 108 109

Frequency (Hz)

4

5678910

2

3

4

56789100

2

3

Penetration Depth (m

ils)

FA28

FS36/BD-MSG

Electrical Conductivity(kS/m)

10

100

1

MWM-Array(based on sense position)

FA24/FA26

FS33

FA41 (far)

FA41 (near)

MWM-Arrayh

FS33

/FA2

8

FA41

(nea

r)

FS36

/BD

-MS

G

FA 4

1 (fa

r)/ F

A24/

FA26

Airworthiness 2012 Slide 13Copyright © 2012 JENTEK Sensors

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MWM-Arrayh

FA26, 90º

Damage regionFA26

0ºFA2690º

FA280º

FA2890º

Approach to Volumetric ImagingCombination of sensor orientation and geometry can help isolate depth and region

of damage: (i) sensor orientation determines plies, (ii) sensor geometry determines depth of sensitivity, (iii) spatial extent of damage determined from

scan image

Airworthiness 2012 Slide 14Copyright © 2012 JENTEK Sensors

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Volumetric Imaging of Composite Impact Damage

Representative MWM-Array Scan Image Sample provided courtesy of Lockheed Martin

Airworthiness 2012 Slide 15Copyright © 2012 JENTEK Sensors

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Representative Quasi-isotropic Panel Scan ImagesSubtractedAfter ImpactBefore Impact Subtracted and Smoothed

5 M

Hz

10 M

Hz

15.8

MH

z

Airworthiness 2012 Slide 16Copyright © 2012 JENTEK Sensors

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Summary Image Individual scans combined together to create composite cross-sectional view

Airworthiness 2012 Slide 17Copyright © 2012 JENTEK Sensors

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Cross Sectional Images: Panel 1, Low Impact Level

MWM-Array FA28 Data

Cross Sectional View along X-axis

Cross Sectional View along Y-axis

Airworthiness 2012 Slide 18Copyright © 2012 JENTEK Sensors

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Cross Sectional Images: Panel 2, Medium Impact Level

Cross Sectional View along X-axis

Cross Sectional View along Y-axis

MWM-Array FA28 Data

Airworthiness 2012 Slide 19Copyright © 2012 JENTEK Sensors

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Cross Sectional Images: Panel 3, High Impact Level

Cross Sectional View along X-axis

Cross Sectional View along Y-axis

MWM-Array FA28 Data

Airworthiness 2012 Slide 20Copyright © 2012 JENTEK Sensors

All Rights Reserved.

COPV Testing

TEST SETUP37-Channel Probe 7 Sensor

Rotary Table and Encoder

0.30 cal gunfire test

bottle

SCI AC-5251 S/N 005

SCI AC-5128A S/N 166

SCI AC-5250 S/N 030

See complimentary presentation:

“Continued Development of Meandering Winding Magnetometer (MWM®) Eddy Current Sensors for the Health Monitoring, Modeling and Damage Detection of Composite Materials”

Session: IVHM - Structural Health Monitoring for Damage DetectionPresentation time: Thursday, April 05, 20122:30 PM

Airworthiness 2012 Slide 21Copyright © 2012 JENTEK Sensors

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Rotation Scan of Vessels AC-5250 S/N:030FA28 MWM-Array Scan

FA24 MWM-Array Scan

FA28

FA24

Shallow/4 = 37 mils

Deeper/4 = 130 mils

Fiber orientation

Material

±9.5°±9.5°±72°90°90°90°

Carbon fiber compositeCarbon fiber compositeCarbon fiber compositeCarbon fiber compositeCarbon fiber compositeGlass fiber composite

0° 360°

360°

Manufacturer Fiber Layup

Airworthiness 2012 Slide 22Copyright © 2012 JENTEK Sensors

All Rights Reserved.

MWM-Array Low Freq. Lift-Off Scans on COPV

Sample AC5250-030; 90° Sensor drive orientation Higher impact energy results in larger dents in the aluminum liner Sensor: MWM-Array FA24

Preliminary FilteringBefore Impact Damage After Impact Damage Baseline Subtracted

axial

angu

lar 30 ft-lbs

~46 mils

15 ft-lbs~22 mils 10 ft-lbs

~6 mils

20 ft-lbs~26 mils

Lift-Off image shows liner damage; freq. 50.11 kHz

Airworthiness 2012 Slide 23Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Periodic Response to Woven Plies FA28 scanned over a Gr/Ep composite with a

coarse woven fabric ply near the surface The spatially periodic sensor response is

consistent with the woven fabric tow width– Distance between peaks ~0.09-in.– This corresponds to 11 oscillations/in.

Power spectrum density plot indicates strong spatial frequency near 11/in.

Magnitude of 1 channel with photograph of specimen

Airworthiness 2012 Slide 24Copyright © 2012 JENTEK Sensors

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MWM Response to Stress in 4pt BendingUnidirectional Carbon Fiber Composite

FA28 Tension

FA28 Compression

FA28

Microstrain

Con

duct

ivity

(%IA

CS)

As presented at NASA Sensors Tech Forum Boston, MA; October 10-12, 2011

Airworthiness 2012 Slide 25Copyright © 2012 JENTEK Sensors

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Tests run under NAVAIR SBIR at Lockheed Martin Aeronautics, Ft. Worth, TX

Surface-Mounted Sensor Damage MonitoringMWM-Array FA24

Airworthiness 2012 Slide 26Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Review: Goals, Technical Approach and Funding

Goal is to develop: - High resolution damage and condition imaging for carbon fiber composite NDT- Volumetric stress sensing magnetic stress gages for composites

The MWM-Array is a linear drive eddy current sensor array construct - Can induce eddy currents in the linear fibers of carbon fiber composites- Use winding geometry changes to alter penetration depth and characterize damage

Detection/characterization of impact and other damage and monitoring of strain/stress as a function of depth and fiber orientation is accomplished by modeling the fiber properties/orientation/density/contact. Simplified models are being used now with advanced models still under development.

Funding- NASA for micromechanical model development and application to composite overwrapped pressure vessels (COPVs)

- Army for rotorblade NDT- Navy for NDT of aircraft composites

Airworthiness 2012 Slide 27Copyright © 2012 JENTEK Sensors

All Rights Reserved.

Questions?

Phone: 781-642-9666Email: [email protected]

Website: www.jenteksensors.com