composite ndt and shm for spacecraft and aircraft, … airworthiness composites...-army for...
TRANSCRIPT
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
0º
90º
-45º
45º
Std half-space
FS36/BD-MSG
0º
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
All Rights Reserved.
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
All Rights Reserved.
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
All Rights Reserved.
Volumetric Imaging of Composite Impact Damage
Representative MWM-Array Scan Image Sample provided courtesy of Lockheed Martin
Airworthiness 2012 Slide 15Copyright © 2012 JENTEK Sensors
All Rights Reserved.
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
All Rights Reserved.
Summary Image Individual scans combined together to create composite cross-sectional view
Airworthiness 2012 Slide 17Copyright © 2012 JENTEK Sensors
All Rights Reserved.
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
All Rights Reserved.
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
All Rights Reserved.
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
All Rights Reserved.
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°
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
All Rights Reserved.
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
All Rights Reserved.
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