Steve Owens, R. L. Royer Jr. and Joseph L. Rose. FBS.Inc. Basavaraju B. Raju. U. S. Army RDECOM /TARDEC. 53RD DEFENSE WORKING GROUP ON.
Nondestructive Inspection of Metal Matrix Tank Shoes with Ultrasounds 53RD DEFENSE WORKING GROUP ON NONDESTRUCTIVE TESTING November 2, 2005 George Zhao, Chiman Kwan, and Mi Bao Intelligent Automation, Inc. Steve Owens, R. L. Royer Jr. and Joseph L. Rose FBS.Inc Basavaraju B. Raju U. S. Army RDECOM /TARDEC Intelligent Automation, Inc.
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Outline • • • • • • •
Problem Statement Delamination detection Crack inspection MMC insert thickness measurement Fixture design considerations Conclusions Acknowledgment Intelligent Automation, Inc.
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MMC Insert Inspection Problem • Army seeks to replace the steel track shoes with SiCx reinforced cast aluminum shoes for the future combat vehicles • MMC insert could suffer from debonding, cracks and porosity at the MMCaluminum core interface or in the MMC itself.
MMC insert lost
SiCw MMC reinforced area
Center guide
Cracked MMC Sprocket window
Fig. 1: XT-172 AL MMC track shoes with center guide and sprocket window area reinforced with SiC whisker preform (MMC).
Intelligent Automation, Inc.
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Project Objective • The objective of this SBIR II is to develop and deliver to the Army a real-time nondestructive inspection prototype inspection hardware that contains: – A portable data acquisition system – Ultrasonic guided wave transducers with a portable fixture customized for the best defect detection in MMC – Advanced signal processing algorithms for defect classification and size estimation – Graphical user interface for displaying results and interacting with the maintenance engineers
Intelligent Automation, Inc.
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Initial Results for Delamination Inspection (a) Piezoelectric Transducers Pulse-Echo Inspection for the Center Spline
No delamination Intelligent Automation, Inc.
Delaminated 5
(b) EMAT Pulse-Echo Inspection for the Center Spline
Figure 2. Response from defect free region, showing echo from opposite side of part
Figure 3. Response from defective region, showing multiple reflections within MMC layer
Intelligent Automation, Inc.
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(c) Ultrasonic C-scan for the ground truth Front Wall Echo
• Transducer frequency: 30MHz • Transducer focal distance: 2 inch • Transducer diameter: 0.25 inch • Scan resolution: 0.01 inch • The thickness of the MMC layer is estimated around 3mm
Intelligent Automation, Inc.
Interface Echo
Gate
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(d) Verification of the inspection results Position 3
2 1.5
Position 2
1
Position 1
0.5 0 -0.5 -1 -1.5 -2 0
2
4
6
8
10
12
2
14
1.5
Pulse-echo waveforms at positions 1
1
2
0.5
1.5
0
1
-0.5
0.5
-1
0
-1.5
-0.5
-2 0
2
4
6
8
10
12
14
-1 -1.5 -2 0
2
4
6
8
10
12
Pulse-echo waveforms at positions 2 Intelligent Automation, Inc.
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Pulse-echo waveforms at positions 3 8
(e) Sprocket window inspection concept
Fig. 4: Guided waves travel along (a) interface of the MMC and aluminum, (b) through the MMC layer only, and (c) through a layer and a relatively thin underlying structure, such as the MMC and aluminum together.
Intelligent Automation, Inc.
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Guided Wave Principle and Advantages Basics of guided waves Guided wave possibilities: (a) Rayleigh (surface) waves; (b) Lamb waves; (c) Stoneley waves.
(a)
(b)
Some natural wave guides (c) • Plates (aircraft skins) • Rods (cylindrical, square or rail) • Hollow cylinders (pipes and tubing) Fig. 5 Guided waves possibilities • Multilayer structures • Curved or flat surfaces on a half space • Layer or multiple layers on a half space • Composite materials such as MMC track shoes Intelligent Automation, Inc.
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Initial Results for Crack Inspection
Receiver
Transmitter
Transmi tter
Receive r
Crack Dimensions: 0.01” deep 0.20” in length
Experimental setup for generating surface waves for crack detection 0.2
1 0.8
0.15
0.6 0.1 0.4 0.05
0.2 Before Crack
0 0
5
10
-0.05
15
20
25
After Crack
Before Crack
0 -0.2
0
5
10
15
20
25
30
After Crack
-0.4 -0.1 -0.6 -0.15
-0.8
-0.2
-1
Waveforms captured before and after introducing surface crack. Note the decrease in signal amplitude observed in the waveform taken after the crack. Intelligent Automation, Inc.
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Insert Thickness Measurement with Guided Waves A1
Normalbeam transducers
Phase Velocity (mm/ µ s)
25
A3 S3
S2
A4
S4
S5
20
A2 New Insert
15
S1
Degraded Insert
10
S0 5
A0 0 0
0.5
1
1.5
2
2.5
3
Frequency (MHz) 7
S0 Group Velocity (mm/ µ s)
S3
S2
S1
6 5
A3
A2
New Insert
4 3
Degraded Insert
A0
2
Series1
A1
1 0 0
0.5
1
1.5
2
2.5
3
Frequency (MHz)
Phase and group velocity dispersion curve concept for an MMC insert Intelligent Automation, Inc.
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S2 mode at 1 MHz 0.5 0.4
Amplitude (dB)
0.3 0.2 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5 0
10
20
30
40
50
60
70
80
90
100
time (µs) 0.8
Amplitude (dB)
0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 0
10
20
30
40
50
60
70
80
90
100
time (µs)
The guided wave signal and the Fourier transform of the S2 mode acquired by spike excitation for the MMC specimens, of different thickness, when using 1 MHz normalbeam transducers. Intelligent Automation, Inc.
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A1 mode at 500 kHz 1 0.8
Amplitude (dB)
0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 0
10
20
30
40
50
60
70
80
90
100
60
70
80
90
100
time (µs)
0.6
Amplitude (dB)
0.4
0.2
0
-0.2
-0.4
-0.6 0
10
20
30
40
50
time (µs)
The guided wave signal and the Fourier transform of the A1 mode acquired by spike excitation for the MMC specimens, of different thickness, when using 500 kHz normalbeam transducers. Intelligent Automation, Inc.
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The peak frequency shifts higher in frequency for the degraded specimen
4.4 mm MMC Specimen
4.08 mm MMC Specimen
Peak Frequency
.98 MHz
1.07 MHz
Measured Group Velocity
2.58 mm/µs
2.61 mm/µs
Intelligent Automation, Inc.
4.4 mm MMC Specimen
4.08 mm MMC Specimen
Peak Frequency
521 kHz
535 kHz
Measured Group Velocity
3.00 mm/µs
3.00 mm/µs
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Mechanical Fixture Design Considerations Custom design sensors and devices necessary for the detection of each type of defect. – Customize sensors for each type of defect and investigate the smallest defect size that can be detected. – Design mechanical devices to inspect the different parts of the track shoe.
Intelligent Automation, Inc.
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One possible design would be to have a device that contains the crack detection sensors on one side and the delamination/porosity detection sensors on the other side. The device would be place on the spline and have to be “flipped” for complete inspection of both sides. Ultrasonic Transducer
Compressed Air Frelon Bearing Upper Plate
Thin Latex Sheet Sensor Housing Dry Coupling Pad Spline Surface
Pneumatic fixture concept for mechanically press against the spline Intelligent Automation, Inc.
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Conclusions • Ultrasound technology has great potential for delamination and crack detection in the MMC track shoes • Guided waves can also be used as a tool for measuring the thickness reduction of the MMC insert • Innovative fixture design will be indispensable for reliable defect inspection • Challenges remain for sensor and fixtures to accommodate various used track shoes
Intelligent Automation, Inc.
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Acknowledgment Thanks for the support by Army TACOM, (Contract #: DAAE07-03-C-L054) and technical assistance from Dr. Basavaraju B. Raju.
Intelligent Automation, Inc.
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