microwave imaging of subsurface defects in coated metallic ...ndt in canada 2015 conference...

NDT in Canada 2015 Conference

Microwave Imaging of Subsurface Defects in Coated

Metallic Structures Using Small Ring Resonators

Abdulbaset M. Ali, PhD candidate

Omar M. Ramahi, FIEEE

NDT in Canada 2015 Conference 15/06/2015 2

Agenda

• Background

• Microwave Testing

• Microwave Imaging

• Sensor Design & Operation

• Results

• Conclusions

• Future works

• References

Background

(EM Spectrum)

15/06/2015 3

[1]


Wavelength (m)

Background (cont.)

(Microwave Bands)

15/06/2015 4 NDT in Canada 2015 Conference

Band Frequency Range (GHz)

L 1 - 2

S 2 - 4

C 4 - 8

X 8 -10

Ku 12 -18

K 18- 26.5

Ka 26.5- 40

Q 30 - 50

U 40 - 60

V 50 - 75

E 60 - 90

W 75 - 110

F 90 - 140

D 110 - 170

(MW)

15/06/2015 5

Meta

llic

MUT


Microwave signals can not penetrate

metals

Material Under Test (MUT)

MW Signal Interactions with Materials

MW Signal Interactions with Materials


Die

lectric

Microwave signals can penetrate

dielectrics

MUT


MW Signals & New Materials

Advances in material science

have led to new composites:

New composites are

coating or replacing old materials

Advantages

lighter

More durable

Challenges:

Penetrating Testing Methods: Pulsed eddy currents testing

X-rays testing

Microwave testing

Material Use (%)

Aluminum 20%

Titanium 15%

Steel 10%

Advanced composites

50%

Other 5%

[2]

Boeing 787

Dreamliner

Microwave NDT

Advantages Non-contact evaluation

Works on uncoated /coated metallic structures

Works on dielectric structures

Enables small flaw detection

Enables two-sided testing or one-sided testing


MU

T

Receiving

Unit

Transmitting

Unit

Signal

Generator

Vector Network

Analyzer

Microwave NDT (cont.)

One-sided MW sensors:

Waveguides

(large penetration/ low resolution )

Coaxial cables

(high resolution/time consuming)

Transmission lines with small resonators:

Tunable

Good resolution

Less time consuming than coaxial

Low penetration


MU

T

Vector Network

Analyzer

Transmitting

Unit

Sensor Design


Transmission line

(copper)

Dielectric substrate

Ground plane

(copper) Etched Ring

resonators

“sensing element ”

High Frequency Structural Simulator (HFSS)

has been used in this study

a= 4mm

Equivalent circuit model

Sensor Operation


Transmission Coefficient Magnitude in (dB) vs. Operating Frequency

Shift

Transmitting

(Port 1)

Receiving

(Port 2)

s21

movieNDT1.avi

Sensor Operation


Raster scan of Aluminum plate with corroded region at lift-off

distance 0.5mm

Corroded

region

Scanning

pattern

Raster scan

Sensor

Cross-section view Top view

Aluminum Plate

Teflon coating

Results

2-D or 3-D images

“One Picture is Worth a Thousand Words’’

Informative (size, shape, location, etc…..)


Sensor

Matlab

Output

(Image format)

[3]


Scaled image of Aluminum plate with corroded region

(15 mm by 7.5 mm)

X (mm) / ∆ X=1mm scanning step

Y (

mm

) / ∆

Y =

1m

m

Results (Cont.)

movieNDT33.avi

Surface plot of transmission coefficient (S21) vs. scanned area

0

5

10

15

20

25 0

10

20

30

-40

-20

0

S2

1(d

B)

Results (Cont.)


movieNDT3d.avi

Raster scan of MUT with two corroded regions that

have different depths

Results (Cont.)


Region A

Depth=2mm Region B

Depth=1mm

Scaled image of Aluminum plate with two corroded regions

Results (Cont.)


Y (m

m)

X (mm)

Surface plot of transmission coefficient vs scanned area

for MUT with two corroded regions

0

10

20

30

0

5

10

15

20

25

-15

-10

-5

0

S2

1 d

B

Results (Cont.)


S2

1 (

dB

)

Side view

Results (Cont.)


S2

1 (

dB

)

X (mm)

Conclusions

This work has demonstrated the ability of small

microwave ring resonators to image flaws in

coated metallic structures

This approach produces clear images

Good flaw localization and depth characterization

were achieved by mapping the results to a surface

plot


Future work

Correlating the sensor’s response to the physical flaw

depths through

curve fitting

regression models

Performing experimental measurements


References and useful links 1. http://www.wisegeek.org/what-is-microwave-radiation.htm

2. http://www.boeing.com/commercial/aeromagazine/articles/qtr_4_06/article_04_2.html

3. https://en.wikipedia.org/wiki/A_picture_is_worth_a_thousand_words

4. S. Kharkovsky and R. Zoughi, "Microwave and millimeter wave non-destructive testing and evaluation - Overview and recent advances," IEEE Instrumentation and Measurement Magazine, vol. 10, pp. 26–38, 2007.

5. Testing and Applied Microwave Non-destructive lab, "Microwave and Millimeter Wave NDT & E Principles, Methods and Applications," [Online]. Available: http://amntl.mst.edu/media/research/amntl/documents/Microwave_Milimeter_Wave_NDT_E_Tutorial.pdf.

6. Qaddoumi, N.N.; Saleh, W.M.; Abou-Khousa, M., "Innovative Near-Field Microwave Non-destructive Testing of Corroded Metallic Structures Utilizing Open-Ended Rectangular Waveguide Probes," Instrumentation and Measurement, IEEE Transactions on , vol.56, no.5, pp.1961,1966, 2007

7. Deng, Yiming, and Xin Liu. “Electromagnetic Imaging Methods for Non-destructive Evaluation Applications.” Sensors ,Basel, Switzerland 11.12, 2011.

8. Hong Zhang, Bin Gao, Gui Yun Tian, Wai Lok Woo, Libing Bai, “Metal defects sizing and detection under thick coating using microwave NDT,” NDT & E International, Volume 60, pp 52-61, 2013.

9. Boybay, M.S.; Ramahi, O.M., "Non-Destructive Thickness Measurement Using Quasi-Static Resonators," Microwave and Wireless Components Letters, IEEE , vol.23, no.4, pp.217,219, 2013


http://www.wisegeek.org/what-is-microwave-radiation.htm








Thank You

Q/A

NDT in Canada 2015 Conference 15/06/2015 23

microwave imaging of subsurface defects in coated metallic ...ndt in canada 2015 conference...

Documents