TY - GEN
T1 - Comparative performance of high and medium resolution cameras for defect detection in carbon-fiber reinforced composites by digital shearography
AU - Abedin, Kazi Monowar
AU - Tao, Nan
AU - Anisimov, Andrei G.
AU - Groves, Roger M.
N1 - Publisher Copyright:
© 2023 SPIE.
PY - 2023/8/15
Y1 - 2023/8/15
N2 - The performance of defect detection in composite materials using digital shearography is important for correct decision-making in non-destructive testing. In this work, we compared a high-resolution 24-megapixel digital still camera (DSLR) and a conventional medium-resolution 5-megapixel camera to determine the detectability of blind holes in an aerospace-graded carbon-fiber reinforced polymer (CFRP) sample. The hole diameters ranged from 0.2 to 3 mm with a material thickness of 4 mm and the test sample dimensions of 200×200 mm. The sample was heated and observed from the front (defect-free side) by three halogen lamps for 5 minutes in pulsed heating mode. Speckle interferograms were acquired during the heating and cooling phases from both cameras simultaneously using identical shearing interferometers and shearing distances. Phase maps were calculated using the 4+4 temporal phase step algorithm and then unwrapped. Further, defect-induced deformation (DID) phase maps were obtained by polynomial curve fitting. The DID phase maps obtained from the two cameras were compared. Blind holes with diameters up to 1 mm were detected, which are one of the smallest defects detected with shearography and reported in literature. In addition, the DLSR camera was able to detect holes of 0.8 mm in diameter. We observed that nearly comparable detection capabilities were obtained from both cameras, even though the spatial resolution of the second camera (DLSR) was 5 times higher. Possible reasons of this limitation include effects such as fiber-related deformation in CFRP and speckle noise.
AB - The performance of defect detection in composite materials using digital shearography is important for correct decision-making in non-destructive testing. In this work, we compared a high-resolution 24-megapixel digital still camera (DSLR) and a conventional medium-resolution 5-megapixel camera to determine the detectability of blind holes in an aerospace-graded carbon-fiber reinforced polymer (CFRP) sample. The hole diameters ranged from 0.2 to 3 mm with a material thickness of 4 mm and the test sample dimensions of 200×200 mm. The sample was heated and observed from the front (defect-free side) by three halogen lamps for 5 minutes in pulsed heating mode. Speckle interferograms were acquired during the heating and cooling phases from both cameras simultaneously using identical shearing interferometers and shearing distances. Phase maps were calculated using the 4+4 temporal phase step algorithm and then unwrapped. Further, defect-induced deformation (DID) phase maps were obtained by polynomial curve fitting. The DID phase maps obtained from the two cameras were compared. Blind holes with diameters up to 1 mm were detected, which are one of the smallest defects detected with shearography and reported in literature. In addition, the DLSR camera was able to detect holes of 0.8 mm in diameter. We observed that nearly comparable detection capabilities were obtained from both cameras, even though the spatial resolution of the second camera (DLSR) was 5 times higher. Possible reasons of this limitation include effects such as fiber-related deformation in CFRP and speckle noise.
KW - carbon-fiber reinforced polymer
KW - composites
KW - digital shearography
KW - high-resolution camera
KW - nondestructive testing
KW - thermal loading
UR - http://www.scopus.com/inward/record.url?scp=85172657717&partnerID=8YFLogxK
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U2 - 10.1117/12.2669718
DO - 10.1117/12.2669718
M3 - Conference contribution
AN - SCOPUS:85172657717
T3 - Optical Measurement Systems for Industrial Inspection XIII
BT - Optical Measurement Systems for Industrial Inspection XIII
A2 - Lehmann, Peter
PB - SPIE
T2 - Optical Measurement Systems for Industrial Inspection XIII 2023
Y2 - 26 June 2023 through 29 June 2023
ER -