Comparative performance of high and medium resolution cameras for defect detection in carbon-fiber reinforced composites by digital shearography

Kazi Monowar Abedin*, Nan Tao, Andrei G. Anisimov, Roger M. Groves

*Corresponding author for this work

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

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Abstract

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.

Original languageEnglish
Title of host publicationOptical Measurement Systems for Industrial Inspection XIII
EditorsPeter Lehmann
PublisherSPIE
ISBN (Electronic)9781510664456
DOIs
Publication statusPublished - 2023
EventOptical Measurement Systems for Industrial Inspection XIII 2023 - Munich, Germany
Duration: 26 Jun 202329 Jun 2023

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume12618
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

ConferenceOptical Measurement Systems for Industrial Inspection XIII 2023
Country/TerritoryGermany
CityMunich
Period26/06/2329/06/23

Keywords

  • carbon-fiber reinforced polymer
  • composites
  • digital shearography
  • high-resolution camera
  • nondestructive testing
  • thermal loading

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