Spatially modulated thermal excitations for shearography non-destructive inspection of thick composites

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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With the increasing application of thick composites in marine, wind energy and aerospace industries, the inspection of thick composites becomes more and more challenging when considering the variety of thick structures (e.g., laminate, sandwich, honeycomb structures). Shearography is a full-field and non-contact optical non-destructive testing (NDT) method which is normally used to inspect composite laminates up to 10 mm while for the thick composite laminates (e.g., with the thickness of more than 50 mm), its performance is not clear yet. In shearography NDT, a defect-induced anomaly is revealed from fringe or phase maps obtained by comparing two states of deformation of the specimen to be inspected. Thermal loading is widely used to deform the specimen due to its advantages of convenience for on-site inspection and cost-effectiveness. The objective of this study is to improve the defect detection capabilities of shearography when used to inspect thick composites. For that, spatial modulated thermal excitations are investigated. A thick composite model has been built in Abaqus to assist the shearography inspection. Various kinds of spatially modulated heating including local heating and global heating are explored for thick composite inspection with shearography in order to evaluate the corresponding efficacies in defect detection. We will present both experimental and numerical results on spatial modulated thermal loading. Defect-induced shearographic responses subjected to local and global thermal excitations will be discussed in this paper, including the influence of short-time heating and long-time heating on thick composite inspection. Current results indicate that long-time heating is more favorable when inspecting deep defects in thick composites, and with local heating it is possible to increase the defect-induced signal when compared with global heating.

Original languageEnglish
Title of host publicationOptical Measurement Systems for Industrial Inspection XII
EditorsPeter Lehmann, Wolfgang Osten, Armando Albertazzi Goncalves
Number of pages6
ISBN (Electronic)9781510643987
Publication statusPublished - 2021
EventOptical Measurement Systems for Industrial Inspection XII 2021 - Virtual, Online, Germany
Duration: 21 Jun 202125 Jun 2021

Publication series

ISSN (Print)0277-786X


ConferenceOptical Measurement Systems for Industrial Inspection XII 2021
CityVirtual, Online


  • Finite-element modelling
  • Shearography
  • Spatial modulation
  • Thick composite inspection


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