Investigations on pulse compression favourable thermal imaging approaches for characterisation of glass fibre‐reinforce polymers
Anju Rani, Ravibabu Mulaveesala
Abstract
Active infrared imaging is one of the promising remote and whole field characterisation techniques for non‐destructive testing and evaluation of various solids irrespective of their electrical and magnetic prosperities. This technique relies on a mapping of thermal response for a predefined incident heat flux over the test object to detect the presence of surface and subsurface anomalies. Due to its fast, non‐contact, safe and quantitative testing capabilities, infrared thermography has gained significant importance in the testing of fibre reinforced polymers. This Letter highlights testing and evaluation of glass fibre‐reinforced polymer (GFRP) specimen for detection of subsurface hidden defects using pulse compression favourable thermal wave imaging techniques (for an imposed digitised chirp as well as a 7‐bit Barker coded modulated heat fluxes over the test specimen). Further depth scanning capabilities of the proposed schemes have been compared using a time‐domain pulse compression based approach. Proposed analytical, as well as simulation studies, have been validated with the experimental results on GFRP material having flat bottom holes as defects.