Novel pulse compression favorable excitation schemes for infrared non-destructive testing and evaluation of glass fibre reinforced polymer materials

Abstract

Infrared thermography (IRT) has been extensively used in the field of non-destructive testing and evaluation (NDT&E) as a condition monitoring tool in commercial as well as industrial applications. It is a fast, non-contact, whole field and quantitative technique for NDT&E applications by mapping the thermal profile over the test sample. This paper presents a novel three-dimensional analytical model for characterization of glass fibre reinforced polymer (GFRP) sample having flat bottom hole defects. The capability of the proposed method is highlighted with recently introduced pulse compression favorable thermal wave imaging modalities. Further, the analytical results have been validated with simulated and experimental studies on the proposed frequency modulated thermal wave imaging (FMTWI), Barker coded thermal wave imaging (BCTWI) and digitized frequency modulated thermal wave imaging (DFMTWI) techniques to analyze the performance of the defect detectability by taking normalized correlation coefficient as a figure of merit. Obtained results clearly shows the capabilities of the DFMTWI over the FMTWI and BCTWI using correlation based matched filter post-processing approach.