Non-destructive testing of composite structures using self-heating based vibrothermography and dedicated benchmark
Dominik Wachla, Andrzej Katunin, Angelika Wronkowicz-Katunin
Quarterly No. 4, 2019 pages 143-149
DOI:
keywords: self-heating based vibrothermography, non-destructive testing, polymer matrix composites, damage detectability enhancement, benchmark
abstract The newly developed self-heating based vibrothermography method is a non-destructive testing method applicable to polymeric and polymer-based composite structures, which is based on the self-heating effect used as thermal excitation of a structure during testing. The mechanical excitation with multiple resonant frequencies causes viscoelastic energy dissipation in the whole structure, which allows the observation of eventual flaws and damage in the form of differences in the surface temperature distribution observed by an infrared camera. The effectiveness of damage detectability depends on the visibility of thermal signatures of potential flaws and damage, which is often masked by measurement noise and artefacts in thermograms. Therefore, it is suitable to apply post-processing procedures that allow the enhancement of damage detectability. The developed set of tools for thermogram post-processing covers primary methods based on statistical features, and more advanced ones like methods based on derivatives, wavelet transform as well as post-processing methods dedicated for thermogram enhancement such as thermographic signal reconstruction, partial least squares regression or principal component thermography. These methods were implemented in the form of an integrated GUI-based benchmark based on Matlab routines, dedicated to the post-processing of thermographic data acquired using self-heating vibrothermography.