Analysis of defect detectability in polymeric composites using self-heating based vibrothermography

The self-heating based vibrothermography (SHVT) is a new non-destructive testing method dedicated for testing of polymer matrix composite structures, where the excitation is performed by externally applied mechanical vibrations in a low frequency range. Exciting a structure with several resonant frequencies, the heating up of this structure is possible due to the occurrence of the thermoviscoleastic effect called the self-heating, whose nature originates from the mechanical energy dissipation. In order to examine an efficiency of the SHVT an analysis of defect detectability on composite specimens with milled artificial defects was performed. The post-processing of the series of resulting thermograms was performed in order to enhance defect detectability. The obtained results allow to conclude about high efficiency of SHVT NDT technique, which can be used especially in cases when a direct access to the testing structure in order to excite it externally is difficult or impossible.