A comparison between optimized active thermography and digital shearography for detection of damage in aerospace composite structures

Abstract

The main goal of this research is to compare capabilities of two different Non-Destructive Testing (NDT) methods, thermosonics and digital shearography (DISH), to recognize and image back drilled hole defects. Thermosonics was optimized by varying magnitude of the heat flux, the excitation frequency, the number of excitation cycles, acquisition time, frame rate etc. DISH was optimized by investigating the test objects by dynamic loading approach in order to identify per each defect the (0 1) mode shape and the corresponding resonance frequency. In this way, whilst thermosonics provided the initial infrared imaging of the panel for a pass/fail test, DISH has been performed to provide the delamination quantitative assessment. © RILEM 2013.