Quantifying the width and angle of inclined cracks using laser-spot lock-in thermography

Abstract

In this work we introduce a method to determine the width and the orientation of tilted cracks. This method combines laser-spot lock-in thermography and calculations of the sample temperature by means of finite elements modelling. The fitting of the surface temperature, calculated from the numerical model, to experimental lock-in thermography data obtained by focusing the laser spot close to an artificial calibrated inclined crack delivers its width and angle. The agreement between nominal and retrieved values proves the ability of the method to size inclined cracks, even those of micrometric width.