Theoretic Modelling and Correlation Detection of Pulsed Laser Film Spallation Technology

With the aim of measuring quantitatively the dynamic adhesive strength of Al 2O 3film/Fe, we use a modified laser spallation setup, and let high power laser pulse shock the energy absorbing thin coats, then cause a pressure pulse propagates to matrix. At the free surface, a laser probe is used to record the epicentral surface displacement history caused by stress wave which propagates to the free surface. Through the analysis of stress wave, data processing and a computer simulation, we propose a novel model of the attenuation and the dispersion of the stress wave. After characterizing, we obtain new spallation criteria corresponding to progressive damages at the film matrix interface, i.e. interface delamination, film spallation and film expulsion, respectively. At the same time, according to the arrival time and attenuation pattern of the stress wave, we also propose a new computer algorithm for estimating the source fracture dimension.