Numerical simulation of laser-generated ultrasonic by finite element method in the transparent coating-substrate system

The finite element model of the thermal conductive equation and the thermo-elastic equation in the system consisting of a transparent coating and a opaque substrate is established based on the analysis of the stability of solution and two important parameters,meshing size and time step.Taking into account the temperature dependence of material properties,the transient temperature is obtained.The near-axis normal waveforms at the epicenter generated by thermo-elastic effect are obtained.The influence of the coating thickness on the waveform is analyzed.