Numerical simulation of laser-generated ultrasonic by finite element method in the plate material

A laser pulse incident on a material generates the transient temperature field. As rapid and localized thermal expansion occurs, energy is released in the form of propagating ultrasound in all directions. Laser-generated ultrasound is non-contact, broadband, and multiple propagation modes. Considering the temperature dependence of material properties, the transient temperature distribution is simulated using the finite element method in the plate material, and a finite element is developed to simulate the laser thermo-elastic generation and propagation of laser ultrasound. The numerical results indicate that the heat-affected zone is very localized, such a distribution of the transient temperature is considered as a body source in the generation of ultrasound. The propagation features of surface waveforms in the near and far field are analyzed; the relation between the laser input parameters and the generated ultrasonic wave characteristics is discussed; A quantitative basis for the thermo-elastic mechanism in nondestructive evaluation of the material properties is established.