Modeling of Laser Ultrasound Generation in a Weld Pool

Finite element techniques are used to model laser generation of ultrasound and its propagation through a weld pool. The laser generation is modeled by assuming the reactive force to the laser ablation of the liquid is a stress perpendicular to the surface of the pool. The boundary of the pool is assumed to be spherical. The propagation of the sound waves from the laser source through the boundary into the solid metal is calculated assuming homogeneous properties in both the liquid and solid metal and temperature gradient effects are neglected. The results are compared to a series of experiments on real and simulated weld pools [1]