Flexural waves generated due to pressure force during the laser induced evaporation process

During the laser ablating of surfaces, the pressure is generated at the int erface between the vapor front and the solid substrate. In some cases, the magnitude of the pressure attains considerably high values, which in turn d evelops a pressure force acting normal to the workpiece surface. The magnit ude of the pressure force is sufficient to generate flexural waves propagat ing along the workpiece. In the present study, a flexural wave generation d uring laser ablation of steel surface is modeled. The pressure rise at the interface is predicted and the resulting pressure force is determined. The flexural wave characteristics are examined at different locations at the wo rkpiece surface. In order to examine the effect of reflected waves, from th e free ends of the workpiece, on the traveling waves radiating boundary con ditions on the element sides is considered. It is found that the flexural w ave amplitude decays as the location at the surface moves towards the workp iece end. The radiating conditions on the element sides show that the refle cted waves have significant effect on the traveling wave characteristics. ( C) 2001 Laser Institute of America.