Flexural wave generation and stress analysis during laser evaporative heating of steel

Abstract

Flexural waves are generated during the laser evaporative heating process. In this case, vapour pressure developed at the workpiece surface generates a pressure force acting normal to the surface. This, in turn, results in waves in the workpiece. Moreover, a stress field arises in the substrate material during the flexural motion. Consequently, investigation into the flexural waves and stress levels developed in the substrate material on account of the laser evaporative heating process becomes necessary. In the present study, laser evaporative heating of steel is considered. The flexural waves generated by teh normal pressure force are formulated and the stress levels inside the substrate material are computed numerically using the finite element method (FEM). To investigate the effect of an additional element, as an impurity in the substrate material, on the stress levels, aluminium is added to the steel substrate. It is found that a displacement of the surface of the order of 2μm occurs, and that the maximum stress level is of the order of 10⁵ Pa during the heating process. The additional aluminium lowers the displacement and stress levels in the substrate material.