FE Modeling and Analysis of Patterning Micron Surface Structures by Laser Shock Peening

Laser shock peening (LSP) is a potential fabrication process to pattern micron surface structures. The purpose of this paper is to model 3D shock pressure and dynamic mechanical behavior at high strain rates during laser patterning process. The 3D shock pressure was modeled using a user defined subroutine. The mechanical behavior at high strain rates is predicted by the Bammann, Chiesa, and Johnson (BCJ) model. A 3D FEA model of microscale LSP was created using the developed loading and material subroutines. For comparison, a direct input of measured material properties was also used. The results show that decreasing pulse time shifts the maximum transient stress from the surface to the subsurface. The rapid loading causes increased magnitudes of compressive stress throughout the depth. The BCJ model predicts higher stresses than the direct input method.