FEM calculation of Microscale Laser Shock Processing on MEMS material with excimer laser

Abstract

Microscale Laser Shock Processing (μLSP) can generate plastic deformation and compressive residual stresses in Micro Electromechanical Systems (MEMS) components through a laser-induced plasma, for improving fatigue, wearing or stress corrosion cracking resistance. Numerical simulation of μLSP is conducted using ABAQUS software to calculate the plastic deformation and residual stress fields induced by excimer laser in pure aluminum. The laser intensities are 2.0 GW/cm2 and 4.0 GW/cm2, respectively. A 2D axisymmetric model for shock pressure computation is given to account for the microscale involved. The 3D graphics of plasma shock pressure is investigated for the first time, under considering the spatial nonuniform distribution of shock pressure for microscale level. The mode of 'P4NU' with 'DLoad' loading type of ABAQUS is used for the element-based surface load for nonuniform shock pressure in Visual Fortran subroutine for pressure loading. The plastic deformation and residual stress distribution of the target material are discussed at different laser intensities. The simulation results of dented area are consistent with Zhang & Yao's experimental work.