Microstructural Modeling and Dynamic Process Simulation of Laser-Assisted Machining of Silicon Nitride Ceramics With Distinct Element Method

Abstract

The distinct element method (or discrete element method, DEM) is applied to simulate the dynamic process of laser-assisted machining (LAM) of silicon nitride ceramics. This is motivated by the fact that LAM of ceramics shows a few complicated characteristics such as spontaneous crack formation, discontinuous chips, etc. Thus, using the two-dimensional distinct element code, PFC2D, the microstructure of a β-type silicon nitride ceramic is modeled, and the resulting temperature-dependent synthetic specimens are created first, and then, machining simulations are conducted. The DEM model is validated through comparing the predicted results with those from the experiments under different cutting temperatures in terms of cutting force, chip size, and depth of subsurface damage. Furthermore, the mechanisms of LAM are analyzed from the aspects of material removal, chip segments, surface/subsurface damage, as well as crack initiation, propagation, and coalescence.