A thermal stress and failure model for laser cutting and forming operations

A transient, full three-dimensional mathematical model that describes the ablation phenomena, the thermal stress evolution, and the failure process that occur during laser cutting or forming operations on ceramic plates is developed. The model development is based on the finite element simulation of thermal field and stress development during laser cutting or forming operations. To treat the ablation phenomena during laser cutting, a fixed-grid algorithm is applied to handle complex ablation geometries with discontinuities. This algorithm is essential for applications to multiple-laser cutting operations. The thermal and stress evolution model is further integrated with a probabilistic fracture model to assess the failure probability during both laser cutting and forming processes. Numerical results show that the groove shapes as well as the temperature and stress distributions are similar in front of the cutting laser for both single and dual lasers but differ in the region when the lead laser becomes effective in dual-beam machining.