Numerical Modeling of Laser Repair Process and Stress Analysis

Laser repair uses a laser additive process to repair a part so that the additive material is metallurgically bonded to the base material. A full understanding of the associated physical phenomena, such as melting, solidification and evaporation, is necessary to obtain qualified product. In this study, a mathematical model is established to investigate the influence of powder injection, thermal capillary force and gas pressure which are the primary driven forces for fluid flow in the repair process. Energy balance at liquid-vapor (L/V) and solid-liquid (S/L) interface is calculated. The level set method is employed to track the evolution of the free surface and simulate the dynamic motion of the melt pool. Information on the cooling rate in the heat affected zone (HAZ) is incorporated into the stress model to analyze the stress distribution