Integrated Technology for Detection and Repair of Mechanical Component Surface Fatigue Microcracks Using Pulsed Laser

Abstract

During processing and service, various types of fatigue microcracks inevitably occur on the surfaces of mechanical components. If the microcrack is not repaired in a timely manner, it will continue to expand, affecting the safety and stability of the equipment. To this end, we introduce pulsed laser technology and propose an integrated technology for the detection and repair of mechanical component surface fatigue microcracks using pulsed laser. A finite element model is established to simulate the nonlinear interaction between fatigue microcracks and laser-generate Rayleigh wave, and the effects of parameters such as crack depth and width on the acoustic nonlinear index are investigated. On the basis of detection, the feasibility of the fatigue microcrack repair using laser melting effect is investigated. Simulation results show that contact and friction between crack interfaces must be considered, and the nonlinear modulation for Rayleigh wave mainly originates from the nonlinear interaction between the longitudinal wave component and the fatigue microcrack. The acoustic nonlinear index of longitudinal wave increases and decreases with the increase of crack depth and width, respectively. In addition, fatigue crack repair is feasible by properly adjusting laser parameters.