Influence of laser shock peening on fatigue life of transmission gears in aeroengine

摘要

As a surface processing technique, laser shock peening (LSP) is recently being developed fast and has been applied to improve fatigue performance of the target metal. AISI9310 known for its superior mechanical properties is widely used to manufacture transmission gears in the aeroengine for which high reliability is required. To investigate the influence of LSP on fatigue life of AISI9310 gears, LSP is conducted on the gear root. Residual stress distribution induced by LSP is predicted by means of finite element modelling, and the result is verified with X-ray diffraction. Subsequently, the bending stress on the gear root at its functioning state is calculated before and after LSP. Finally, the local stress-strain method is employed to predict fatigue life at crack initiation stage. At crack propagation stage, stress field factor is introduced to calculate the fatigue life theoretically. It is demonstrated from the prediction result that by introducing residual compressive stress of great intensity on the root fillet surface, fatigue life of the laser peened gears in aeroengine can be significantly improved compared to the non-peened gears theoretically.