TC4钛合金激光冲击强化数值模拟

采用连续显式动态冲击策略对航空用TC4钛合金进行激光冲击强化数值模拟研究。根据冲击波能量变化曲线确定单次冲击求解时间为3 000 ns,并分析了应力波传播过程。在此基础上开展多点冲击模拟,分析了功率密度、冲击次数和光斑搭接率对残余应力、应变场的影响。得出增加功率密度对增大表面残余压应力的效果更好;增加冲击次数对增大残余压应力影响深度的效果更好;50%光斑搭接率有效地避免了冲击不均匀和搭接空隙现象。实验和仿真所得的试件表面残余压应力变化趋势相同,数值大小基本吻合。冲击1、3次时,两者的误差分别为4.1%、2.6%,说明仿真结果具有一定的参考意义。 

Numerical simulation on laser shock peening of TC4 titanium alloy

The continuous explicit dynamic impact strategy was used to carry out the numerical simulation study on laser shock peening of TC4 titanium alloy for aviation. According to the shock wave energy change curve, the solution time 3 000 ns of a single shock was determined, and the stress wave propagation process was analyzed. On this basis, a multi-point impact simulation was carried out, and the effects of power density, impact times and spot overlap rate on residual stress and strain field were analyzed. It was concluded that increasing the power density had a better effect on increasing the residual compressive stress on the surface; increasing the number of impacts had a better effect on increasing the depth of the residual compressive stress; the 50% spot overlap rate effectively avoided uneven impact and overlap gaps phenomenon. The change trend of the residual compressive stress on the surface of the specimen obtained by the experiment and the simulation was the same, and the numerical value was basically consistent. When the impact was 1 and 3 times, the errors of these two were 4.1% and 2.6%, respectively, indicating that the simulation results have certain reference significance.