激光冲击强化有限元仿真时间步长选择方法

The Time Step Choosing for FEM Simulation of Laser Shock Processing

根据激光冲击强化处理过程在材料内部引起的残余应力场受冲击压力的峰值和冲量的影响较大的特点,结合显式动力有限元基本理论和时间步长的确定方法,分析比较了有限元分析过程中实际的加载过程与定义的加载曲线之间的误差.提出激光冲击强化有限元分析时间步长的选取,需要首先选择计算结果趋于稳定的网格密度,然后根据硬件条件选择冲击压力与冲量误差均趋于零的时间步长.通过算例,分析了有限单元尺寸与时间步长选取对分析结果的影响,对时间步长选择方法进行了验证.

According to the fundamental theory of explicit finite algorithm,the effect of time step choosing on loading process during simulation was analyzed.And the strategy for time step choosing was suggested that should be accomplished by two steps: first,choose the meshing density properly that is densely(enough) to obtain a stable calculated results;then,choose the time step that can acquire the minimum error of peak and impulse of the shock pressure based on the computation ability of the computer.Numerical simulations were carried out to investigate the effect of different time steps on the residual stress compared with that from experiments and the choosing strategy was validated.