一种用于汽车碰撞模拟的网格变量映射算法及其验证

Mesh Variables Mapping Algorithm Used in Car Crash Simulation and Its Verification

在汽车碰撞模拟中,需要考虑零件冲压后的板料厚度变化、材料硬化以及残余应力对仿真结果的影响。由于冲压仿真后的零件仿真模型中网格变形大,单元尺寸小,并且总的单元数量多,冲压后的网格模型并不适合碰撞仿真。在有限元仿真结果分析基础上,提出一种把冲压仿真模型网格变量(如应力、应变和厚度分布)映射到碰撞仿真模型网格上的变量映射算法,并开发计算程序。通过比较采用不同网格的汽车B柱冲击仿真模型的计算结果,验证上面的算法。该算法解决了网格重划后其变量的映射问题,可以减少网格重划工作,为在汽车碰撞仿真中考虑冲压效应提供一种有效的方法。

In car crash simulation, the effects of thickness change, hardening and residual stress occurring during the forming process of sheet metal part on the car crash simulation results should be considered. The mesh model transferred directly from the forming equipment is usually not suitable to simulate the car crash due to obvious deformation of mesh, large number and small size of elements. An algorithm to transfer the element variables such as stress, strain and thickness distribution from the sheet metal forming mesh system to car crash forming simulation mesh system is proposed. A calculation program is also developed according to the proposed algorithm. The effectiveness of the algorithm is verified by comparison of one car body B pillar crash result with two different meshes. The algorithm can decrease the remeshing of model and avoid the variables mapping after remeshing. It provides a convenient method to incorporate forming effect in car crash model.