考虑单元网格尺寸影响的RTCL准则修正及应用研究

Modification and application of RTCL criterion considering mesh size effect

考虑单元网格尺寸对船体碰撞失效仿真结果的影响,开展拉伸试验与仿真,通过回归分析得到网格尺寸与失效应变的函数关系,基于该函数对RTCL失效准则进行修正并编写VUMAT子程序。最后开展多种应力状态下的拉伸试验与仿真,对比修正前后仿真结果可知:修正方法可有效降低不同应力状态下仿真的网格尺寸效应,其中对于中低应力三轴度状态的修正效果显著,对于高应力三轴度状态的修正效果稍差。

Considering the effect of mesh size on hull collision failure simulation results, the tensile tests and simulations were carried out. The function between mesh size and failure strain was obtained through regression analysis. Based on this function, the RTCL failure criterion was modified and VUMAT subroutine was written.Finally, tensile tests and simulations under various stress states were carried out. Compared with the simulation results before and after modification, it can be seen that the modified method can effectively reduce the mesh size effect under different stress states, of which the effect is significant for medium and low stress triaxiality, and slightly worse for high stress triaxiality.