为了解决冲击动力学中的大变形问题,提出了一种光滑粒子流体动力学-有限元法(SPH-FEM)转换算法,以等效Mises应力作为转换判据,将冲击过程q-局部大变形区域的有限元网格转换为SPH粒子.该算法在大变形区域使用具有优势的SPH,在小变形区域使用精度和效率更高的FEM,为冲击动力学问题的数值计算提供了一条有效途径.使用SPH-FEM转换算法对圆柱形钢弹正冲击钢板发生冲塞破坏的过程进行了三维数值计算,计算结果与实验吻合较好,显示了该算法在计算精度方面的优势.在实际工程中,需要根据具体材料的失效模式,选择更加合适的转换判据.%An algorithm to automatically convert 3D distorted finite elements into SPH (smoothed particle hydrodynamics) particles is proposed, which handles the problems with extreme distortions in impact dynamics. Mises stress criterion is taken, and the SPH-FEM(finite element method) conversion algorithm allows to use accurate and efficient FEM in the lower distortion regions,and SPH in the higher distortion regions. The perforation of a cylindrical steel projectile impacting a plate target is simulated in 3D using the SPH-FEM conversion algorithm. The good agreement between the computed result and the experimental observation shows the accuracy superiority of this algorithm. Corresponding conversion criterion should be chosen according to the material failure mode in engineering application.
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