中文摘要：

为解决基于连续介质力学的离散元方法（CDEM）在高速冲击模拟中因网格畸变导致的系统能量发散问题,提出了一种基于颗粒接触的二维无网格方法（PCMM）。该方法基于颗粒间复杂丰富的接触信息构建三角形单元,通过接触对的演化更新实现旧单元（满足删除条件的单元）的删除及新单元（满足创建条件的单元）的重建,通过在单元内引入流体弹塑性模型实现高速冲击问题的模拟。给出了三角形单元创建的3个必备条件：组成单元的3个颗粒必须彼此接触,任意一个内角必须在30°~150°之间,任意一条边长必须大于平均半径的0.5倍。弹性杆撞击、泰勒杆、碎片云、子弹入射靶板等算例的结果表明了PCMM方法在模拟高速冲击问题方面的正确性及合理性。

英文摘要：

To solve the no convergence problem due to grid distortion when simulating hypervelocity impact problems using continuum-based discrete element method （CDEM）, a 2D particle contactbased meshfree method （PCMM） is presented. In PCMM, triangle elements are created based on complex and abundant contact information between particles. According to the evolution and renewal of contact pairs, old elements （satisfying the deletion condition） will be deleted and new elements （satisfying the creation condition） will be created. By introducing fluid-elastic-plastic model for elements, the hypervelocity impact problems could be simulated well. Three conditions to create triangle element are given： the three particles which the element consisted of should contact with each other; each internal angle of the triangle element should locate between 30 and 150 degree; each edge length of the element should be larger than 0.5 times of average radius. The results of numerical cases （elastic bar impacting rigid wall, Taylor bar, debris clouds, and bullet penetration） show the accuracy and rationality of PCMM.