中文摘要：

对含垂直穿透裂纹板受拉伸载荷作用的断裂过程进行了数值模拟.选用增量型弹塑性本构关系,采用有限元方法求解虚功原理方程.首先对弹塑性杆的动态响应进行了数值计算.参照LS_DYNA中处理断裂问题的单元失效方法,对受拉伸载荷作用的垂直穿透裂纹板断裂过程进行了计算.结果表明：一维杆的弹性波和塑性波的计算结果和解析解相符,说明了该方法和计算程序计算结构动态响应的可靠性.受冲击拉伸载荷作用,应力波在板中传播并在裂纹表面反射后出现畸变,裂纹尖点出现应力集中,裂纹沿初始方向扩展,当裂纹扩展长度为初始长度2倍时,裂纹在板边界处出现分叉,裂纹扩展过程和理论分析结果相符.

英文摘要：

Three-dimensional computation was carried out on the evolution of a crack embedded in an elastic-plastic metal plate.An increased type constitutive relation was adopted to describe elastic-plastic material,and the governing equation in Lagrangian form was solved with the finite element method（FEM）.The computed elastic and plastic waves propagating in the bar are in good agreement with analytical solutions,validating the methods and codes.Employing criteria used in LS-DYNA software to tell the failure element,propagation of a vertical crack embedded in a plate was computed,too.Von Mises stress contours at different time demonstrated the crack evolution.Under the shock loading,stress waves were formed and propagated inwards from the plate edge.The stress waves reflected on the crack surface and deformed.The stress concentrated on the sharp corners of the crack and caused the crack to expand further.As far as the crack length was twice its initial length,the crack started to bifurcate till it arrived at the plate edge.The crack evolution is in good agreement with theoretical estimation.