周边切口短圆柱试件的杆杆型冲击拉伸试验系统的弹塑性有限元分析

基于一维试验原理提出了用带有周边切口的短金属圆柱试件进行平面应变型弹塑性动态断裂韧度的测试方法；对该复杂的动力学系统进行了轴对称的弹塑性有限元分析，并计算了动态围道^J积分；根据对试件功能转换关系的分析和Rice公式的物理意义，提出了用试件两端平功载荷－两端相对位移曲线（P^-△）推广Rice公式计算试件的远场J积分，由此得到的P^-△曲线基本上消除了与裂纹运动无关的质心运动动能的影响。论证了J积分作为裂端的表征参量，且当切口深度比大于70％时，Rice公式有较高的计算精度，为平面应变型弹塑性动态断裂韧度的表征与测试提供了依据。

ELASTIC-PLASTIC FEM ANALYSIS FOR THE BAR-BAR TENSILE IMPACT APPARATUS WITH A CIRCUMFERENTIALLY NOTCHED SHORT METAL BAR

Based on one dimensional experiment priciple and by using the self designed bar bar tensile impact apparatus, we have developed a novel test methed for studying the fracture properties of materials under impact loading. The specimen of the short round bar with a circumferentially notch is used in fracture test condition. Dynamic elastic plastic FEM analyses of the testing system with a circumferentially notched short round bar are performed. An invariant finite domain (t) integral expression employed as dynamic energy release rate is calculated. The analyses demonstrate that (t) integral can be regarded as the crack tip characterizing paprameter for the circumferentially notched short round bar. We also calculated the value of the J integral from load displacement curve. By comparing (t) with J dc and J * dc , we evaluated the accuracy of a deep crack formula based on the load displacement behavior. Our analyses provide a criterion for characterizing and measuring the plane strain mode elastic plastic dynamic initiation fracture toughness.