扩展有限元方法和水平集理论在裂纹扩展中的应用

pplication of Extended Finite Element Method and Level Set Theory in Crack Growth

针对弹靶裂纹等不连续因素导致常规有限元方法计算量大和结果精度低的问题,设计一种将水平集法和扩展有限元法相结合的方法。以具体的杆弹侵彻实验为依据,采用指数间断函数来表征裂纹对位移的影响,利用水平集理论定义比界面高一维的零水平集函数来表示裂纹界面,建立相应模型并进行数值模拟计算。计算结果显示,该方法能够准确地分析裂纹的扩展,并可生成侵彻过程中不同阶段的侵彻图和等塑性应变图。

For solving the problem of discontinuous factors （such as target crack）, that resulting in large amount of calculation and low precision of finite element method, design the extended finite element method procedure through combination of the extended finite element method and level set theory. Based on experiment about projectile penetrates the target, adopt index discontinuous function to show the influence of crack on displacement, use level set theory to define the zero level set function which dimension is higher than interface to express crack interface, build models and carry on numerical calculate. The result shows this method can analysis crack growth accurately, and it can create the pictures of projectile penetrates the target and plastic strain in different stage.