黏弹性界面断裂分析的增量“加料”有限元法

提出了一种适用于黏弹性界面裂纹问题的增量“加料” 有限元方法. 利用弹性界面裂纹尖端位移场的解答,通过对应原理和拉普拉斯逆变换近似方法,得到了黏弹性界面裂纹的尖端位移场. 用该位移场构造了黏弹性界面裂纹“加料” 单元和过渡单元位移模式,推导了增量“加料” 有限元方程,求解有限元方程可获得应力强度因子和应变能释放率等断裂参量. 建立了典型黏弹性界面裂纹平面问题“加料” 有限元模型,计算结果表明,对于弹性/黏弹性界面裂纹和黏弹性/黏弹性界面裂纹,该方法都能得到相当精确地断裂参量,并能很好地反映蠕变和松弛特性,可推广应用于黏弹性界面断裂问题的计算分析.

THE INCREMENTAL ENRICHED FINITE ELEMENT METHOD FOR FRACTURE ANALYSIS OF VISCOELASTIC INTERFACE

The incremental enriched finite element method (FEM) is developed for viscoelastic interface crack problems. According to the basic displacements fields of elastic interface crack tip, the crack tip displacement fields of viscoelastic interface crack are derived through the correspondence principle and an approximate Laplace inverse transform method. By incorporating the displacement expressions to the common element, the displacement models of enriched and transition elements are obtained, and then the incremental formulations of the enriched FEM are deduced. The fracture parameters, stress intensity factors and strain energy release rate can be obtained through solving the finite element equation. The enriched finite element model of typical plane problems containing viscoelastic interface crack are constructed, and the fracture parameter solutions show that the presented method is quite accurate for both elastic/viscoelastic and viscoelastic/viscoelastic interface crack and can reflect the creep and relaxation characteristics. It can be applied to the fracture analysis of viscoelastic interface crack.