埋藏裂纹应力强度因子的有限元分析

Finite element analysis of stress intensity factor of embedding cracks

采用三维奇异单元模拟裂纹前缘应力应变场的奇异性,建立了计算球形压力容器中埋藏裂纹应力强度因子的有限元模型,有限元分析结果和经验公式计算结果吻合较好,证明所建有限元模型具有较高的准确性和可靠性。通过仿真计算,分析不同因素对应力强度因子的影响,得出了裂纹前缘应力强度因子随裂纹形状、容器壁厚以及裂纹中心与壁厚中心的偏移量与壁厚比值的变化规律。

3D singular elements are employed to describe the singularity of stress-strain field of crack front, and the finite element model for calculating stress intensity factor of embedding cracks in spherical pressure vessel is established. The FEM results agree well with the data calculated from em- pirical formula, which proves the built finite element model is accurate and reliable. The influences of different factors on the stress intensity factor are analyzed by simulation, and the varying patterns of stress intensity factor at the crack front with crack shape, wall thickness of vessel and the ratio of the offset of crack center and wall center to wall thickness are obtained.