三维裂纹扩展轨迹的厚度效应研究

Research on Thickness Effect of Three-Dimensional Crack Propagation Path

基于ANSYS有限元分析软件,构建了不同厚度穿透裂纹结构在拉伸载荷作用下的计算模型,将含裂结构分为非裂纹体和含裂纹体,独立建模和划分网格,通过位移法求解三维裂纹前缘的应力强度因子值,利用Paris公式计算裂纹扩展量,依据Richard判据确定裂纹偏转角度,借助三次样条曲线拟合新的裂纹前缘曲线,建立三维裂纹扩展仿真方法,开发三维裂纹扩展程序,研究不同厚度下的三维裂纹扩展轨迹。通过数值模拟结果和试验实测结果对比,验明了本文裂纹扩展轨迹分析方法的有效性。研究结果表明,在相同载荷及边界条件下,对于不同厚度的三维穿透裂纹,厚度效应对内部的应力应变场影响很大,裂纹前缘也呈现出完全不同的形态。

Based on ANSYS finite element analysis software,the calculation models of penetrating crack structures with different thickness under tension load were constructed.The cracked structures were divided into non-cracked and cracked bodies,independently modeled and meshed.The stress intensity factors of three-dimensional crack front were solved by displacement method,and the cracks were calculated by Paris formula.The crack deflection angle was determined according to Richard criterion,and the new crack front curve was fitted by cubic spline curve.A three-dimensional crack propagation simulation method was established.A three-dimensional crack propagation program was developed to study the three-dimensional crack propagation path under different thickness.By comparing the numerical simulation results with the experimental results,the validity of the crack propagation path analysis method in this paper was proved.The results show that,under the same load and boundary conditions,for three-dimensional penetrating cracks with different thicknesses,the thickness effect has a great influence on the internal stress-strain field,and the crack front also presents a completely different shape.