双向荷载下多裂纹弹塑性双参数断裂分析

Elastic-plastic fracture analysis of multiple-cracks with two-parameters under biaxial loads

运用J-A2双参数理论,对具有共线双裂纹的平板进行弹塑性断裂分析.采用ABAQUS有限元分析软件,分别计算单向加载及双向加载,在不同载荷比时,具有不同裂纹尺寸与不同裂纹间距情况下主裂纹的断裂驱动力和约束参数.分析结果表明:与裂纹平行的横向荷载对裂纹尖端约束参数A2影响很大,在J-积分相同的情况下,横向荷载越大裂纹尖端约束水平越低;在单向加载情况下,随着相邻次裂纹长度的增加,主裂纹尖端约束水平提高;而在双向加载情况下,随着相邻次裂纹长度的增加,主裂纹尖端约束水平降低;但无论是单向加载还是双向加载,随着裂纹间距的增加,主裂纹尖端约束水平均降低.

The elastic-plastic fracture J- A2 method was performed to study the collinear two cracks in plate under biaxial load. By using finite element analysis, the fracture driving force J - integral and constraint parameter A2 of the main crack-front were calculated with different crack sizes and different dis- tances of cracks in biaxial load condition for different load ratios. As a comparison, the analysis result under uniaxial load condition was also presented. Results show that the constraint parameter A2 strongly depends on the tension that parallels with the crack, and the constraint increases with the tension when the J - integrals are the same. The constraint level of main crack-tip increases with the increasing length of the adjacent crack under uniaxial load condition, but it decreases with the increasing length of the ad- jacent crack under biaxial load condition. The constraint level of main crack-tip decreases with the increasing distance of the cracks under all load conditions.