Ⅰ-Ⅱ复合型尖V形切口脆断准则

Brittle Fracture Criterion for Mixed Ⅰ-Ⅱ type of Sharp V-notch

基于最大周向应力和Seweryn-Novozhilov准则,用线弹性奇异应力场,给出Ⅰ-Ⅱ复合型尖V形切口的脆性断裂准则;并把裂纹作为切口张角为零的V形切口,这样就把V形切口问题与裂纹问题的断裂准则统一起来.为了验证该准则,本文采用有机玻璃板材加工多种V形切口试件进行了拉伸实验;同时,应用该准则对文献[16]中复合载荷下双边切口试件进行了起裂方向和临界载荷预测,并与其实验结果相比较.结果表明,本文所给出的Ⅰ-Ⅱ复合型尖V形切口脆性断裂准则与实验是相吻合的,适合于实际工程应用。

Based on the maximum circumferential stress and the Seweryn-Novozhilov criterions,the brittle fracture criterion for mixed sharp Ⅰ-Ⅱ type of V-notches is proposed according to the singular stress fields,and the crack is considered as the V-notch with zero open angle,thus the fracture criterion for crack problems is unified with that of V-notch . To verify the validity,tensile experiments were carried out on several kinds of V-notched PMMA specimens. Following the criterion,the predicted crack orientations and critical loads for the double-edge V-notched specimens in some references are compared with the experimental observations to ensure the engineering applications.