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从理论和数值两个方面进行分析,发现受径向集中力和围压作用的中心裂纹圆盘(CCBD)试件裂纹面接触会对II型应力强度因子产生较大的影响。通过理论研究,分析CCBD受集中力和围压作用裂纹面接触时圆盘内部的应力场,采用断裂力学权函数理论,推导得出在集中力和围压共同作用下,考虑裂纹面闭合时应力强度因子的解析解。然后,使用ANSYS软件建立了相应的数值模型计算应力强度因子,并与理论解和相关文献进行对比验证,证明了理论公式的正确性。无论裂纹张合与否,所提出的解析公式都能计算出不同裂纹长度、加载角、围压和摩擦系数的应力强度因子。最后,利用公式分析摩擦系数对应力强度因子的影响,结果表明:随着摩擦系数的增大,I型裂纹的应力强度因子不变,II型裂纹的应力强度因子随之显著减小;当加载角较大时,裂纹面产生更为复杂的二次裂纹,故压剪断裂测试的推荐加载角范围为30°~50°。
From the theoretical and numerical analysis, it is found that the contact of cracked surface of the center cracked disc (CCBD) subject to radial concentration and confining pressure will have a greater influence on the type II stress intensity factor. Through the theoretical study, the stress fields inside the disc when the CCBD is subjected to the confining pressure and the confining pressure are analyzed. The fracture mechanics weight function theory is used to deduce that under the combined action of the concentrated force and the confining pressure, Analytic Solution of Intensity Factor. Then, using ANSYS software to establish the corresponding numerical model to calculate the stress intensity factor, and compared with the theoretical solution and related literature to verify that the theoretical formula is correct. The proposed analytical formulas can calculate the stress intensity factors of different crack lengths, loading angles, confining pressures and friction coefficients no matter whether the crack is open or not. Finally, the influence of the friction coefficient on the stress intensity factor is analyzed by the formula. The results show that the stress intensity factor of type I crack decreases with the increase of the friction coefficient, and the stress intensity factor of type II crack decreases significantly. When the angle is larger, the crack surface produces more complicated secondary cracks, so the recommended load angle range of the compression shear test is 30 ° ~ 50 °.