围压对巴西裂纹圆盘应力强度因子影响分析

为了研究围压对巴西裂纹圆盘应力强度因子的影响，使用权函数方法得到了围压作用下巴西裂纹圆盘的应力强度因子，进而得到径向集中荷载与围压共同作用下的应力强度因子的计算公式。在此基础上，从理论上分析了围压对巴西裂纹圆盘应力强度因子的影响，分析结果表明：围压对II型应力强度因子无影响，纯围压作用下裂纹趋于闭合；围压和集中力共同作用下，I型应力强度因子随着围压的增大而减小。对比分析了数值分析与理论结果，分析表明，理论与数值结果吻合良好，从而表明了理论分析的正确性。此外，还研究了围压对纯II型裂纹加载条件的影响，结果表明，纯II型裂纹的临界加载角随着围压增大而减小，直至为0。因此，当围压较大时，加载角为0°左右所发生的断裂不一定全是纯I型断裂。

Effect of confining pressure on stress intensity factors determined by cracked Brazilian disk

To analyze the effect of confining pressure on the stress intensity factors (SIFs) determined by the cracked Brazilian disk, the weight function method is employed to obtain the closed-form expressions of SIFs under various confining pressures; and the explicit expressions of the SIFs subjected to both the confining pressure and diametrical force are obtained. Based on the expressions of the SIFs, the effects of confining pressure on SIFs of the cracked Brazilian disk are analyzed. It is shown that the confining pressure has no effect on the SIF of mode II; and the crack subjected to pure confining pressure always tends to close up. The SIF of mode I decreases with the increase of confining pressure when the cracked Brazilian disk is subjected to the combined effect of confining pressure and diametrical force. By comparing the numerical results and theoretical results, it is found that two results are in good agreement, indicating the validity and reliability of the theoretical analysis. In addition, the effect of confining pressure on the loading conditions is also analyzed for pure mode II crack. The results show that the critical loading angle for pure mode II crack decreases with the increase of confining pressure, and gradually tends to 0 degrees. Therefore, the crack generated at about 0 degree of the loading angle is not always the pure mode I fracture at a high confining pressure.