Using ring-shape specimens containing two aligned cracks on the internal surface of the ring, two test configurations subjected to tensile or compressive loads namely (i) diametrically compressed ring (DCR) and (ii) diametrically tensile ring (DTR) specimens were suggested to investigate the full mixed-mode I/II fracture problem. The fracture parameters, including modes I and II stress intensity factors and T-stress, were determined numerically for these two test specimens with different crack lengths and crack angles. Also, the ability of the specimens was examined by conducting experimental fracture tests on gypsum material. In addition, the direction of fracture kinking was investigated both experimentally and theoretically. The experimental results were then compared and predicted using the mixed mode fracture criteria such as maximum tangential stress (MTS) and generalized maximum tangential stress (GMTS). The normalized fracture toughness (K_IIc/K_Ic) ratios of the tested DCR and DTR specimens were about 0.72 and 0.95, respectively. Such difference was related to the considerable effect of T-stress values and it was shown that the GMTS criterion provides more accurate predictions for the test results of both DCR and DCT samples compared to the MTS criterion.

使用在环内表面上包含两个对齐裂纹的环形试样，建议采用两种承受拉伸或压缩载荷的测试配置，即 (i) 径向压缩环 (DCR) 和 (ii) 径向拉伸环 (DTR) 试样研究完全混合模式 I/II 断裂问题。断裂参数，包括模式 I 和 II 应力强度因子和 T 应力，对这两个具有不同裂纹长度和裂纹角度的试样进行数值确定。此外，通过对石膏材料进行实验性断裂测试来检查样品的能力。此外，对断裂扭结的方向进行了实验和理论研究。然后使用最大切向应力（MTS）和广义最大切向应力（GMTS）等混合模式断裂准则对实验结果进行比较和预测。归一化断裂韧性 (测试的 DCR 和 DTR 试样的K _IIc /K _Ic ) 比率分别约为 0.72 和 0.95。这种差异与T应力值的显着影响有关，并且表明与 MTS 标准相比，GMTS 标准对 DCR 和 DCT 样品的测试结果提供了更准确的预测。