摘要：The I-II mixed crack is one of the most common cracks contained in the engineering materials. In this study, the theoretical solutions of the brittle tensile failure capability K J , the tensile strength σ c , and the initial fracture angle θ 0 are developed for the engineering materials containing the mode I-II mixed cracks (the crack angle is β ) under uniaxial tensile stress loading based on the maximum circumferential stress criterion. Additionally, under the same frame and boundary conditions, it is concluded that the preponderant crack angle β is 68.09 which making the cracks are most easy to fail and propagate; the corresponding brittle tensile capability K J is 0.97 K I C , and the tensile strength σ c is σ c =0.97K IC /√pa . Based on the results stated above, it is further concluded that, in the engineering structure design, if the tensile strength of materials σ c is given, the allowed maximum length of cracks a 0 is limited to 0.94 K 2 IC / pσ c 2 , which would provide the theoretical foundations for limiting the maximum length of cracks, and detecting cracks in engineering design.
