In the present research, a new criterion based on maximum shear stress (MSS) theory is developed for fracture investigation of orthotropic materials under mixed mode I/II loading. The crack is assumed to be embedded both along and across the fibers in the isotropic matrix. Self-similar crack propagation is assumed based on experimental observations and the reinforcement isotropic solid (RIS) concept is utilized for theoretical derivation of the criterion. In this model, an istropic crack tip stress field is assumed and the effects of fibers are supposed as stress reduction factors. The superiority of employing MSS theory in conjunction with RIS model is proved by derivation of a direct MSS-based mixed mode fracture criterion with respect to the orthotropic crack tip stress field. Verification of the results is performed by comparison of the fracture limit curves with available experimental mixed mode fracture data.

中文翻译：

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验证钢筋各向同性实体模型结合最大剪应力准则预测复合材料 I/II 型混合断裂

在目前的研究中，基于最大剪应力 (MSS) 理论的新准则被开发用于混合模式 I/II 载荷下正交各向异性材料的断裂研究。假定裂纹沿着和穿过各向同性基体中的纤维嵌入。基于实验观察假设自相似裂纹扩展，并利用钢筋各向同性固体 (RIS) 概念来推导准则的理论。在该模型中，假设各向同性裂纹尖端应力场，纤维的影响被认为是应力降低因素。将 MSS 理论与 RIS 模型结合使用的优越性通过关于正交各向异性裂纹尖端应力场的直接基于 MSS 的混合模式断裂准则的推导得到了证明。