Abstract Modified nonlinear Mohr–Coulomb (M–C) fracture criteria for isotropic materials and transversely isotropic unidirectional (UD) composites are proposed in the present study. The classic linear M–C fracture criterion for isotropic materials is briefly revised, and its deficiencies and limitations are identified. Based on the modification of a nonlinear variation of the M–C criterion for UD composites, the mathematical expressions of the proposed fracture criteria are formulated. The undetermined parameters in the expressions are calibrated by the experimental data from the simple tension, compression and shear tests. The presented fracture criteria show good agreement with the test data of various kinds of isotropic materials and transversely isotropic UD composites under different stress states.

中文翻译：

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各向同性材料和横向各向同性 UD 复合材料的修正非线性 Mohr-Coulomb 断裂准则

摘要 本研究提出了用于各向同性材料和横向各向同性单向 (UD) 复合材料的修正非线性 Mohr-Coulomb (M-C) 断裂准则。对各向同性材料的经典线性 M-C 断裂准则进行了简要修订，并确定了其缺陷和局限性。基于对 UD 复合材料的 M-C 准则非线性变化的修改，提出了所提出的断裂准则的数学表达式。表达式中未确定的参数由简单的拉伸、压缩和剪切测试的实验数据校准。所提出的断裂准则与各种各向同性材料和横向各向同性UD复合材料在不同应力状态下的试验数据吻合良好。