A criterion is developed for the unhomogeneous yielding of materials containing arbitrarily oriented ellipsoidal voids. The criterion is built upon classical estimates for pure pressure and pure shear. A data-driven approach is then followed to incorporate the effects of void shape and orientation. A large number of micromechanical unit cell results are used to calibrate the yield criterion. A key feature of the criterion is that it predicts a significant reduction of the effective shear yield strength due to mere void inclination, with the reduction increasing with the void dimension perpendicular to the shear. The coupling between tension and shear deformation results in an apparent rotation of the yield surface, which provides a sound micromechanical basis for predicting void closure in shear among other new features. Once supplemented with evolution equations of relevant internal parameters, the resulting constitutive formulation will enable ductile failure simulations heretofore impossible to carry out on a sound physical basis for general loading conditions.

中文翻译：

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多孔材料非均匀屈服准则


针对含有任意方向的椭圆体空隙的材料的不均匀屈服制定了标准。该标准建立在纯压力和纯剪切的经典估计之上。然后采用数据驱动的方法来合并空隙形状和方向的影响。大量的微机械晶胞结果用于校准屈服准则。该准则的一个关键特征是，它预测仅由于空隙倾斜而导致有效剪切屈服强度的显着降低，并且随着垂直于剪切力的空隙尺寸的减小而增加。拉伸和剪切变形之间的耦合导致屈服面明显旋转，这为预测剪切中的空隙闭合以及其他新特征提供了良好的微观力学基础。一旦补充了相关内部参数的演化方程，所得的本构公式将使延性破坏模拟成为可能，而迄今为止，在一般载荷条件下，无法在良好的物理基础上进行延性破坏模拟。