All yield criteria that determine the onset of plastic deformation in crystalline materials must be invariant under the inversion symmetry associated with a simultaneous change of sign of the slip direction and the slip plane normal. We demonstrate the consequences of this symmetry on the functional form of the effective stress, where only the lowest order terms that obey this symmetry are retained. A particular form of yield criterion is obtained for materials that do not obey the Schmid law, hereafter called non-Schmid materials. Application of this model to body-centered cubic and hexagonal close-packed metals shows under which conditions the non-Schmid stress terms become significant in predicting the onset of yielding. In the special case, where the contributions of all non-Schmid stresses vanish, this model reduces to the maximum shear stress theory of Tresca.

在与滑移方向和滑移平面法线的符号同时变化相关的反转对称性下，所有决定结晶材料塑性变形开始的屈服标准必须是不变的。我们证明了这种对称性对有效应力函数形式的影响，其中仅保留了遵守这种对称性的最低阶项。对于不遵守施密德定律的材料，以下称为非施密德材料，可获得特定形式的屈服准则。将该模型应用于体心立方和六方密堆积金属表明在哪些条件下非施密德应力项在预测屈服开始时变得重要。在特殊情况下，所有非施密德应力的贡献都消失了，