This paper addresses the rheometrical flow that combines squeezing and rotating between coaxial parallel discs. Experimental results obtained with this flow have been used as evidence that the von Mises criterion holds for the materials tested. In fact, these results are frequently referred to as a proof of the validity of the von Mises criterion. However, the detailed analysis described here shows that conditions for a viscometric motion are met at the walls (at the walls only), just like in other geometries used in shear rheology. Therefore, the shear component of the yield stress tensor should be identical to the one measured in all other viscometric flows. Since no assumptions are needed with respect to the normal stresses, this identity holds for general isotropic yield stress materials, i.e. with a yielding criterion of the form $f(J_{2,y},J_{3,y})=0$. In this regard, we emphasize the need to measure the normal stresses in this geometry in order to obtain the full yield stress tensor and, consequently $J_{2,y}$ and $J_{3,y}$. Moreover, we highlight the necessity to test the material in at least two different types of load to check the validity of a yielding criterion.

本文讨论了在同轴平行盘之间挤压和旋转相结合的流变流。通过该流程获得的实验结果已被用作证明冯·米塞斯标准适用于所测试材料的证据。实际上，这些结果经常被称为von Mises标准有效性的证明。但是，此处描述的详细分析表明，与剪切流变学中使用的其他几何形状一样，在壁上（仅在壁上）满足了粘度运动的条件。因此，屈服应力张量的剪切分量应与在所有其他粘度流中测得的相同。由于不需要关于正应力的假设，因此该等式适用于一般的各向同性屈服应力材料，即屈服准则为$F（{Ĵ}_{2，ÿ}，{Ĵ}_{3，ÿ}）=0$。在这方面，我们强调需要测量这种几何形状的法向应力，以获得完整的屈服应力张量，因此${Ĵ}_{2，ÿ}$ 和 ${Ĵ}_{3，ÿ}$。此外，我们强调必须在至少两种不同类型的载荷中测试材料以检查屈服准则的有效性。