It has been observed that for polycrystalline materials (ductile metals), von Mises condition of constant shearing stress intensity in the state of yielding agrees somewhat better, in general, with experimental data. There are other cases, however, that the Tresca-Saint Venant conditions appear to be in better agreement with experimental data. Thus, the two methods may be regarded as equally possible formulations of the yield condition.
- For the states of uniaxial or equibiaxial stress, the two criteria are equivalent.
- At other stress states yielding occurs at lower stress values according to the Tresca conditions; under equal loading conditions, the Tresca criterion predicts larger plastic deformation than the von Mises.
- Maximum deviation between the two models occurs for the state of pure shear. At this stress state, based on the Tresca conditions, yielding occurs at 87% of von Mises stress