The equivalent stress σv is determined from the basic stresses (normal and shear stresses). It can be determined according to various stress hypotheses.
Von Mises: Distortion Strain Energy Hypothesis
This hypothesis assumes that the material fails when the distortion strain energy exceeds a certain limit.
Tresca: Shear Stress Hypothesis
The hypothesis assumes that failure is caused by the maximum shear stress.
Rankine: Normal Stress Hypothesis
This hypothesis assumes that the greatest principal stress leads to failure.
Bach: Principal Strain Hypothesis
According to this hypothesis, failure occurs in the direction of greatest strain. This statement is similar to the stress analysis according to Rankine. However, the principal strain is used instead of the principal stress in this case.
