Isn’t it better to sum von Mises stresses directly ?
Actually yes, but, von Mises is a scalar value. So, in order to make superposition effect, A+B, the components of the stress tensor should be summed (A_σ_xx + B_σ_xx, A_σ_xy + B_σ_xy, …). Then, all the summed σ and tangential stresses should be used to calculate von mises.
I don’t know if the direct sum of Von Mises Arrays does what I said, or it makes only the sum point per point.