Tresca and von Mises models are exa

Tresca and von Mises models are examples of homogeneous yield functions of degree 1 and 2, respectively. Higher orderhomogeneous yield functions were proposed, for instance, by Hershey (1954) and Karafillis and Boyce (1993). Nevertheless,as mentioned above, these functions reduce to homogeneous functions of degree one. Due to their isotropic nature, the par-ticular functions mentioned above are expressible in the principal reference frame using the corresponding eigenvalues ofthe stress deviator. In order to formulate them in a general reference frame, the principal stresses need to be written in termsof invariants, which are themselves functions of the stress components in this non-principal frame.