Trajectories of principal stresses in the plane-stress state of material obeying the Tresca and Coulomb-Mohr yield conditions.

The article presents as study about trajectories of principal stresses in the plane-stress state of material obeying the Tresca and Coulomb-Mohr yield conditions. The study considered the plane stress state of an ideally plastic material obeying the Tresca yield condition. It also introduced the curvilinear system of coordinates (q1, q2), the coordinate lines of which are the trajectories of the principal stresses o1 and o2 , respectively.