The problem of the flow of a plastic material along a surface (Q579006)

The equations of the perfect, rigid-plastic membrane theory of shells whose thickness is variable and unknown, are studied. The equations were studied earlier for the case of a smooth surface of flow or for regular modes; singular modes are discussed below. It is shown that in the case of such modes and equations in question split into two systems. The first system yields the forces and the shell thickness, and after this the velocities are found from the second system. The Tresca flow conditions and the maximum reduced stress are studied as examples.