A theory of linear plasticity for plane strain

A reformulation is made of the classical von Mises theory of plane strain rigid-perfect plasticity. The adoption of an anisotropic piecewise linear yield criterion results in two sets of field equations, each equivalent to the classical vibrating string equation. The development of the theory is routine. Certain properties of discontinuous stress and velocity fields are discussed, but the complete development of this aspect of the theory is not given here.By way of example, the complete solution of the classical rigid punch problem is presented.