Shakedown Analysis by Displacement Method and Equilibrium Finite Element

Elastic perfectly-plastic structures subjected to variable loading are studied under plane stress conditions. Lower bounds of the safety factor with respect to shakedown are obtained by use of an equilibrium finite-element approach and nonlinear programming techniques. The yield condition is defined in each element by a mean yield criterion; the elastic stresses are computed by the displacement method. Numerical Results are presented for two examples. A physical interpretation is given for the Kuhn-Tucker coefficients associated with the nonlinear programming problem.