A Two-grids/projection Algorithm For Dynamic Elasto-plastic Torsion Problem

In this paper, a two-grids method with projection for the dynamic elasto-plastictorsion problem is presented. First, backward Euler time scheme is used to transform theoriginal parabolic variational inequality(PVI) into an elliptic variational inequality(EVI)of the first kind with a constraint on the solution space; then two different penaltymethods are applied and it reduces the EVI of first kind to an EVI of the second kind,and also the equivalent nonlinear penalized variational equation is given.Marchuk-Yanenko splitting scheme is used to transform the penalized variationalequation to two coupling subproblems. Applying different approximate schemes andmeshes on the two subproblems, a two-grids projection algorithm is introduced toestablish the relation between discontinuous and continuous approximations on differentmeshes. Finally the specialized algorithm implement and numerical experiments arepresented.