Adaptive control for finite element analysis in plasticity

摘要

An error on the constitutive law, called dissipation error, is used to measure and to enhance the quality of finite element computations of plastic structures whose behaviour is described by internal variables. This measure takes into account all the classical sources of error involved in the computation: the space discretization (the mesh), the time discretization and the iterative techniuqe used ot solve the nonlinear discrete problem. To quantify more specifically the contribution of these three error sources to the error, three error indicators are calculated: a space indicator, a time indicator and an iteration indicator. Then, the error and the three indicators are used in an adaptive strategy: the space indicator allows us to adapt the mesh, the time indicator to adapt the time discretization and the iteration indicator makes it possible to limit the number of iterations of the global iterative algorithm.