Conditions for locking-free elasto-plastic analyses in the Element-Free Galerkin method Original Research Article

The use of finite elements with linear displacement fields in volume-preserving elasto-plastic problems can lead to volumetric locking. Due to the inability of the shape functions to describe certain displacement modes, a response of the structure can be obtained which is much too stiff. The Element-Free Galerkin (EFG) method can provide shape functions that have an intrinsic richer nature and do not exhibit volumetric locking. It is shown that the finite element (FE) method can be conceived as a specialisation of the EFG method, and that for a specific choice of the EFG parameters the FE shape functions are retrieved. Then, volumetric locking behaviour is found again. However, for other choices of the EFG parameters shape functions are obtained that are able to describe isochoric elasto-plasticity without volumetric locking.