Progress in mixed Eulerian-Lagrangian finite element simulation of forming processes

A review is given of a mixed Eulerian-Lagrangian finite element method for simulation of forming processes. This method permits incremental adaptation of nodal point locations independently from the actual material displacements. Hence numerical difficulties due to large element distortions, as may occur when the updated Lagrange method is applied, can be avoided. Movement of (free) surfaces can be taken into account by adapting nodal surface points in a way that they remain on the surface. Hardening and other deformation path dependent properties are determined by incremental treatment of convective terms. A local and a weighed global smoothing procedure is introduced in order to avoid numerical instabilities and numerical diffusion. Prediction of contact phenomena such as gap openning and/or closing and sliding with friction is accomplished by a special contact element. The method is demonstrated by simulations of an upsetting process and a wire drawing process

Elements of plasticity : theory and computation

311 p. : ill. ; 24 cm

Numerical analysis and design of industrial superplastic forming

In the aerospace industry, the production of structural shell components with a prescribed thickness distribution by superplastic forming requires the specification of the initial thickness profile in the undeformed sheet. To this purpose, a finite element simulation methodology developed previously for the analysis of superplastic deformation processes along with the optimum monitoring of the forming pressure is extended to the determination of the initial thickness profile. The utilization of the procedure is shown for the pre-contouring of the blank for the industrial production of a satellite tank. The examination of the produced part confirms that the requested thickness distribution is achieved fairly well and thus proves the appropriateness of the proposed computational approach as a tool for the process design in superplastic net-shape forming