An elasto-plastic finite-element analysis of the axisymmetric sheet stretching process

Abstract

This paper applied the incremental updated Lagrangian elasto-plastic finite-element method to sheet stretching under the axisymmetric condition. The extended r-minimum technique is utilized such that each incremental step size is determined by not only the yielding of an element Gaussian point but also the change of the boundary condition along the tool-metal interface. Experimental tests were performed to demonstrate the formulation of the theory and the development of the computer code. The experimental load shows good agreement with the value of the punch load predicted in the finite-element method. In the solution of the numerical calculation, the entire loading process history, the deformed geometry, the nodal velocity and the distribution of strain are obtained also by carefully considering the moving boundary condition. From the results of the experiment and the FEM, it may be concluded that the method proposed here provides a good model to simulate the axisymmetric sheet stretching process.