COMPARATIVE INVESTIGATION INTO IMPLICIT, EXPLICIT, AND ITERATIVE IMPLICIT EXPLICIT SCHEMES FOR THE SIMULATION OF SHEET-METAL FORMING PROCESSES

Abstract

The objective of the paper is to make comparison of the effectiveness of implicit, explicit and iterative implicit/explicit finite-element analysis methods for the analysis of static and dynamic sheet-forming problems. In the finite-element simulation of sheet-metal forming processes, the robustness and stability of computation are important requirements, since the computation time and convergency became major points of consideration due to the complexity of the geometry and the boundary conditions. The implicit scheme employs a more reliable and rigorous scheme in considering the equilibrium at each step of deformation, while in the explicit scheme the problem of convergency is eliminated at the cost of solution accuracy. In the present work the rigid-plastic finite-element method using both the usual membrane elements and bending-energy-augmented membrane elements (BEAM) is employed for computation. Computations are carried out for some typical sheet-forming examples by implicit, explicit, iterative implicit/explicit schemes, including deep-drawing involving two-dimensional hemispherical stretching, a square box and an oil pan. From comparison of the methods, their advantages and disadvantages are discussed.