Limiting drawing ratio of the cup-drawing process with stabilization matrices approach

This paper adopts a four-node bi-linear quadrilateral element incorporating stabilization matrices to analyze the prediction of the limiting drawing ratio (LDR) in the axisymmetric cylindrical cup-drawing process. These stabilization matrices can control the 'hour-glass' effect occurring with the reduced integration scheme. To validate the formulation the theory and the development of a computer code, experimental dies for the cup-drawing process have been signed and tested in a sheet-forming machine. The predicted value of the punch load and thickness distribution in the simulation correlate well with the experimental results. In particular. the extended r(min) technique, used to determine the punch travel in each step, is proven adequate for tracing the penetration and separation phenomena between the node and tool contact over the entire deformation history of the cup-drawing process. (C) 1999 Elsevier Science S.A. All rights reserved.