Expert drawbead models for finite element analysis of sheet metal forming processes

摘要

The expert drawbead model which computes the drawing characteristics of the drawbead used in a finite element analysis of sheet metal forming processes is developed. The mathematical models of the basic drawbeads such as the circular drawbead, stepped drawbead, and squared drawbead, whose dimensions and processes are various, are first derived using the bending theory, belt-pulley equation, and Coulomb friction law. Next, the experiments for finding the drawing characteristics of the drawbead are performed. Based on the mathematical model, the expert model of the basic drawbead is then developed employing a linear multiple regression method by which the difference in drawing characteristics between the drawing test and the mathematical model is minimized. For the expert models of combined drawbeads such as the double circular drawbead, double stepped drawbead, circular-and-stepped drawbead, etc., those of the basic drawbeads are summed. Finally, to verify the expert models developed, the drawbead restraining force and bead-exit pre-strain calculated by the expert models of the double circular drawbead and circular-and-stepped drawbead are compared with those obtained from the experiments. The predictions by expert models agree well with the measurements by the experiments. (C) 2001 Elsevier Science Ltd. All rights reserved. [References: 15]