DETERMINATION OF OPTIMAL MOTION OF TOOLS IN METAL-FORMING PROCESSES BY CONTROLLED FEM SIMULATION

A method for determining optimal motion of tools in metal forming proc esses from the finite element simulation is proposed. In this method, the calculated results such as the deforming shape and the stress and strain distributions are monitored in each deformation step of the fin ite element simulation, and the forming motion of tools is iteratively optimized on the basis of a feedback control referring to the monitor ed results. The present method is applied to determination of the moti on of rolls for forming plates into desired curvatures in plane-strain three-roll bending. Fuzzy reasoning is used to obtain the movement of the top roll in each deformation step, and the effects of the plate t hickness and the difference between the desired and the calculated cur vatures are taken into consideration. To avoid the delay of the contro l, the effect of the curvature distribution during bending is included in the fuzzy reasoning. It is shown that decrease in the curvature ne ar both ends of the bent plate in three-roll bending is prevented by t he use of the present method.