THE BEHAVIOR OF THIN-WALLED, ALUMINUM-ALLOY PROFILES IN ROTARY DRAW BENDING - A COMPARISON BETWEEN NUMERICAL AND EXPERIMENTAL RESULTS

This paper deals with elasto-plastic finite element (FE) analysis of a rotary draw bending process using eight-node brick elements and contact elements. The objective of the study is to determine the applicability of using numerical simulation to predict bendability and elastic springback in industrial bending. Particular attention is paid to studying the effects of die radius and interface friction on flange sagging and springback. The computations have been validated by experiments conducted in a standard rotary draw bending machine. Single and double chambered cross-sectional shapes in alloy AA6063 were bent into different radii, with and without use of internal mandrels. The results show that by applying models that give an accurate description of material strain-hardening and interface friction, the simulated behaviour coincides well with the experimental behaviour. It is concluded that FE analysis has been used successfully to reproduce experimental results. The simulations appeared to be extremely time-consuming, even on a Cray Y-MP supercomputer, but in the near future it is to be expected that simulations are to be regularly used for die design and optimization purposes of bent aluminium alloy shapes.