On Dimensional Control in Rotary Stretch Bending of Aluminum Profiles: Loading-Path Effects

Abstract

In this research, the influences of loading paths on dimensional accuracy in a newly developed flexible rotary stretch bending process were investigated by experimental and numerical approaches. A series of carefully controlled bending experiments were conducted using AA6082-T4 rectangular, hollow profiles. Several representative loading paths — including (i) kinematically-controlled simultaneous stretching and bending; (ii) pre-stretching prior to bending; (iii) post-stretching subsequent to bending; (iv) pre-stretching prior to and post-stretching subsequent to bending — were designed and tested for a given geometrical configuration of bent parts. The critical dimensional characteristics, such as global shape (elastic springback) and cross-sectional deformation, were analyzed and discussed for the products formed under the above-designed loading paths (i)-(iv). Furthermore, finite element analysis was conducted to gain additional insights into the deformation mechanisms that take place for various loading paths. Finally, a guideline for designing the loading paths was developed, thus providing improved process control for achieving formed products with high dimensional accuracy.