Stretch Bending of Aluminum Extrusions: Effect of Tensile Sequence

Abstract

An experimental stretch bending study is presented in this paper. A total of 29 tests on 2 m long rectangular hollow section aluminum specimens were performed in a purpose-built stretch bending rig. The tests were carried out under different tensile force combinations, or tensile sequences, in order to investigate the influence of the force on certain response parameters. Stretch bending is an important industrial forming process, and die force, sagging, and springback are thus considered the most relevant response parameters. The tests show that the sagging is very sensitive to the applied tensile sequence. Furthermore, a close correlation between sagging development and strain evolution is observed. The springback is controlled by the tensile force level immediately before unloading. Finally, the difference in response between two tests performed with different constant, tensile force levels is insignificant.