Numerical study on the force-controlled stretch bending of aluminum extrusion with complex cross section

The high precision stretch bending of aluminum extrusion is the key technology for aluminum space frame (ASF) car body. A numerical study on the force-controlled forming process for two typical kinds of car used extrusion using dynamic explicit FEM software PAM-STAMP is presented. The effect of cross section rigidity, post-stretching force on forming precision is investigated. It is shown that increasing the rigidity of cross section can decrease cross section distortion and springback. The larger is the post-stretching force, the larger is the cross section distortion. Increasing post-stretching force can reduce springback effectively. The effect of friction coefficient is also investigated, finding that increasing the friction coefficient will decrease the cross section distortion and increase the springback.