Abstract
The evolution of environmentally driven legislation is driving car manufacturers to reduce fuel consumption and increase recycling rates for vehicle construction materials. These considerations have resulted in the need for weight-saving structures composed of low-density materials with good recyclability. Aluminium is an ideal candidate, and in this context, Pechiney continues to develop cast, rolled and extruded automotive aluminium products.
Aluminium extrusions provide many advantages: low specific weight, multi-functional properties, compatibility with various joining techniques and low tooling costs. Automotive applications may also require forming (typically stretch bending or hydroforming), and in this case aluminium extrusions with optimised mechanical characteristics and careful choice of section geometry are necessary.
This work presents a method to aid designers in the choice of aluminium alloys for bent extruded components. The method is based on experimental tests, numerical tools and analytical calculations. Experimental measurements have been conducted in collaboration with automotive suppliers. They involved different alloys of the 6000 series with various heat treatments. Numerical calculations, validated with experimental results, are based on an explicit finite element code. The analytical calculations predict the springback of extrusions after bending. A correlation between bending limits and mechanical properties is proposed.