Concepts for Manufacturing a Seat Backrest Structure Dominated by an Extruded Magnesium Alloy

Abstract

Concepts for a lighter seat backrest structure using a MgMnCe-type alloy have been developed, dimensioned and evaluated. The underlying predevelopment process is based on numerical as well as experimental methods at different levels. At component level, profile tests in bending reveal large deformation without local failure. This deformation makes the use of closed rectangular profiles promising for the application in seat frame structures. Two alternative structural concepts have been developed utilizing different joining technologies - a primary concept using friction stir welding and a secondary one basing on injection adhesive bonding. Both concepts use the same magnesium frame. In the consideration and development of associated process routes, the major challenge has been the magnesium-steel joint between frame and gusset. For welding, the joining direction is essential. Therefore, the magnesium material needs to be accessible. On the other hand, injection adhesive bonding demands sufficient joint areas and a filling concept to perform the bonding process. The two alternative concepts respectively illustrate and demonstrate engineering solutions.