Weight reduction in automotive structures—an experimental study on torsional stiffness of box sections

Abstract

Torsional rigidity is an important performance related property of an automotive body-in-white (BIW) structure, which consists of many box hat structures or box sections. An experimental study has been carried out to determine mainly the torsional stiffness but also the elastic limit and the strength of spot-welded and adhesively bonded (and weld-bonded) box sections. The relative contribution of a variety of factors, including joining system used, steel strength, sheet thickness, section area and section design, to the properties of box sections was analysed using factorial design experimentation techniques. It was found that a significant increase in torsional stiffness could be achieved by changing the joining technique, increasing the sheet thickness, increasing the section area and, to a lesser extent, changing the section design. The results are examined and discussed in the context of weight reduction in automotive structures.