Automotive box section design under torsion Part 2: behaviour and implications on weight reduction

A well-calibrated and validated finite element procedure, described in companion paper 1, was used in producing data on the stiffnesses, elastic limits and strengths of automotive box sections under torsion. The modelling procedure was first used in analysing all the experimental geometries, and these preliminary analyses helped to define the scope of further numerical work. This work, which consisted of 76 analyses, investigated the main effects identified-section thickness, cross-sectional area, model length and section design-and their interactions. Particular emphasis was given to quantifying the implications of the various effects on weight reduction by replacing spot welding with adhesive bonding as the fabrication technique. Further tests and analyses were also conducted to investigate the effects of weld pitch on torsional stiffness and to compare the properties of adhesively bonded, laser-welded and spot-welded sections.