An outlook on multi material body solutions in the automotive industry – possibilities and manufacturing challenges

In the automotive industry, mass reduction and lightweight design is a continuing trend that does not show signs of declining. When looking at where to reduce weight in a vehicle, the body is a preferential subsystem due to its large contribution to overall mass and the stability of body composition over a specific model range. The automotive industry of today moves toward a greater differentiation in materials that compose a car, which can be seen in the several different multi material vehicle bodies that have been introduced by manufacturers in recent years. But while mixing materials may contribute to a good compromise between weight reduction and vehicle cost, it also proposes a number of challenges that need to be addressed. Among other material factors, the different coefficients of thermal expansions might introduce new stresses during painting and curing. Joining processes and possible chemical reactions between materials also needs to be taken into account, the same with the question of whether to integrate or differentiate different functions in a system. If the manufacturing plant uses mixed model assembly lines, design of end effectors for gripping multiple different materials is another challenge not previously encountered in this context. In this paper, a number of production and manufacturing related challenges are discussed, and the authors highlight different areas where the requirements of design engineering tools needs to be evaluated for these new multi material concepts and design decisions in order for automotive manufacturers to ensure future market competitiveness.