Bi-Material Joining for Car Body Structures: Experimental and Numerical Analysis

Crashworthiness is an important issue in car body design: it describes the ability of the vehicle structure to behave efficiently by absorbing and dissipating energy in a stable and controlled manner during a crash event. Energy management during frontal impact is mainly done through crash boxes in the front rails. These crash boxes are usually slender, thin-walled steel columns, progressively collapsing during impact. Due to a trend in lightweight materials use, it is necessary to gain knowledge about the material behaviour and alternative joining systems. The use of an adhesive as a joining system for different materials was investigated by means of experimental tests on specimens and simple components, made of aluminium and deep drawing steel. A numerical simulation technique was developed to describe and understand the phenomenon. Furthermore, since the behaviour is influenced by the loading rate and the materials used in this application are known to be strain-rate sensitive, static and impact loading conditions were examined.