An update on the development of techniques for the determination and modelling of the impact behaviour of adhesives and bonded structures used in the automotive sector

The automotive sector is one of the key users of adhesive bonding, adopting this technology for the manufacture of high performance multi material structures, seeking to reduce vehicle weight and increase overall stiffness. In these industrial applications, the design of bonded structures is supported by numerical models, which require the determination of the mechanical properties of the adhesives and the adherends, taking into account factors such as temperature and strain rate dependence. However, while the design of bonded joints under quasi-static loadings is currently well understood, the design of impact resistant structures is much more complex, since it requires the establishment of accurate models for the strain rate dependent behaviour of the materials used in vehicle construction. This document provides an updated outlook on the research work being performed by the authors in this specific field. Most of the work is devoted to the analysis of the effects of strain rate on the behaviour of adhesives and adhesive joints. This includes high strain rate characterisation of the mechanical behaviour of modern crash resistant adhesives, using both standardised and custom testing procedures. Special experimental equipment has also been developed for impact testing procedures, including high strain rates and mixed mode conditions and full-size specimens.