Testing and modeling of the strenght of structural hybrid joints

The work deals with the evaluation of the strength and the simulation of the mechanical behaviour of structural hybrid joints. In particular it is addressed to the transportation vehicle construction field, and therefore only suitable technique for this field are taken into account. In the first chapter an overview of the most relevant joining techniques (resistance spot welding, riveting, clinching, self piercing riveting and adhesive bonding) is shown, pointing out some scientific studies useful to understand and discuss the following parts. Later on, a review of the most important works concerning hybrid joints is given. Afterwards, the work done for this thesis is described: first of all a series of interview with industries potentially interested to the application of hybrid joints was done with the aim to understand the needs in terms of working conditions, type of loading etc. Then the experimental campaign is defined, using appropriate statistical methodologies, and finally the result are shown and discussed. In particular the stiffness, the strength and the energy absorption are compared for the different kinds of joints, giving emphasis to the differences between simple and hybrid joints. Since one of the most important needs of the industry is the possibility to simulate the joint behaviour, appropriate techniques to simulate the hybrid joint mechanical behaviour, were developed and shown in the final chapter.