The aim of this study is the development of a macro modelling FEM approach for the characterization of the mechanical behaviour and failure of the spot welds under different loading conditions. In a vehicle, the spot welds are widely used to join the different frame components. The vehicle capability to provide adequate safety in the case of crash situations is affected also by the mechanical properties of the spot welds. It is therefore necessary to take into account the spot weld behaviour in a structural crashworthiness analysis in order to accurately predict the vehicle response. Since the FEM model of the spot weld will be implemented in larger FEM models (vehicle frame), a single solid element was used to model the spot weld and the mechanical properties of both the weld nugget and heat affected zone of the welded area.