Mechanical Requirements of Tailored Joining Technologies for Spring Elements in Multi-Material-Design

Abstract

The conflict of targets between mass reduction, strength and costs of a multi-material-design module is addressed by the example of a multi-material hybrid leaf spring. A rather simple model is defined such that one portion of the spring is made by glass fiber reinforced plastic (GFRP) and the other portion by a high strength spring steel.In a rather basic approach the leaf spring is exposed to uniaxial bending. The mass of this module is discussed as a function of the strength of the joint. Subsequently, the leaf spring is exposed to a multi-axial bending, e.g. as an effect of side loads. Hence, the relative strength of the anisotropic portion (GFRP) of the leaf spring is diminished whereas the strength of the isotropic portion (high strength spring steel) is only slightly affected. The mass of the module is discussed in the same way. It is shown up by this analysis that the conflict of targets can be solved in different ways by considering the specific strength of the joint.It is the target of this basic study to derive the mechanical requirement of strength of this tailored joint which has to be met by its design in order to solve the addressed conflict of targets in a preferable optimal way.