Mechanical Characterization of a Polymer-Metal Hybrid Structure for Automotive Applications: Quasi-static and Repeated Impact Tests

Vehicle weight reduction is a core topic in the automotive industry, due to the growing demand for an emission abatement and for the design of sustainable products. This target is usually pursued by the car manufacturer by design lightweight structural and non-structural components. The vehicle suspension system draws particular attention due to its impact on the overall vehicle weight. In this square, in this work, a polymer metal hybrid (PMH) solution for the suspension system of a vehicle is proposed. PMH structures combines the high ductility of the metals with the high mechanical performance and lightweight of the composite materials. The proposed PMH demonstrator replicates, in a simplified geometry, the lower arm of a MacPherson suspension, that is usually subjected to bending loads. As the suspension arms must often withstand to dynamic stresses repeated over time, an experimental campaign was carried out to characterize the bending properties of a PMH demonstrator in repeated impact loads. The test configuration can be associated to a three-point bending. The demonstrator is produced by injection moulding, and it is made of an aluminium insert co-moulded in a short fibre reinforced polyamide main structure. The structure showed good performance when subjected to repeated dynamic impact test in terms of strength and stiffness. The metal insert provided a no-separation function avoiding catastrophic failure, confirming the goodness of the PMH solution for suspension arm applications.