Simulation of welded aluminium automotive components

A successful lightweight construction can only be achieved by an optimised combination of material selection, design and fabrication. When using aluminium alloys for light weight components welding is one of the most important joining technologies. Numerical simulation of weld fabrication can be a powerful tool to over come costly trial-and error experiments and to improve the in-service quality of the component. In joint projects of the Fraunhofer-Institute for Mechanics of Materials (IWM) with partners in the automotive industry the capabilities of Finite Element (FE) - analyses using SYSWELD® for the simulation of the weld fabrication have been investigated. The analysis of part of an automotive space-frame-structure, made of aluminium extrusions and casting, is described as an example. The material data needed as input to the simulations have been determined experimentally for the relevant aluminium materials and different zones in laser welds. Results of the numerical simulations in terms of temperature, distortion and residual stresses during and after welding were compared to data measured for the real component. Numerical parameter studies show the influence of heat input, material specific input data, clamping conditions and welding sequence on component behaviour and how to influence it in a favourable way. The results validate the numerical simulation of weld fabrication as a useful tool to support advanced production.