Simulation of Warm Forming of Aluminium 5754 for Automotive Panels

The work described in this paper has been carried out as part of a project investigating implementation of an innovative metal forming process into the automotive industry to produce lightweight, high accuracy, complex-shaped automotive Aluminium panel components using one operation. The project, lasting three years, is a collaboration between industrial and academic partners lead by a Premium Automotive Manufacturer with funding from the UK Technology Strategy Board. As part of the objective to not only investigate but also industrialize the technology, finite element simulation methods have been included in the scope of work. This paper will report on the extensive program of material characterization carried out by the academic partner Imperial College London in order to develop and correlate the simulation models. Focus is on the sensitivity of key material properties to both temperature and forming rate, as well as the variation of friction with temperature for various lubricants. The Simulation method has been developed on two fronts. The initial approach takes an existing model and applies it to warm forming processes, chiefly under isothermal conditions; the required input parameters will be discussed. In parallel, a new and more comprehensive user- defined material model incorporating not only thermal and strain rate parameters but also a continuum damage mechanics (CDM) approach has been developed at Imperial College. The capability of the model to predict Forming Limit Curve measurements of 5754 aluminium sheet at various temperatures will be shown. The project is now in its final phase of forming trials using a prototype tool that has been manufactured based on the simulation work to date.