Combining Forming Results via Weld Models to Powerful Numerical Assemblies
Forming simulations generally give satisfying results with respect to thinning, stresses, changed material properties and, with a proper springback calculation, the geometric form. The joining of parts by means of welding yields an extra change of the material properties and the residual stresses. Welding simulations are also possible to a very accurate degree, they are however very time consuming, even on large computer systems. Therefore, it is not feasible to include a complete incremental welding simulation in the virtual model of car parts. Instead, simplified weld models are developed that retain the features needed for subsequent calculations (e.g. structural und fatigue calculations), but do not increase the computation time significantly. Thus, a good numerical approximation of the welded construction for specific tasks can be achieved. The proposed method is aimed at early development stages. Usually design variations have to be compared and material and process data are incomplete. The focus of the method is therefore on the speed. At an early stage the tendency of results indicating if a change to a construction or a process yields better results or not is more important than the accuracy. The objective of this paper is to show how the integration of the complete history of manufacturing of the single parts and its combination to larger car components, enhances the capabilities of the virtual model. This integration procedure must be adapted specifically to the different subsequent calculations in order to combine a maximum of reliability with a minimum of computer effort. In this paper it is demonstrated how the performance of a chassis part changes with the inclusion of both the plastic forming effects and the effects of welding as provided by the simplified weld models. The results are compared to the results of the same part where the manufacturing stages were neglected, which is industrial standard nowadays.
Kim KOSE, Bert RIETMAN
Welding, Process Chain, Virtual Prototyping.