Advanced numerical method for fast prediction of welding distortions of large aircraft structures

Abstract

An advanced method for efficient numerical simulation of welding distortion is developed. This method is based on combination of the local non-linear thermo-mechanical FEM calculation of plastic strain distribution after the welding process and the global linear FEM calculation of welding distortion of the whole structure. As the application example, the new method was used for numerical simulation of welding distortion after laser beam welding of large samples imitating parts of aircraft panels. The welding process and the final structure shape was calculated for several series of so-called 'stringer-to-skin' weldments (T-joints) having different stringer height. The second application example shows the results of fast calculation of welding distortion of a large aircraft structure containing laser beam welds of total length of ten metres and its comparison to the experiment. The obtained results show a very good agreement with experimentally measured welding distortions. Using the new method the final form of the structures was calculated with the gain factor of approx. 10,000 in comparison with conventional 3D non-linear FEM calculation.