Finite element analysis for the dynamic behaviour investigation of a spot-welded structure under initial stress influence / Crystal Peter

The development of accurate analytical modelling of the representation of laser spot welds in assembled structures has become an interesting topic of challenge in the structural dynamics community. This is because laser spot welds contribute significantly to the integrity of the structure and the overall dynamic behaviour of an assembled structure. However, accurately determining the dynamic behaviour of a laser spot welded structure using the finite element method is challenging due to the difficulties in representing laser spot welds, which are usually associated with initial stresses. These problems are the main motivation for achieving the goal of this research, which is to investigate the influence of initial stresses on the dynamic behaviour of a laser spot welded structure. The structure under investigation is a hat-plate structure, a simplified structure taken from a car Body in White (BiW) joined by laser spot welding. For the experimental modal analysis, the dynamic behaviour of the hat-plate structure was measured with an impact hammer and a roving accelerometer under free-free boundary conditions. Meanwhile, the CWELD element connector for the laser spot welds of the FE model was developed to predict the dynamic behaviour of the structure. A new scheme was developed to include the initial stresses in the FE model.