Buckling Analysis of Aluminium Alloy Structures accounting for Friction Stir Welding Effects

The joining of aluminium alloy parts using welding techniques can be responsible for changes in the final structures such as geometrical distortions, variation of material properties and residual stresses. These effects can influence the strength of structures and must be taken into account at the design stage. The main objective of the work, described in this paper, is to assess the influence of friction stir welding processes on the load capacity of a stiffened panel subjected to longitudinal compressive loads. A numerical model, based on a finite element approach and simulating the friction stir welding process, is developed in order to evaluate these induced effects on a stiffened panel structure. Afterwards, a compressive load is applied on the structure until the collapse load is reached. The results are compared with those coming from a model not including welding simulation. It is inferred that welding effects (namely, residual stresses and material properties changes) can strongly reduce the collapse load level of the studied structure

Numerical simulation of AA2024-T3 friction stir welding (FSW) process: sensitivity analyses and influence of decisions during modelling stages

The main objective of the present work is to assess the influence of several parameters relevant for Finite Element Analysis (FEA) in modelling Friction Stir Welding (FSW) processes on AA2024-T3 plates. Several tests were performed including variations on the type of shell elements, number of integration points across thickness direction and mesh refinement levels, aiming for good accuracy and low computational cost. On the one hand, several setups of the mechanical boundary conditions, modelling the clamping systems, were also tested, leading to the conclusion that the results, in terms of longitudinal residual stresses, are significantly affected by this factor. On the other hand, variations on the heat input distribution showed a reduced effect, or almost null, on the final results