Imperfections generation in finite element models of welding

Welded components contain certain geometrical imperfections which may affect buckling behaviour of the final product. However, geometrical perfect models are usually used in the finite element method simulation. When a simple weld model is used, the mode of the end-distortion is predictable. Imperfections are created in the same shape as predicted. This paper presents a novel numerical approach on how to generate geometrical imperfections in finite element models. In this approach, as first, a large temperature gradient for the weld seam elements is prescribed. Then a linear steady-state thermal analysis is conducted and is followed by a structural analysis to determine the initial stress stiffness matrix for an eigenvalue analysis. The mode shapes of eigenvalue analysis are finally used to generate the imperfections. The results obtained in the course of this work allowed to calculate resultant welding distortion more accurate.