Validation and model updating of weld in finite element model of K-node structure using experimental data for fatigue analysis

Several methods for modelling and finite element analysis of tubular welded joints are described in various design codes. In this paper, experimental strain results from a full-scale K-node fatigue test are compared to the corresponding finite element models in order to investigate the accuracy of three different weld modelling techniques for predicting strains in the welds. The first model is made without any weld geometry, the second model is made using triangulated geometry as proposed by the DNVGL and the last is modelled using a simple fillet blend. The results have shown a good accuracy between the experimental results and the FE models using the simple fillet blend weld and weld from DNVGL, however small discrepancies between finite element predictions and experimental results are observed. Subsequently, a parameter-based finite element model updating technique is applied to the simple fillet blend weld, to reduce the discrepancies. The results have shown that the updated finite element of simple fillet bend weld represents the tubular weld in the full-scale K-node accurately.