Several approaches have been proposed in the technical literature to analytically represent residual stress fields near the weld toe of welded structures in order to include their effects in fatigue criteria. recently performed a finite element (FE) simulation by coupling weld mechanics and the arc plasma process and obtained a good agreement between numerically calculated residual stress fields and experimental measurements carried out using the X-ray diffraction method. For this purpose, numerical simulations aimed at predicting residual stress distributions due to the welding process should be as reliable as possible, but they must also be rapid to meet industrial needs. The development of fatigue approaches that account for the effect of residual stresses induced by the arc welding process is a topic of increasing interest not only in the scientific literature but also in the industrial context. Accordingly, the PSM based on tetra elements further enhances the rapid estimation of R-NSIFs using coarse meshes and could be effective in analyzing complex 3D joint geometries. The R-NSIF distribution at the weld toe line is estimated by applying the PSM to coarse meshes of 3D 10-node tetra elements, and the results are in agreement with those obtained using 3D 8-node brick elements. The aim of this work is to investigate the applicability of the PSM to estimate R-NSIFs in a butt-welded joint using coarse meshes of 3D 10-node tetra elements. In this context, the Peak Stress Method (PSM) has recently been adopted to estimate R-NSIFs due to residual stresses by means of coarse meshes of 2D 4-node plane or 3D 8-node brick elements. However, the numerical calculation of R-NSIFs through finite element (FE) simulations of the welding process requires extremely refined meshes to properly capture the residual stress singularity. Once R-NSIFs are determined, they might be included in local fatigue criteria for the structural strength assessment of welded joints based on NSIFs due to external cyclic loading.

Approaches based on calculating Residual Notch Stress Intensity Factors (R-NSIFs) assume the weld toe to be a sharp V-notch that gives rise to a residual singular stress distribution close to the weld toe.

Sysweld crack