Strain analysis at notch root in laser welded samples using material properties of individual weld zones

•The strain analysis in a notch root of laser weld was presented in this paper.•This analysis was conducted using the material properties of the individual zones (IWZP) of the laser welded joint.•The strain analysis at the notch root t was carried out using a Neuber’s rule, FEM and experimental method.•Results of research using IWZP showed good efficacy numerical analysis of strain in the low cyclic fatigue.•The use of IWZP has not produced the desired effects in medium and high cycle fatigue.

This paper presents results of the strain analysis at a notch root in a laser-welded joint subjected to cyclically variable stresses. The examined welds were made of S355JR (PN-EN 10025-2) ferritic steel. A theoretical analysis of strain was performed using cyclic material properties determined for individual weld zones. For the purpose of comparison, values of strains at a notch root were also determined using base metal properties. Experimental verification of determined strain values was performed using the laser grating interferometry method. Cyclic variations of material properties for base metal and welded joint zones were determined as per the standard and the methodology presented in previous study and described with the Ramberg–Osgood relationship. The above material properties were used to calculate strain at the root of two types of geometric notches machined in a laser-welded joint. Analytical calculations were performed using the Neuber’s rule, while numerical calculations with the use of the finite element method by means of the ABAQUS software.Test results confirmed good efficiency of the numerical strain analysis using cyclic material properties of the individual weld zones in low cycle fatigue.