Finite element analysis of lap joint based on various geometrical parameters to study the behavior of weld strength

Abstract

This paper reports on study of lap joint weld shear strength of resistance spot weld. Resistance Spot Welding (RSW) is a very cost effective joining technology in automobile industry used to join sheets or plates. The research papers present the effect of various parameters like welding time, welding current, electrode force and squeeze time on strength of joint formed by spot welding of similar and dissimilar metals and thicknesses. Optimization of these parameters is obtained by the micro-hardness test, tensile shear test and fatigue test and the papers presented the methodologies to increase the fatigue life of the joint. In this paper MSC Nastran software is used to analyze the strength of the joint formed by the resistance spot welding. Steel Plates or sheets are modeled with Shell elements of type CQUAD4 and weld element between two plates (Nuggets) are modeled with 1D element with CBAR elements. Various FE models are generated with the consideration of geometrical parameters like thickness of the plate, nuggets along the span length and edge distance. FE models will be subjected to constant pre-defined loads on the various FE models and the weld shear strength were captured for each model and compared against the other models to study the weld behavior. Outcome of the present study provides the insight towards the selection of the optimized weld spots (nuggets) distribution for the various thicknesses of the plate, location of the nuggets along the length and the selection of optimum edge distance. The present study is used to compare the stresses induced in the plates and nuggets for the given load.