T-joint fillet welding is the most common welding in engineering applications. Transport vehicles, marine ships, mobile plant equipment are few examples where fillet welding are used extensively. Analysis of welded structures are still remains a challenge for the designer to produce desired output results. In welding process rapid heating and cooling introduced residual stress and geometrical deformations. Heat effected zone play pivotal role in determining the strength of a welded joint which changes the properties of parent material and reduce the strength after welding operation. There are many case which structures are continuously under cyclic loading when the fatigue life of the welded joints are a major design consideration.
The aim of this project is to analyse the normal stress and fatigue life of fillet welded joints using computer modelling and experiments. Finite element based tool ANSYS Workbench 15.0 was been used to analyse the normal stress and the fatigue life under cyclic loading. Computer model of the joint developed using three different types of material which was parent metal, heat affected zone metal and weld metal. Experimental tests were carried out at USQ laboratory on double side welded T-joints. Grade 250 Structural steel was used to prepare specimen and gas metal arc welding (GMAW) process applied to welding the joints.
The ultimate purpose of the project has been achieved with developing techniques of the finite element analysis of fillet welded joint. The experimental investigation validate the performance of the FEA analysis results were found 1.2% error on tensile test. The experiment yield stress was found 263.4 MPa and simulation yield stress at the same location appears 266.7 MPa. In order to calculate fatigue life of welded joint used iterative process to define stress at one million cycle. The analysis found 274 MPa stress and 7740 cycle fatigue life applying yield load. After reduced load at 12kN and found the fatigue life one million cycle where shows 88 MPa stress which is 35% of yield stress. So that designer can consider 35% of yield strength when design structure for fluctuating and repeated loading conditions
