Fillet Weld Fatigue Lifetime : Parametric Finite Element Analysis

Abstract: The fatigue life time of welded components is the dominant factor at the design of mechanical and automotive structures and components where fatigue failure has a crucial outcome in use of fillet welded structures and it commences mostly from the weld toe and propagate to the parent material or even to the weld root area. Fillet welds are the imperative type of weld used in many industries because of the geometry and fabrication cost of the structure. The main objective of this research is to increase the fatigue life of welded components using the Effective Notch Stress Method (ENSM). Different radius and angle combinations are used and tested using the Palmgren-Miner’s damage accumulation method and from this testing, life at different combinations can be estimated. Since this research is based on parametric Finite Element Analysis - FEA, a 2-D finite element model is used to evaluate fillet weld joints fatigue life time. In this model the throat thickness of the fillet weld determines the leg length and its impact on the fatigue life time of the weld. The fatigue life at the weld toe differs from the throat thickness although it is affected from it. The variations made in the weld toe using different radius and angles gives a significant improvement in fatigue life and also increases the strength of the weld root. The Effective Notch Stress Method (ENSM) is used to estimate the fatigue life of the weld structures where the weld toe is easily accessible. This method can also be used to determine the fatigue strength which in turn can be useful in real time applications.