Abstract:To address the problem that fatigue failures of excavator movable arms mostly occured at the weld joints, a fatigue life prediction model for refined welds was established and the fatigue life of excavator movable arms was analyzed based on the measured loads. Based on the load inversion technique, the hinge point load of the arm in stone and earthwork work condition was obtained, and the finite element modeling of the movable arm weld part was refined, and the S-N curve of the weld material and linear Miner damage theory were combined to predict the fatigue life of the movable arm weld part in stone and earthwork work condition respectively. The fatigue life of the movable arm weld area under rock and earthwork conditions was predicted by combining the S-N curve of the weld material and linear Miner damage theory. The analysis shows that the minimum fatigue life of the weld part in stone and earthwork work condition is 5.815×105 and 1.160×106 times respectively, and the analysis method can provide reference for the fatigue life analysis of the weld structure of the same type of machinery.