Fatigue life prediction method of laser lap welding joints

摘要

PROBLEM TO BE SOLVED: To provide a method for predicting a fatigue life by which a stress distribution of a laser lap-welded joint is acquired with high accuracy using a finite element method, and the fatigue life is predicted based on the acquired stress distribution.SOLUTION: The method for predicting a fatigue life of the laser lap-welded joint comprises: an analysis model preparation step of preparing an analysis model 5 of a laser lap-welded joint 4; an elastic structure analysis step of calculating a stress by performing an elastic structure analysis on the analysis model 5; an evaluation stress distribution acquisition step of acquiring an evaluation stress distribution excluding an end part of a laser weld zone 7 based on the calculated stress; a maximum evaluation stress acquisition step of acquiring an evaluation stress maximum value by preparing the evaluation stress distribution of an entire length of a weld zone by acquiring the evaluation stress of the end part of the laser weld zone from the acquired evaluation stress distribution by extrapolation; an evaluation stress amplitude acquisition step of acquiring an evaluation stress amplitude based on an evaluation stress amplitude maximum value per unit load by dividing the evaluation stress maximum value by an analysis load and the load amplitude in a fatigue test; and a fatigue life prediction step of predicting the fatigue life based on the evaluation stress amplitude and a fatigue life diagram.