Finite Element Analysis And Prediction Of Fatigue Life For Weld Bead Of The Structural Parts Of A Roller

Based on the engineering projects and market feedback, statistics show that the frame of the 33 tons vibratory roller is the most severely damaged within ten thousand hours. Most of the damage is caused by weld fatigue in the joint of the stringer and the bottom beam, which is the key factor affecting the service life. Due to the large volume, high weight, big load, vibration of wheels, interaction of steering cylinder and the complex operation environment, the frame of the vibratory roller suffers impact and alternating load chronically, resulting in cracks near the weld. In order to improve the service life of the frame,it is necessary to predict the fatigue life of frame weld.The traditional methods predicting the fatigue life usually weaken the effect of the residual stress, so the results have a larger gap with the actual situation and lost the reference significance. In order to improve the accuracy and reliability of the fatigue life prediction and provide references for the follow-up design and process improvement, the 3D model of the frame based on the finite element analysis is established. After meshing, calculation and post-processing, the distribution of residual stress and extreme value point of the welding are known. There have differences between the experiment results and simulation results, but the trend is similar, which verifies the simulation model is reliable. The welding process parameters are optimized by orthogonal test design. The residual stress of arc and linear welding seam can be uniform by process improvement. The magnitude and distribution of residual stress are close to the ideal state, and the effect of residual stress is reduced in the prediction of fatigue life. With vibration aging technology, the average residual stress of the frame declines 60%.Through the static strength analysis of the frame and the stress distribution cloud, the weak points of the strength are found, which lays the foundation for the fatigue life analysis of the frame and weld. Compared the frame fatigue life under the condition of no load and full load, weld fatigue life of the simulation results and the position of the frame fatigue damage in the process of using are relatively close, which verifies the simulation study is effective. And the results paves for the roller frame improvement and optimization subsequently.