The Technology Research Of Ultimate Crack Parameter Evaluation For Remanufacturing Recycled Loader Drive Axle Shaft

The thesis selected the loader drive axle shaft of the drive system to study the evaluation of the reusability of the remanufacturing recycled axle shaft.We explored the worst loading position in the axle shaft finite element model,investigated the introduction method of the tooth root crack in the semi-axis finite element model,and utilized the nonlinear contact finite element theory and the Miner fatigue analysis theory to evaluate the axle shaft life.Based on these data we probed the evaluation criteria according to which we could obtain the limit parameters of the axle shaft tooth root crack of the remanufactured axle shaft.According to the description form of the involute frame of the axle shaft,we created the accurate 3-D model base on the UG modeling function,which would lay the foundation for the finite element analysis to determine its optimal loading position and the introduction of the tooth root crack.The method of nonlinear contact finite element was used to analyze the strength of the axle and the distribution of the maximum equivalent stress of the axle shaft under the condition of the most evil loading.Then,according to the crack propagation path proposed by Lewicki and J.Kramberger,a crack model was introduced and simplified set up at the position of ?=300?340 where the tooth root stress is the largest.According to the material structure and other conditions of the axle shaft we obtained the S-N curve of the axle shaft.By analyzing the actual working condition of a loader and the law of normal distribution of load,the "3?" rule and probability statistic method both used to determine the load stress spectrum of loader drive axle shaft.Based on the Miner fatigue analysis theory we analyzed the fatigue life of the remanufactured parts drive axle shaft.Combined with the variation law of the crack stress under different load conditions,the maximum fatigue stress was deduced by reverse thrust method.Finally,the limit value of the tooth root crack was acquired by comparison.Based on the research contents of the thesis,the method of judging the ultimate crack of the semi-axle receiver is established,which can provide reference for the use of remanufacturing the axle shaft and other remanufacturing parts.