Structural Optimization And Fatigue Analysis Of Cross Shaft Universal Coupling

With the rapid development of computer technology,the finite element method and the virtual prototyping method have been greatly developed.In recent years,the fatigue and strength analysis of parts based on the finite element,multi-body dynamics and fatigue theory has also become one of the hot topics in the research of product design.Universal coupling is a key part of the mechanical transmission system.The cross shaft universal coupling has the advantages of simple structure and strong reliability.It is widely used in automobile drive shaft and rolling field.The universal joint coupling bears the action of alternating load during the working process,and it is easy to suffer fatigue damage.Therefore,fatigue strength design is essential for universal joint coupling.In past,the method of strength and fatigue analysis of component was to establish the physical prototype experiment.But the experimental method is costly and slowly,which is not conducive to improve the productivity of enterprises.However,this paper used the finite element technique and virtual prototype technology to analysis the fatigue life and strength of the key parts of a cross shaft,which can effectively shorten the cycle of design and research.Firstly,the finite element model of the key parts of a universal coupling of truck was established and strength and fatigue life of cross shaft and universal joint fork was analyzed.With the basis of strength analysis,the topology optimization of cross shaft and universal joint fork was come up with and the structure of them was modified.Secondly,the finite element model of the transmission shaft was established and the modal analysis was carried out,and the critical speed of the transmission shaft was checked according to its natural frequency.Based on the modal stress recovery method,the fatigue analysis of cross shaft and universal joint fork was carried out.This paper used ANSYS workbench to obtain the topology optimization of flexible body of cross shaft.These flexible bodies are modal neutral file for the corresponding replacement of universal coupling multi rigid body model in Adams,which can establish the rigid flexible coupling simulation model of transmission shaft test bench file;the load spectrum file is the key components for fatigue analysis of model,the load spectrum file is used to be inserted to Ncode design life,which was used to analysis the fatigue of cross shaft and universal joint fork.The fatigue distribution of cross shaft and universal joint fork head in a specific condition were come up with.Finally,the fatigue life,quality and strength of the cross shaft and the fork head optimization were analyzed and compared and the evaluation was made.The result showed that the optimized cross shaft parts weight was reduced by 5.56%,the fatigue life of cross shaft was obviously improved with meeting the strength requirements;universal joint fork's weight was reduced by 8.96% with meeting the strength requirements,the fatigue life was slightly decreased,which can still meet the requirements.Through comparing the fatigue life of cross shaft and universal joint fork parts which were topology optimized with different materials,it was found that 20 CrMnTi material can significantly improve the service life of cross shaft and universal joint fork.The results of this study can provide some reference for the research and development of the new universal joint shaft and the optimization of the existing model universal joint.