Rigid-Flexible Coupling Simulation And Fatigue Failure Analysis On The Track Link Of Excavator

Track link,as an important component of the crawler walking device,is usually prone to crack failure because of the complex outside loads from the harsh working condition,and it will affect the working efficiency of the whole machine when the track link is failure.This paper explores the causes of failure of the track link with the support of a school-enterprise cooperation project named “performance analysis and failure mechanism research of XE60 CA hydraulic excavator crawler chassis”.In this paper,the crack is judged as the fatigue crack by carrying out static strength check of the track link combined with the scanning electron microscope analysis of the crack surface.In order to further analyze the formation mechanism of the fatigue crack,the rigid-flexible coupling dynamic simulation is carried out.Fatigue analysis is carried out based on the simulated time load history of the track link.Based on the relevant domestic and foreign literature,the paper summarizes the research status related to the failure of track link.The virtual prototype model of the crawler walking device is established.The correctness of the model is verified by experiment,and the dynamic load is obtained from the model.By selecting three extreme conditions that may occur in the excavator and checking the finite element static strength of the link section,it is determined that the static strength of the chain link satisfies the requirement.In order to study the causes of fatigue crack in the chain link,this paper studies the fatigue failure analysis of the chain link by RecurDyn system-level fatigue analysis.A pair of chain links in the excavator crawler walking device model are made flexible and the rigid-flexible coupling dynamics simulation is carried out to obtain the load time history of the chain section under the three conditions of straight traveling,climbing and turning in situ.The load time histories of the track chain section under different working conditions are introduced into the fatigue analysis module,and the load cycles are counted for the load time histories,and the parameters such as the mean stress correction method and the material S-N curve are set.Furthermore,the fatigue failure of the chain links is analyzed.The fatigue analysis results show that the location of the most easily fatigue failure on the track link is coincides with the location of the crack on the real track links,which is the connection between the shaft ring and the bottom of the track link,and the correctness of the research method used in this paper is verified.In this paper,the crack failure type of the chain link is judged by the finite element static strength calculation combined with the crack fracture electron microscope image analysis.Fatigue failure analysis of the track link is carried out based on the load time histories which are from the rigid-flexible coupling simulation.The research method adopted in this paper and the related conclusions provide an effective reference for the research and design of the track links,which is of great significance to optimize the design of the track link and improve its service life.