Study On The Fatigue Life Of Working Device Of Hydraulic Excavator

The Backhoe hydraulic excavator is a kind of typical earthwork construction machinery.It plays an important role on construction work such as road construction,oilfield exploitation and etc.While digging,the working device of excavator contacts with the object and suffers complex impulsive load.The intensity,reliability and durability of working device affect the work efficiency and construction progress.Therefore,it is significant to study the intensity and reliability of working device.In this paper,the fatigue life of working device on excavator is studied.It centres on digging resistance of working device,mechanics modeling of nodes,finite simulative analysis of working device,the modification of S-N curve and calculation of fatigue life.The study process is shown as:Firstly,the mechanical model of digging resistance and each node are deduced based on kinetic analysis of component and dynamic load test.Secondly,a finite simulation model of working device is established for static state and dynamic analysis.The static test proves that the result of finite simulation model static analysis is valid.It offers reliability to the dynamic analysis.The load spectrum of high stress region is obtained via applying external force on swing arm and bucket rod model in dynamic analysis.Then,the rain flow counting program is written in MATLAB software for data processing on the load spectrum.Lastly,the residue fatigue life in the high stress region is calculated.The detail fatigue rating(DFR)method is introduced to modify the S-N curve.The Miner linear fatigue cumulative criteria is applied to calculate the fatigue life of component integrating the result of rain flow counting.Furthermore,the result of fatigue prediction is analyzed in the end.