Research On The Fatigue Analysis Method Of Working Device Of Hydraulic Excavator

Among all kinds of engineering machinery, hydraulic excavator is the most widely used and plays an important role in infrastructure construction. Working device is the executive actuator to complete various tasks of hydraulic excavator and it bears many types of complicated loads directly. Due to unreasonable design and manufacture process, complicated loads and poor working conditions, fatigue failure often occurs in the structure of working device, which causes serious economic losses to the enterprises. So, it is very meaningful to make fatigue research on the working device of hydraulic excavator and improve its working life.As there has been little research on the fatigue life of the working device and it is hard to measure the load history used in the fatigue analysis at present, a novel method is proposed in this article:Firstly, the complete process of digging resistance called as the digging resistance load spectrum is obtained by simulating the process of digging soil in LS-DYNA with Arbitrary Lagrangian-Eulerian method. Secondly, according to the digging resistance load spectrum, the load histories of each hinge of the working device are calculated out through the complete operation simulation of a typical working cycle of hydraulic excavator in ADAMS and are verified by comparing with the actual cylinder pressures measured from the experiment similar to the working condition in the simulation. Thirdly, the article proposes a strategy that takes the conditions when the load at each hinge of the working device reaches largest into account to determine the most dangerous working conditions, and then analyzes the static strength of the working device of hydraulic excavator in ANSYS. Finally, with the verified load histories of the hinges and the static strength analysis results, the fatigue analysis of the boom and arm of the working device of hydraulic excavator are accomplished in ANSYS FE-SAFE.The method proposed in this article to calculate the fatigue life of working device of excavator can compensate for the shortcomings of traditional methods efficiently, and it can also be used to solve the fatigue problems of other engineering machineries.