Anti-fatigue Reliability-Based Sensitivity Calculation Of The Shearer Rocker Arm System

In the mining industry,the shearer is an equipment of fully mechanized coal mining face,mainly playing the role of cutting big coal from the coal wall.As the key part of shearer,the rocker arm system should meet the requirements of stable operation and good performance.Therefore,it's very important to do reliability evaluations of the fatigue life.Taking a shearer rocker arm system of the MG300/700-WD type shearer as research object,a finite element model of the system is established,and the dynamic characteristics analysis of the system is done.Based on the reliability theory,the influences of structure design variables on the system reliability are studied,providing theoretical support for improving reliability and security of the system further.The main contents are as follows:(1)The shearer rocker arm system is simplified into the gear-rotor-bearing system.Then the finite element model of the system is established by ANSYS and Matlab.Through the existing model,system natural frequencies are calculated,and then the correctness of the model are verified by comparing the calculation results.(2)The random load of a single cutting tooth is built.Three-axis force and three-axis torque of terminal system output by superposing force on the cutting teeth.The direct integral method of Newmark is applied to solve the dynamic equation,getting dynamic meshing force of each gear pair.Finally,the bending stress and contact stress of gears are obtained.(3)Two anti-fatigue reliability models of the gear 1 and gear 2 as well as the sun gear and planet gear are established.The anti-fatigue reliability and reliability sensitivity are respectively calculated by AFOSM and the perturbation method.Based on second-order narrow boundary theory,merely considering the correlation between primary and secondary failure mode,the system reliability and reliability sensitivity that more parts are failed relatively are obtained.(4)The software for anti-fatigue reliability sensitivity calculation of shearer rocker transmission system is developed by Graphical User Interface.It doesn't only simplify the operation steps,but also provide large amounts of data for the design,machining and manufacturing of shearer rocker arm system as a reference,having some practical value on engineering.