Dynamic Response and Failure Analysis of Shearer Rocker arm Housing Under Nonlinear Impact Loads

Purpose In coal mining, the rocker arm housing of the shearer is subjected to nonlinear impact loads, which induce deformation and fracture, seriously affecting the safety and production efficiency of coal mining. Method In this study, the MG2x55/250-BW type shearer rocker arm was taken as the engineering object. In this study, the external load on the shearer drum was simulated using DEM-MFBD (Discrete Element Method-Multi Flexible Body Dynamics) technology to model the interaction between the flexible rocker arm housing and coal-rock, and validated experimentally. Using the dynamic load of the drum as external excitation, the vibration, deformation, stress distribution, and weak points of the rocker arm housing under nonlinear impact loads were investigated. Based on the stress-strength interference theory, the failure rate of the housing was analyzed, considering strength degradation under cyclic loading. Results and ConclusionThe results show that the errors between theoretical calculations, experimental validations, and numerical simulations for drum load are less than 15%, accurately characterizing the drum load under complex geological conditions. During cutting, the Z-axis vibration of the rocker arm housing is the most intense, with a peak acceleration of 52,451.6580 mm/s(2), primarily caused by coupling modal excitations such as torsional deformation of the motor mounting hole and expansion of the drum mounting hole. The maximum deformation of the housing reaches 0.0748 mm. Stress concentrations occur at critical regions including the housing transition zones, motor mounting holes, and pin ears, with a maximum stress value of 228.30 MPa, revealing the structural weak points. Reliability analysis indicates that the rocker arm housing of this shearer model can operate reliably for 47.58 days before failure is highly probable. The research results can provide reference for the life prediction and maintenance inspection of shearer rocker arm housing.