Fatigue life prediction of shearer rocker shell based on DEM−MFBD bidirectional coupling technology

Shearer rocker arm shell is an important component and weak link of shearer, and its life directly affects the working performance of shearer. In order to study the influence of the load on the drum about the life of the rocker arm shell when the shearer is cutting complex coal seams. Taking MG325 shearer to cut 17 layers of gangue containing coal wall in Yangcun Coal Mine of Yanzhou mining area as the project object, the external load of shearer spiral drum is obtained based on the actual working conditions by using Discrete Element Method-Multi Flexible Body Dynamics (DEM−MFBD ) two-way coupling technology, discrete element simulation software EDEM and multi-body system dynamics simulation software RecurDyn. In the RecurDyn simulation platform, the three-dimensional model of the shearer rocker arm is established, and the boundary conditions are set and the rocker arm shell is flexible. The fatigue life of the rocker shell is calculated through the Durability fatigue durability analysis module of the software itself. The professional drawing software Origin is used to draw the post-processing load curve of the two software. It is found that the trend was relatively consistent, and the post-processing data mean and standard deviation is close, which proved that the coupling effect between the two is good. The results show that when the MG325 shearer is used with a drum speed of 83.5 r/min, a cut-off depth of 600 mm and traction speed of 5 m/min to cut complex coal seams, the load on the drum has a strong load fluctuation phenomenon. The maximum equivalent stress of the shell is 230.51 MPa. The higher equivalent stress of the shell is concentrated at each gear shaft hole, groove and the transition of upper and lower ear. After stress fatigue analysis, the minimum life is located at the gear shaft hole of the shearer shell, and the number of cycles is 8.3215×10⁶ times. This research method can provide a reference for the optimization design of large structural parts of industrial and mining equipment under complex conditions.