Impact damage to the middle trough of a scraper conveyor based on the engineering discrete element method and orthogonal matrix analysis

The middle trough serves as a key part of a scraper conveyor. During the working process, falling raw coal lands on the middle plate of the trough, causing impact damage. This study aims to find the optimal working condition combination to minimize impact damage to the middle trough based on the engineering discrete element method (EDEM) and orthogonal matrix analysis (OMA). In EDEM software, simulation data of the impact damage depth and normal cumulative contact energy of the middle trough corresponding to the four influencing factors of the transverse laying roll angle, front lean angle, raw coal particle size, and chain layout and spacing under different horizontal conditions are obtained. Matrices of the impact damage depth and normal cumulative contact energy are separately established. Based on the respective factor layer, level and evaluation index weight matrices, a global weight matrix is finally obtained. The optimal combination of working conditions is obtained, and the weight of each factor on impact damage to the middle trough is determined by the weight coefficient. The accuracy of the simulation results is then verified in experiments. Among the considered factors, the raw coal particle size achieves the highest impact damage coefficient. When the raw coal particle size is the smallest (0.5 times the basic particle size), the transverse roll angle and front lean angle of the middle trough are positive (5° and 10°, respectively), the chain adopts the double-center chain arrangement, and minimal impact damage to the middle trough occurs. OMA reduces the test times to determine the optimal working conditions of a scraper conveyor.