Study on vibration characteristics of shearer spiral drum and fatigue life prediction of cutting unit housing under multi-factor coupling

Severe vibration and fatigue damage of the cutting unit housing remain key problems in thin-coal-seam shearers because coal-rock heterogeneity, drum structure, and motion parameters jointly generate nonlinear, time-varying cutting loads. Because field tests cannot efficiently isolate these coupled effects or reproduce long-term loading, a validated numerical workflow is needed for vibration-control design and preliminary fatigue assessment. This study develops a DEM-MFBD bidirectional rigid-flexible coupling model of the MG2 × 55/250-BW shearer using EDEM, Pro/E, and RecurDyn. Cutting tests validate the drum vibration response, and a Taguchi L18(3 4 × 2 1 ) mixed-level design evaluates gangue hardness, blade spiral angle, traction speed, drum speed, and pick arrangement. Fixed-effects ANOVA shows that gangue hardness is dominant, contributing 81.68%−82.03% of the variation in the maximum, minimum, and RMS responses; traction speed and pick arrangement are secondary. Increasing gangue hardness raises the peak and RMS vibration accelerations by approximately 35%, whereas the cross-type pick arrangement reduces them by 7.73% and 8.57%, respectively. The validated load spectrum is then combined with rainflow counting, the Palmgren-Miner rule, and RecurDyn's stress-based Manson-Coffin criterion, to identify fatigue-critical housing regions. Weak regions occur at the lug transition, drum connection, and gear-shaft holes.Under the worst working condition, the cycle number corresponding to the node with the minimum fatigue life of the housing is 3.5053 × 10 10 , which meets the service requirements. The workflow links cutting-load generation, vibration response, factor sensitivity, and model-based fatigue screening. The research lays a theoretical foundation and provides technical support for the structural optimization of shearer helical drums, operating parameter matching, and reliability design of cutting unit housings, which is of great significance for improving the operational efficiency and safety of coal shearers.