Coupled Multi-Body and Particle Dynamics Simulation of a Nutating Mill

Nutating mills offer intense comminution dynamics without the gravitational constraints of conventional tumbling mills; however, their structural response and charge–structure interaction mechanisms remain insufficiently characterized. This work examines the dynamic behavior of a laboratory-scale nutating mill (NuMill) with granular charge through combined experimental characterization and a two-way coupled numerical framework integrating multi-body dynamics (MBD) with the discrete element method (DEM). This study expands on previous work, extending the characterization of the NuMill to include mount stiffness, damping, and charge–structure coupling. The NuMill was adapted with vibration isolation mounts and internal chamber ribs to more closely emulate the operating behavior of industrial Hicom mills. Measurements of forces, torques, and accelerations were obtained across a range of mounting, charge, and chamber geometry configurations. Results show that approximating the granular charge in a ribbed chamber as a rigid body leads to substantial predictive error, overestimating crank-pin forces by 21% and underestimating driveshaft torque by 82% at 700 RPM. Incorporating experimentally characterized stiffness into the coupled MBD–DEM model showed good prediction accuracy for granular charge at 700 RPM. The simulation overestimated crank-pin force by 34%, underestimated driveshaft torque by 25%, and reproduced rigid-body natural frequencies within 1%. These findings demonstrate that structural compliance and charge–structure coupling play a central role in determining operational loads in nutating mills. The validated modeling framework developed here provides a more reliable basis for design assessment and parameter selection in industrial nutating milling applications and extends existing experimental foundations for laboratory-scale systems.