Dynamics of a Nutating Mill with Charge-Structure Interaction

Nutating mills achieve high-intensity particle motion without the gravitational limitations of conventional tumbling mills, yet their structural dynamics and charge-structure interactions remain poorly characterised. This study investigates the dynamic behaviour of a laboratory-scale nutating mill (NuMill) through experimental testing and a two-way coupled simulation combining multi-body dynamics and the discrete element method. The NuMill included vibration isolation mounts and chamber ribs to replicate industrial Hicom mill characteristics. Force, torque, and accelerations were measured under varying mounting, charge, and geometric conditions. The re-sults revealed that representing the charge in a ribbed chamber as a rigid mass, instead of the granular material that it is, overpredicts the crank pin force by 21 % and underpredicts the drive shaft torque by 82 % at 700 RPM. The coupled simulation predicted the experimental dynamic behaviour with good agreement, showing a 34 % overprediction of crank-pin force, a 25 % underprediction of drive-shaft torque and rigid body natural-frequency errors within 1 %. These findings confirm that structural flexibility and charge-structure coupling significantly affect operational loads. The validated framework developed, improves predictive capability for nutating mill design and operation, enabling enhanced mechanical reliability and informed parameter selection in industrial applications.

Grantor dc:publisher

Stellenbosch : Stellenbosch University

Year dc:date.issued

2026

Author dc:creator

• Janse van Vuuren, Hendrik Christoffel

Advisors dc:contributor.advisor

• Bredell, J. R.
• Coetzee, C.

Language dc:language.iso

en

Repository record dc:identifier.uri

https://scholar.sun.ac.za/handle/10019.1/136094

OAI identifier oai:identifier

oai:scholar.sun.ac.za:10019.1/136094