Assessment of safety for axial fluctuations of head sheaves in mine hoist based on coupled dynamic model

• Collision between two adjacent hoisting ropes is likely to occur in mine hoist.
• Axial motions of head sheaves can excite transverse vibrations of inclined ropes.
• A dynamic model was established and validated to reveal the coupling relationship.
• Safety assessment criteria for axial fluctuations of head sheaves were established.

This investigation was primarily to establish assessment criteria for axial fluctuations of head sheaves in a multi-rope friction mine hoist. Large axial fluctuating displacements of head sheaves can excite intense transverse vibrations in inclined ropes, which can result in dangerous collision between two adjacent ropes. A coupled dynamic model was established and then validated by experimental tests and numerical simulations. In this case, it can be concluded that double rotational frequency of head sheave is the primary excitation frequency and rope tension can change the resonance frequency range. Finally, to avoid large transverse displacements of inclined ropes in a multi-rope friction hoist, based on response–excitation displacement curves, assessment criteria for axial fluctuating displacements of head sheaves were established.