Dynamic analyses of hoisting ropes in a multi-rope friction mine hoist and determination of proper hoisting parameters

To avoid the failure of rope collision caused by large amplitude transverse vibrations, this study aimed to determine proper hoisting parameters of a multi-rope friction mine hoist. To explore dynamic behaviors of the hoisting catenaries with constant length and the vertical hoisting ropes with variable length which are both subjected to the periodic external excitations induced by the fluctuations of the head sheaves, a dynamic model was established and experimentally validated. Through comparative analysis, it was found that the large amplitude transverse vibrations are usually associated with hoisting catenaries. Hence, the effects of the hoisting parameters on the transverse vibrations of the hoisting catenaries were further investigated. The results show that large amplitude transverse vibrations will be excited when the external excitation frequency is within the dangerous resonance frequency range and possible rope collision is thereby induced. According to displacement-frequency response curves, employing analogy method, the proper maximum hoisting speed of the hoist and the hoisting rope tensions can be determined to decrease the large transverse amplitude to a safe one. Therefore, the failure of rope collision can be thoroughly avoided.