Modelling and simulation of a nonstationary high-rise elevator system to predict the dynamic interactions between its components

Lateral vibrations of the suspension and compensating ropes in a high-rise elevator system are induced by the building motions. When the elevator is in motion the length of the ropes change so that the natural frequencies vary, rendering the system nonstationary. In this scenario large displacements of the ropes occur when a passage through resonance takes place. Due to the nonlinear coupling, interactions between the in-plane and out of plane motions of the ropes occur. Furthermore, the car, counterweight and compensating sheave suffer from vertical vibrations due to the coupling with lateral vibrations of the ropes. This paper presents a mathematical model of a high-rise elevator system which can be used to predict the dynamic interactions taking place during its operation. The model is implemented in a high performance computational environment and the dynamic response of the system when the building is subjected to a low frequency sway, is determined through numerical simulation with the car following the kinematic profile dictated by the drive control algorithm. A case study is used to demonstrate resonance phenomena taking place during the operation of the system. The results predict a range of nonlinear dynamic interactions between the components of the elevator system, during travel and when the system is stationary.