The dynamics of vertical transportation systems in deep underground and high-rise applications

High speed and high capacity lifting installations move heavy payloads and passengers to / from depths in excess of 3000 m and service buildings of nearly 1000 m tall. This lecture will describe how the principles and methods of applied mechanics are used to solve practical engineering problems in the modern vertical transportation (VT) technologies, from material handling problems in deep underground mines to lift engineering projects in high-rise applications. In these systems long slender continua (LSC) such as steel wire ropes and composite belts play pivotal roles as suspension means and weight-compensation members. The natural frequencies of VT systems employing LSC are slowly varying, rendering them non-stationary. The dynamic interactions involve exchanges of energy between various modes of vibration. An adverse situation arises when the system is excited near its natural frequency and one of the time varying frequencies of the system approaches the frequency of the excitation. In this context the lecture will demonstrate how the prediction of dynamic behaviour of vertical transportation systems is essential for developing vibration suppression and control strategies to minimize the effects of adverse dynamic responses so that the installation will operate without compromising the structural integrity and safety standards. The lecture will also highlight future research directions in this area of engineering.