Mechanical Vibrations: Theory and Practice

5

Torsional Vibrations

5.1 INTRODUCTION

The analysis of torsional vibrations assumes a very important role in the design of rotating systems such as multi-span rotors of power plants, compressors, pumps, etc., since these equipments are often subject to fluctuating torques, which at times may lead to their failures. This becomes much more critical because, unlike transverse vibrations where it is possible to measure and analyse the shaft as well as bearing vibrations using suitable transducers. However, it is a complex affair to measure and monitor the torsional vibrations, and hence in most of the rotating machinery, torsional vibrations are neither measured nor possible to measure. The torsional vibrations induce torsional-shear stresses, ...