CONDITION MONITORING OF CRACKED ROTORS THROUGH TRANSIENT-RESPONSE

In the present study a simple Laval rotor with a transverse crack is c onsidered. The analysis assumes that the vibrations remain small in co mparison to the sag of the rotor under its own weight. If a cracked sh aft rotates slowly under the load of its own weight, then the crack wi ll open and close once per revolution, i.e. it breathes. Considering a simple hinge model which is a very good model for small cracks with t he breathing action of crack, the transient vibration response of a cr acked rotor passing through its critical speed is analysed as an attem pt for crack detection and monitoring. Effects of different factors su ch as crack depth, unbalance eccentricity with phase and acceleration influencing vibration are investigated. (C) 1998 Elsevier Science Ltd. All rights reserved.