This paper outlines a different technique in vibration analysis,namely modal testing/analysis for preventive/predictive maintenance inproductive machinery. Instead of just using a signal analysis approachas has been used widely, a system analysis approach is proposed in thispaper. The system analysis has been widely used for passive structures(structures with no moving parts), however its application for machineswith high speed rotating components has yet to be explored. Anexperimental set-up is used to demonstrate the feasibility andpracticality of this technique with all the problems associated withthis type of structure. Several excitation techniques are used, such astransient, random, sinusoidal, pseudo-random, to perturb the system.Several experiments are carried out with different combinations ofexcitation and response measurement locations (rotating and nonrotating)and the nature of the forcing function on the system. It is shown thatthe predicted gyroscopic effect may be detected by exciting thefoundation and carrying out measurement on the rotor and vice-versa. Thegyroscopic effect results in bifurcation of the critical speed of therotor and this is reflected in the frequency response function measuredon the system. The various results are compared and the damping effectis also measured
展开▼
