Experimental and Numerical Investigation of Rotating Bladed Disk Forced Response Using Under-Platform Friction Dampers

In this paper we present a methodology and results from an experimental investigation of forced vibration response for a bladed disk with fitted under-platform ‘cottage-roof’ friction dampers, together with the corresponding numerical predictions. A carefully-designed and constructed rotating test rig is used to make precise measurements which involve only the phenomena of interest. For this purpose, the measurement rig is operated under vacuum to eliminate aerodynamic effects on the rotating blisk and non-contact excitation and measurement techniques are employed so as not to modify the bladed disk dynamics. The experimental data measured are used for validation of multi-harmonic balance-based prediction tools developed at Imperial College. Predictions are carried out both with and without taking inherent mechanical mistuning into account, which is identified from measured data. Measured and predicted response curves are compared with each other and the degree of correlation is discussed.