Identification of Integrally Bladed Rotor (IBR) Damping

At a time when the DoD is trying to find ways to reduce costs, the use of IBRs in gas turbine engines is becoming prevalent. While they are the future, IBRs tend to be expensive components, so proper care and maintenance is both necessary and warranted. At the core of their upkeep is the characterization of their vibrational properties and, more specifically, the damping characteristics of the individual blades. The physical phenomenon is complicated because the component is one piece of material and the behavior of each blade influences the behavior of the others. The objective of the proposed work is to develop a method for extracting information about the damping, excitation forces, and frequency mistuning of individual blades from the vibratory response of the IBR as a whole. The vibration data could be from non-rotating bench-top experiments or rotating experiments such as a spin-pit or engine test. The method would work with non-linear coatings so that the bench-top experiments could serve as the basis of an inspection machine for coated IBR/Blisks. In addition, a nonlinear forced response prediction code will be developed for predicting how IBR/Blisks with nonlinear coatings will vibrate when they are used in the engine.