Identification of Integrally Bladed Rotor (IBR) Damping

This proposal addresses the development of methods to accurately determine from spin rig test data the damping associated with individual blades of an integrally bladed rotor (IBR) or blisk. The general approach which will be used here has two key components. The first part involves the development of analytical methods to extract the modal parameters (frequency, damping, and some shape information). The second part involves hypothesis testing which will provide the data to verify that the modes can be extracted independently and verify that damping values can be assigned to each blade. The analytical methods will be based on application of advanced modal parameter extraction methods combined with the use of formal multivariate statistical hypothesis testing techniques. This will allow us to by-pass most of the limitations of using a modal formulation to assess damping behavior. The technology which will be developed here will also be sufficiently robust to be able to measure the required data in operational environments that are typical of a turbine engine, particularly military jet turbines.