Analysis of blade vibration frequencies from blade tip timing data

Abstract

Blade tip timing is a non-intrusive technique used for detection, measurement and analysis of blade vibration in rotating blade assemblies. The main recent focus in the application of blade tip timing system has been the determination of blade vibration frequencies. Although the fundamentals of the technique are fully developed, the analysis of data obtained in the presence of simultaneous excitation response is problematic. A number of methods have been introduced for the analysis of blade tip timing data from assemblies undergoing synchronous excitation or asynchronous vibration, each of them has its inherent limitation in practice. The approaches to the analysis of blade tip timing data were presented with its theoretical principle and application requirement. Several of the techniques were found to perform effectively on asynchronous resonances or synchronous resonances, with accurate vibration frequency estimates yielded.