Influence of Mistuning on Rotor-Blade Vibrations

Abstract

This analysis is aimed at determining the influence of blade mistiming on the vibratory stress levels of turbine and compressor blades. A frequency response analysis for a given rotor configuration shows that a large number of resonances may occur over a frequency band, the width of which is nearly 20% of the mean blade frequency. The resonant amplitudes are a function of blade frequency and location on the rotor, and the amount of damping present in the system. A parametric study is carried out to evaluate the response levels due to engine order excitation, aerodynamic and mechanical damping, and blade frequency deviation. The resulting mode shapes and frequencies are in good agreement with the experimental findings reported earlier in the literature.