Control of vibration and resonance in aero engines and rotating machinery – An overview

This paper presents an overview of the vibration problems which are experienced in running gas turbines, and other high-speed machinery. The primary problem is that of resonance, where response levels under dynamic loading can be 100 or 1000 times greater than the levels resulting from static loading of the same magnitude. These resonances can be caused by steady, non-oscillatory, forces being applied to a rotating disc and their prediction and observation from measurement under running conditions are essential capabilities for the machinery dynamics engineer. Additional problems can arise if instabilities are encountered, either from aerodynamic sources (flutter) or from rotor dynamics. In all cases where severe vibrations are encountered, they must be controlled by the introduction of extra damping to the critical components, usually by incorporating friction devices. The use of visual displays to illuminate and help to understand the complexities of vibration in rotating machinery structures is presented.