Investigations on Transient Amplitude Amplification by Applying Intentional Mistuning

Abstract

Due to the changing demands in the energy production sector which leads to higher numbers of run ups and run downs, the importance of transient processes increase. Further information on the occurring blade vibration amplitudes during these processes could be used to explore new potential for longer lifetime and efficiency. Recent publications have shown that the amplitude of a mistuned blisk during a resonance passage can exceed the stationary response of the same system [1]. This underlines the importance of a better understanding of what happens during resonance passage. The effect is described as transient amplitude amplification of mistuned structures (TAMS). In this paper the effect will be investigated theoretically as well as in experiments. The main cause of the described effect seems to be the splitting of double eigenfrequencies due to mistuning. Therefore, the focus lies on methods to deliberately influence and seperate eigenfrequencies. First, simulations are done to predict parameter values which tend to show the TAMS effect. It is then shown how a significant transient amplitude amplification can be created on a test rig depending on the intentional mistuning. For realization an experimental setup with contactless measurement and acoustic excitation is deployed on a simplified blisk.