An adaptive structural excitation system as a tool for structure-borne noise research

Kurzfassung

Engine vibration has been identified as one of the main sources of structure-borne cabin noise. Researchers could benefit from having the ability to reproduce operational vibro-acoustic excitation on the ground instead of requiring flight testing in order to investigate its generation and transmission paths. While realistic excitation generated by engine operation can be obtained through simulations the injection of these forces is not a trivial task. The excitation system needs to compensate for all modifications introduced not only by the amplification chain but also by the interaction of injected forces in different directions to achieve precise excitation in each individual direction. The development of a multi-channel controller able to perform all required compensations can enable a new approach for vibro-acoustic characterization of aircraft fuselages. The adaptive controller presented here is able to provide all counteractions required in order to replicate translational and rotational forces at the injection points on the structure. The system capabilities are demonstrated on a laboratory structure that resembles typical fuselage subcomponents as skin fields, stringers and frames. The following work describes the adaptive MIMO controller, presents results and discusses its applicability.