Non-stationary vibration power:Definition and application to a model miniature airplane

Abstract

Mechanical and other structures with excitation sources such as engine, compressor, and electric motor are often modeled as a source-path-receiver. In order to tackle with noise and/or vibration problems in the receiver structure, e.g. assessment on sources, often overall vibration level of the receiver structure over operational speeds of the excitation source should be known first of all. Since estimation of the overall vibration level by direct measurements on the whole receiver structure requires huge efforts, use of vibration power at a few critical paths would be beneficial. Based on definitions of vibration power for simple harmonic and stationary random motions, non-stationary vibration power is defined in this presentation and a procedure by harmonic wavelet transform is introduced. The method is applied to vibrations of a model miniature airplane when the engine speed changes with time. Usefulness of the method is demonstrated by showing the non-stationary vibration power at 1 path between the engine and fuselage in comparison with the whole vibration level obtained from measurements on 12 points on the plane body.