Use Of The Source Descriptor Concept In Studies Of Multi-Point And Multi-Directional Vibrational Sources

Abstract

A study of the influence of multi-point and multi-component coupling on structure-borne sound source characterization has been carried out. In particular, the effects of cross-coupling between different components of excitation and motion at a contact point have been examined. Theoretical results are supported by results of experiments on real machines, a family of fan units. The significance of the various components of excitation and motion is interpreted in terms of the source descriptor, a quantity defined on a power basis. It is shown that measured source descriptors associated with force and moment can be equally important and, accordingly, none can be excluded a priori. It is also shown that multi-point and multi-component coupling can have a profound influence. The ability of the source to impart vibrational power at global anti-resonances of the source structure is demonstrated. In addition, this ability is spectrally transposed to a higher frequency range than that predicted from a single point, single component analysis.