The measurement of bending wave intensity in a two-dimensional structure

I.IntroductionOfallstructuralwaves,bendingwaveismostimportant.Itiseasilyexcitedandresultsinairbornenoiseradiation'Inpractice,itisnecessarytodeterminetheenergydistributionandpowertransmissionincoupledstructl1res.Bendingwaveenergycanbecalculatedfrombendingwaveaccelerationwhilebendingwavepowertransmissionischaracterizedbybendingwaveintensitywhichisavectorgivillgthemagnitudeanddirection.TheengineeringaPplicationofthevectorpropertyofbendingwaveilltensityisnumerous1~3]buttheinvestigationinitispre…

The measurement of bending wave intensity in a two-dimensional structure

In a two-dimensional bending wavefield, the intensity vector is the sum of the effec-tive intensity vector and the intensity variation vector. The effective intensity vector gives the magnitude and direction of bending wave power flow per unit width in structures. The illtensity variation vector characterizes the circulation of local bending wave energy and varies harmon ically with space and wavenumber. This paper studies the relationship between the analysis frequency bandwidth and the measurement acctiracy of effective bending wave intensity, and ex-amines the accuracy of source localization using measured intensity vectors in two-dimensional structures. It is shown that if the analysis frequency bandwidth is wider than the sum of several one-third octave frequency bandwidths, the intensity variation can be suppressed to a negligible value in comparison with the effective intensity Moreover, a structure-borne source can be localized by measuring effective bending wave intensity vectors at a few positions, but the accuracy is dependent on the analysis frequency bandwidth, the property of the wavefield and the distance between source and measurement position. The more active the wavefield, the higher the accuracy of 8ource localization.