The estimate and measurement of longitudinal wave intensity
- 6 Downloads
Quasi-longitudinal waves are one type of structural waves, which are important at high frequencies. This paper studies the estimate theory and measurement technique of quasi-longitudinal waves, analyzes the bias error due to the effect of bending waves. In a two-dimensional quasi-longitudinal wave field, the intensity vector is the sum of the effective intensity vector and the intensity variation vector. Its axial component is proportional to two imaginary parts of cross spectral densities and in the measurement, it is measured by a pair of two-transducer arrays. In a onedimensional quasi-longitudinal wave field, the intensity variation is zero, the intensity is proportional to only one imaginary part of a cross spectral density and it can be measured using a two-transducer array. If bending and quasi-longitudinal waves coexist and the contribution from bending waves cannot be eliminated or reduced to a certain extent, the measured quasi-longitudinal wave intensity will contain a large error. The results measured on the three-beam structure show that quasi-longitudinal wave intensity can be accurately measured using the intensity technique when bending waves are negligible in comparison with quasi-longitudinal waves.
Key Wordsquasi-longitudinal wave intensity power flow bias error measurement technique
Unable to display preview. Download preview PDF.
- 5.Ming R S. The measurement of structural wave intensity applied to buildings: [Dissertation]. U.K: Heriot-Watt University, 1993Google Scholar
- 6.Bendat J S, Piersol A G. Random data: analysis and measurement procedures. New York: John Wiley & Sons Inc., 1986Google Scholar
- 7.Ming Ruisen. Bending wave intensity in a thick beam.Chinese Journal of Acoustics, 1995, 14(3): 265–275Google Scholar