PROPAGATION OF MECHANICAL VIBRATION IN STRUCTURES; EXPERIMENTAL DEVELOPMENT OF THE VIBRATIONAL INTENSITY METHOD

This study deals with the measuring techniques for estimating and characterising vibration propagation in thin beams and plates. The measurement method applied was the vibrational intensity technique for bending waves, which uses two or four motion sensors. This study contributes to method development and to the experimental verification of the methods. The aim of the experiments was (a) to test the accuracy and limitations of the known methods in controlled conditions and (b) to verify the alternative forms and extensions to the known methods that were developed. For bending vibrations of beams, estimates for the moment and shear force components of power and the impedance are derived, and new estimates for the reflection coefficient are given. The frequency response technique with one reference signal is introduced and applied in experiments. For bending waves in plates, the applicability of the approximate two-transducer intensity method in practice is investigated, paying particular attention to the effect of the near fields. The applicability of commercial laser-doppler vibrometers as motion sensors for use in vibrational intensity measurements is assessed. New energetic quantities, apparent intensities and field descriptions, are proposed to be used in connection with intensity measurements. Approximations for these quantities, which may be regarded as extensions of the two-transducer method, are derived and implemented in the experiments.

  • Supplemental Notes:
    • Technical Research Centre of Finland, VTT Publication 170, March 1994 [81 p, 94 ref, 2 tab, 35 fig]
  • Authors:
    • Linjama, J
  • Publication Date: 1994

Language

  • English

Subject/Index Terms

Filing Info

  • Accession Number: 00727561
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Nov 1 1996 12:00AM