A COMPARISON OF EXPERIMENTAL AND FINITE ELEMENT STRUCTURAL INTENSITIES IN THE SUB-PANELS OF THE INCE STANDARD LEXAN RIBBED PANEL STRUCTURE

摘要

Existing finite difference methods for inferring structural intensities from the normal vibration fields of thin plates appear to be applicable to the vibrations of the sub-panels of rib-stiffened thin plates as well. Structural intensities computed from finite element and measured vibrations agreed well with those predicted using pure finite element techniques. The ribs sometimes carry significant power themselves, however, and rib intensities should be added to plate intensities to accurately depict the total structure-borne sound field.Some differences in finite element and experimental intensity levels were observed. New measurements may be performed by driving ribs on different corners of the panel. Since the structure is symmetric, the results from the different drive locations should establish an an uncertainty range for the power measurements.Finally, in future Lexan ribbed panel experiments, power input spectra should be measured so that power fields may be presented relative to power input. Past experience has shown, however, that power input measurements require great care to ensure that the phase difference between the input force and corresponding velocity is correct.