FLEXURAL INTENSITY MEASUREMENT ON FINITE PLATES USING MODAL SPECTRUM IDEAL FILTERING

Abstract Flexural intensities on various plate-like structures with arbitrary boundary conditions are calculated using measured and FEM yielded mobility. In doing so, a two-dimensional spatial Fourier transform has been implemented along with a refined k-spectral filtering concept. Intensity is decomposed into individual contributions from bending moments, twisting moments and shear forces. The source and energy sink localization and energy flow have been analyzed through these contributions. The effect of reflections from the plate edges and that of the uncorrelated noise, on the intensity, are discussed. It is shown that the width of the k -filters may have a non-negligible influence on the shape of the intensity field. Damping in the structure can efficiently control the edge reflections and therefore help to localize the energy sources and sinks. A link has been found, at certain excitation conditions, between the radiated acoustic intensity and the active flexural intensity. It is also observed that the classical method of studying the vibration transmission, using vibration amplitude measurements, does not reflect the transmitted vibration energy but rather provides information on non-propagating, reactive energy. The FEM study, further explains some of the experimental observations and suggests the possibility of applying intensity to complex analytical models.

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