<title>Predicting and measuring flexural power flow in plates</title>

Abstract

Structural power flow is an alternative way of analyzing vibrations, where, differently from traditional techniques, the emphasis is put on the active part of the vibration energy instead of the total. The active vibration energy is directly related to the injection and dissipation of energy in the structure and can, therefore, be a valuable tool for solving vibroacoustical problems. However, measuring the active part of the vibration energy in the presence of a highly reverberant field is often impractical. This paper presents an experimental method especially adapted for the computation of structural power flow using spatially dense vibration data measured with scanning laser Doppler vibrometers. In the proposed method, an operational deflection shape measured over the surface of the structure is curve-fitted using a 2D discrete Fourier series approximation. This approximation minimizes the effects of spatial leakage. From the wavenumber-frequency domain data thus obtained, it is straightforward to compute the spatial derivatives that are necessary to determine the structural power flow. An example consisting of a rectangular aluminum plate supported by four rubber mounts and excited by an electrodynamic shakes is used to appraise the proposed method. Both numerically simulated data and experimental data are used.