Structural Intensity analysis can be a powerful tool in noise and vibration control problems. The active part of the structural intensity is usually measured. It corresponds to the period-averaged value of the force times the velocity, and is related to energy propagation in a waveguide. The reactive part of the structural intensity, related with the energy of standing waves within the waveguide, is usually not analyzed. The authors have recently shown that if properly separated into its wave components, reactive intensity maps agree well with operational modes, clearly indicating the nodal lines in thin flat plates. It is well established that active intensity plots show the energy flow paths and the divergence of the active intensity can indicate the location of energy sources and sinks. For highly reverberant structures, however, measuring active intensity becomes awkward, and intensity plots fail to indicate the region where the energy is injected or dissipated in the structure. In this paper, the possibility of localizing energy sources based on the divergence of the reactive structural intensity and on the distribution of the potential and kinetic energy densities within the structure is investigated. Numerical and experimental results are presented for beams with point excitation. The structural intensity formulation is based on the Euler-Bernoulli theory. A finite element model is used in the numerical simulation. The conditions under which it is possible to effectively detect the location of point energy sources using the proposed method are addressed.
展开▼
