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Optimization of structure‐borne sound popagation using structural intensity
Author(s) -
Rothe Sebastian,
Langer Sabine C.
Publication year - 2019
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.201900482
Subject(s) - sound energy , acoustics , energy flow , homogenization (climate) , structural acoustics , energy (signal processing) , sound pressure , computer science , sound (geography) , physics , vibration , biodiversity , ecology , quantum mechanics , biology
Reducing noise in mobile applications such as cars, aircrafts and trains is a major challenge for today's engineers. In most cases, sound sources and sound radiating structures are locally separated. The airborne sound field is a result of the excitation and the transfer through the mechanical system. The resulting structure‐borne sound is propagated on transfer paths and finally radiated through plate‐like structures. Therefore, the structure‐borne sound energy should already be efficiently insulated and damped on the way of propagation. The structural intensity (STI) is a complex vectorial quantity that represents the flow of sound energy in the structure. The real part of STI, can identify areas with a high absorption of structure‐borne sound. These areas should correlate with high damping in the structure, e.g. areas with additionally applied damping measures. If the damping is homogeneously distributed, a uniform distribution of structure‐borne sound energy should be the objective in order to make optimal use of the material damping. The energy flow can be influenced by introducing structural changes. With the help of the direction information and the quantitative value of the STI, the position of such structural changes can be optimized. In this paper, an optimization procedure is investigated, with which a homogenization of the structure‐borne sound flow is aimed. Numerical studies on generic structures are carried out. The STI for a homogeneously and an inhomogeneously damped plate is calculated and specifically influenced by various measures (e.g. point masses, beads). The aim is the targeted guidance of sound in areas of high damping or the uniform distribution in the structure as well as a shift of eigenfrequencies in order to reduce the mean surface velocity in a defined frequency range.