The basic parameter of materials used in constructional solutions of anti-noise protection, is sound insulation, which can be determined in laboratory conditions and also using theoretical models. The use of numerical methods in the form of the Finite Element Method to calculate the mechanical impedance of a baffle and then the sound insulation of homogeneous baffles was presented in the article. A 1 mm thick steel plate with a square, rectangular and round shape was analyzed. The boundary conditions for simply supported and clamped plate were taken into account in the numerical calculations. The results of the calculations were compared to both the commonly used the mass law and to the experimental tests. These analyzes will be the starting point for analyzes of multi-layer baffles, for which it is no longer possible to apply the mass law.
The article presents the results of an experimental study and calculations, using theoretical models, of the insertion loss of acoustical enclosures. The research used a developed prototype stand for testing acoustical enclosures. The sound power levels of the source without and with the enclosure, needed to determine the insertion loss, were determined by the approximate method in accordance with standard requirements. To calculate of the insertion loss for enclosures with sound absorbing and insulating walls, a known calculation model using the transmission loss of baffles was used. A new calculation model for enclosures with sound insulating walls is proposed in the article.
The article presents a comparative analysis of determined spectral responses of the airborne sound insulation of single homogeneous baffles using computational and experimental methods. Calculations using theoretical models, such as mass law, the Sharp and Davy models, SoundFlow software and laboratory tests concerned nine plates made of plastic, steel, aluminium and rubber, which are homogeneous materials. These materials are used in the construction of walls in vibroacoustic protection, such as acoustic barriers, machine operating field shields and sound insulating enclosures. Apart from analysing the spectral responses of the sound insulation of the plates, the weighted single-number sound reduction indices Rw, calculated by using prediction methods and laboratory measurements, were compared. Research has shown computational errors of about 6-7 dB for mass law and the Sharp model and about 3 dB for the Davy and Davy-Sharp models and SoundFlow software.
W artykule przedstawiono zastosowanie modelu regresji do oszacowania współczynnika izolacyjności akustycznej przegrody niejednorodnej na przykładzie przegrody dwumateriałowej. Sformułowano model regresji, następnie zastosowano go do wyznaczenia izolacyjności płyty. Uzyskane wyniki porównano z wynikami pomiarów.
EN
Paper discussed the regression model which was used to determine the sound insulation of a two-materials baffle based on the known sound insulation of its layers.
W artykule, do wyznaczania izolacyjności akustycznej przegród warstwowych, wykorzystano podstawowe metody teoretycznego wyznaczania izolacyjności akustycznej właściwej przegród jednorodnych. Niezbędne do obliczeń wartości wielkości wykorzystywanych w modelach wyznaczono w wyniku homogenizacji. W pracy autor rozważania ograniczył do modeli opartych na wykorzystaniu impedancji mechanicznej przegrody. Przegrodę zamodelowano jako: bryła sztywna, odkształcalna płyta cienka (opisana modelem Kirchhoffa-Love’a) i gruba (model Mindlina-Reissnera).
EN
In the paper basic theoretical models of transmission loss calculation are described. Four different methods of homogenisation used for building of the simplified panel model are describeb. Simplified model is the single homogeneous isotropic plate panel. For this panel three impedance values of one rigid and two flexible body models of panel are described and analysed. As flexible models the thin plate (Kirchhoff-Love plate model) i thick (Mindlin-Reissner model) are analysed. All results are compared to results of 3D FEM model.
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