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The conventional SEA model considers only the resonant part of the structural response to an acoustic excitation. Therefore,
this study investigates non-resonant responses of isotropic and orthotropic plates to acoustically induced vibrations in a
reverberation chamber. A modified SEA model is introduced to predict the non-resonant plate response....
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... the setup of the acousti- cally induced vibration test for an aluminum plate and an FRP plate, respectively. These two plates were hung in a reverberation chamber during the test. White noise generated by a non-directional loud- speaker was adopted to excite acoustically the test plate, and the acceleration responses of the plates were measured. Fig. 2 presents the dimensions and plan view of the reverberation chamber, which is an irregularly shaped concrete building with a volume of 204 m 3 and a sur- face area of 202 m 2 . The temperature and relative humidity during the test were 21°C and 70%, respec- tively. Under these conditions, the density of air was 1.18 kg/m 3 and the speed ...
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Citations
... The traditional SEA model was limited to the resonant part of an acoustic excitation of the structural response. In order to improve the prediction results, Cheng et al. [19] investigated the non-resonant part of an acoustic excitation of isotropic and orthotropic plate materials. They have developed a modified SEA model to determine non-resonant part of an acoustic excitation plate response. ...
In the field of acoustic and vibration analysis, statistical energy analysis proven to be an efficient tool for evaluation of the crucial parameters like damping loss factor (DLF), modal density and coupling loss factor of complex structures. In the present study, modal densities and DLFs of idealised subsystems i.e. rectangular plates comprised of different materials were evaluated experimentally and numerically. In addition, the effects of various boundary conditions (BCs) like free-free, simply supported and cantilever on the statistical energy parameters have been studied. The results obtained using both experimental and numerical approaches are in close agreement. In the case of comparison of all the considered materials, the highest modal density was observed for aluminium, whereas the lowest frequency was observed for graphene doped epoxy composite. The highest DLF was observed for GFR epoxy composite, whereas the lowest DLF was observed for stainless steel.
... Renji et al. [12] mettent enévidence que l'hypothèse de troncature modale peutêtre difficilè a respecter dans le cas d'une plaque fine séparant deux cavités. L'étude de Cheng et al. [13] confirme ces dernières observations. La présenteétude s'inscrit dans la continuité des travaux précédents concernant les hypothèses de champ diffus, d'équipartition modale et d'excitation rain-on-the-roof [4]. ...
La méthode Statistical Energy Analysis (SEA), développée dans le cadre théorique de deux oscillateurs couplés, est basée
sur de nombreuses hypothèses (couplage faible, excitation de type rain-on-the-roof, couplage non-dissipatif, etc). Lorsque ces
hypothèses sont respectées, les énergies des oscillateurs peuvent être reliées `a la puissance transmise entre eux par la relation
dite de ”coupling power proportionality” (CPP). Étendue aux couplages entre sous-systèmes multi-modaux, la SEA peut être
appliquée à des structures complexes. Il est toutefois nécessaire de souligner que la SEA est théoriquement juste tant que toutes
ses hypothèses sont respectées. Avant d’envisager d’appliquer la SEA à un système industriel, il est donc impératif de s’assurer
qu’il est bien dans le domaine de validité de la SEA.
Cet article est une discussion sur l’hypothèse de couplage faible et l’influence des modes non-résonants dans l’utilisation de
la SEA. Dans le cas de deux oscillateurs couplés, il est montré que la relation de CPP reste valable quelque soit la force de
couplage. L’hypothèse de couplage faible n’est théoriquement nécessaire qu’à partir de trois oscillateurs couplés. Une simulation
numérique est présentée et confirme cette observation. Dans ce cas la relation de CPP n’est plus vérifiée et on constate l’apparition
de facteurs de couplage indirects.
Par ailleurs, il est montré que si la fréquence de résonance du troisième oscillateur est en dehors de la bande de fréquence
d’excitation (c’est `a dire si le mode est non-résonant) alors la relation de réciprocité établie en SEA n’est plus valable.
Statistical energy analysis (SEA) has been extensively used for predicting the transmission loss of sound and vibration through the complex structural-acoustic systems. The SEA method proved to be an effective tool for analysing the response of such complex systems at early design stage of the product. In the present study, the SEA parameters such as modal density, damping loss factor, and coupling loss factor have been evaluated by a theoretical and experimental approaches. In order to analyse the effect of different material properties on the SEA parameters, conventional materials such as mild steel, stainless steel, aluminium, and glass fibre epoxy composite have been considered. Beside in case of composite plates, the effects of different fibre orientation on the SEA parameters have been studied. The free-free boundary condition is considered for evaluating the SEA parameters.
As research works of the transient statistical energy analysis (TSEA) and transient local energy approach (TLEA) mostly focus on simple structures, TSEA and TLEA are adopted to quantify the transient response of a complex vibro-acoustic system at the mid-high frequency range in this paper. Numerical examples of a coupled oscillator system, an L-shaped plate, and a launch vehicle fairing model are conducted to demonstrate the effectiveness and accuracy of TSEA and TLEA. The computational precision of TSEA and TLEA is verified by the analytical solution and finite element method. Furtherly, the transient energy responses of subsystems with different coupling ratios between subsystems are investigated. Results show that TLEA has a better performance than TSEA. With the increasing coupling ratio between subsystems, the rise time and peak energy of transient energy response of subsystems decrease gradually. Both ratios of rise time and peak energy predicted by TLEA to these of the TSEA increase as the rising of the coupling ratio.
The interior sound pressure levels of a commercial vehicle cab at the driver’s right ear position and head rest position are determined as evaluation indices of vehicle acoustic performances. A statistical energy analysis model of the commercial vehicle cab was created by using statistical energy analysis method. The simulated interior acoustic performance of the cab has a significant coincidence with the experimental results. A response surface model was presented to determine the relationship between sound package parameters and evaluation indices of the interior acoustic performance for the vehicle cab. A multi-objective optimization was performed by using NSGA II algorithm with weighting coefficient method. The presented method provides a new idea for the multi-objective optimization design of the acoustic performances in vehicle noise analysis and control field.
