Double-leaf Partition Research Articles

Studs' impact on sound transmission in double-leaf partitions

Double-leaf partitions constructed by two parallel plasterboard panels installed on steel studs are widely used in building constructions. Although it is known that the studs significantly influence vibroacoustic behavior of the plates, there has not been extensive research on this topic. This study focuses on the impact of steel studs on the sound transmission in double-leaf constructions. In order to fully analyze the impact of the steel stud element, a comparison between experimental data from a double leaf partition with a mechanical connection using steel studs and a theoretical model that disregards any mechanical connection between the parallel plasterboard panels was conducted. Results presenting radiation efficiency, transmission loss, and velocity level differences in a grid of points equally distributed on the radiating side of a structure highlight the influence of steel studs in double-leaf constructions indicating frequency ranges, where the studs’ impact is mostly significant.

Effect of absorption material in cavity and laminated gypsum board with adhesive on sound insulation performance of double leaf partition

Effect of absorption material in cavity and laminated gypsum board with adhesive on sound insulation performance of double leaf partition

Noise and Vibration Pollution: Analytical Analysis of Double-leaf Partition

This paper treats the noise control engineering using a double-leaf partition by the means of an analytical approach. This technique is widely used due to its efficiency in providing better acoustic insulation over a wide frequency range compared to single-leaf structures. The double-leaf partition is a construction comprising two leaves separated by an air space or cavity which will dynamically couples the two leaves. Therefore, its analysis is complicated and introduces several scientific aspects This paper deals with a very common case of the double-leaf partitions which is the double glazing: an analytical approach will be used to analyze the influence of the different parameters on the acoustic insulation e.g. plate thickness, gap width, etc.. Several simulations are then performed for different double glazing configurations to assess the influence of the variables on the final acoustic insulation. At low frequencies a better performance was achieved for thicker air layers, while at higher frequencies a thinner air layer is preferable. The use of wall panels with different mass resulted in the wall performing better, particularly for high frequencies.

Normal Incidence of Sound Transmission Loss of a Double-Leaf Partition Inserted with a Microperforated Panel

A double-leaf partition in engineering structures has been widely applied for its advantages, that is, in terms of its mechanical strength as well as its lightweight property. In noise control, the double-leaf also serves as an effective noise barrier. Unfortunately at low frequency, the sound transmission loss reduces significantly due to the coupling between the panels and the air between them. This paper studies the effect of a microperforated panel (MPP) inserted inside a double-leaf partition on the sound transmission loss performance of the system. The MPP insertion is proposed to provide a hygienic double-leaf noise insulator replacing the classical abrasive porous materials between the panels. It is found that the transmission loss improves at the troublesome mass-air-mass resonant frequency if the MPP is located closer to the solid panel. The mathematical model is derived for normal incidence of acoustic loading.

English

In noise control applications, a double-leaf partition has been applied widely as a lightweight structure for noise insulation, such as in car doors, train bodies, and aircraft fuselages. Unfortunately, the insulation performance deteriorates significantly at mass-air-mass resonance due to coupling between the panels and the air in the gap. This paper investigates the effect of a micro-perforated panel (MPP), inserted in the conventional double-panel partition, on sound transmission loss at troublesome resonant frequencies. It is found that the transmission loss improves at this resonance if the MPP is located at a distance of less than half that of the air gap. A mathematical model is derived for the diffuse field incidence of acoustic loading.

Estimation method for parameters of construction on predicting transmission loss of double leaf dry partition

For improving sound insulation of a double leaf dry partition, each leaf is often consisted of more than one panel. Previous study on predicting a transmission loss of double leaf partition, treats with the leaf varied just two kinds of panels and restricted to a leaf having same kind and same thickness. These restrictions are unfit for variety of current building materials and constructions. This study makes a prediction formula for a transmission loss of the double leaf partition with laminated leaves by a theoretical analysis and an experiment, and will discuss the predicted value with measured value in previous studies and catalogs.

A symmetric weak form of Biot's equations based on redundant variables representing the fluid, using a Helmholtz decomposition of the fluid displacement vector field

AbstractA novel symmetric weak formulation of Biot's equations for linear acoustic wave propagation in layered poroelastic media is presented. The primary variables used are the frame displacement, the acoustic pore pressure, the scalar potential and the vector potential obtained from a Helmholtz decomposition of the fluid displacement. Also a symmetric weak form based on the frame displacement, the pore pressure and the fluid displacement is obtained as an intermediate result. hp finite element simulations of a double leaf partition based on this new weak formulation is verified against simulation results from the classical frame displacement, fluid displacement formulation and a frame displacement pore pressure formulation. All three formulations simulated, displays the same rate of convergence with respect to finite element bases polynomial degree. The novel formulation also extends a previously published frame displacement, pore pressure, scalar fluid displacement potential formulation with an implicit irrotational fluid displacement assumption to a full representation of Biot's equations. Copyright © 2010 John Wiley & Sons, Ltd.

Effect of inserting a Helmholtz resonator on sound insulation in a double-leaf partition cavity

We investigated the improvement of sound insulation of a double-leaf partition using Helmholtz resonators. We proposed a method of predicting the sound reduction index R0 at normal incidence using impedance transfer, under the assumption that the resonators installed in the air cavity between the two leaves were independent components of a wall, similarly to boards and studs. Furthermore, for experimentation, a small sample without studs was used to prevent flanking transmission through them. Theoretical and empirical examinations revealed that installing the resonators in the cavity in the following manner was sufficient to control sound insulation at low frequencies. High sound insulation occurred at the resonance frequency f0 of resonators; the sound insulation decreased at higher and lower frequencies than f0. The sound insulation at f0 depended on the acoustic resistance of resonators. When an air layer existed behind the resonators, other peaks and dips appeared at higher frequencies than f0. Installing both a fibrous absorber and resonators in the cavity was sufficient to recover the decreased performance of sound insulation owing to the installation of resonators.

609 クラスタ制御による二重壁構造物から発生する放射音の抑制

609 クラスタ制御による二重壁構造物から発生する放射音の抑制

Passive Vibroacoustic Isolation for Payload Containers

This paper presents analysis and experimental results which examine key issues related to passive vibroacoustic isolation for container type structures. The key noise reduction principle examined is the passive application of a characteristic impedance mismatch in conjunction with a vibration isolation suspension system to limit structural transmission. The characteristic impedance mismatch is created by imposing a near vacuum condition between partitions of a container structure. Unlike active boundary control techniques, this approach is insensitive to the grazing angle of the source acoustics, is simple, and avoids technology challenges such as the need to develop efficient large stroke actuators. The analysis for this problem is performed by extending Fahy's double-leaf partition model. Using the extended model, numerical simulations are conducted to study the effect of various design parameters on acoustic transmission. Guidelines developed from this study are then used to construct an experiment to show the viability of the concept. The experiment demonstrates that at least a 19 dB reduction in sound pressure level (SPL) may be achieved, with a modest level of vacuum.

Passive Vibroacoustic Isolation for Payload Containers

This paper presents analysis and experimental results which examine key issues related to passive vibroacoustic isolation for container type structures. The key noise reduction principle examined is the passive application of a characteristic impedance mismatch in conjunction with a vibration isolation suspension system to limit structural transmission. The characteristic impedance mismatch is created by imposing a near vacuum condition between partitions of a container structure. Unlike active boundary control techniques, this approach is insensitive to the grazing angle of the source acoustics, is simple, and avoids technology challenges such as the need to develop efficient large stroke actuators. The analysis for this problem is performed by extending Fahy's double-leaf partition model. Using the extended model, numerical simulations are conducted to study the effect of various design parameters on acoustic transmission. Guidelines developed from this study are then used to construct an experiment to show the viability of the concept. The experiment demonstrates that at least a 19 dB reduction in sound pressure level (SPL) may be achieved, with a modest level of vacuum.

Active control of sound transmission through a double-leaf partition by volume velocity cancellation

The paper considers the active control of harmonic sound transmitted through a double-leaf partition by cancelling the volume velocity of the radiating panel. The double-leaf partition consists of a pair of small plates, 300×380 mm, separated by a 100-mm air-gap. The panel volume velocity can be sensed by a single shaped film of piezoelectric PVDF material attached to the plate. Cancellation of volume velocity using a single point force is compared with the result using a matched, distributed actuator which applies a uniform force to the plate and does not give rise to control spillover. Comparison with earlier work in which the volume velocity of a single plate was cancelled [Johnson and Elliott, J. Acoust. Soc. Am. 98, 2174–2186 (1995)] shows that substantial reductions in the transmitted sound power are only possible up to around 350 Hz, as opposed to 600 Hz in the single panel case. A radiation mode analysis of the panels shows that the double-leaf construction provides good passive attenuation of the first radiation mode at high frequencies, so that inefficiently radiating even modes of the radiating panel make a dominant contribution to the radiated sound power. Thus there is no advantage in controlling volume velocity in this frequency range.

Sound transmission through a double leaf partition with edge flanking

Lightweight double leaf partitions are widely used and with proper design give good sound isolation. However, when these walls are used as party walls between dwellings, then precautions are necessary to prevent the transmission of fire and smoke. This is usually carried out by placing a firestop in the cavity. This firestop introduces flanking transmission paths reducing the airborne transmission loss of the wall. A simple model is developed which can predict vibration transmission across this type of structural connection. The structural vibration transmission loss can then be used with a more general statistical energy analysis model to give the sound transmission through the entire system. Predicted airborne transmission loss results for a variety of different materials are compared with measured results and good agreement is obtained.

Criticism of statistical energy analysis for the calculation of sound insulation: Part 2-double partitions

The theory of statistical energy analysis has been applied to the problem of estimating the transmission loss of a single finite panel. This theory was extended to the problem of a finite double-leaf partition structure. This paper deals with the degree of agreement of the measured values with the theoretical results of the sound insulation of double partitions according to this theory. In addition, the advantages and disadvantages of this method compared with classical methods are discussed. A comparison between the method of statistical energy analysis and classical methods for the calculation of the sound insulation of double partitions is given.

Effect of sound-absorptive facings on partition airborne-sound transmission loss

Laboratory measurements of the improvement of partition airborne-sound transmission loss in the presence of sound-absorptive partition facings are presented. For a double-leaf partition of 1/2-in.-thick gypsum board on 2×4-in. studs, the application of such facings has led to improvements in transmission loss in excess of 10 dB in the 1/3-octave bands above 1 kHz. Corresponding, but smaller, improvements have been measured at lower frequencies.

Effect of sound-absorptive facings on partition airborne sound-transmission loss

Laboratory measurements of the effect of sound-absorptive facings on partition airborne sound-transmission loss are presented. For a double-leaf partition of 1/2-in. gypsum board on 2×4 in. studs, the application of sound-absorptive facings has led to improvements in transmission loss of as much as 10 dB or more in the 1/3-octave bands above 1 kHz. Corresponding, but smaller, improvements have been measured at lower frequencies. A preliminary theoretical analysis is presented.

The influence of absorbent linings on the transmission loss of double-leaf partitions

Under certain circumstances the insertion of a porous blanket into the cavity of a double-leaf partition can produce a pronounced increase in transmission loss, particularly when the leaves have a low critical frequency and a broad coincidence plateau. In the measurements reported, improvements of between 7 and 10 dB have been obtained, depending on the size of the cavity. The authors show that a similar improvement in transmission loss is obtainable, even with quite small quantities of absorbent, if placed either round the reveals or in other limited regions in the cavity.