Calculations of the sound transmission over theater seats and methods for its improvement in the low‐frequency range

1982 ◽  
Vol 72 (2) ◽  
pp. 443-448 ◽  
Author(s):  
Yoichi Ando ◽  
Masako Takaishi ◽  
Koji Tada
Keyword(s):  
Low Frequency ◽  
Sound Transmission ◽  
Frequency Range

Sound transmission through triple plates separated by air cavities in the low-frequency range

2018 ◽  
Vol 230 (3) ◽  
pp. 965-977
Author(s):  
Akintoye Olumide Oyelade ◽  
Obanishola Mufutau Sadiq ◽  
Omotayo A. Fakinlede
Keyword(s):  
Low Frequency ◽  
Sound Transmission ◽  
Frequency Range ◽  
Air Cavities

Low-frequency impact sound of timber floors: A finite element–based study of conceptual designs

2020 ◽  
pp. 1351010X2091787
Author(s):  
Jörgen Olsson ◽  
Andreas Linderholt
Keyword(s):  
Finite Element ◽  
Low Frequency ◽  
Sound Transmission ◽  
Human Perception ◽  
Finite Element Simulations ◽  
Building Industry ◽  
Frequency Range ◽  
Floor Surfaces ◽  
The Impact ◽  
Selection Of

Traditionally, product development concerning acoustics in the building industry is measurement oriented. For lightweight floors, frequencies that are lower than the frequency range for heavy concrete floors are an issue. The frequency range of from 50 Hz down to 20 Hz influences the human perception of impact sound in multi-story apartment buildings with lightweight floor constructions, such as timber floors, for example. It is well known that a lower frequency range of interest makes finite element simulations more feasible. Strategies for reducing impact sound tend to be less straightforward for timber floors because they have a larger variation of designs when compared to concrete floors. This implies that reliable finite element simulations of impact sound can save time and money for the building industry. This study researches the impact sound transmission of lightweight timber floors. Frequency response functions, from forces on excitation points to sound pressure in the receiving cavity below, are calculated. By using fluid elements connected to reflection-free boundary elements under the floors in the models, the transmission and insulation can be studied without involving reverberation. A floor model with a hard screed surface will have a larger impact force than a softer floor, although this issue seems less pronounced at the lowest frequencies. To characterize floor surfaces, the point mobilities of the impact points are also calculated and presented. The vibration and sound transmission levels are dependent on the selection of the excitation points.

scholarly journals Numerical analyses of the sound transmission at low frequencies of a calibrated domestic wooden window

2021 ◽  
pp. 095440622110036
Author(s):  
Chaima Soussi ◽  
Mathieu Aucejo ◽  
Walid Larbi ◽  
Jean-François Deü
Keyword(s):  
Numerical Models ◽  
Low Frequency ◽  
Sound Transmission ◽  
The Finite Element Method ◽  
Acoustic Response ◽  
Frequency Range ◽  
Low Frequencies ◽  
Structure Interaction ◽  
Free Fields ◽  
Main Components

This work focuses on the numerical prediction of the sound transmission of wooden windows in the low frequency range. In this context, the finite element method is used to solve the multiphysics problem. This choice is justified by the fact that this approach is suitable for the resolution of fluid-structure interaction problems in low frequencies, due in particular to its flexibility in taking into account the coupling between domains and the geometrical and material complexities of the structures. To reach the desired objective, experimental modal analyses of the main components of a window, and then of a complete one, are performed in order to calibrate the numerical models. Then, a configuration that combines free-fields on both sides of the structure is employed to evaluate the intrinsic acoustic response of the window. The numerical results for a symmetric and an asymmetric glazing are compared to experimental ones to evaluate the efficiency and validity of the developed models.

Active attenuation of sound transmission through a soft-core sandwich panel into an acoustic enclosure using volume velocity cancellation

2015 ◽  
Vol 229 (17) ◽  
pp. 3096-3112 ◽  
Author(s):  
Kiran Chandra Sahu ◽  
Jukka Tuhkuri ◽  
JN Reddy
Keyword(s):  
Active Control ◽  
Sandwich Panel ◽  
Control Method ◽  
Low Frequency ◽  
Sound Transmission ◽  
Soft Core ◽  
Frequency Range ◽  
Broad Frequency Range ◽  
Volume Velocity ◽  
Numerical Studies

In this paper, active control of harmonic sound transmitted through a soft-core sandwich panel into a rectangular enclosure is studied. As it has already been shown for the low frequency region, the noise transmission through a soft-core sandwich panel mainly occurs due to the flexural and the dilatational modes. Therefore, in this study, volume velocity cancellation control strategy is used to control these modes, and achieve sound attenuation in a broad frequency range. Point force and uniformly distributed force actuators are used as the secondary actuator to cancel the volume velocity of the bottom faceplate, which opens to the cavity, of the sandwich panel. Cancelling the net volume velocity of the bottom faceplate is compared not only in terms of the reduction in sound transmission through the sandwich panel into cavity but also in terms of the faceplate velocities. Also, the effectiveness of the volume velocity cancellation strategy has been studied for different values of isotropic loss factor of the core. Sound transmission into the cavity has also been calculated by considering the effect of cavity pressure on the sandwich panel. Numerical studies indicate that the active control method controls both the flexural and the dilatational modes of the sandwich panel and therefore, attenuates significant amount of sound pressure inside the cavity irrespective of the isotropic loss factors of the viscoelastic core in a broad frequency range. Also a finite element study has been done in the commercially available COMSOL Multiphysics software to compare with the analytical results.

Analysis of Sound Transmission Loss of Double-Leaf Walls in the Low-Frequency Range Using the Finite Element Method

2004 ◽  
Vol 11 (4) ◽  
pp. 239-257 ◽  
Author(s):  
Peter Davidsson ◽  
Jonas Brunskog ◽  
Per-Anders Wernberg ◽  
Göran Sandberg ◽  
Per Hammer
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Transmission Loss ◽  
Low Frequency ◽  
Sound Transmission ◽  
Sound Transmission Loss ◽  
The Finite Element Method ◽  
Frequency Range ◽  
Element Method

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

Dynamic Damping and Stiffness Characteristics of the Rolling Tire

2001 ◽  
Vol 29 (4) ◽  
pp. 258-268 ◽  
Author(s):  
G. Jianmin ◽  
R. Gall ◽  
W. Zuomin
Keyword(s):  
Dynamic Behavior ◽  
Variable Parameter ◽  
Low Frequency ◽  
Vertical Load ◽  
Frequency Range ◽  
Inflation Pressure ◽  
Vehicle Simulation ◽  
Dynamic Damping ◽  
Speed Range ◽  
Stiffness Characteristics

Abstract A variable parameter model to study dynamic tire responses is presented. A modified device to measure terrain roughness is used to measure dynamic damping and stiffness characteristics of rolling tires. The device was used to examine the dynamic behavior of a tire in the speed range from 0 to 10 km/h. The inflation pressure during the tests was adjusted to 160, 240, and 320 kPa. The vertical load was 5.2 kN. The results indicate that the damping and stiffness decrease with velocity. Regression formulas for the non-linear experimental damping and stiffness are obtained. These results can be used as input parameters for vehicle simulation to evaluate the vehicle's driving and comfort performance in the medium-low frequency range (0–100 Hz). This way it can be important for tire design and the forecasting of the dynamic behavior of tires.

scholarly journals An Improved Time Integration Method Based on Galerkin Weak Form with Controllable Numerical Dissipation

2021 ◽  
Vol 11 (4) ◽  
pp. 1932
Author(s):  
Weixuan Wang ◽  
Qinyan Xing ◽  
Qinghao Yang
Keyword(s):  
High Frequency ◽  
Integration Method ◽  
Time Integration ◽  
Low Frequency ◽  
Weak Form ◽  
High Accuracy ◽  
Numerical Dissipation ◽  
Frequency Range ◽  
Time Integration Method ◽  
Numerical Damping

Based on the newly proposed generalized Galerkin weak form (GGW) method, a two-step time integration method with controllable numerical dissipation is presented. In the first sub-step, the GGW method is used, and in the second sub-step, a new parameter is introduced by using the idea of a trapezoidal integral. According to the numerical analysis, it can be concluded that this method is unconditionally stable and its numerical damping is controllable with the change in introduced parameters. Compared with the GGW method, this two-step scheme avoids the fast numerical dissipation in a low-frequency range. To highlight the performance of the proposed method, some numerical problems are presented and illustrated which show that this method possesses superior accuracy, stability and efficiency compared with conventional trapezoidal rule, the Wilson method, and the Bathe method. High accuracy in a low-frequency range and controllable numerical dissipation in a high-frequency range are both the merits of the method.

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