Characteristic Evaluation of Impact Sound Reduction by Floor Coverings Using Floor Impact Sound in a Test Building

2015 ◽  
Vol 752-753 ◽  
pp. 800-803
Author(s):  
Jun Oh Yeon ◽  
Kyoung Woo Kim ◽  
Kwan Seop Yang ◽  
Myung Jun Kim
Keyword(s):  
South Korea ◽  
High Frequency ◽  
Reduction Rate ◽  
High Frequency Range ◽  
Frequency Range ◽  
Different Types ◽  
Specific Frequency ◽  
High Reduction ◽  
Floor Coverings ◽  
Sound Reduction

Impact sound reduction under various conditions for a total of eight different types of Floor cosverings currently used in South Korea. The results of floor impact sound within the test building under bare slab conditions indicated a high reduction rate for lightweight impact sound, but poor reduction during heavyweight impact sound testing (Bang Machine, Impact Ball). However, a reduction was identified in the mid-high frequency range (315 Hz–3150 Hz) for the lightweight impact sound, as was a reduction of approximately 2 dB–3 dB at specific frequency ranges, depending on the thickness of the floor coverings, for the heavyweight impact sound on the Ondol structure.

Prediction of the sound reduction index of clay hollow brick walls

2020 ◽  
Vol 27 (2) ◽  
pp. 155-168 ◽  
Author(s):  
Nicola Granzotto ◽  
Antonino Di Bella ◽  
Edoardo Alessio Piana
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Sound Insulation ◽  
Frequency Range ◽  
Proposed Model ◽  
Different Types ◽  
Classic Approach ◽  
Hollow Brick ◽  
Sound Reduction ◽  
Reduction Index

Clay hollow brick walls are still popular in building industry, but the prediction of their sound insulation properties is not straightforward due to their inhomogeneous and anisotropic characteristics. In this article, a classic approach has been used to determine the sound transmission coefficient of brick walls, assuming an orthotropic behaviour and deriving the mechanical and dynamic characteristics from datasheet information. Different types of walls with horizontal and vertical mortar joints have been analysed. Experimental measurements of the sound reduction index carried out according to ISO 10140-2 standard have been performed, and the resulting values are compared with the predictions in the proposed model. It was found that the sound reduction index can be fairly predicted in the low-frequency range and it is correctly predicted in the mass law region, whereas in the high-frequency range the inner block structure is responsible for a loss of performance which is difficult to predict with the analytical methods.

Electromagnetic Property of La0.7Sr0.3MnO3/Ag Composite at High Frequency

2015 ◽  
Vol 655 ◽  
pp. 182-185
Author(s):  
Ke Lan Yan ◽  
Run Hua Fan ◽  
Min Chen ◽  
Kai Sun ◽  
Xu Ai Wang ◽  
...  
Keyword(s):  
High Frequency ◽  
Single Phase ◽  
Low Frequency ◽  
Electromagnetic Property ◽  
High Frequency Range ◽  
Frequency Range ◽  
Free Electron Concentration ◽  
Theoretical Simulation ◽  
Electrical And Magnetic Properties ◽  
Three Phase

The phase structure, and electrical and magnetic properties of La0.7Sr0.3MnO3(LSMO)-xAg (xis the mole ratio,x=0, 0.3, 0.5) composite were investigated. It is found that the sample withx=0 is single phase; the samples withx=0.3 and 0.5 present three phase composite structure of the manganese oxide and Ag. With the increasing of Ag content, the grain size of the samples increases and the grain boundaries transition from fully faceted to partially faceted. The permittivity of spectrum (10 MHz - 1 GHz) and the theoretical simulation reveal that the plasma frequencyfpincrease with Ag content, due to the increasing of free electron concentration, which is further supported by the enhancement of conductivity. While for the permeability (μr'), theμr'decrease with the increasing of Ag content at low frequency range (f< 20 MHz), while at the relative high frequency range (f> 300 MHz), theμr'increased with Ag content. Therefore, the introduction of elemental Ag resulted in a higherμr'at the relative high frequency range.

An Impedance-Based Approach for Rods With Shear-Type Damping Layer Treatment

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
P. W. Wang ◽  
D. Q. Zhuang
Keyword(s):  
High Frequency ◽  
Continuous Model ◽  
Damping Coefficient ◽  
System Response ◽  
Traditional Model ◽  
Constrained Layer Damping ◽  
High Frequency Range ◽  
Frequency Range ◽  
Shear Type ◽  
Shear Spring

An impedance-based approach for analyzing an axial rod with shear-type damping layer treatment is proposed. The rod and shear-type damping layer are regarded as two subsystems and both impedances are calculated analytically. The system impedance can be obtained through the impedance coupling between the host rod and the damping layer. The shear-type damping layer is regarded as a shear spring with complex shear modulus. Under the traditional model, the damping coefficient diminishes with the increasing frequency. The paper develops two shear-type damping layer models, including the single degree-of-freedom (SDOF) model and continuous model to predict the behavior of the damping layer. Both damping layer models are compared with the traditional model and the system responses from these models are validated by finite element method (FEM) code COMSOL Multiphysics. Results show that the damping coefficients of both the traditional shear-spring model and SDOF model diminish as the increasing frequency so that the system responses are discrepant with that from COMSOL in the high frequency range. On the other hand, the system response from the continuous model is consistent with that from COMSOL in the full frequency range. Hence, the continuous damping layer model can predict a correct damping coefficient in the high frequency range and this property can be also employed to improve the analysis of the constrained-layer damping treated structures. Finally, the modal loss factor and fundamental frequency of the system with respect to different damping layer thicknesses are presented using the developed approach.

Electromagnetic properties of porous 3D carbon-based structures in high frequency range

2021 ◽  
pp. 76-83
Author(s):  
E.G. Shashkova ◽  
◽  
N.I. Valunets ◽  
M.I. Demidenko ◽  
A.G. Paddubskaya ◽  
...  
Keyword(s):  
High Frequency ◽  
Electromagnetic Properties ◽  
High Frequency Range ◽  
Frequency Range ◽  
Carbon Based
Sign in / Sign up

Export Citation Format

Share Document