Sound Transmission Loss in Electrorheological Fluids Under DC Voltage

2000 ◽  
Author(s):  
Marek L. Szary ◽  
Maciej Noras
Keyword(s):  
Shear Stress ◽  
Sound Pressure ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Electrorheological Fluids ◽  
Sound Transmission Loss ◽  
Dc Voltage ◽  
College Of Engineering ◽  
Er Fluids ◽  
Er Fluid

Abstract Extensive investigations of sound transmission loss (STL) in electrorheological (ER) fluids were conducted in the Acoustics Laboratory in the College of Engineering, Southern Illinois University Carbondale. The STL was investigated for different kinds of ER suspensions in frequency ranges from 100 Hz to 2kHz. Applied DC voltage to the different electrodes allowed normal and shear stress to develop in the ER fluid respectively. The electric field density was variable. Sound transmission loss was obtained by measurement of the sound pressure level in front of and behind the sample. Under both normal and shear stress in ER fluid, STL decreases with increasing stress. Those properties of ER fluids can be useful in noise and vibration control applications.

Experimental Study of Sound Transmission Loss in Electrorheological Liquids

2002 ◽  
Author(s):  
Marek L. Szary ◽  
Maciej Noras
Keyword(s):  
Electric Field ◽  
Sound Propagation ◽  
Transmission Loss ◽  
Active Vibration Control ◽  
Sound Transmission ◽  
Sound Transmission Loss ◽  
Frequency Range ◽  
Field Density ◽  
Active Vibration ◽  
College Of Engineering

Electrorheological (ER) liquids possess the ability to change their physical properties like the apparent viscosity and modulus of elasticity under the influence of an external electric field. They serve successfully in the field of active vibration control—as well as in many other areas. In the Acoustic Laboratory at the College of Engineering, Southern Illinois University in Carbondale, research on the possibility of applying ER liquids to the control of a sound transmission loss (STL) was conducted. The STL was investigated for various kinds of ER suspensions in the frequency range 100 Hz to 2 kHz. An influence of the electric field density on the STL was different for normal and shear stress developed by DC voltage. In both cases the STL decreased with the increasing electric field density. These properties could be potentially useful in sound propagation control applications.

Acoustic Parts in Vehicle Sound Transmission Loss Test Method Research

2013 ◽  
Vol 380-384 ◽  
pp. 73-76
Author(s):  
Xiu Feng Wang ◽  
Jie Shi
Keyword(s):  
Sound Pressure ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Sound Intensity ◽  
Pressure Level ◽  
Test Method ◽  
Intensity Level ◽  
Sound Transmission Loss ◽  
Passenger Compartment ◽  
Exterior Panel

The sound transmission loss (STL) of the acoustic parts in the vehicle was proposed to be computed using the Sound Pressure Level measured at the several locations inside the vehicle and the transmitted Sound Intensity Level on the vehicles exterior panel, which the acoustic treated vehicle passenger compartment is assumed as a small reverberation room. The necessary parts retrofits and acoustic treatments for Sound transmission loss tests of the acoustic parts in the vehicle were listed. The values of the appropriate number and positions of the loud speakers, microphones and sound intensity probes for Sound transmission loss of the acoustic parts in the vehicle were recommended. The in vehicle sound transmission loss tests of the acoustic parts such as the doors, carpets, wheel house etc. were achieved in the semi-anechoic room. Based on the door system, the correlation work has been done among the methods of the proposed in vehicle STL test, the reverberation - semi-anechoic chamber buck STL test and SEA analysis.

scholarly journals On the Determination of Acoustic Properties of Membrane Type Structural Skin Elements by Means of Surface Displacements

2021 ◽  
Vol 11 (21) ◽  
pp. 10357
Author(s):  
Daniel Urbán ◽  
N. B. Roozen ◽  
Vojtech Jandák ◽  
Marek Brothánek ◽  
Ondřej Jiříček
Keyword(s):  
Plane Wave ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Transmission Loss ◽  
Laser Doppler Vibrometer ◽  
Sound Transmission ◽  
Acoustic Properties ◽  
Sound Transmission Loss ◽  
Membrane Type

The article focuses on the determination of the acoustic properties (sound transmission loss, sound absorption and transmission coefficient under acoustic plane wave excitation) of membrane-type of specimens by means of a combination of incident plane wave sound pressure and membrane surface displacement information, measuring the sound pressure with a microphone and the membrane displacement by means of a laser Doppler vibrometer. An overview of known measurement methods and the theoretical background of the proposed so-called mobility-based method (MM) is presented. The proposed method was compared with the conventional methods for sound transmission loss and absorption measurement in the impedance tube, both numerically and experimentally. Finite element model (FEM) simulation results of two single layer membrane samples of different shape configurations were compared, amongst which six different variations of the backing wall termination. Four different approaches to determine the sound transmission loss and two methods to determine sound absorption properties of the membranes were compared. Subsequently, the proposed method was tested in a laboratory environment. The proposed MM method can be possibly used to measure the vibro-acoustic properties of building parts in situ.

Dependence of the shear stress on particle properties in electrorheological fluids

2001 ◽  
Vol 15 (06n07) ◽  
pp. 938-946 ◽  
Author(s):  
Kunquan Lu ◽  
Yucheng Lan ◽  
Shouqiang Men ◽  
Xiaoyu Xu ◽  
Zhao Xianpeng ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Shear Stress ◽  
Silicone Oil ◽  
Theoretical Calculations ◽  
Ferroelectric Material ◽  
Electrorheological Fluids ◽  
Particle Properties ◽  
Er Fluids ◽  
Er Fluid ◽  
Curie Temperature Tc

By measuring the shear stress of a ferroelectric particle/silicone oil ER fluid varying with the temperature across Tc, the dependence of ER effect on permittivity mismatch is quantitatively obtained. The dielectric property of ferroelectric material behaves a dramatic change at Curie temperature (Tc) either in the dielectric constant and the conductivity. TGS and KNO 3 ferroelectric particles are chosen for studying the dielectric constant and conductivity dependence of the shear stress in ER fluids respectively. The measured results are more reliable, because the conditions, such as size, shape, composition of particles, especially chemical nature of particles and interface property between particles and liquid, all are same. The available theoretical calculations can not well fit our measured results. In order to consider the properties of whole suspensions, the orientation of the particles with spontaneous polarization under an electric field was studied in advance.

Coating of Polyaniline with an Insulating Polymer to Improve the Power Efficiency of Electrorheological Fluids

1999 ◽  
Vol 13 (14n16) ◽  
pp. 1931-1939 ◽  
Author(s):  
J. Akhavan ◽  
K. Slack ◽  
V. Wise ◽  
H. Block
Keyword(s):  
Power Efficiency ◽  
Electrorheological Fluids ◽  
Emeraldine Base ◽  
Heavy Duty ◽  
Base Form ◽  
Static Yield ◽  
High Fields ◽  
Er Fluids ◽  
Er Fluid ◽  
A Current

Currents drawn under high fields often present practical limitations to electrorheological (ER) fluids usefulness. For heavy-duty applications where large torques have to be transmitted, the power consumption of a ER fluid can be considerable, and for such uses a current density of ~100μ A cm -2 is often taken as a practical upper limit. This investigation was conducted into designing a fluid which has little extraneous conductance and therefore would demand less current. Selected semi-conducting polymers provide effective substrates for ER fluids. Such polymers are soft insoluble powdery materials with densities similar to dispersing agents used in ER formulations. Polyaniline is a semi-conducting polymer and can be used as an effective ER substrate in its emeraldine base form. In order to provide an effective ER fluid which requires less current polyaniline was coated with an insulating polymer. The conditions for coating was established for lauryl and methyl methacrylate. Results from static yield measurements indicate that ER fluids containing coated polyaniline required less current than uncoated polyaniline i.e. 0.5μ A cm -2. The generic type of coating was also found to be important.

scholarly journals Analysis of the transmission loss of double-leaf panels with an equivalent spring–mass model for studs

2020 ◽  
Vol 37 ◽  
pp. 126-133
Author(s):  
Yuan-Wei Li ◽  
Chao-Nan Wang
Keyword(s):  
Distribution Curve ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Experimental Results ◽  
Sound Insulation ◽  
Sound Transmission Loss ◽  
Mass Model ◽  
Steel Stud ◽  
Panel Thickness ◽  
Stiffness Distribution

Abstract The purpose of this study was to investigate the sound insulation of double-leaf panels. In practice, double-leaf panels require a stud between two surface panels. To simplify the analysis, a stud was modeled as a spring and mass. Studies have indicated that the stiffness of the equivalent spring is not a constant and varies with the frequency of sound. Therefore, a frequency-dependent stiffness curve was used to model the effect of the stud to analyze the sound insulation of a double-leaf panel. First, the sound transmission loss of a panel reported by Halliwell was used to fit the results of this study to determine the stiffness of the distribution curve. With this stiffness distribution of steel stud, some previous proposed panels are also analyzed and are compared to the experimental results in the literature. The agreement is good. Finally, the effects of parameters, such as the thickness and density of the panel, thickness of the stud and spacing of the stud, on the sound insulation of double-leaf panels were analyzed.

Sign in / Sign up

Export Citation Format

Share Document