Sound transmission modeling of advanced multilayered composite structures using enhanced T‐matrices for two‐phase materials

2005 ◽  
Vol 118 (3) ◽  
pp. 2010-2010
Author(s):  
Roland L. Woodcock ◽  
Rebecca S. Bryant
Keyword(s):  
Composite Structures ◽  
Sound Transmission ◽  
Two Phase ◽  
Multilayered Composite ◽  
Transmission Modeling

Polarization behavior of ferroelectric multilayered composite structures

2003 ◽  
Vol 93 (7) ◽  
pp. 4112-4119 ◽  
Author(s):  
Y. T. Or ◽  
C. K. Wong ◽  
B. Ploss ◽  
F. G. Shin
Keyword(s):  
Composite Structures ◽  
Multilayered Composite ◽  
Polarization Behavior

scholarly journals Comparative Study of Sound Transmission Losses of Sandwich Composite Double Panel Walls

2020 ◽  
Vol 10 (4) ◽  
pp. 1543 ◽  
Author(s):  
Chukwuemeke William Isaac ◽  
Marek Pawelczyk ◽  
Stanislaw Wrona
Keyword(s):  
Composite Structures ◽  
Transmission Loss ◽  
Optimization Problems ◽  
Sound Transmission ◽  
Industrial Applications ◽  
Sandwich Composite ◽  
Acoustic Response ◽  
Transmission Losses ◽  
Emission Index ◽  
Selection Of

The increasing motivation behind the recently wide industrial applications of sandwich and composite double panel structures stems from their ability to absorb sounds more effectively. Meticulous selection of the geometrical and material constituents of both the core and panels of these structures can produce highly desirable properties. A good understanding of their vibro-acoustic response and emission index such as the sound transmission loss (STL) is, therefore, a requisite to producing optimal design. In this study, an overview of recent advances in STL of sandwich and composites double panels is presented. At first, some salient explanation of the various frequency and controlled regions are given. It then critically examines a number of parameter effects on the STL of sandwich and composite structures. Literatures on the numerical, analytical and experimental solutions of STL are systematically presented. Efficient and more reliable optimization problems that maximize the STL and minimize the objective functions capable of degrading the effectiveness of the structure to absorb sounds are also provided.

scholarly journals Giant magnetoelectric effect in sintered multilayered composite structures

2008 ◽  
Vol 104 (4) ◽  
pp. 044103 ◽  
Author(s):  
Rashed A. Islam ◽  
Yong Ni ◽  
Armen G. Khachaturyan ◽  
Shashank Priya
Keyword(s):  
Composite Structures ◽  
Magnetoelectric Effect ◽  
Multilayered Composite

Studies of Mechanical Properties of Multiwall Nanotube Based Polymer Composites

2014 ◽  
Vol 5 (3) ◽  
Author(s):  
A. K. Gupta ◽  
S. P. Harsha
Keyword(s):  
Mechanical Properties ◽  
Polymer Composites ◽  
Composite Structures ◽  
Secondary Reinforcement ◽  
Chemical Vapor ◽  
Carbon Composite ◽  
Diglycidyl Ether ◽  
Two Phase ◽  
Three Phase ◽  
Structural Applications

The two phase polymer composites have been extensively used in various structural applications; however, there is need to further enhance the strength and stiffness of these polymer composites. Carbon nanotubes (CNTs) can be effectively used as secondary reinforcement material in polymer based composites due to their superlative mechanical properties. In this paper, effects of multiwall nanotubes (MWNTs) reinforcement on epoxy–carbon polymer composites are investigated using experiments. MWNTs synthesized by chemical vapor deposition (CVD) technique and amino-functionalization are achieved through acid-thionyl chloride route. Diglycidyl ether of bisphenol-A (DGEBA) epoxy resin with diethyl toluene diamine (DETDA) hardener has been used as matrix. T-300 carbon fabric is used as the primary reinforcement. Three types of test specimen of epoxy–carbon composite are prepared with MWNT reinforcement as 0%, 1%, and 2% MWNT (by weight). The resultant three phase nanocomposites are subjected to tensile test. It has been found that both tensile strength and strain at failure are substantially enhanced with the small addition of MWNT. The analytical results obtained from rule of mixture theory (ROM) shows good agreement with the experimental results. The proposed three phase polymer nanocomposites can find applications in composite structures, ballistic missiles, unmanned arial vehicles, helicopters, and aircrafts.

Sound transmission in the lung as a function of lung volume

2002 ◽  
Vol 93 (2) ◽  
pp. 667-674 ◽  
Author(s):  
T. Bergstresser ◽  
D. Ofengeim ◽  
A. Vyshedskiy ◽  
J. Shane ◽  
R. Murphy
Keyword(s):  
Transit Time ◽  
Lung Volume ◽  
Cross Correlation ◽  
Sound Transmission ◽  
Phase System ◽  
Two Phase ◽  
Tissue Properties ◽  
Air Content ◽  
Transit Times ◽  
Cross Correlation Analysis

We were interested in how the transmission of sound through the lung was affected by varying air content in intact humans as a method of monitoring tissue properties noninvasively. To study this, we developed a method of measuring transthoracic sound transit time accurately. We introduced a “coded” sound at the mouth and measured the transit time at multiple microphones placed over the chest wall by using a 16-channel lung sound analyzer (Stethographics). We used a microphone placed over the neck near the trachea as our reference and utilized cross-correlation analysis to calculate the transit times. The use of the coded sound, composed of a mix of frequencies from 130 to 150 Hz, greatly reduced the ambiguity of the cross-correlation function. The measured transit time varied from 1 ms at the central locations to 5 ms at the lung bases. Our results also indicated that transit time at all locations decreased with increasing lung volume. We found that these results can be described in terms of a model in which sound transmission through the lung is treated as a combination of free-space propagation through the trachea and a propagation through a two-phase system in the parenchyma.

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