K. Koppenhoefer, S.Yushanov, and M.H. McKenna
AltaSim Technologies, LLC, Columbus, Ohio, USA
U.S. Army Engineering Research and Development Center
Aging infrastructure requires frequent inspections to assess their structural integrity. However, the large amount of existing infrastructure, and the distance between these structures present significant challenges to inspectors. Acoustics-based technologies represent a simple, and relatively inexpensive, technique to monitor the integrity of a structure. To develop these techniques, designers ...
On The Use of a Diffusion Equation Model for Sound Energy Flow Prediction in Acoustically Coupled Spaces
Y. Jing, and N. Xiang
Rensselaer Polytechnic Institute, Troy, NY, USA
This paper studies sound energy flows through an aperture across two coupled spaces using a diffusion equation model. The so-called double sloped sound energy decay is believed to be caused by the sound energy exchange through the aperture coupling the two rooms. The room diffusion equation is first solved by COMSOL, then the time dependent energy flow is visualized via COMSOL arrow plotting, ...
M. Herring Jensen
Widex A/S, Vaerloese, Denmark
In this study we model the sound attenuation properties of a hearing aid earmold tube. The model includes thermoviscous acoustic effects and it couples structural vibrations to the external acoustic field. Moreover, the finite element domain is coupled at two boundaries with an electroacoustic model of a hearing aid and an acoustic 2-cc coupler.
Glass Plates Noise Transmission Suppression by Means of Distributed Piezoelectric Composite Actuators Shunted by an Active Circuit
K. Novakova, P. Mokry
Research Centre for Special Optics and Optoelectronic Systems (TOPTEC), Institute of Plasma Physics, Academy of Sciences of the Czech Republic, Turnov, Czech Republic
Institute of Mechatronics and Computer Engineering, Technical University of Liberec, Liberec, Czech Republic
Glass windows represent a virtual sound source for buildings interior. It is very easy to make them vibrate by action of incident acoustic pressure wave. Therefore, non-negligible part of the wave is transmitted through the window. We propose and simulate a method based on the change of mechanical properties of the plate using flexible piezoelectric Macro Fiber Composite actuators distributed on ...
SRM University & BITS Pilani University, Chennai, Tamil Nadu, India
Vibration analysis of perforated plates is extremely important when designing structures where resonance is the possible mode of failure. This paper deals with the vibration analysis of rectangular perforated plates with three different types of perforations. Vibration analysis is to be carried out by both COMSOL Multiphysics® Software and Experimental set-up. The applications of perforated ...
Poznan University of Technology
This paper concerns the problem of obtaining proper acoustic attenuation performance through computations. COMSOL was used to solve acoustics systems with helicoidal resonators in the frequency domain. Based on the studies of insertion and transmission loss of helicoidal resonators, a high consistency between the results obtained by numerical calculations with experimental measurements was ...
Acoustic Attenuation Performance Of Helicoidal Resonator Due To Distance Change From Different Cross-Sectional Elements Of Cylindrical Duct
Poznań University of Technology, Poznań, Poland
This work presents acoustic attenuation performance of helicoidal resonator due to distance change from different cross-sectional elements of cylindrical duct. The helicoidal resonator properties are described mainly in in infinite long cylindrical duct. For practical applications it is important to know the limits of use of this solution. This paper describes how the helicoidal resonator should ...
S. Ni, C. Yang Koh, S. Kooi, and E. Thomas
Institute for Soldier Nanotechnologies
Dept. of Materials Science and Eng.
Recently, the concepts of fractal geometry have been introduced into electromagnetic and plasmonic metamaterials. With their self-similarity, structures based on fractal geometry should exhibit multi-band character with high Q factors due to the scaling law. However, there exist few studies of phononic metamaterials having fractal geometry. COMSOL is used to investigate vector elastic and ...
R. Venegas, and O. Umnova
Acoustics Research Centre, University of Salford, Salford, United Kingdom
Granular materials have been conventionally used for acoustic treatment due to their sound absorptive and sound insulating characteristics. An emerging field is the study of acoustical properties of multi-scale porous materials. An example of these is a double-porosity granular material in which the grains are porous themselves. In this work, a computational methodology for modelling this type ...
Alcon Research Ltd., Lake Forest, CA, USA
Anomalous acoustic streaming is observed from sharp edges of vibrating solid bodies in fluids. The streaming velocities can be orders of magnitude higher than expected from the Rayleigh streaming at similar amplitudes of vibrations. Acoustic velocity of a fluid relative to a solid body diverges at a sharp edge giving rise to a localized time-independent body force acting on the fluid. The ...