David S. Burnett
Naval Surface Warfare Center
Panama City, USA
The author is integrating a suite of software tools for modeling the scattering of acoustic beams (sonar) from undersea targets (mines) that may be buried or partially buried in the sedimentary ocean bottom in littoral (shallow water) environments. This is a Multiphysics problem involving acoustic waves in the water, acoustic or poro-elastic waves in the sediment, and both elastic and acoustic ...
R.Christensen, and U. Skov
A compression driver is a certain type of electrodynamic loudspeaker which has a phase plug with slits in front of the diaphragm. The slits are narrow enough that the so-called viscothermal effects are of significant importance. In this paper a 2D axisymmetric finite element model of a commercial compression driver is established where the vibroacoustic behavior can be evaluated. The ...
V. Chatziioannou, and W. Kausel
Institute of Music Acoustics
University of Music and Performing Arts
The vibration of the walls of brass wind instruments has been a subject of study in the field of musical acoustics throughout the last decades. The amplitude of such vibrations, stimulated by the oscillating air pressure inside the instrument bore, is very small compared to the dimensions of the instrument. However, it has been recently shown that at the flaring regions of the bell of brass ...
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 ...
P. Olsson, F. Larsson, A. Khlopotin, S. Razanica
Chalmers University of Technology, Gothenburg, Sweden
In solid mechanics, there is considerable interest in achieving “invisibility”. The applications in mechanics include protection of structures and parts of structures from potentially harmful transient waves and steady state vibrations. A suggested large scale application is that protection against seismic waves from earthquakes could be achieved by using cloaking to re-route the waves around ...
R. Sisto, L. Cerini, D. Mambro, A. Moleti, F. Sanjust
INAIL Research, Monteporzio Catone, Italy
Università di Roma, Tor Vergata, Italy
The otoacoustic emissions (OAEs) are acoustic signals emitted by the inner ear as a consequence of the activity of a nonlinear feedback mechanism capable of amplifying the signal near to the hearing threshold level. The otoacoustic emissions can be used as an acoustic imaging of the cochlear functionality. They are used in clinics for screening purposes but due to the extreme variability between ...
E. Nesvijski[1,2], R. Sahul
Western New England College, Springfield, MA, USA
TRS Technologies, State College, PA, USA
Finite element analysis (FEA) is a modern tool for exploration of new horizons in science, technology and engineering. Different computer software such as ANSYS, ABACUS, PZFLEX and COMSOL Multiphysics® based on FEA are used for modeling and simulation of acoustic phenomena, for design of new and optimization and improvement of existing acoustic engineering systems. This work presents application ...
Design of a MEMS Resonator for a Centre Frequency Greater than 26.35 MHz and Temperature Coefficient Frequency Less than 0.5 ppm
S.Manikandan, R.Radeep krishna
Kalasalingam University, Department of ECE, Srivilliputtur ,Krishnan koil, Tamil Nadu, India
The variability of the design parameters caused by material properties like thermal conductivity is the major challenge in Micro Electromechanical System (MEMS). In resonator design the basic problem is that the frequency changes with temperature variation and quantitative explanation with respect to this varies. The change can be attributed to the stability in terms of frequency drift in parts ...
Simulation of Helmholtz Resonators for Optical Gas Sensing: Comparison Between Pressure Acoustics and Thermoacoustics
B. Parvitte, C. Risser, R. Vallon, V. Zéninari
Université de Reims, Reims, France
Among optical gas sensing methods, photoacoustic (PA) spectroscopy combined with a laser source has proven to be a very robust and sensitive method for trace gas detection. COMSOL Multiphysics® software was used to calculate the frequency response of differential Helmholtz resonator cells in order to optimize the detection limit of PA sensors. Two different kind of simulation were performed: ...
R. Sugumar, C. S. Kumar, T. K. Datta
Sharda University, Greater Noida, Uttar Pradesh, India
MVN University, Palwal, Haryana, India
Indian Institute of Technology Delhi, New Delhi, Delhi, India
Earthquakes have always been a threat to the safety of buildings, sometimes even causing fatality due collapse of the structure. Various methods have evolved in the recent past to control/reduce the response of a structure subjected to earthquake forces. One of the widely used passive control methods is Base Isolation System. This paper discusses the study of the response of the base isolated ...