In questa sezione troverete i lavori presentati alle Conferenze mondiali COMSOL. Le presentazioni descrivono ricerche e prodotti innovativi progettati con COMSOL Multiphysics da colleghi di tutto il mondo. I temi delle ricerche presentate abbracciano un'ampia gamma di settori produttivi e aree applicative, in ambito elettrico, meccanico, fluidodinamico e chimico. Lo strumento di Ricerca Rapida vi permetterà di trovare le presentazioni che si riferiscono all'area di vostro interesse.

Modeling Acoustic Waveguides for Ear Impedance Measurements

R. Sisto[1], L. Cerini[1], D. Mambro[2], A. Moleti[2], F. Sanjust[1]
[1]INAIL Research, Monteporzio Catone, Italy
[2]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 ...

Simulation of Acoustical Transfer Paths for Active Noise Control

L. Fromme [1], J. Waßmuth [1], D. Wehmeier [1],
[1] Bielefeld University of Applied Sciences, Bielefeld, Germany

The knowledge of the acoustical transfer paths in active noise control systems is very important for the performance of the system. Unfortunately, simulation is challenging since even simple configurations require comprehensive experience in physics and modeling. Two test setups were chosen for basic investigations on modeling, simulation and validation. The first results presented here are ...


郁殿龙 [1], 温激鸿 [1], 尹剑飞 [1],
[1] 国防科学技术大学,长沙,湖南,中国

汽车、飞行器、舰船、高速列车等工程装备中,振动和噪声问题会严重影响装备可靠性、安全性、使用寿命和人员的健康。因此,减振降噪需求迫切,相关技术和研究也得到了前所未有的重视。 国防科技大学振动与噪声控制研究团队从2003年开始,致力于基于人工周期结构理论的弹性波传播特性、调控机理及其应用探索研究。将物理学领域中声子晶体、声学超材料等人工周期结构中的新概念与工程减振降噪应用相结合,设计研发了多种声波控制器件与结构。 COMSOL Multiphysics® 声学模块的丰富接口及其处理多物理场耦合问题的强大功能,为研究团队解决复杂多尺度结构的声振特性预报和减振降噪设计提供了有力的工具。在此平台上,研究团队设计了局域共振低频吸声材料,并依托学校“天河二号”超级计算机并行计算环境,开展了元胞尺度(mm量级)到部件尺度(m量级)模型的声学特性有限元建模求解 ...

An Acoustical Finite Element Model of Perforated Elements

P. Bonfiglio[1][2] and F. Pompoli[1][2]
[1]Materiacustica S.r.l., Ferrara, Italy
[2]Engineering Department, University of Ferrara, Ferrara, Italy

The present work deals with a numerical investigation of resonating systems used for noise control applications. In literature one can find analytical models based on fluiddynamics concepts for evaluating losses occurring across the holes of the perforates. In the paper an acoustical formulation based on the equivalent dissipative fluid approach will be analyzed. It will be firstly applied to ...

Support-Q Optimisation of a Trapped Mode Beam Resonator - new

T. H. Hanley[1], H. T. D. Grigg[1], B. J. Gallacher[1]
[1]Newcastle University, Newcastle-Upon-Tyne, UK

Introducing a disorder into a finite periodic oscillatory system induces the presence of a 'trapped mode': a mode in which the displacement field is localised to the region of the disorder. A main inhibitor to MEMS resonators achieving a high quality (Q) factor is energy radiation through the support to the substrate. The trapped modes present a way to tune this to a minimal value. An initial ...

Feed-forward/Feed-backward Mechanical Amplification in the Mouse Cochlea

J. Soons[1,2], C. Steele[2], S. Puria[2]
[1]Lab of Biomedical physics, University of Antwerp, Antwerp, Belgium
[2]Department of Mechanical Engineering, Stanford University, Stanford, USA

Sound vibrations are collected from the external environment by the eardrum and are guided to the basilar membrane in the cochlea. Pressure differences in the two scalae of the cochlea result in a traveling wave on the basilar membrane. The tiny displacements are detected by the deflection of thousands of hair cells, situated along this membrane. It is hypothesized that some 3/4 of these hair ...

Simulation of SAW-Driven Microparticle Acoustophoresis Using COMSOL Multiphysics® Software

N. Nama [1], R. Barnkob [2], C. J. Kähler [2], T. J. Huang [1], F. Costanzo [1]
[1] Department of Engineering Science and Mechanics, Pennsylvania State University, PA, USA
[2] Institute of Fluid Mechanics and Aerodynamics, Bundeswehr University Munich, Neubiberg, Germany

Introduction - The ability to precisely manipulate fluid and particles at microscales is one of the essential requirements for various lab-on-a-chip applications such as drug diagnostics, chemical synthesis etc.[1] Recently, the nonlinear interaction of surface acoustic waves (SAW) with fluid at microscales has been utilized to achieve this aim. When surface acoustic waves interact with fluid ...

Compression Driver Simulation Including Air Damping in Phase Plug

R.Christensen, and U. Skov
iCapture ApS
Gadstrup, Denmark

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 ...

Modeling of a Jecklin Disk for Stereophonic Recordings

G. McRobbie[1]
[1]University of the West of Scotland, Paisley, Renfrewshire, UK

The Jecklin Disk is a sound absorbing disk placed between two omnidirectional microphones. It is used to recreate some of the frequency-response, time and amplitude variations human listeners’ experience, but in such a way that the recordings also produce a useable stereo image through loudspeakers. This paper presents a finite element model able to simulate the effects on sound propagation ...

Sound Propagation through Circular Ducts with Spiral Element Inside

W. Lapka
Poznan University of Technology, Poland

This paper examines a sound propagation without airflow through circular ducts with spiral element inside. Models are numerically computed in three-dimensions. The spiral element in the duct is a newly analyzed acoustical element, geometrically similar to the well-known Archimedes screw. It can be applied significantly in ducted systems, such as ventilation, air-conditioning and heat ...