Here you will find presentations given at COMSOL Conferences around the globe. The presentations explore the innovative research and products designed by your peers using COMSOL Multiphysics. Research topics span a wide array of industries and application areas, including the electrical, mechanical, fluid, and chemical disciplines. Use the Quick Search to find presentations pertaining to your application area.

Modeling and Experimental Verification of the Power Transfer and Thermal Characteristics of Piezoelectric Transformers Subjected to Combined Mechanical and Electrical Loading

S. Tuncdemir[1], W.M. Bradley[2]
[1]Solid State Ceramics, Williamsport, PA, USA
[2]QorTek, Williamsport, PA, USA

A piezoelectric transformer allows purely mechanical transfer and scaling of electrical energy via simultaneous utilization of both the direct and converse piezoelectric effects. This mechanical energy transfer enables a wide range of functional differences from typical magnetic-based electrical power transformers. Comparing to their electromagnetic counterparts, piezoelectric transformers are ...

On the Numerical Modeling of Elastic Resonant Acoustic Scatterers

V. Romero-García[1], A. Krynkin[2], J.V. Sánchez-Pérez[1], S. Castiñeira-Ibáñez[3], and L.M. Garcia-Raffi[4]
[1]Centro de Tecnologías Físicas Acústica, Universidad Politécnica de Valencia, Valencia, Spain
[2]School of Computing, Science & Engineering, University of Salford, Salford, United Kingdom
[3]Depto. Física Aplicada, Universidad Politécnica de Valencia, Valencia, Spain
[4]Instituto Universitario de Matemática Pura y Aplicada, Universidad Politécnica de Valencia, Valencia, Spain

The elastic and geometrical properties of Low Density Polyethylene (LDPE) foam are used in this paper to improve the attenuation properties of periodic arrangements of acoustic scatterers known as Sonic Crystals (SCs). A specific recycled profile of LDPE foam is used as elastic-acoustic scatterer. The acoustic spectrum of the single scatterer shows two attenuation peaks in the low frequency ...

Study of an Electroacoustic Absorber

A-S. Moreau[1], H. Lissek[1], and R. Boulandet[1]
[1]EPFL-STI-IEL-LEMA, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

In this paper, the underlying concept of electroacoustic absorbers is studied with the help of Comsol Multiphysics® Acoustics Module. Among the different ways to obtain variable acoustic properties on an electroacoustic transducer's voicing face, there is the shunting of the transducer's electrical input. With such shunt devices, the acoustic impedance that the transducer's membrane presents ...

Simulation of a Piezoelectric Loudspeaker for Hearing Aids and Experimental Validation - new

G. C. Martins[1], P. R. Nunes[1], J. A. Cordioli[1]
[1]Federal University of Santa Catarina, Florianópolis, SC, Brazil

The use of piezoelectric materials in hearing aid loudspeakers, also called receivers, presents technical and economic advantages such as reducing the number of parts of the system and its manufacturing cost. However, the performance of such systems is still not competitive when compared to traditional electrodynamic loudspeakers. In order to achieve an appropriate performance, one option is to ...

基于声学超材料的近场点声源亚波长分辨率显微成像模拟

韩建宁 [1],
[1] 中北大学,太原,山西,中国

所谓近场声学,是相对于远场声学而言。传统的声学理论,通常只研究远离光源或者远离物体的声场分布,一般统称为远场声学。远场声学在原理上存在着一个远场衍射极限,限制了利用远场光学原理进行显微和其它光学应用时的最小分辨尺寸和最小标记尺寸。而近场声学则研究距离光源或物体一个波长范围内的光场分布。在近场声学研究领域,远场衍射极限被打破,分辨率极限在原理上不再受到任何限制,可以无限地小,从而基于近场声学原理可以提高显微成像与其它光学应用时的光学分辨率。 声学超材料自问世之日起就受到了国内外科学家们的广泛追捧,在很多领域都可以看到其踪迹,以声子晶体为代表的声超材料具有很多天然材料所不具备的声学特性,为声学信号处理带来了很多创新的思路和途径。 声超材料的突出特点在于采用尺寸远小于入射波长的人工结构构建出等效参数,利用等效参数实现“小尺寸结构调控大尺寸波长”的目的。 ...

Acoustical Design of Stethoscope for Improved Performance

C. Thiagarajan[1], Gururajan R.[2], A. H. Baig[2], Prema S.[3]
[1]ATOA Scientific Technologies Pvt Ltd, Whitefield, Bangalore, Karnataka India
[2]University of Southern Queensland, Toowoomba Qld 4350, Australia.
[3]RMK Engineering College, Chennai, Tamil Nadu, India

Stethoscope is in use for more than 200 years for medical diagnostics, especially for auscultation. Recently, the unprecedented growth in mobile technology revived the use of stethoscope for Telehealthcare. Digital or electronic stethoscopes are increasingly researched for use in Telehealthcare. This paper mainly focuses on the acoustical and multiphysics design aspects of the stethoscope for ...

COMSOL Multiphysics® Software for Simulation of Surface Response to Excitation Method for Manufacturing Process Performance Monitoring - new

H. Fekrmandi[1], N. Miniello[1], R. Kiflemariam[1], I. Nur Tansel[1]
[1]Mechanical & Materials Engineering Department, Florida International University, Miami, FL, USA

In this study, COMSOL Multiphysics® software was used to simulate the surface response to excitation method (SuRE). An aluminum beam with a piezoelectric element bonded is modeled using the COMSOL Acoustics Module. A frequency domain sweep study was performed to simulate the sweep sign generation. The frequency spectrum of the structure is monitored through a frequency range of (20kHz-400kHz). A ...

Modeling Thermal Bridging at Interface Conditions: Analysis of Solutions for Reducing Thermal Bridges Effects on Building Energy Consumption

C. Balocco[1], E. Marmonti[1]
[1]Dipartimento di Energetica, Università di Firenze, Firenze, Italy

In Europe considerable building activity can be expected over the coming decades; Net Zero Energy Buildings refers to a building with minimal power, until maximum 15 kW/m^2. In both cases this requires very well insulated buildings with minimal thermal bridges. Concrete balconies, that extend the floor slab through the building envelope, are a common example of thermal bridging, where structural ...

梯度多孔玻璃丝吸声性能的数值研究

张秀海 [1], 王琼 [1], 屈治国 [1],
[1] 西安交通大学,西安,陕西,中国

引言 多孔材料能够吸收大量声能且只反射少量声波,因此具有良好的吸声性能而被广泛地用于噪声的控制。梯度多孔材料吸声性能的实验研究已经有所开展,但相应的数值研究却很鲜见。 COMSOL Multiphysics® 的使用 本文分别用3层和6层孔隙度呈等差数列的多孔玻璃丝组合成梯度多孔玻璃丝(图1为由3层不同孔隙度的多孔玻璃丝组成的梯度多孔玻璃丝,空气区域为宽W、高H的矩形,余下区域为多孔玻璃丝区域),并根据 DBM 模型采用 COMSOL Multiphysics® 模拟组合成的梯度多孔玻璃丝的吸声性能。 结果 由图2,梯度多孔玻璃丝(3层)与相同厚度、相同孔隙度普通多孔玻璃丝比较,前者在声音处于低频段情况吸声效果有明显的改善。梯度多孔玻璃丝(3层)和梯度多孔玻璃丝(6层)的吸声系数如图3所示,在 100Hz-400Hz 的低频段,两者吸声系数有较大的误差。 结论 ...

Sound Attenuation by Hearing Aid Earmold Tubing

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.