Artigos Técnicos e Apresentações

Aqui você encontrará apresentações realizadas nas Conferências de Usuários COMSOL de todo o mundo. As apresentações englobam pesquisas e produtos inovadores feitas por engenheiros e cientistas usando o COMSOL Multiphysics. Os tópicos abramgem uma grande gama de indústrias e aplicações, como elétrica, mecânica, escoamento e química. Use a função de busca "Quick Search" para encontrar apresentações na sua área de interesse.

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 ...

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 ...

Modeling the response of photoacoustic gas sensors

S.L. Firebaugh[1], F. Roignant[2], and E.A. Terray[3]

[1]United States Naval Academy, Annapolis, Maryland, USA
[2]Polytechnique Nantes, Nantes, France
[3]Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA

A fast, high-sensitivity detector is required for studies of environmentally relevant gases. Photoacoustic spectroscopy (PAS), an absorption spectroscopy technique in which absorption is detected as sound, is explored as a possible solution. A tuning-fork based PAS sensor is modeled using COMSOL. The model combines the acoustic and piezoelectric modules and also includes viscous damping. The ...

FEM Simulation of Generation of Bulk Acoustic Waves and their Effects in SAW Devices

A.K. Namdeo[1], N. Ramakrishnan[2], and H.B. Nemade[1]
[1]Department of Electronics and Communication Engineering, Indian Institute of Technology Guwahati, Guwahati, India
[2]Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati, India

This paper presents finite element method (FEM) simulation study of the generation of bulk acoustic waves (BAWs) and their effect on the performance of surface acoustic wave (SAW) devices, using COMSOL Multiphysics. A SAW delay line structure using YZ-cut lithium niobate substrate is simulated. The radiation of the bulk waves in all angles into the interior of the substrate is analyzed. The bulk ...

Analysis of Sound Propagation in Lined Ducts by Means of a Finite Element Model

D. Borelli[1] and C. Schenone[1]
[1]DIPTEM, University of Genova, Genova, Italy

The present paper describes the results of a Finite Element Model used to analyze sound propagation in lined ducts. By means of a numerical model it was possible to predict the insertion loss inside rectangular lined ducts in a frequency range from 250 Hz to 4000 Hz. The model was validated by a comparison with experimental data obtained in accordance to ISO 11691 and ISO 7235 standards. The ...

Acoustic Emission Simulation for Online Impact Detection

C. Yang, M. A. Torres-Arredondo, and C.-P. Fritzen
Institute of Mechanics and Control Engineering
Mechatronics
University of Siegen
Siegen, Germany

Impact monitoring has been extensively studied by several researchers and it has been shown that damage extent can be correlated with the impact magnitude. In order to make the process cost-effective, simulation of the impact has been performed, to get the big training data set from modeling. The structural dynamic responses captured by PZT transducers due to impact events are recorded from ...

Using COMSOL to Support a Cost-Effective, Non-Destructive Evaluation Approach for Predicting Bolt Failure in Highway Bridges

A. Elyea, B. Doubek, G. Hubbard, and D. Ozevin
Department of Civil Engineering
University of Illinois at Chicago
Chicago, IL

The development of a quantitative nondestructive evaluation method, as an alternative to visual inspection, for inspecting pre-tensioned bolts in fracture critical bridges is presented. In order to understand the ultrasonic behavior of a wide variety of bolt geometries used in bridges, numerical models of nine different bolt geometries were developed. The numerical models included the ...

A Study of the Effects of Mounting Supports, and Dissipation on a Piezoelectric Quartz Double-Ended Tuning Fork Gyroscope

G. Choi[1], Y. Yong[1]
[1]Rutgers University, New Brunswick, NJ, USA

A COMSOL model of a piezoelectric quartz double ended tuning fork gyroscope was implemented. The gyroscope has two detection modes; the first mode detects the angular velocity about a z-axis perpendicular to the tuning fork plane (x-y plane), while the second mode detects the angular velocity about a y-axis that is the longitudinal axis along the length of the tuning fork. Eigenfrequency analyses ...

Improving the Performance of Hearing Aids Using Acoustic Simulations

Mads Jakob Herring Jensen
Dr., Widex A/S, Denmark

In modern hearing aids, the performance of directional microphone systems is dependent on both the acoustics around thehearing aid and on the specific signal processing algorithms. The sound pressure at the microphone inlets depends on microphone location in the hearing-aid shell, the inlet shape, and on the placement of the hearing aid on the head of the user. In the present work, the ...

Transient Heat Transfer Effects from a Flapping Wing

Lind, R.J., Abedian, B.
Department of Mechanical Engineering Tufts University, Medford, Massachusetts

This presentation is a numerical study of fluid flow around a two-dimensional rigid flapping plate and its effects on the resultant transient heat transfer effects on the solid interface. In this study, a flat inflexible thin plate surrounded by air undergoes sinusoidal angular motion from one end while the other end is kept stationary, simulating a flapping motion. The two-dimensional ...

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