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 the Sound Radiation by Loudspeaker Cabinets - new

M. Cobianchi[1], M. Rousseau[1]
[1] B&W Group Ltd, Steyning, UK

While musical instruments often rely on a body which resonates on purposefully to amplify the vibration produced by a string or a membrane, such as in a violin or a guitar, loudspeaker cabinets should not contribute at all to the total sound radiation, but aim instead to be a perfectly rigid box which encloses the drive units in charge to transform the electrical signal at their terminal into ...

Prediction of Transformer Core Noise - new

R. Haettel[1], A. Daneryd[1], M. Kavasoglu[1], C. Ploetner[2]
[1]ABB Corporate Research, Västerås, Sweden
[2]ABB Transformers, Varennes, QC, Canada

Today, low noise is a mandatory feature for power transformers to comply with customer specifications and environmental regulations. Therefore, it is crucial to develop sound prediction tools with sufficient accuracy to avoid overkill margins in design and costly modifications after transformer completion. The paper will focus on core noise which is a typical multiphysics phenomenon involving ...

Bloch Waves in an Infinite, Periodically-perforated Sheet

W. Maysenhölder[1]
[1]Fraunhofer Institute for Building Physics, Stuttgart, Germany

Bloch waves in infinite periodic structures – much in vogue in the present metamaterial age – can be conveniently studied by COMSOL Multiphysics® software. This is demonstrated by a simple, yet rich two-dimensional example: a perforated sheet with square symmetry. Instead of plane waves in homogeneous media, one has to deal with their generalizations: the Bloch waves. The frequencies of such ...

MEMS Electrostatic Acoustic Pixel

A. Arevalo [1], D. Conchouso [1], D. Castro [1], I. G. Foulds [2],
[1] Computer, Electrical, & Mathematical Sciences & Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
[2] The University of British Columbia, School of Engineering, Vancouver, BC, Canada

The growth of the electronics industry demand better components for the electronic systems. Such components need to be improve to keep up with the evolution of the digital era. The loudspeaker design has not been changed for almost a century [1-5]. The acoustic transducer is the last analogue component needed for a true digital audio system. We want to validate the feasibility of using an ...

Prediction of the Loudspeaker Total Harmonics Distortion Using COMSOL Multiphysics® Software

F. Malbos [1], M. Bogdanski [2], M. Strauss [2],
[1] Harman, Paris, France
[2] Harman Becker Automotive Systems, Straubing, Germany

For automotive applications, simulation methods are used to get the best audio acoustic performance. Because a loudspeaker is a non linear device, the sound pressure in the vehicle includes harmonics which are mainly created by the force factor, suspension stiffness and voice coil inductance of the loudspeaker. This paper shows how to simulate those non linear components using COMSOL ...

Acoustic Field Comparison of High Intensity Focused Ultrasound Using Experimental Characterization and Finite Element Simulation

J. L. Teja[1], A. Vera[1], L. Leija[1]
[1]Department of Electrical Engineering, Cinvestav-IPN, Mexico D.F., Mexico

High Intensity Focused Ultrasound (HIFU) is used as a noninvasive technique of tissue heating and ablation for different medical treatments. This paper presents a quantitative comparison of HIFU acoustic fields experimentally obtained versus simulated acoustic fields. Acoustic field characterization was realized in two HIFU transducers using water as a propagation medium. Also, simulations were ...

Multiphysics Modeling of Sound Absorbing Fibrous Materials

T. G. Zielinski [1]
[1] Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland

Many of fibrous materials are very good sound absorbers, because the acoustic waves, which propagate in air and penetrate a fibrous layer, interact with the fibers so that the wave energy is dissipated. The dissipation is related to some viscous and thermal effects occurring on the micro-scale level. On the macroscopic level, a fibrous medium can be treated as an effective inviscid fluid, ...

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 ...

An Improved Loudspeaker Frequency Response by Using a Structure of Rigid Absorptive Panel in a Vented Cabinet - new

R. Balistreri[1]
[1]Community Light & Sound Inc., Chester, PA, USA

When placing a loudspeaker in a cabinet, standing waves inside the cabinet affect the frequency response with ripples. This peaks and dips due to pressure cancellation inside the cabinet have an effect on the diaphragm and generating sound out from the vents. If it was in a condition of total absorption of the sound waves at the back of the diaphragm, the transducer would otherwise have a much ...

Laser-Ultrasonics Wave Generation and Propagation FE Model in Metallic Materials

A. Cavuto[1], G.M. Revel [1], M. Martarelli [2], F. Sopranzetti [2]
[1]Università Politecnica delle Marche, Ancona, Italy
[2]Università e-Campus, Novedrate (CO), Italy

A 2D axisymmetric model was considered in order to evaluate the propagation paths of the ultrasonic waves generated inside an aluminum plate sample due to a rapid thermal expansion produced by laser pulse. Laser Doppler Vibrometer is used to experimentally validate the numerical results of the wave propagation in the material. The presented numerical model is able to identify directivity ...