Technical Papers and Presentations

Ici vous trouverez les présentations issues des Conférences COMSOL à travers le monde. Réalisées par des utilisateurs de COMSOL Multiphysics, ces présentations explorent tous les domaines actuels d'innovation. Les applications couvrent pratiquement tous les secteurs industriels et impliquet des phénomènes électriques, mécaniques, fluidiques et chimiques. utilisez la recherche rapide pour trouver les présentations les plus intéressantes dans votre domaine d'intérêt.

Beam Characteristics of Ultrasonic Transducers for Underwater Marine Use

G. McRobbie[1], P. Marin-Franch[2], and S. Cochrane[1]
[1] University of Paisley
[2] Piezo Composite Transducers, Ltd

This paper illustrates how finite element analysis with COMSOL Multiphysics can be used to simulate the mechanical and electrical characteristics of piezoelectric transducers. It also shows how beam transmit plots and performance measurements can be modeled by coupling between a piezo domain and a second domain governed by the wave equation.

Ultrasonic Beam Steering in Isotropic Media

S. Jeyaraman, B. Ganesan, and M. Kumar
GE Global Research, Bangalore

In this paper, a numerical model for time-domain ultrasound plane wave propagation for a desired angle is presented. The propagating angle is a function of the distance and the time-delay between the individual elements, and the propagating sound speed. In this model, the control parameter 'time' is used for steering the beam at the desired angle. We present an application of the proposed ...

Analysis of Acoustic Response of Rooms

J.S. Crompton[1], L.T. Gritter[1], S. Yushanov[1], K.C. Koppenhoefer[1], and D. Magyari[2]
[1]AltaSim Technologies, LLC, Columbus, OH, USA
[2]Golden Acoustics, Detroit, MI, USA

The preferred acoustic response of recording studios, auditoriums and conference halls is to have an even energy response over the entire room and throughout full audio spectrum. This can be accomplished by using acoustic panels with complex surface structures that scatter acoustic waves and diffuse sound level variability over the room volume or through the use of sound absorbing materials to ...

Effects of Fluid and Structural Forces on the Dynamic Performance of High Speed Rotating Impellers.

C. Thiagarajan[1], G. Shenoy[2], B. S. Shenoy[3]
[1]ATOA Scientific Technologies Pvt Ltd, Whitefield, Bangalore, India.
[2]Department of Mechanical & Manufacturing Engineering, Manipal Institute of technology, Manipal, India
[3]Department of Aeronautical & Automobile Engineering, Manipal Institute of Technology, Manipal, India

Vibration and Dynamic performances of the rotating machinery are conventionally evaluated based on the dominant structural forces such as the centrifugal forces. The increase in rotational speed, miniaturization and performance, demands for improved and accurate evaluation of the vibration performance. The inclusion of coupled effects of fluid and centrifugal forces can contribute significantly ...

Finite Element Modeling of Ultrasonic Transducers for Polymer Characterization

S. De Paolis[1], F. Lionetto[1], and A. Maffezzoli[1]

[1]Department of Innovation Engineering, University of Salento, Lecce, Italy

Finite element analysis has been used to model the ultrasonic wave propagation both in a custom made transducer and in the tested polymer sample. The model consists of acoustic (passive elements) and electroacoustic (active elements) transmission lines. The simulation of the acoustic propagation accounts for the interaction between the transducer and the materials in the buffer rods, and the ...

Finite Element Models for the Solution of Underwater Acoustics Problems

Zampolli, M., Tesei, A., Jensen, F.B.
NATO Undersea Research Centre, 19138 La Spezia, Italy

Acoustic waves are used in SONAR systems for the detection and classification of objects which may be swimming in the water column, proud on the seafloor, or buried below the sediment. In some applications, such as low frequency detection and classification of structurally complex objects immersed in a fluid, signal processing techniques must be aided by a-priori model based knowledge of the ...

A Novel FEM Method for Predicting Thermoacoustic Combustion Instability

G. Campa[1] and S.M. Camporeale[1]
[1]DIMEG, Politecnico di Bari, Bari, Italy

Modern gas turbines suffer of the phenomenon of combustion instability, also known as “humming”. The main origin of the instability is considered to be related to the interaction between acoustic waves and fluctuations of the heat released by the flame. This paper presents a novel numerical method in which the governing equations of the acoustic waves are coupled with a flame heat ...

Optimization of an Acoustic Waveguide for Professional Audio Applications

M. Cobianchi[1] and R. Magalotti[1]
[1] B&C Speakers S.p.a., Bagno a Ripoli, FI, Italia

In modern live sound reinforcement there is a growing use of line sources, obtained through the stacking of many loudspeakers with properly controlled wavefront shape. Thus the use of waveguides is mandatory in order to modify the shape and size of the wavefront exiting from professional compression drivers. With the help of COMSOL Multiphysics®, we have designed a waveguide featuring an ...

Identification of Noise Sources by Means of Inverse Finite Element Method

M. Weber[1], T. Kletschkowski[1], and B. Samtleben[2]
[1]Helmut-Schmidt-University Hamburg, Germany
[2]Airbus Germany

An inverse finite element method for noise source identification in an aircraft cabin is presented. If all sound sources are located on the boundary of the cabin, the equation system resulting from a matching FE model can be re-sorted in such a way that computation of the unknown boundary data is possible from measurement data taken in the cavity. The method is first validated using a simplified ...

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 ...

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