Technical Papers and Presentations

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.

Electro-acoustic Coupling in Nematic Liquid Crystals

G. Rosi[1], L. Teresi[1], A. DiCarlo[1], and F. dell'Isola[2]
[1]LaMS - Università degli Studi Roma Tre, Roma, Italy
[2]Università degli Studi di Roma "La Sapienza", Roma, Italy

Liquid crystals - as all liquids - are generally modelled as incompressible media. In fact, mass-density changes occurring in these mesophases are minuscule and inconsequential in most regimes of interest. However, liquid crystals exhibit also phenomena that call for a more refined theory. In particular, it is experimentally well established that the Fréedericksz transition - i.e., the sudden ...

Calibration of Ultrasonic Testing for Faults Detection in Stone Masonry

M. Usai[1], S. Carcangiu[1], G. Concu[2]
[1]Department of Electrical and Electronic Engineering, University of Cagliari, Cagliari, Italy
[2]Department of Civil Engineering, Environmental and Architecture, University of Cagliari, Cagliari, Italy

In the field of assessment methodologies, particular importance is given to Non-Destructive Testing Techniques, which aspire to achieve the highest number of information about materials and structures without altering their condition. Ultrasonic Testing exploits the transmission and reflection characteristics of mechanical waves with appropriate frequencies passing through the investigated item. ...

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 ...

Towards a Finite Element Calculation of Acoustical Amplitudes in HID Lamps

B. Baumann[1], M. Wolff[1], J. Hirsch[2], P. Antonis[2], S. Bhosle[3], and R. Valdivia Barrientos[4]
[1]Hamburg University of Applied Sciences, Hamburg, Germany
[2]Philips Lighting, Eindhoven, The Netherlands
[3]LAPLACE, Université de Toulouse and CNRS, Toulouse, France
[4]National Institute of Nuclear Research, Salazar, Ocoyoacac, Mexico

High intensity discharge lamps can experience flickering and even destruction, when operated at high frequency alternating current. The cause of these problems has been identified as acoustic resonances inside the lamp’s are tube. Here, a finite element approach for the calculation of the acoustic response function is described. The developed model does not include the plasma dynamics.

Earth Pressure as a Boundary Condition to Bridge Piers and Abutments

M. Quinn[1], D. Whitlow[1], O.D.S. Taylor[1], M.H. McKenna[1]
[1] Engineer Resource and Development Center, United States Army Corps of Engineers, Vicksburg, MS, USA

Bridge piers and abutments makeup the bridge substructure and transmit loads from the superstructure to the bridge foundation material (Figure 1). The bridge abutment serves three purposes: to provide vertical support to the bridge superstructure where the bridge ends, to connect the bridge with the approach roadway, and to retain roadway base materials. There are several types of abutment ...

Towards Rotordynamic Analysis with COMSOL Multiphysics

M. Karlsson[1]
[1]ÅF, Stockholm, Sweden

In this paper a pre-study on using COMSOL Multiphysics for rotordynamic analysis is presented. It is concluded that it is possible to use COMSOL Multiphysics to perform rotordynamical analysis. However, there are no standard environment for rotordynamics, hence the user has to extend the structural model with the rotordynamics effect such as gyroscopic effect and rotordynamical coefficients. By ...

Innovating New Products using Multiphysics Modeling

Dr. Shekhawat is currently the General Manager for New Products Development at Secure Meters Ltd., Udaipur. Prior to this, he was with CEERI, Pilani for 23 years. He has a Ph.D., MS, M. Sc. (Physics) and BE (EEE) from BITS, Pilani. He is the recipient of several honours including the DAAD Fellowship, Germany and National Science Talent Fellowship. His areas of research include Ultrasonic ...

Toward an Evaluation of the Tonal Colouring of the Japanese koto using COMSOL Multiphysics and Acoustics Module

K. Coaldrake[1]
[1]The University of Adelaide, Adelaide City, South Australia, Australia

This paper investigates the potential for a multidisciplinary approach using COMSOL Multiphysics for the evaluation of the tonal colouring of the Japanese koto (13-stringed zither). It uses Ando’s classic acoustic studies (1986; 1996) as a benchmark for the analysis of the natural resonant frequencies and design of the sounding body of the koto. It reports on the development of the model and ...

Numerical Simulations of Ultrasonic Non Destructive Techniques of Masonry Buildings

S. Carcangiu[1], B. Cannas[1], M. Usai[1], and G. Concu[2]
[1]Department of Electric and Electronic Engineering, Cagliari, Italy
[2]Department of Structural and Infrastructural Engineering and Geomatics, Cagliari, Italy

An experimental program has been developed, with the purpose of evaluating the reliability in building diagnosis and characterization of an integrated analysis of several parameters, associated with acoustic waves propagating through the material. The Direct Transmission Technique has been applied. In this paper we developed a numerical model using the Transient Acoustics-Piezoelectric ...

Two- and Three-Dimensional Holey Phononic Crystals with Unit Cells of Resonators

Y.F. Wang[1][2], Y.S. Wang[1], L. Wang[2]
[1]Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing, China
[2]Department of Mechanical Engineering, Østfold University College, Halden, Norway

We show in this paper that by careful design of the geometry of the resonators, complete bandgap with relatively low center frequency can be obtained for 2D and 3D Phononic Crystals with resonators. The generation of the bandgap is due to the local resonance of the unit cell. Spring-mass and spring-pendulum models are developed to predict the boundaries of the complete bandgap. The predicted ...

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