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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.

Acoustic Emission Simulation for Online Impact Detection

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

Designing Materials for Mechanical Invisibility Cloaks

P. Olsson[1], F. Larsson[1], A. Khlopotin[1], S. Razanica[1]
[1]Chalmers University of Technology, Gothenburg, Sweden

In solid mechanics, there is considerable interest in achieving “invisibility”. The applications in mechanics include protection of structures and parts of structures from potentially harmful transient waves and steady state vibrations. A suggested large scale application is that protection against seismic waves from earthquakes could be achieved by using cloaking to re-route the waves around ...

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 ...

Mathematical Model for Prediction of Transmission Loss for Clay Brick Walls

J. Ratnieks[1], A. Jakovics[1], J. Klavins[1]
[1]Laboratory for Modeling Technological and Environmental Processes, University of Latvia, Riga, Latvia

A 2D numerical model for determination of sound reduction index is set up in this work. Results are in good agreement in middle and high frequency range when using solid structure approximation. Results are compared with experiment.

Temperature Gradients Controlled Broadband Acoustic Omnidirectional Absorber - new

F. Qian[1], L. Quan[1], X. Liu[1]
[1]Institute of Acoustics and School of Physics, Nanjing University, Nanjing, China

Previous research into acoustic omnidirectional absorber (AOA) has shown the feasibility of forming acoustic black hole to guide the incident wave into the central absorptive cavity. However, major restrictions to practical applications exist due to complexity of designing metamaterials and unchangeable working states. Here, we propose two cylindrical, two-dimensional AOA schemes based on ...

Modeling Acoustic Waveguides for Ear Impedance Measurements

R. Sisto[1], L. Cerini[1], D. Mambro[2], A. Moleti[2], F. Sanjust[1]
[1]INAIL Research, Monteporzio Catone, Italy
[2]Università di Roma, Tor Vergata, Italy

The otoacoustic emissions (OAEs) are acoustic signals emitted by the inner ear as a consequence of the activity of a nonlinear feedback mechanism capable of amplifying the signal near to the hearing threshold level. The otoacoustic emissions can be used as an acoustic imaging of the cochlear functionality. They are used in clinics for screening purposes but due to the extreme variability ...

Analysis of the Acoustic Response of a Railroad Bridge

K. Koppenhoefer[1], S.Yushanov[1], and M.H. McKenna[2]

[1]AltaSim Technologies, LLC, Columbus, Ohio, USA
[2]U.S. Army Engineering Research and Development Center

Aging infrastructure requires frequent inspections to assess their structural integrity. However, the large amount of existing infrastructure, and the distance between these structures present significant challenges to inspectors. Acoustics-based technologies represent a simple, and relatively inexpensive, technique to monitor the integrity of a structure. To develop these techniques, designers ...

Application of COMSOL to Acoustic Imaging

K. Mcilhany, and J.C Hernandez
U.S. Naval Academy, Annapolis, MD, USA

Acoustic Imaging of hand movement is being studied with COMSOL and Matlab. A hardware implementation is being pursued that will be an array of 16x16 ultra-sonic speakers placed in a grid facing a similar grid of 16x16 microphones, operating at 40kHz. COMSOL is used to repeatedly calculate the diffraction pattern from a small scattering center, approximately 1.0cm in diameter. In conjunction ...

Structured Ultrasonic Metasurfaces

R. C. Thiagarajan
ATOA Scientific Technologies Private Limited
Bangalore, India

Ultrasonic acoustic waves usually encounter interfaces with significant impedance mismatch in practical medical or industrial imaging applications. A transparent interface can help to improve the performance of medical and industrial imaging and overall innovative applications. Similarly, a broadband total reflection interface can help to improve the architectural or transportation barrier ...

On The Use of a Diffusion Equation Model for Sound Energy Flow Prediction in Acoustically Coupled Spaces

Y. Jing, and N. Xiang
Rensselaer Polytechnic Institute, Troy, NY, USA

This paper studies sound energy flows through an aperture across two coupled spaces using a diffusion equation model. The so-called double sloped sound energy decay is believed to be caused by the sound energy exchange through the aperture coupling the two rooms. The room diffusion equation is first solved by COMSOL, then the time dependent energy flow is visualized via COMSOL arrow plotting, ...