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.

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 ...

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 ...

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 ...

Linear Water Wave Propagation around Structures

L. Martinelli, and A. Lamberti
Universita di Bologna, Italy

Objective of this contribution is to show how to implement the Mild Slope Equations with COMSOL Multiphysics. These equations are commonly used to study the propagation of waves in harbors. Some interesting features are presented, namely the use of weak terms (used for the modelling of the source term); the evaluation of a smooth phase gradient from the complex dependent variable; a robust ...

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 ...

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 ...

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 ...

Vibration and Acoustic Analysis of a Trussed Railroad Bridge under Moving Loads

R. Costley[1], H. Diaz-Alvarez[1], M. McKenna[1], A. Miller[1]
[1]U.S. Army Engineer Research and Development Center, Vicksburg, MS, USA

Two finite element models have been developed to investigate the acoustic radiation from a Pratt truss train bridge. The first model was a time dependent structural model that determined the vibration response of the structure due to two wheels, representing a single axle, moving across the bridge at constant speed. This model was expanded to include multiple axles to represent a locomotive. The ...

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 ...

Effects Of The Microstructure Of Fibrous Media On Their Acoustic Properties

C. Peyrega, and D. Jeulin
Center of Mathematical Morphology, Mines ParisTech, Fontainebleau, France

This study is a part of the Silent Wall ANR project, to which the Center of Mathematical Morphology is associated. Its main objective is to build an acoustical and thermal insulating system for buildings, composed of fibrous materials. The material is composed of two phases: the fibrous network and the air surrounding it. At the microscopic scale the absorption of the acoustic wave is mainly due ...

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