M. Swamy, L. J. van Lier, J. Smeulers
TNO, Delft, The Netherlands
In one of the screw compressor system, designed silencer was not optimal. A great challenge was the large variation in operating conditions, especially the variation of the molecular weight of the gas. There was need to optimize the silencer. This paper describes the acoustic modelling tools to optimize the acoustic performance of the silencer. Optimization steps carried out are based on the ...
Dynamic Characterization and Mechanical Simulation of Cantilevers for Electromechanical Vibration Energy Harvesting
N. Alcheick, H. Nesser, H. Debeda, C. Ayela, I. Dufour 
Univ. Bordeaux, IMS Lab, Pessac, France
Energy harvesting from ambient vibrations has become an interesting topic for powering wireless sensor networks. Resonant microdevices based on MEMS have become of central importance at low frequency. The power produced at resonance is at least one order of magnitude larger than off frequency power since the largest strain is obtained at resonance. In order to obtain large strain for efficient ...
M. Dossi , M. Brennan , M. Moesen ,
 Huntsman Polyurethanes, Everberg, Belgium
Flexible and semi-rigid polyurethane foams are widely used as noise and vibration damping materials. Their porous random microstructure is composed of a visco-elastic frame structure with an interstitial fluid, normally air, filling the voids. The viscoelasticity of the foams is due to the polymer morphology in the foam skeleton structure, which can be adapted depending on application ...
Danieli Automation S.p.A., Buttrio, UD, Italy
The acoustoelastic effect relates the change in the speed of an acoustic wave travelling in a solid, to the pre-stress of the propagation medium. In this work the possibility of assessing nondestructively the stress status in metal sheets, by using the acoustoelastic effect, is investigated. As the effect turns out to be very small for practical values of applied stress, the proposed technique ...
G. Zhu, E.M. Dede
Toyota Research Institute of North America, Ann Arbor, MI, USA
In previous work, a two-dimensional (2D) model was carried out to simulate the phononic band structure of a phononic crystal with square lattice structure, but this model did not account for the out-of-plane phonon dispersions . In fact, for 2D films used for coating materials, it is more interesting to understand their cross-plane properties. In this work, the phonon dispersion relation of ...
D. Rubinetti , D. A. Weiss , J. Müller , A. Wahlen ,
 Institute of Thermal and Fluid Engineering, University of Applied Sciences Northwestern Switzerland, Windisch, Switzerland
 Institute of Product and Production Engineering, University of Applied Sciences Northwestern Switzerland, Windisch, Switzerland
Acoustic streaming (AS) describes a physical phenomenon where an oscillating sound emitter induces a steady fluid motion. Metal processing industry applies this treatment for grain morphology adjustments during the solidification of metal. Improvement and further development of this technique focus on numerical modeling to reduce substantial costs for test rigs and field tests. This study ...
A. Castellano, P. Foti, A. Fraddosio, S. Marzano, M.D. Piccioni, D. Scardigno
DICAR, Politecnico di Bari, Bari, Italy
Introduction: Improving the capability of nondestructive evaluations requires the analysis of suitable models dealing with the physical and mechanical phenomena involved in the experiments. For example, ultrasonic tests may be a powerful, fast and effective method for nondestructive characterization of mechanical properties of materials. This requires the study of the related elastodynamic ...
M. A. B. Andrade , N. Pérez , J. C. Adamowski ,
 Instituto de Física, Universidade de São Paulo, São Paulo, SP, Brasil
 Centro Universitario de Paysandú, Universidad de la República, Paysandú, Uruguai
 Departamento de Engenharia Mecatrônica e Sistemas Mecânicos, Escola Politécnica, Universidade de São Paulo, São Paulo, SP, Brasil
Este trabalho apresenta a simulação numérica de um sistema de levitação acústica para manipulação de partículas em ar. O sistema de levitação consiste de dois transdutores de ultrassom e um refletor de face plana. Através da simulação é calculado o potencial da força de radiação acústica que atua numa esfera. Os resultados da simulação são verificados experimentalmente através da comparação da ...
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 ...
Solving the Inverse Problem of Resonant Ultrasound Spectroscopy on Dumbbell-shaped Compression Samples Using COMSOL Multiphysics®
M. C. Golt
U.S. Army Research Laboratory*, Aberdeen Proving Ground, MD, USA
*Contracted through Dynamic Science, Inc.
The dumbbell geometry is an ideal shape for testing the compressive strength of advanced ceramic materials. This paper details the combined use of COMSOL Multiphysics® and LiveLink™ for MATLAB® for determining the elastic properties of dumbbell-shaped samples by measuring their acoustic resonance frequencies. Degenerate bending modes which are sensitive to inhomogeneities or machining defects ...