Numerical Study on Shear Horizontal Electromagnetic Acoustic Transducers for Generation of Ultrasonic Guided Waves for Absorber Tubes used in Concentrated Solar Plants - new
L. Cheng, A. Mohimi, M. Kogia, V. Kappatos, C. Selcuk, T.-H. Gan
Brunel Innovation Centre, Brunel University, Uxbridge, UK
Absorber tubes are one of the most critical components of parabolic trough Concentrated Solar Plants, which is very likely get damaged such as crack and mass loss. Therefore, the monitoring of their structural health via Non-Destructive Testing (NDT) techniques is regarded as essential for preventing them from being significantly defective and thereby reducing maintenance cost. Non-contact ...
Finite Element Analysis into Eigenfrequencies of a Total Hip Stem with Different Levels of Loosening
T. Bender , M. Sass , W. Mittelmeier , R. Bader , D. Kluess 
 Department of Orthopaedics Research Laboratory for Biomechanics & Implant Technology, University Medicine Rostock, Rostock, Germany
A finite element model of a total hip replacement (THR) has been developed from the approach of modal analysis. The model is capable of determining the first 15 Eigenmodes of a THR with an artificial bone model. The model was equipped with several different defects to simulate a loosening of THR and to enforce a shifting of the frequency spectrum of the system’s Eigenfrequencies. Using the ...
B. Marmo, and B. Carruthers
Reactec Ltd., Edinburgh, United Kingdom
The onshore wind turbine industry must overcome many technical, commercial, and environmental difficulties. A significant element for planning consent is operational noise. Acoustic limits are strictly enforced and can lead to near-neighbour complaints as well as contractual disputes. Reactec have diagnosed, analysed and solved a problematic tonal resonance for a major wind turbine generator ...
D. Neihguk , M. L. Munjal , A. Prasad ,
 Mahindra & Mahindra Ltd, Chennai, India
 Indian Institute of Science, Bangalore, India
Perforated pipes are extensively used to control exhaust noise in automobiles [1-4]. The energy loss associated with the perforations leads to back pressure which needs to be quantified and minimized . An objective approach presented in  is the introduction of friction factor for perforated ducts as a function of the porosity. In this article, the utilization of the CFD Module of COMSOL ...
I .F. Melikhov , A. S. Amosov , S. A. Chivilikhin ,
 Corning Scientific Center, Saint Petersburg, Russia
 ITMO University, Saint Petersburg, Russia
Ultrasonic levitation is a novel technology for contactless handing of various objects. It is already used in various manufacturing processes where it is important to keep untouched surface. In this paper we introduce a model of so-called near-field ultrasonic levitation which allows flying heights of the hundred-micron order. Our model computes air flow in the gap between a vibration source and ...
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 ...
R. Langkemper , R. Külls , J. Wilde , S. Nau , S. Schopferer ,
 Fraunhofer-Institut für Kurzzeitdynamik, Ernst-Mach-Institut, EMI, Freiburg, Germany
 Albert-Ludwigs-Universität Freiburg, Institut für Mikrosystemtechnik, Freiburg, Germany
Acceleration is an important quantity to be measured in high-speed dynamics. A new piezoresistive sensor for the measurement of high-amplitude, short-duration transient accelerations of up to 100,000 g has been developed at the Fraunhofer EMI. Its figure of merit (sensitivity x resonance frequency²) is about one order of magnitude higher than that of comparable state-of-the-art sensors. ...
H. Chen , J. Li , S. Xia ,
 Hunan University, Changsha, Hunan, China
 Xi'an Jiaotong University, Xi'an, Shaanxi, China
Introduction In order to understand the detection mechanism of the PZT based nondestructive testing (NDT) technology for interface debonding of CFSTs, numerical simulation on a multi-physical model composed of surface-mounted PZT patches and CFST structural member is established in COMSOL Multiphysics®. The stress propagation process and the electrical signal output of an embedded PZT patch as ...
JBL Professional, Northridge, CA, USA
The author presents an overview of methods to build virtual prototypes of both horns and loudspeaker drivers which allows a significant reduction in the number of physical prototypes, as well as reduced development time. This paper will present some of the practical results from work the author has performed in the course of designing both transducers and horns using COMSOL Evolution of the ...
J. M. Stauber , B. A. Marmo ,
 Xi Engineering Ltd, Edinburgh, United Kingdom
Tonal noise from wind turbines can have effects on neighboring residences and its emission can result in strong regulatory penalties that can include the closure of wind farms. The authors present a model of a new broadband damping approach where containers filled with EniDamp™, an Advance Particle Damping (APD) material. The containers, so-called APD pods, are magnetically fixed to wind ...