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 ...
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. ...
S. Sushma, R. Surekha, K. J. Rudhresha, S. Sahu , S. Singh4 , S. L. Pinjare6 ,
 Dept. of ECE, Nitte Meenakshi Institute of Technology, Bangalore, Karnataka, India.
This poster focuses on the development of a capacitive pressure sensor for condition monitoring applications. One method to measure vibrations is to mount an pressure sensor on the vibrating machinery or object and measure the pressure exerted due to vibrations. Measured pressure level helps to detect any deviations from the normal conditions.
H. Lissek, R. Boulandet, and M. Maugard
Ecole Polytechnique Federale de Lausanne
An \"electroacoustic absorber\" is a loudspeaker, used as an absorber of sound, which acoustic impedance can be varied by electrical means. This can be achieved either by plugging passive shunt electric networks at the loudspeaker terminals (“shunt loudspeakers”) or by feeding back the loudspeaker with a voltage proportional to acoustic quantities, such as sound pressure and diaphragm normal ...
M. Satthiyaraju , T. Ramesh ,
 National Institute of Technology, Tiruchirappalli, Tamil Nadu, India
The dynamic response of microcantilever, which is a simple microelectromechanical system (MEMS) structure, to sine wave excitation is studied using the vibrational speaker set up in the atmospheric damping. Microcantilever is fabricated using micro wire cut EDM process for high precision. Mostly silicon material is used for microsystems based structure. Here stainless steel was used and machined ...
J. Holt , C. Torres-Sanchez , P. Conway , M. G. Garcia-Romero ,
 The Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Leicestershire, UK
Functionally graded materials (FGM) are those that contain chemical, phase or structural gradients. Whilst the design of functionally graded structures is well researched in areas such as shape optimisation and topology optimization, their manufacture is still in development. One potential method for manufacturing functional gradients within materials is the application of sonication, this is, ...
M. Cobianchi and R. Magalotti
 B&C Speakers S.p.a., Bagno a Ripoli, FI, Italia
In modern live sound reinforcement there is a growing use of line sources, obtained through the stacking of many loudspeakers with properly controlled wavefront shape. Thus the use of waveguides is mandatory in order to modify the shape and size of the wavefront exiting from professional compression drivers. With the help of COMSOL Multiphysics®, we have designed a waveguide featuring an ...
T. Kaufmann, F. Kassubek, D. Pape , M. Lenner
ABB Corporate Research, Baden-Dättwil, Switzerland
Lamb waves are elastic waves propagating in free solid plates. In the case of plates loaded with a fluid, the equations describing these waves have to be modified to include the effects of the fluid. In our work we have tackled this problem using COMSOL Multiphysics®. We have used the two-dimensional plane strain model of the solid mechanics interface to calculate the eigenmodes of the coupled ...
P. Jatzlau , F. Seybold , C. Grosse ,
 Technical University of Munich, Chair of Non-destructive Testing, Munich, Germany
The vibration behavior of carbon fiber reinforced composites (CFRP) specimens with impact damage is presented in order to evaluate if an before/after modal analysis can be used as a non-destructive testing method to detect delaminations. The impact damage is modeled by decreasing the stiffness in the described area of delamination. As detailed experimental data exists for the modeled structure, ...
F. Berger , T. Hummel , P. Romero , M. Schulze , B. Schuermans , T. Sattelmayer ,
 Lehrstuhl für Thermodynamik, TU München, Germany
 GE Power, Switzerland
Modern gas turbine systems for power generation are prone develop so-called thermosacoustic instabilities in the combustion chamber. Physically, these instabilities emerge as large amplitude pressure oscillations within the combustor, which are caused by constructive feedback interactions between the flame and the combustor's natural acoustic modes. The oscillations disturb the combustion ...