Articles techniques et présentations

One of the main design questions in loudspeaker enclosures concern vibrations reduction. An ideal cabinet would be infinitely rigid, so a section of an engineer work is focused on this goal. Solutions depend by loudspeaker system audio field: Line Arrays, Automotive environments or hi ... En savoir plus

Seismic evaluation of existing dams is a major issue that has been even more highlighted by the recent events in Italy. In this regard, researchers and engineers need a reliable and quick tool to assess the complex behaviour of the structure – fluid – soil system. In this paper the soil ... En savoir plus

This paper presents a simulation model of a rotary damper filled with a magnetorheological fluid (MRF). The most important characteristic of the MRF is the variable viscosity, which can be controlled by an external magnetic field. In the simulation model, the fluid is described as a ... En savoir plus

Perfectly matched layers (PML) are an efficient alternative for emulating the Sommerfeld radiation condition in the numerical solution of wave radiation and scattering problems. The key ingredient of the PML formulation is the complex scaling function, which controls the anisotropic ... En savoir plus

Wind turbine towers can often become modal if matched closely in frequency with the excitation associated with rotating components in the drive train, such as gearboxes and generators. When these conditions are met, the modal response is greatly amplified due to the very low structural ... En savoir plus

Here we optimize the geometry: proof mass length Lm to total length L, thickness of the piezoelectric material (Tp) to total cantilever thickness (T) for obtaining the maximum stress distribution (Smax), output voltage (Vout) and power performance (Pout) of the unimorph Cantilever beam ... En savoir plus

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 ... En savoir plus

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 ... En savoir plus

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 ... En savoir plus

Introduction: Acoustic levitators are used to levitate small samples (ca. 0.01 - 6 mm) at a stable position in a gas or liquid environment. Acoustic levitators were first developed und used for experiments in space (1970s, by NASA / ESA), the application later became terrestrial (1990s). ... En savoir plus