Comprehensive beam tracing method is a simulation method that calculates refraction as well as reflection of sound. Due to the non-linear nature of Snell’s law, refraction (in contrast to reflection) is not a linear transformation. Because of this triangular beams used in comprehensive beam tracing simulation lose focus after refraction. In this paper the problem of non-linearity of refraction ...

Heterodyne holography is an extremely versatile and powerful holographic technique that is able to fully control the amplitude, phase and frequency of both the illumination and holographic reference beams. Applied to vibration analysis, this technique is able to detect the signal of the carrier or the one of any vibration sideband. A complete analysis of the vibration signal can thus be made, a...

A polarimetric fiber-optic vibration sensor immune to temperature variations is reali2ed by forming coils using a standard single-mode fiber. The phase drift due to the linear birefringence changes induced by a modification of the environmental temperature is balanced by a feedback compression of a non vibrating coil. Experimental results show that without the

For linear Hamiltonian systems, the reconstruction of the Poisson bracket from a given energy function and an Hamiltonian flow leads to simple quantization rules. They can also be used in the infinite dimensional case. From this point of view, we consider the examples of oscillators, free electro-magnetic fields and vibrating strings.

Energy dissipation experienced by vibrating microcantilever beams immersed in fluid is strongly dependent on the mode of vibration, with quality factors typically increasing with mode number. Recently, we examined energy dissipation in a new class of cantilever device that embeds a microfluidic channel in its interior-the fundamental mode of vibration only was considered. Due to its importance ...

This article describes experimental investigations of the dynamical behaviour of conventional and negative Poisson's ratio foamed materials in torsional vibration. Dispersion of standing waves and cut-off frequencies were observed. Consequently, foamed materials do not obey the classical theory of elasticity or viscoelasticity. The dynamical effects were attributed to micro-vibrations of the ce...

An overview of the key micromachining technologies that enable communications applications for MEMS is presented with a focus on frequency-selective devices. In particular, micromechanical filters are briefly reviewed and key technologies needed to extend their frequencies into the high VHF and UHF ranges are anticipated. Series resistance in interconnect or structural materials is shown to be ...

The problem of characterizing response variability and assessing reliability of vibrating skeletal structures made up of randomly inhomogeneous, curved/straight Timoshenko beams is considered. The excitation is taken to be random in nature. A frequency-domain stochastic "nite element method is developed in terms of dynamic sti!ness coe$cients of the constituent stochastic beam elements. The dis...

A laser Doppler vibrometer with single photodetector is introduced to measure the vibration on multiple points of target simultaneously. A 2 x 5 beam array with various frequency shifts is generated by three acousto-optic devices, illuminating different points on a vibrating object. The reflected beams interfere with a reference beam on a high-speed photodetector, and the signal is amplified an...