we report in this paper the development of a spectral-domain optical coherence vibration tomography (OCVT) using a broadband CCD-based spectrometer and a shortcoherence white light source. We demonstrate that both the vibration amplitude and frequency can be quantified, in the frequency range of 0–250 Hz, with an axial resolution of 1 m. Furthermore, the inner structure (layer thickness) of a ...

A method is derived to detect and localize linear damage in a structure using the measured modal vibration parameters. This method is applicable when the vibration strain energy is stored in the axial or torsional modes, which differentiates it from previously derived strain-energy-based methods. The new method is compared to the previously derived flexibility-change method for comparison. Both...

This paper explores the vibration damping properties of thermal barrier coatings (TBCs) containing thin plastically deformable metallic layers embedded in an elastic ceramic matrix. We develop an elastic–plastic dynamical model to study how work hardening, yield strain, and elastic modulus of the metal affect the macroscopic damping behavior of the coating. Finite element (FE) simulations valid...

This paper investigates the natural frequency, steady-state resonance and stability for the transverse vibrations of a nanobeam subjected to a variable initial axial force, including axial tension and axial compression, based on nonlocal elasticity theory. It is reported that the nonlocal nanoscale has significant effects on vibration behavior, which results in a new effective nonlocal bending ...

Combining working principle and failure mechanism of RZU2000HM hydraulic press, with its present fault cases being collected, the working principle of the oil pressure and faults phenomenon of the hydraulic power unit –swash-plate axial piston pump were studied with some emphasis, whose faults will directly affect the dynamic performance of the oil pressure and flow. In order to make hydraulic ...

We use an ultrafast electro-optic dual comb interferometer to perform single-point vibrometry on the submillisecond time scale. As an example, we resolve the vibration of an ultrasound speaker driven at 50 kHz, achieving a sub-nanometer axial resolution through a measurement of the optical phase carrier. OCIS codes: (320.7100) Ultrafast measurements; (120.6200); Spectrometers and spectroscopic ...

In the current work, the nonlinear vibration of an embedded double-walled carbon nanotube (DWCNT) aroused by nonlinear van der Waals (vdW) interaction forces from both surrounding medium and adjacent tubes is studied. Using both Euler–Bernoulli and Timoshenko beam models, the relation between deflection amplitudes and resonant frequencies of the DWCNT is derived through harmonic balance method....

The tonal noise or vibration of air-cooled or water-cooled chillers with rotary twin screw compressors is crucial for environmental concerns. This work aims to perform the receiver tests regarding the radiated noise and structural vibration due to the compressor in different operating conditions. The sound pressure near the compressor is recorded by the one-third octave and narrow band frequenc...

We report the main characteristics and performances of the first – to our knowledge – prototype of an ultra-stable cavity designed and produced by industry with the aim of space missions. The cavity is a 100 mm long cylinder rigidly held at its midplane by an engineered mechanical interface providing an efficient decoupling from thermal and vibration perturbations. The spacer is made from Ultra...

This paper uses an orthotropic shell model to investigate in detail the long axial wavelength circumferential vibration of microtubules (MTs). The deformation patterns in the vibrations were explored and their phonon dispersion relations were presented for MTs with increasing radius. It was shown that with the growth of the axial wavelength, the associated frequency of MTs would finally approac...