A method of estimating damping parameters for multidegree-of-freedom vibration systems is outlined, involving a balance of dissipated and supplied energies over a cycle of periodic vibration. The power is formulated as the inner product between velocity and force terms, and integrated over a cycle. Conservative terms (mass and stiffness) drop out of the formulation. The displacement response an...

In order to effectively control vibration related problems, the development of a reliable vibration monitoring system and the proper assessment of attenuation characteristics of various vibrations are essential. Various ground vibrations caused by train loading, blasting, friction pile driving and hydraulic hammer compaction were measured using 3D geophones inside of the borehole as well as on ...

The simple harmonic vibration, damping vibration and forced vibration of an oscillator attached to the massless spring are always discussed in general mechanics courses. In this article, we focus on the heavy-spring conditions. We first investigate the general situation where both viscous resistance and applied force are considered under the perspective of the renormalization group theory. Then...

(d) Mechanical propert, Defiexion method, brittle coating method, bonded wire technique, moist coating method, vibration methods involving frequency and damping or damping changes during fatigue test. (e) Penetrating radiation tests. (f) Ultrasonic testing Reflection or through transmission methods. (g) Magneto-inductive tests. (h) Electrical tests. Electrical resistance or tribo-electrical met...

Thepresent paper discusses active vibration control of a cantilever beam subjected to random base excitation. The smart materials used are piezoelectric patches for both as sensor and actuator, and actuation based on the surface strains. Finite element model of the smart beam is obtained using Euler-Bernoulli formulation. Positive Position Feedback (PPF) controller is proposed for active dampin...

Synchronized switch damping (SSD) techniques have recently been developed, as an alternative to active vibration control techniques, to address the problem of structure vibration control. In these techniques, a piezoelectric patch is bonded on the vibrating structure and shunted by a network of electrical elements. During the structure motion, the piezoelectric patch is connected and disconnect...

This paper presents the design and experimental study of a voice coil motor (VCM)-based Stewart platform used for active vibration isolation. The high precision payloads carried on the satellites always require an extremely stable environment to work properly. Installing a vibration isolation device between the vibration sources and precision payloads is an efficient method for dissipating vibr...

Design The feasibility study, focuses on building up knowledge of and experience with the technology of using the "d31-effect" of piezoelectric material to damp the internal vibrations of the system. The investigation starts by specifying the mathematical relations that describes the piezoelectric "d31-effect" and particularising these relations for the actuator and sensor situation. The two vi...

Piezoelectric elements connected to shunt circuits and bonded to a mechanical structure form a dissipation device that can be designed to add damping to the mechanical system. Due to the piezoelectric effect, part of the vibration energy is transformed into electrical energy that can be conveniently dissipated. Therefore, by using appropriate electrical circuits, it is possible to dissipate str...

We present measurements of the acoustic vibrations of single gold nanorods deposited on a glass substrate immersed in air and water by ultrafast pump-probe spectroscopy. The nanorods display two vibration modes, the breathing mode and the extensional mode. The damping time of the two modes is influenced by the environment, and a reduction of the quality factor is observed when the particles are...