A variation of a hanging pendulum thrust stand capable of measuring the performance of an electric thruster operating in the vertical orientation is presented. The vertical orientation of the thruster dictates that the thruster must be horizontally offset from the pendulum pivot arm, necessitating the use of a counterweight system to provide a neutrally stable system. Motion of the pendulum arm...

Magnetorheological (MR) dampers represent one of the most promising semi-active control devices for applications aiming at the seismic risk mitigation of new or existing civil structures. Two 30 kN MR dampers were experimentally tested subjecting them to assigned conventional displacement laws at their ends. The paper describes the main results of the above experimental activity and aims at imp...

Semi-active control devices have been shown to be more energy efficient than active devices and more effective in reducing seismic structural vibration than passive devices. A new type of semi-active control device, the piezoelectric friction damper has been made in this paper. Piezoelectric actuators used in the dampers can quickly and accurately respond to a voltage signal. They are also effe...

A study on the evaluating equivalent damping and response modification factors of frames equipped by Pall Friction Dampers is presented. To do so, buildings with various stories were considered. Nonlinear and linear dynamic time history analysis has been performed to evaluate equivalent damping for Pall Friction Dampers. Ground motions with various frequency characteristics scaled with Iranian ...

A particle impact damper (PID) dissipates the vibration energy of a structure through impacts within damper. The PID is not commonly used in practice mainly because its low damping-to-mass ratio and difficulty achieving optimal design due to nonlinear characteristics. In contrast, Coulomb friction (FD) can offer higher damping force-to-mass than other dampers, but it also difficult be controlle...

This paper investigates the effect of span cantilevered RC wall, in-plane stiffness roof, layout friction damper support on both response control walls in gymnasiums with metal spatial roofs and proposed evaluation method. According to history analysis results, method was proved be available various formula column base moment modified following appropriate diagram.

Reduction of structural vibrations is of major interest in mechanical engineering for lowering sound emission of vibrating structures, improving accuracy of machines and increasing structure durability. Besides optimization of the mechanical design or various types of passive damping treatments, active structural vibration control concepts are efficient means to reduce unwanted vibrations. In t...

Abstract This paper focuses on a topic frequently involved in the dynamics of transient phenomena rotary machines driven by an AC induction motor supplied three-phase four-wire electrical system: free response dynamic system mirrored torsional vibrations its rotor. is reducible at single degree freedom system, equivalent spring-mass-damper but as vibratory composed rotor (having moment inertia)...

A new self-powered magnetorheological (MR) damper control system was developed to mitigate cable vibration. The power source of the MR damper is directly harvested from vibration energy through a rotary permanent magnet direct current (DC) generator. The generator itself can also serve as an electromagnetic damper. The proposed smart passive system also incorporates a roller chain and sprocket,...

High cycle fatigue failure of turbine and compressor blades due to resonance in the operating frequency range is one of themain problems in the design of gas turbine engines. To suppress excessive vibrations in the blades and prevent high cycle fatigue, dry friction dampers are used by the enginemanufacturers. However, due to the nonlinear nature of friction contact, analysis of such systems be...