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Tuned Mass Damper
A tuned mass damper (TMD), also known as a harmonic absorber or seismic damper, is a device mounted in structures to reduce mechanical vibrations, consisting of a mass mounted on one or more damped springs. Its oscillation frequency is tuned to be similar to the resonant frequency of the object it is mounted to, and reduces the object's maximum amplitude while weighing much less than it. TMDs can prevent discomfort, damage, or outright structural failure. They are frequently used in power transmission, automobiles and buildings. Principle Tuned mass dampers stabilize against violent motion caused by harmonic vibration. They use a comparatively lightweight component to reduce the vibration of a system so that its worst-case vibrations are less intense. Roughly speaking, practical systems are tuned to either move the main mode away from a troubling excitation frequency, or to add damping to a resonance that is difficult or expensive to damp directly. An example of the lat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torsional Vibration
Torsional vibration is angular vibration of an object—commonly a shaft along its axis of rotation. Torsional vibration is often a concern in power transmission systems using rotating shafts or couplings where it can cause failures if not controlled. A second effect of torsional vibrations applies to passenger cars. Torsional vibrations can lead to seat vibrations or noise at certain speeds. Both reduce the comfort. In ideal power generation, or transmission, systems using rotating parts, not only the torques applied or reacted are "smooth" leading to constant speeds, but also the rotating plane where the power is generated (or input) and the plane it is taken out (output) are the same. In reality this is not the case. The torques generated may not be smooth (e.g., internal combustion engines) or the component being driven may not react to the torque smoothly (e.g., reciprocating compressors), and the power generating plane is normally at some distance to the power takeoff pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stockbridge Dampers On An English 400 KV Line Arp
Stockbridge may refer to: Places United Kingdom * Stockbridge, Edinburgh, a suburb of Edinburgh, Scotland * Stockbridge, Hampshire * Stockbridge, West Sussex * Stockbridge Anticline, one of a series of parallel east–west trending folds in the Cretaceous chalk of Hampshire * Stockbridge Village, Liverpool * Stockbridge (UK Parliament constituency) United States * Stockbridge, Georgia * Stockbridge, Massachusetts * Stockbridge, Michigan * Stockbridge Township, Michigan * Stockbridge, New York * Stockbridge, Vermont * Stockbridge, Wisconsin * Stockbridge (town), Wisconsin * Stockbridge Bowl, artificially impounded body of water north of Stockbridge, Massachusetts * Stockbridge Falls, a waterfall located on Oneida Creek southwest of Munnsville, New York Structures * Stockbridge Casino, a historic building in Stockbridge, Massachusetts * Stockbridge House, historic building in Colorado Springs, Colorado, a.k.a. Amarillo Motel * Stockbridge High School, a high schoo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eddy Current
Eddy currents (also called Foucault's currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor according to Faraday's law of induction or by the relative motion of a conductor in a magnetic field. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. They can be induced within nearby stationary conductors by a time-varying magnetic field created by an AC electromagnet or transformer, for example, or by relative motion between a magnet and a nearby conductor. The magnitude of the current in a given loop is proportional to the strength of the magnetic field, the area of the loop, and the rate of change of flux, and inversely proportional to the resistivity of the material. When graphed, these circular currents within a piece of metal look vaguely like eddies or whirlpools in a liquid. By Lenz's law, an eddy current creates a magnetic field that opposes the change in the mag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nutation (engineering)
In engineering, a nutating motion is similar to that seen in a swashplate mechanism. In general, a nutating plate is carried on a skewed bearing on the main shaft and does not itself rotate, whereas a swashplate is fixed to the shaft and rotates with it. The motion is similar to the motions of coin or a tire wobbling on the ground after being dropped with the flat side down. ''Precession'' is the physical term for this kind of motion. Nutating mixers are used in gentle three-dimensional (gyrating) agitation of chemical or biological scientific procedures by repetitively moving the vessels holding the liquids. The nutating motion is widely employed in flowmeters and pumps. The displacement of volume for one revolution is first determined. The speed of the device in revolutions per unit time is measured. In the case of flowmeters, the product of the rotational speed and the displacement per revolution is then taken to find the flow rate. A nutating disc engine was patented in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NASASpaceFlight
''NASASpaceflight.com'' is a private news website and forum which launched in 2005, covering crewed and uncrewed spaceflight and aerospace engineering news. Its original reporting has been referenced by various news outlets on spaceflight-specific news, such as MSNBC, USA Today and ''The New York Times'' among others. NASASpaceflight also produces videos and live streams of rocket launches online, with a special focus on developments at SpaceX's Starbase facility, for which they were recognized with an award by SpaceNews. NSF is owned and operated by managing editor Chris Bergin and content is produced by a team of spaceflight reporters, journalists, contributors, editors, photographers, and videographers across the United States and other countries. NASASpaceflight and NASASpaceflight.com are not affliated with NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibration Isolation
Vibration isolation is the process of isolating an object, such as a piece of equipment, from the source of vibrations. Vibration is undesirable in many domains, primarily engineered systems and habitable spaces, and methods have been developed to prevent the transfer of vibration to such systems. Vibrations propagate via mechanical waves and certain mechanical linkages conduct vibrations more efficiently than others. Passive vibration isolation makes use of materials and mechanical linkages that absorb and damp these mechanical waves. Active vibration isolation involves sensors and actuators that produce disruptive interference that cancels-out incoming vibration. Passive isolation "Passive vibration isolation" refers to vibration isolation or mitigation of vibrations by passive techniques such as rubber pads or mechanical springs, as opposed to "active vibration isolation" or "electronic force cancellation" employing electric power, sensors, actuators, and control systems. Passive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ares I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars. Ares I was originally known as the "Crew Launch Vehicle" (CLV). NASA planned to use Ares I to launch Orion, the spacecraft intended for NASA human spaceflight missions after the Space Shuttle was retired in 2011. Ares I was to complement the larger, uncrewed Ares V, which was the cargo launch vehicle for Constellation. NASA selected the Ares designs for their anticipated overall safety, reliability and cost-effectiveness. However, the Constellation program, including Ares I, was cancelled by U.S. president Barack Obama in October 2010 with the passage of his 2010 NASA authorization bill. In September 2011, NASA detailed the Space Launch System as its new vehicle for human exploration beyond Earth's orbit. Development Advanced Transportation System Studies In 1995 Lockheed Martin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resonance
Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscillating force is applied at a resonant frequency of a dynamic system, the system will oscillate at a higher amplitude than when the same force is applied at other, non-resonant frequencies. Frequencies at which the response amplitude is a relative maximum are also known as resonant frequencies or resonance frequencies of the system. Small periodic forces that are near a resonant frequency of the system have the ability to produce large amplitude oscillations in the system due to the storage of vibrational energy. Resonance phenomena occur with all types of vibrations or waves: there is mechanical resonance, orbital resonance, acoustic resonance, electromagnetic resonance, nuclear magnetic resonance (NMR), electron spin resonance (ESR) and reso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Citroën 2CV
The Citroën 2CV (french: link=no, deux chevaux(-vapeur), , lit. "two steam horse(power)s", meaning "two ''taxable'' horsepower") is an air-cooled front-engine, front-wheel-drive, economy family car, introduced at the 1948 Paris Mondial de l'Automobile, and manufactured by Citroën for model years 1948–1990. Conceived by Citroën Vice-President Pierre Boulanger to help motorise the large number of farmers still using horses and carts in 1930s France, the 2CV has a combination of innovative engineering and straightforward, utilitarian bodywork — at first with extra thin panels, reinforced by ''corrugating'' the metal. The 2CV featured overall low cost of ownership, simplicity of maintenance, an easily serviced air-cooled engine (originally offering 9 hp), and minimal fuel consumption. In addition, it had literally been designed to cross a freshly ploughed field, because of the great lack of paved roads in France then; with a long-travel suspension system, that con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Combustion Engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons ( piston engine), turbine blades (gas turbine), a rotor (Wankel engine), or a nozzle ( jet engine). This force moves the component over a distance, transforming chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to. This replaced the external combustion engine for applications where the weight or size of an engine was more important. The first commercially successful internal combustion engine was created by Étienne Lenoir around 1860, and the first modern internal combustion engine, known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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