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Encyclopedia > Tuned mass damper
Tuned mass damper atop the Taipei 101.
Tuned mass damper atop the Taipei 101.
Stockbridge dampers on power lines.
Stockbridge dampers on power lines.

A tuned mass damper, or harmonic absorber, is a device mounted in structures to prevent discomfort, damage or outright structural failure by vibration. Typically, the dampers are huge concrete blocks mounted in skyscrapers or other structures, and moved in opposition to the resonant frequency oscillations of the structure by means of springs, fluid or pendulums. High-tension lines often have small barbell-shaped Stockbridge dampers hanging from the wires[citation needed] [See also damping]. Image File history File links Information. ... Image File history File links Download high resolution version (1555x1037, 292 KB) Description: Tuned mass damper of the Taipei 101. ... Image File history File links Download high resolution version (1555x1037, 292 KB) Description: Tuned mass damper of the Taipei 101. ... Taipei 101 (Traditional Chinese: ; Simplified Chinese: ; Hanyu Pinyin: Táiběi Yīlíngyī; Wade-Giles: Tai-pei I-ling-i) is a 101-floor landmark skyscraper located in Taipei City, Republic of China (Taiwan). ... Image File history File links Metadata Size of this preview: 450 × 600 pixelsFull resolution (1704 × 2272 pixel, file size: 400 KB, MIME type: image/jpeg) A set of stockbridge dampers on some power lines north of Fresno, CA. File history Legend: (cur) = this is the current file, (del) = delete this... Image File history File links Metadata Size of this preview: 450 × 600 pixelsFull resolution (1704 × 2272 pixel, file size: 400 KB, MIME type: image/jpeg) A set of stockbridge dampers on some power lines north of Fresno, CA. File history Legend: (cur) = this is the current file, (del) = delete this... Structural failure refers to loss of the load-carrying capacity of a component or member within a structure or of the structure itself. ... Look up vibration in Wiktionary, the free dictionary. ... This article does not cite any references or sources. ... This article is about resonance in physics. ... Helical or coil springs designed for tension A spring is a flexible elastic object used to store mechanical energy. ... Transmission lines in Lund, Sweden Electric power transmission is one process in the delivery of electricity to consumers. ... A U.S. Army soldier uses a barbell with Olympic plates (but no collars) to perform a bench press. ... Power line redirects here. ... Damping is any effect, either deliberately engendered or inherent to a system, that tends to reduce the amplitude of oscillations of an oscillatory system. ...


Small devices working on the same principles were used as shock absorbers to damp rear wheel bounce on the Citroën 2CV. Gasfilled Shock absorber. ... First generation Ripple Bonnet Citroën 2CV built from 1948 to 1960 The Citroën 2CV (French: deux chevaux, literally two horses, from the tax horsepower rating) was an economy car produced by the French automaker Citroën from 1948 to 1990. ...

Contents

Sources of vibration and resonance

Unwanted vibration may be caused by environmental forces acting on a structure, such as wind or earthquake, or by a seemingly innocuous vibration source causing resonance that may be destructive, unpleasant or simply inconvenient.


Earthquakes

The seismic waves caused by an earthquake will make tall buildings sway and oscillate in various ways depending on the frequency and direction of ground motion, and the height and construction of the building. Seismic activity can cause oscillations of the building which may lead to structural failure. Body waves and surface waves Earthquake wave paths p-wave and s-wave from seismograph A seismic wave is a wave that travels through the Earth, most often as the result of a tectonic earthquake, sometimes from an explosion. ... An earthquake is a result from the sudden release of stored energy in the Earths crust that creates seismic waves. ... Structural failure refers to loss of the load-carrying capacity of a component or member within a structure or of the structure itself. ...


Mechanical human sources

Dampers on a pedestrian bridge - the Millennium Bridge, London (the disk is not part of the damper)

Masses of people walking up and down stairs at once, or great numbers of people stomping in unison, can cause serious problems in large structures like stadiums if those structures lack dampening measures. Vibration caused by heavy industrial machinery, generators and diesel engines can also pose problems to structural integrity, especially if mounted on a steel structure or floor. Large ocean going vessels may employ tuned mass dampers to isolate the vessel from its engine vibration. London Millennium Bridge - Damper beneath deck, north side - 240404. ... London Millennium Bridge - Damper beneath deck, north side - 240404. ... For other uses, see Millennium Bridge. ...


Wind

The force of wind against tall buildings can cause the top of skyscrapers to move more than a metre. This motion can be in the form of swaying or twisting, and can cause the upper floors of such buildings to move. Certain angles of wind and aerodynamic properties of a building can accentuate the movement and cause motion sickness in people. The metre (American English:meter) is a measure of length. ... Aerodynamics is a branch of fluid dynamics concerned with the study of gas flows, first analysed by George Cayley in the 1800s. ... It has been suggested that airsickness, seasickness be merged into this article or section. ...

How they work

Tuned mass dampers stabilize against violent motion caused by harmonic vibration. The presence of a tuned damper allows the inertia of a great mass to be balanced by a comparatively lightweight structural component, such as a heavy concrete block placed in such a way that the block moves in one direction as the structure moves in the other, thus damping the structure's oscillation. The counterweight may be mounted using massive spring coils and hydraulic dampers. If the axis of the vibration is fundamentally horizontal or torsional, leaf springs and pendulum-mounted weights are employed. Tuned mass dampers are engineered, or "tuned" to specifically counter harmful frequencies of oscillation or vibration. Inertia is the property of an object to remain at constant velocity unless acted upon by an outside force. ... This article or section does not cite its references or sources. ... A traditional leaf spring arrangement. ... Simple gravity pendulum assumes no air resistance and no friction of/at the nail/screw. ...

System schematic of a simple spring/mass/damper system used to demonstrate the tuned mass damper system.
System schematic of a simple spring/mass/damper system used to demonstrate the tuned mass damper system.

This system consists of a main mass m1, such as a wheel and suspension arm, with a spring and damper k1/c1 between it and the body. The force into the body is F0, this is what we are trying to minimise. A variable force F1 is applied to m1, this is the excitation force. The system is modified by adding another spring/damper/mass system k2/c2 and m2. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...

Response of the system excited by a 1 N force, with (red) and without (blue) the 10% tuned mass. The peak response is reduced from 9 N to 5.5 N.

The graph shows the effect of a Tuned mass damper on a simple spring/mass/damper system, excited by a 1 N force applied to the main mass. The important measure for this system is the ratio of the force applied to the body, F0, as a result of F1. The blue line represents the baseline system, with a maximum response of 9 N into the base at 9 Hz. The red line shows the effect of adding a tuned mass of 10% of the baseline mass. It has a maximum response of 5.5 N, at 7 Hz. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... The newton (symbol: N) is the SI unit of force. ...


The relative heights of the two peaks can be adjusted by changing the stiffness of the spring in the tuned mass damper. Changing the damping also changes the height of the peaks, in a complex fashion. The split between the two peaks can be changed by altering the proportion of the baseline mass used in the damper.

A Bode plot of displacements in the system with (red) and without (blue) the 10% tuned mass.
A Bode plot of displacements in the system with (red) and without (blue) the 10% tuned mass.

The Bode plot is more complex, showing the phase and magnitude of the motion of each mass, for the two cases, relative to F1. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... The Bode plot for a first-order Butterworth filter A Bode plot, named after Hendrik Wade Bode, is usually a combination of a Bode magnitude plot and Bode phase plot: A Bode magnitude plot is a graph of log magnitude against log frequency often used in signal processing to show... The Bode plot for a first-order Butterworth filter A Bode plot, named after Hendrik Wade Bode, is usually a combination of a Bode magnitude plot and Bode phase plot: A Bode magnitude plot is a graph of log magnitude against log frequency often used in signal processing to show...


The black line is for the baseline, and only shows the motion of m1. The blue line is the motion of m2 in the case with the tuned mass absorber. It goes into resonance early, in phase with m1, but with a higher amplitude. Therefore some of the energy that would have been used to vibrate the body (via F0) is absorbed in the damping element at c2. As the frequency increases m2 starts to move out of phase with m1, until at around 9.5 Hz it is moving in antiphase with m1, thereby pumping maximum energy into the damper at c2.


Examples of buildings and structures with tuned mass dampers

The Berliner Fernsehturm seen from a distance. ... This article is about the capital of Germany. ... The Burj al-Arab (Arabic: برج العرب, Tower of the Arabs) is a luxury hotel in Dubai, United Arab Emirates, built by Said Khalil. ... Coordinates: , Emirate Dubai Government  - Sheikh Mohammed bin Rashid Al Maktoum Area [1]  - Metro 4,114 km² (1,588. ... The Spire of Dublin (main nickname: The Spike) is a large, pin-like monument, 120 metres in height and lit from the top, whose erection was completed on January 21, 2003 on the site of the former Nelson Pillar on OConnell Street in Dublin, Ireland. ... This article is about the city in Ireland. ... The Citigroup Center is one of the largest skyscrapers in New York City, United States, located at 601 Lexington Avenue between 53rd Street and 54th Street in midtown Manhattan. ... New York, New York and NYC redirect here. ... The engineer responsible for the structural desing of the Citicorp headquarters tower, in New York, (1977). ... John Hancock Tower, 200 Clarendon St. ... Nickname: City on the Hill, Beantown, The Hub (of the Universe)1, Athens of America, The Cradle of Revolution, Puritan City, Americas Walking City Location in Massachusetts, USA Counties Suffolk County Mayor Thomas M. Menino(D) Area    - City 232. ... Taipei 101 (Traditional Chinese: ; Simplified Chinese: ; Hanyu Pinyin: TáibÄ›i YÄ«língyÄ«; Wade-Giles: Tai-pei I-ling-i) is a 101-floor landmark skyscraper located in Taipei City, Republic of China (Taiwan). ... For the arena in College Park, Maryland, see Comcast Center (arena). ... This article refers to the largest city of Pennsylvania. ... The London Millennium Footbridge is a pedestrian-only steel suspension bridge crossing the River Thames in London between the existing Southwark Bridge and Blackfriars Bridge, linking Bankside with the City. ... The Park Tower Park Tower located at 800 Michigan Avenue in Chicago ( ) is a skyscraper completed in 2000. ... Nickname: Motto: “Urbs in Horto” (Latin: “City in a Garden”), “I Will” Location in the Chicago metro area and Illinois Coordinates: , Country United States State Illinois Counties Cook, DuPage Settled 1770s Incorporated March 4, 1837 Government  - Mayor Richard M. Daley (D) Area  - City  234. ... Trump World Tower Trump World Tower, as seen from the Empire State Building in Midtown Manhattan. ... One Wall Centre is the tallest building in Vancouver, British Columbia, Canada as of 2005. ... Motto: By Sea, Land, and Air We Prosper Location of Vancouver within the Greater Vancouver Regional District in British Columbia, Canada Coordinates: , Country  Canada Province  British Columbia Region Lower Mainland Regional District Greater Vancouver Incorporated 1886 Government  - Mayor Sam Sullivan (NPA)  - City Council List of Councilors Suzanne Anton (NPA) Peter... One Rincon Hill or 425 First Street is a residential complex that is currently under construction on the apex of Rincon Hill in San Francisco. ... // Random House is a publishing house based in New York City. ... Bally Technologies logo Bally (with its distinctive Rolling Ball logo) Bally Technologies, Inc. ... Sakhalin Offshore Fields The Sakhalin-I project, like its sister project Sakhalin-II, is a consortium to locate and produce oil and gas on Sakhalin Island and immediately offshore, in the Sea of Okhotsk, from three fields: Chayvo, Odoptu and Arkutun-Dagi. ... Top of Bloomberg Tower Bloomberg Tower, named after Bloomberg L.P., is the unofficial name of a skyscraper on the East Side of Midtown Manhattan. ... The Landmark Tower, in the Minato Mirai 21 district of Yokohama. ... Skywalk from Outside Ledge The Grand Canyon Skywalk is a tourist attraction along the Colorado River on the edge of the Grand Canyon (Grand Canyon West) in the U.S. state of Arizona. ...

Mass dampers in motorsport

The tuned mass damper was introduced as part of the suspension system by Renault, on its 2005 F1 car(the R25), at the 2005 Brazilian Grand Prix. It was deemed to be legal at first, and it was in use up to the 2006 German Grand Prix. The 2005 Brazilian Grand Prix was a Formula One race held on September 25 at Autódromo José Carlos Pace in São Paulo, Brazil. ... The 2006 German Grand Prix is the twelth race of the 2006 Formula One season. ...


At Hockenheim, the mass damper was deemed by the FIA to be a moveable aerodynamic device due to the influence it had on the pitch attitude of the car, and hence, as a consequence, the performance of the aerodynamics. The Fédération Internationale de lAutomobile, commonly referred to as the FIA, is a non-profit association established in 1904 to represent the interest of motoring organisations and motor car users. ... This article does not cite any references or sources. ...


The Stewards of the meeting deemed it legal, but the FIA appealed against that decision. 2 weeks later, the FIA International Court of Appeal deemed the mass damper illegal.


Mass dampers in production cars

Tuned mass dampers are widely used in production cars, typically on the crankshaft pulley to control torsional vibration and bending modes of the crankshaft, on the driveline for gearwhine, and other noises. They are also used on the exhaust, on the body and on the suspension, as in the 2CV example above. Almost all cars will have one mass damper, some may have 10 or more. Torsional vibration is vibration of an object, commonly a shaft, along its axis of rotation. ...


References

  1. ^ Taipei 101's 730-Ton Tuned Mass Damper, Popular Mechanics, May 2005.

External links


  Results from FactBites:
 
Tuned mass dampers (703 words)
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A key element of the design process was finite element modeling of the TMD alone to identify a suitable geometry and VEM for the constrained layer damper, as well as an analytical design of the damped flexure spring and end mass to obtain the desired natural frequency.
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Reference.com/Encyclopedia/Tuned mass damper (838 words)
Typically, the dampers are huge concrete blocks mounted in skyscrapers or other structures, and moved in opposition to the resonant frequency oscillations of the structure by means of springs, fluid or pendulums.
The presence of a tuned damper forces a comparatively lightweight structure to overcome the inertia of a great mass, such as a giant concrete block, placed in such a way that the mass only begins to move in one direction just as the structure begins to move in the other, thus damping the structure's oscillation.
At Hockenheim, the mass damper was deemed by the FIA to be a moveable aerodynamic device due to the influence it had on the pitch attitude of the car, and hence, as a consequence, the performance of the aerodynamics.
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