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What is Tuned Mass Damper (TMD)?
Tuned mass damper (also called vibration absorbers or vibration dampers) is a device mounted to a specific location in a structure, so as to reduce the amplitude of vibration to an acceptable level whenever a strong lateral force such as an earthquake or high winds hit. Consequently, discomfort, damage, or outright structural failure caused by vibration in the structure will be prevented. This article presents different aspects of tuned mass damper and its applications.Components of Tuned Mass Damper
Components of tuned mass damper include:- Spring (K2)
- Oscillating Mass (M2)
- Viscodamper (C2)
![Tuned mass damer components](https://test.theconstructor.org/wp-content/uploads/2016/08/Tuned-mass-damer-components.jpg)
Fig. 1: Tuned mass damer components
![Pendulum tuned mass damer](https://test.theconstructor.org/wp-content/uploads/2016/08/Pendulum-tuned-mass-damer.jpg)
Fig. 2: Pendulum tuned mass damer
![Building Vibrations During Earthquake Building Vibrations During Earthquake](https://test.theconstructor.org/wp-content/uploads/2016/08/building-vibrations-earthquake.jpg)
Fig. 3: Amplitude - Frequency response of a low damped system without (blue) and with (yellow) tuned mass damper
Types of Tuned Mass Damper (TMD)
Horizontal Tuned Mass Damper (TMD)
It is normally found in slender buildings, communication towers, spires and the like. Horizontal tuned mass damper (TMD) as shown in Fig. 1 composed of viscodampers and leaf springs or pendulum suspensions. it eats horizontal and torsional excitations.Vertical Tuned Mass Damper (TMD)
It is usually applied in long span horizontal structures such as bridges, floors and walkways. Vertical tuned mass damper (TMD) as shown in Fig. 2 is a combination of coil springs and Viscodampers and it declines vertical vibrations. Both types have similar functions, though there might be slight differences in terms of mechanism.How Tuned Mass Dampers Work?
A tuned mass damper (TMD) consists of a mass (m), a spring (k), and a damping device (c), which dissipates the energy created by the motion of the mass (usually in a form of heat). In this figure, M is the structure to which the damper would be attached.![Tuned mass damper operating principles](https://test.theconstructor.org/wp-content/uploads/2016/08/Tuned-mass-damper-operationg-principles-2.jpg)
Fig. 4: Tuned mass damper operating principles
![Tuned Mass Damper operations Tuned Mass Damper operations](https://test.theconstructor.org/wp-content/uploads/2010/02/Tuned_mass_damper.gif)
Fig. 5: Tuned Mass Damper operations
Applications of Tuned Mass Dampers
Tuned mass dampers are mainly used in the following applications:- Tall and slender free-standing structures (bridges, pylons of bridges, chimneys, TV towers) which tend to be excited dangerously in one of their mode shapes by wind,
- Stairs, spectator stands, pedestrian bridges excited by marching or jumping people. These vibrations are usually not dangerous for the structure itself, but may become very unpleasant for the people,
- Steel structures like factory floors excited in one of their natural frequencies by machines , such as screens, centrifuges, fans etc.,
- Ships exited in one of their natural frequencies by the main engines or even by ship motion.
Example of Tuned Mass Damper Application
Taipei structure has TMD of weight 730 tonnes and has the largest diameter in the world (Fig. 6). Fig. 7 and Fig. 8 show Tuned Mass Damper of Burj Al Arab and Emirate Tower respectively.![Tuned mass damper of Taipei structure Tuned mass damper of Taipei structure](https://test.theconstructor.org/wp-content/uploads/2016/08/Tuned-mass-damper-of-Taipei-structure-450x186.jpg)
Fig. 6: Tuned mass damper of Taipei structure
![Tuned mass damper of Burj Al Arab Tuned mass damper of Burj Al Arab](https://test.theconstructor.org/wp-content/uploads/2016/08/Tuned-mass-damper-of-Burj-Al-Arab-450x370.jpg)
Fig. 7: Tuned mass damper of Burj Al Arab
![Tuned mass damper of Emirate tower Tuned mass damper of Emirate tower](https://test.theconstructor.org/wp-content/uploads/2016/08/Tuned-mass-damper-of-Emirate-tower-254x450.jpg)
Fig. 8: Tuned mass damper of Emirate tower