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Seismic Dampers – Types, Working Mechanism, and Components

Seismic Dampers- Types, Working Mechanism, and Components

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Damper systems are designed and manufactured to protect structural integrities, control structural damages, and to prevent injuries to the residents by absorbing seismic energy and reducing deformations in the structure.

Seismic dampers permit the structure to resist severe input energy and reduce harmful deflections, forces and accelerations to structures and occupants. There are several types of seismic dampers namely viscous damper, friction damper, yielding damper, magnetic damper, and tuned mass damper.

1. Viscous Dampers

In viscous dampers, seismic energy is absorbed by silicone-based fluid passing between piston-cylinder arrangement. Viscous dampers are used in high-rise buildings in seismic areas. It can operate over an ambient temperature ranging from 40°C to 70°C. Viscous damper reduces the vibrations induced by both strong wind and earthquake.

Fig. 1: Schematic Detailing of Viscous Damper Components

2. Viscoelastic Dampers

Another type of damper is viscoelastic dampers that stretch an elastomer in combination with metal parts. This type of damper dissipates the building's mechanical energy by converting it into heat. Several factors such as ambient temperature and the loading frequency affect the performance and consequently the effectiveness of the damper system.

Fig. 2: Viscoelastic Damper

Viscoelastic dampers have been successfully incorporated in a number of tall buildings as a viable energy dissipating system to suppress wind-and earthquake-induced motion of building structures.

Fig. 3: Installed Viscoelastic Damper

3. Friction Dampers

Generally, a friction damper device consists of several steel plates sliding against each other in opposite directions. The steel plates are separated by shims of friction pad material.

The damper dissipates energy by means of friction between the surfaces which are rubbing against each other. It is also possible to manufacture surfaces from materials other than steel.

Fig. 4: Friction Damper
Fig. 5: Friction Damper Working Mechanism

4. Tuned Mass Damper (TMD)

Tuned Mass Damper (TMD), also known as vibration absorbers or vibration dampers, is a passive control 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.

Fig. 6: Tuned Mass Damper

The application of tuned mass damper can prevent discomfort, damage, or outright structural failure. They are frequently used in power transmission, automobiles and tall buildings.

Fig. 7: Working Mechanism of Tuned Mass Damper

5. Yielding Dampers

Yielding damper or metallic yielding energy dissipation device or passive energy dissipation device is manufactured from easily yielded metal or alloy material.

It dissipates energy through its plastic deformation (yielding of the metallic device) which converts vibratory energy and consequently declines the damage to the primary structural elements. yielding dampers are economical, effective, and proved to be a good energy dissipator.

Fig. 8: Metallic Yielding Damper Installed in Multistory Building
Fig. 9: Working Mechanism of Yielding Damper

6. Magnetic Damper

Magnetic Damper consists of two racks, two pinions, a copper disk and rare-earth magnets. This type of damper is neither expensive nor dependent on temperature. Magnetic damping is not strength that is why it is effective in dynamic vibration absorbers which require less damping.

Fig. 10: Magnetic Damper

Read More: What are the Effects of Earthquake on Structures?
Read More: 10 Construction Mistakes to Avoid in Earthquake-Prone Areas

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