Tuned Mass Damper

The appearance of a Tuned Mass Damper

What is a tuned mass damper?

A tuned mass damper(TMD), also known as a harmonic absorber, is a device mounted in structures to reduce the amplitude of mechanical vibrations. Their application can prevent discomfort, damage, or outright structural failure. They are frequently used in power transmission, automobiles, and buildings. The tuned mass damper is  most effective where the structure's motion is caused by one or more resonant modes of the original structure. In essence, the TMD extracts vibration energy (i.e., adds damping) to the structural mode it is "tuned" to. The end result: the structure feels much more stiff than it actually is.

The structure of Tuned Mass Damper

How does a tuned mass damper work?

A TMD is a combine of three important systems: mass system, stiffness system, and energy dissipation (damping) system, so there are three forms of tuning required in the design of a TMD. The stiffness and mass of the TMD are selected to provide a TMD resonance frequency very close to the structure's resonance frequency. The TMD damping level is selected to optimize the energy dissipation over the effective bandwidth of the TMD. The TMD mass is selected to provide the desired level of vibration mitigation. And when the vibration comes to the structure, the TMD will create a opposite force with similar frequency of the vibration. That will help to reduce and control the vibration effectively.

Where a tuned mass damper applicable for?

The tuned mass damper is suitable for the longspan and vimineous buildings and structures which are easy to be stimulated by external factor(such as wind, people’s walking). It can effectively reduce the vibration stimulated by external factors. The TMDs are widely used in followed application fields.

1, Bridges, pyller of bridges, chimney, tv tower and other tall and vimineous buildings which will be easy stimulated by wind.

2, Ladder, auditorium, passenger foot-bridge and other devices which will be stimulated by people’s walking and jumping.

3, Industry plant and other steel structural buildings and facilities which are easy to be stimulated by inherent frequency of machines.

The TMD used in the passenger foot-bridge

The TMD under testing of walking & jumping in the airport