tuned mass dampers

1. ANNASAHEB DANGE COLLEGE OF ENGINEERING AND
TECHNOLOGY , ASHTA .
Name : Yadav Prasanna Sanjay
Roll No : 440
Urn NO: 18151041
Tuned mass dampers

2. TUNED MASS DAMPERS
 A Tuned Mass Damper (TMD), also known as a harmonic absorber or seismic
damper.
 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 very much less than it.
 TMDs can prevent discomfort, damage, or outright structural failure. They are
frequently used in power transmission, automobiles and buildings.

3. TYPES OF TMD
Based On Control Mechanism
 Active Mass Damper
An active control system is one in which an external power sources the control
actuators are used to that apply forces to the structure in a prescribed manners .
These forces can be used to dissipates energy from the structure
 Passive Mass Damper
A passive control system does not require an external power source. Passive control
devices impart forces that are developed in resonpance to the motion of the
structure.

4. 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.
 Mass dampers are frequently implemented with a frictional or hydraulic
component that turns mechanical kinetic energy into heat, like an
automotive shock absorber.

5. motor with mass m1 attached via motor mounts to the ground,
the motor vibrates as it operates and the soft motor mounts act
as a parallel spring and damper, k1 and c1. The force on the motor
mounts is F0. In order to reduce the maximum force on the motor
mounts as the motor operates over a range of speeds, a smaller
mass, m2, is connected to m1 by a spring and a
damper, k2 and c2. F1 is the effective force on the motor due to its
operation.

6. WHY TO USE TMD
 To reduce the action of earthquake in seismic areas.
 To provide mitigation against wind forces

7. IMPLEMENTATIONS
Tuned mass dampers are mainly used in following applications
 Tall and slender free standing structures (skyscrapers , bridges , TV towers )
 Bridges and pedestrian bridges

8. TMD FOR SKYSCRAPERS
Largest Tuned Damper in the world 730 tons and 5.5 m diameter

10. ADVANTAGES AND DISADVANTAGES
Advantages
 They do not depend on an external power source for their operation.
 They can respond to small level of excitation .
 Their properties can be adjusted I the field.
 They can also be introduced un upgrading structure
 They requires low maintenance
 They can be cost effective
Disadvantages
 A large mass or a large space I needed for their installation.
 The effectiveness of a tuned mass damper is constrained by the maximum weight
that can be practically placed on top of structure

11. THANK YOU!