Structures such as buildings, bridges, industrial structures, equipment,
machinery or other subsystems such as piping are often subjected to severe
vibration motions due to earthquakes, heavy wind or machinery. It is necessary
to reduce the vibrations that are experienced by the structures for safety,
serviceability, or for operation considerations. One strategy for enhancing
safety of such structures is to use vibration isolators.
Prof. Ravi Sinha and his student of Department of Civil Engineering
have patented two types of pendulum isolators (constant and variable period
A constant long period vibration-protective pendulum isolator for
structures has constant fundamental periods of 0.3 to 10 seconds, dissipates
energy through friction and transmits reduced energy into the structure.
system can also be used as a constant long period tuned mass damper. The
designed isolator is illustrated below:
The second type is a variable period protective pendulum isolator for structures
having fundamental time periods
from 0.2 s to 6.0 seconds, which dissipates
energy through friction at sliding surface and transmits reduced energy
into the structure. The variable period
vibration protective pendulum isolator has its time periods varying in
a pre-determined way as the sliding takes place,
which limits the restoring force so that the force transmitted to the structure
is bounded irrespective of magnitude of
sliding displacement of the isolator or the size of the earthquake.
The growing need to counter strong vibrations of large structures
as a protective measure makes these technologies useful
and important. Such applications are typically observed in important
life-safety buildings such as hospitals and communications
facilities, and in facilities such as bridges and pipelines. The application
of these protective measures also
exists for safety of important objects such as displays in museums.
Indian patent application no. 15/MUM/2001 Patent grant no. 197756
Indian patent application no. 867/MUM/2001 Patent grant no. 197850
Inventors: R Sinha and M Pranesh