This document discusses smart structures and how they incorporate sensors and actuators to respond intelligently to external stimuli. A smart structure has five key components: data acquisition, data transmission, a command and control unit, data instructions, and action devices. Magneto-rheological fluid dampers are described as a type of semi-active damping system that can efficiently control vibrations in buildings during earthquakes by changing viscosity when a magnetic field is applied. The document outlines how MR fluid dampers work and the advantages smart structures provide for earthquake-resistant construction.

1. SMART STRCTURES

2. DEFINITION
 A "Smart Material" refers to a material that has one or
more property that can be altered through the application
of an external stimulus.
 A "Smart Structure” is a system that incorporates
particular functions of sensing and actuation to perform
smart actions in an ingenious way.
 Five components of a smart structure
 Data Acquisition
 Data Transmission
 Command and Control Unit
 Data Instructions

3. Data Acquisition
The aim of this
components is to
collect the required
raw data needed for an
appropriate sensing
and monitoring of the
structure
Data Transmission
The purpose of this
part is to forwarded
the raw data to the
local and/or central
command and control
units.

4. Command and Control Unit
 The role of this unit is to manage and
control the whole system by analyzing the
data, reaching the appropriate conclusion,
and determining the actions required

5. Data Instructions
The function of this part
is to transmit the
decisions and the
associated instruction
back to the members of
the structure
Action Devices
The purpose of this
part is to take actions
by triggering the
controlling
devices/units

6. SMART STRUCTURES
CONTROL
ACTUATIORSENSOR
DATA
INSTRUCTIONS
DATA
TRANSMISSION

7. BUILDINGS AND BRIDGES
 Skyscrapers and long bridges are subject to
resonance created by high winds and seismic
activity
 In order to mitigate the resonance effect, it is
important to build large dampers into their design
to interrupt the resonant waves
 If these devices are not in place, buildings and
bridges can be shaken to the ground

8. DAMPERS
 Dampers are used in machines that you likely use
every day, including car, bike suspension systems
 If you take a look the How suspension systems work,
you'll learn that damping systems use friction to
absorb some of the force from vibrations
 A damping system in a building is much larger and is
also designed to absorb the violent shocks of an
earthquake
 The size of the dampers depends on the size of the
building

9. DAMPENING SYSTEMS
 Passive
 Requires no input power to operate
 They are simple and generally low in cost
 They are uncontrollable
 Active
 Require a great deal of power
 They are fully controllable

10.  Semi-Active
 Combines features of passive and active damping.
 They are fully controllable yet require little input
power
 Magneto-Rheological fluid (MR fluid) dampers are
semi-active devices
 That can change their damping level by varying the
amount of current supplied to an internal
electromagnet that controls the flow of MR fluid.

12.  Inside the MR fluid damper, an electromagnetic
coil is wrapped around three sections of
the piston.
 Approximately 5 liters of MR fluid is used to fill
the damper's main chamber.
 During an earthquake, sensors attached to the
building will signal the computer to supply the
dampers with an electrical charge.
 This electrical charge then magnetizes the coil,
turning the MR fluid from a liquid to a near-solid.
 Now, the electromagnet will likely pulse as the
vibrations ripple through the building.

13.  This vibration will cause the MR fluid to change
from liquid to solid thousands of times per second,
and may cause the temperature of the fluid to
rise.
 A thermal expansion accumulator is fixed to the
top of the damper housing to allow for the
expansion of the fluid as it heats up.
 This accumulator prevents a dangerous rise in
pressure as the fluid expands.

14. BUILDINGS EQUIPPED WITH MR FLUID
DAMPERS WILL MITIGATE VIBRATIONS DURING
AN EARTHQUAKE

15.  Depending on the size of the building, there could be
an array of possibly hundreds of dampers.
 Each damper would sit on the floor and be attached to
the chevron braces that are welded into a steel cross
beam.
 As the building begins to shake, the dampers would
move back and forward to compensate for the
vibration of the shock.
 When it's magnetized, the MR fluid increases the
amount of force received in dampers

16. WHAT IS MR FLUID
 MR fluid doesn't seem like such a revolutionary
substance.
 It's a gray, oily liquid that's about three times denser
than water.
 It's not too exciting at first glance, but MR fluid is
actually quite amazing to watch in action.

17. MR Fluid Composition
 Carbonyl Iron Particles -20 to 40 percent of the fluid is
made of these soft iron particles that are just 3 to 5
micrometers in diameter. A package of dry carbonyl
iron particles looks like black flour because the
particles are so fine.
 A Carrier Liquid -The iron particles are suspended in a
liquid, usually hydrocarbon oil. Water is often used in
demonstrating the fluid.
 Proprietary Additives -The third component of MR
fluid is a secret, but Lord says these additives are put
in to inhibit gravitational settling of the iron particles,
promote particle suspension, enhance lubricity,
modify viscosity and inhibit wear.

18.  MR FLUID
AFTER MAGNETIZED 

19. Principle
of a MRF

20. ADVANTAGES
 This structure cut downs a lot of material cost
incurred in using under reamed pile and factor
of safety.
 India has 25% of area prone to earth quake.
This smart technology will help in saving a lot of
men and material.
 The health monitoring of structures will help in
forecasting failure and will provide time for
rehabitation.

21.  35% of deccan pleateau has black cotton soil,
the use of this technology can ensure safe and
economical construction over there.
 As the structure is constantly maintained the
service life increases and the need for repair
decreases.

22. RELATED PROJECT
 Mitigation of wind-rain-induced cable vibration
in cable-stayed bridges using adjustable fluid
dampers
 Control of wind-rain-induced cable vibration of
Dongting Lake Bridge using magneto-
rheological dampers
 Semi-active tuned liquid column dampers
using magneto rheological fluids for vibration
control of tall buildings

23. Wind-rain-induced vibration control of
stay cables in the Dongting Lake Bridge

24. THANK YOU