05.Smart Structure

8/13/2019 05.Smart Structure

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R.MANOJ KUMAR

10 CMR 005

SMART STRCTURES


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Data

Acquisition

Data

Transmission

The aim of thiscomponents is to

collect the requiredraw data neededfor an appropriatesensing andmonitoring of the

structure

The purpose of

this part is to

forwarded the raw

data to the local

and/or central

command and

control units.


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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 actionsrequired


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Data

Instructions Action Devices

The function of this

part is to transmit the

decisions and the

associated instruction

back to the members

of the structure

The purpose of this

part is to take

actions by triggeringcontrolling

devices/units


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Smart Structures

CONTROL

ACTUATIORSENSOR

DATA

INSTRUCTIONS

DATA

TRANSMISSION


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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 theirdesign to interrupt the resonant waves

If these devices are not in place, buildings and

bridges can be shaken to the ground


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Dampers

Dampers are used in machines that you

likely use every day, including car, bike

suspension systems

If you take a look the How suspensionsystems work, you'll learn that damping

systems use friction to absorb some of the

force from vibrations

A damping system in a building is muchlarger and is also designed to absorb the

violent shocks of an earthquake

The size of the dampers depends on the

size of the building


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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


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Semi-Active Combines features of passive and active

damping.

They are fully controllable yet require little input

power

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.


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A full-scale

MR fluid

damperthat is 1-

meter long

and weighs

250

kilograms.This one

damper

can exert

20 tons of

force on abuilding


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Inside the MR fluid damper, an electromagnetic

coil is wrapped around three sections ofthe piston.

Approximately 5 liters of MR fluid is used to fillthe damper's main chamber.

During an earthquake, sensors attached to the

building will signal the computer to supply thedampers 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.


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This vibration will cause the MR fluid to change

from liquid to solid thousands of times persecond, 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.


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Buildings equipped with MR fluid

dampers will mitigate vibrations during

an earthquake


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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 that the dampers


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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.


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MR Fluid Composition

Carbonyl Iron Particles -20 to 40 percentof the fluid is made of these soft ironparticles that are just 3 to 5 micrometers in

diameter. A package of dry carbonyl ironparticles looks like black flour because theparticles are so fine.

A Carrier Liquid -The iron particles aresuspended in a liquid, usually hydrocarbonoil. Water is often used in demonstratingthe fluid.


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MR FLUID

AFTER MAGNETIZED


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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 alot of men and material.

The health monitoring of structures will help

in forecasting failure and will provide time for

rehabitation.


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35% of deccan pleateau has black cottonsoil, the use of this technology can ensure

safe and economical construction over

there.

As the structure is constantly maintained theservice life increases and the need for repair

decreases.


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Related Project

Mitigation of wind-rain-induced cable

vibration in cable-stayed bridges using

adjustable fluid dampers

Control of wind-rain-induced cable vibrationof Dongting Lake Bridge using magneto-

rheological dampers

Semi-active tuned liquid column dampers

using magneto rheological fluids forvibration control of tall buildings


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Wind-rain-induced vibration control of

stay cables in the Dongting Lake Bridge


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THANK YOU

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05.Smart Structure