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BY K.V.RAMANA 2/4CIVIL

Smart Materials

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Page 1: Smart Materials

BY

K.V.RAMANA

2/4CIVIL

Page 2: Smart Materials

DEFINITION:-

. Some materials have the ability to change shape or size simply by adding a little bit of heat, or to change from a liquid to a solid almost instantly when near a magnet; these materials are called smart materials.

•Smart materials have one or more properties that can be dramatically altered.

EX:-if oil is heated it will become a little thinner, whereas a smart material with variable viscosity may turn from a fluid which flows easily to a solid

Page 3: Smart Materials

TYPES OF MATERIALS:-

1.piezoelectric materials

2. magneto-rheostatic materials

3.electro-rheostatic materials

4. shape memory alloys

Page 4: Smart Materials

Piezoelectric Materials :-

•Piezoelectric materials have two unique properties which are interrelated.

•When a piezoelectric material is deformed, it gives off a small but measurable electrical discharge.

•When a piezoelectric material is deformed, it gives off a small but measurable electrical discharge. (up to 4% change in volume)

•Piezoelectric materials are most widely used as sensors in different environments.

Page 5: Smart Materials

•The material senses the force of an impact on the car and sends and electric charge deploying the airbag.

Page 6: Smart Materials

Electro-rheostatic and Magneto-rheostatic :-

•Electro-rheostatic (ER) and magneto-rheostatic (MR) materials are fluids, which can experience a dramatic change in their viscosity.

•MR fluids experience a viscosity change when exposed to a magnetic field, while ER fluids experience similar changes in an electric field

•The most common form of MR fluid consists of tiny iron particles suspended in oil

•while ER fluids can be as simple as milk chocolate or cornstarch and oil.

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•The MR fluid is liquid as shown on the left, when no magenetic field is present, but turns solid immediately after being placed in a magnetic field on the right

•MR fluids are being developed for use in car shocks, damping washing machine vibration

•ER fluids have mainly been developed for use in clutches and valves

Page 8: Smart Materials

APPLICATIONS:-

•They could be used in the monitoring of civil engineering structures to assess durability

•used to safety monitor the structure beyond its original design life .

• ‘Sensual’ materials and structures also have a wide range of potential domestic applications, as in food packaging for monitoring safe storage and cooking.

•Smart materials and structures offer the possibility of structures which not only sense but also adapt to their environment.

Page 9: Smart Materials

ORGANISATION

• Introduction

• Types of Smart Materials

• Color Changing Materials

• Light Emitting Materials

• Moving Materials

• Conclusion

Page 10: Smart Materials

INTRODUCTION

• "Smart" materials respond to environmental stimuli with particular changes in some variables. For that reason they are often also called responsive materials.

Depending on changes in some external conditions, "smart" materials change either their properties (mechanical, electrical, appearance), their structure or composition, or their functions.

Mostly, "smart" materials are embedded in systems whose inherent properties can be favorably changed to meet performance needs.

Page 11: Smart Materials

TYPES OF SMART MATERIALS

• COLOUR CHANGING MATERIALS

• LIGHT EMITTING MATERIALS

• MOVING MATERIALS

Page 12: Smart Materials

COLOUR CHANGING MATERIALS

• PHOTO CHROMIC MATERIALS

• THERMO CHROMIC MATERIALS

Page 13: Smart Materials

PHOTO CHROMIC MATERIALS• Photochromic materials change

reversibly colour with changes in light intensity.

Usually, they are colorless in a dark place, and when sunlight or ultraviolet radiation is applied molecular structure of the material changes and it exhibits colour. When the relevant light source is removed the colour disappears.

Changes from one colour to another colour are possible mixing photo chromic colors with base colors. They are used in paints, inks, and mixed to mould or casting materials for different applications.

Page 14: Smart Materials

THERMO CHROMIC MATERIALS

• Thermo chromic materials change reversibly colour with changes in temperature.

They can be made as semi-conductor compounds, from liquid crystals or using metal compounds. The change in colour happens at a determined temperature, which can be varied doping the material.

They are used to make paints, inks or are mixed to moulding or casting materials for different applications

Page 15: Smart Materials

LIGHT EMITTING MATERIALS

• ELELCTROLUMINESCENT MATERIALS

• FLUORESCENT MATERIALS

• PHOSPHORESCENT MATERIALS

Page 16: Smart Materials

ELECTROLUMINESCENT MATERIALS

• Electroluminescent materials produce a brilliant light of different colors when stimulated electronically (e.g. by AC current). While emitting light no heat is produced.

Like a capacitor the materials is made from an insulating substance with electrodes on each side. One of the electrodes is transparent and allows the light to pass. The insulating substance that emits the light can be made of zinc sulphide or a combination

They can be used for making light stripes for decorating buildings, or for industrial and public vehicles safety precautions

Page 17: Smart Materials

FLOURESCENT MATERIALS

• Fluorescent materials produce visible or invisible light as a result of incident light of a shorter wavelength (i.e. X-rays, UV-rays, etc.). The effect ceases as soon as the source of excitement is removed.

Fluorescent pigments in daylight have a white or light colour, whereas under excitation by UV radiation they irradiate an intensive fluorescent colour.

They can be used for paints, inks or mixed to moulding or casting materials for different applications.

Page 18: Smart Materials

PHOSPHORESCENT MATERIALS• Phosphorescent or afterglow

materials produce visible or invisible light as a result of incident light of a shorter wavelength (i.e. X-rays, UV-rays, etc.), detectable only after the source of the excitement has been removed.

Afterglow effect pigments are polycrystalline inorganic zinc sulphide (green afterglow) or alkaline earth sulphides (red or blue afterglow), and can be used in paints, inks or mixed to moulding or casting materials for different applications.

Page 19: Smart Materials

MOVING MATERIALS

• CONDUCTING POLYMERS

• DIELECTRIC ELASTOMERS

• PIEZOELECTRIC MATERIALS

• POLYMER GELLS

• SHAPE MEMORY ALLOYS(SMA)

Page 20: Smart Materials

CONDUCTING POLYMERS• Conducting polymers are conjugated

polymers, namely organic compounds that have an extended p-orbital system, through which electrons can move from one end of the polymer to the other. The most common are polyaniline (PAni) and polypyrrole (PPY).

Polipyrrole has been used for the development of micro muscles. Polyaniline films sandwiched around a ion-conducting film are considered as material for artificial muscles for robots.

A current flow reduces one side and oxidizes the other. Ions are transferred. One side expands and the other contracts, resulting in a bending of the sandwich. Electrical and chemical energies are so transformed in mechanical energy.

Page 21: Smart Materials

DIELECTRIC ELASTOMERS• Dielectric elastomers (also called

electrostrictive polymers) exhibit a mechanical strain when subjected to an electric field. Their striction capability is much higher than that of piezoceramics (10-30% vs. 0.1-0.3%).

The most common are PMMA-based electrostrictive polymers. Thanks to their electrostrictive strain, they can be sandwiched between two electrodes to emulate the operation of muscles.

In an electric field, the elastomer expands in the plane of the electrodes, amplifying the normal compression due to the electrostatic charges on the electrodes. The result is a muscle with large strain capability, and a large actuation pressures.

Page 22: Smart Materials

PIEZOELECTRIC MATERIALS• They produce an electric field when

exposed to a change in dimension caused by an imposed mechanical force (piezoelectric or generator effect). Conversely, an applied electric field will produce a mechanical stress (electrostrictive or motor effect).

They transform energy from mechanical to electrical and vice-versa. The stress is very small, 0.1-0.3%. They are used for sensing purposes (e.g. microphone, transducer), and for actuating applications.

Similar to piezoelectric materials are electrostrictive and magnetostrictive materials used in high precision actuation. They are ferromagnetic materials which experience an elastic strain when subjected to an electric or magnetic field respectively.

Page 23: Smart Materials

POLYMER GELLS• Polymer gels consist of a cross-linked

polymer network inflated with a solvent such as water. They have the ability to reversibly swell or shrink (up to 1000 times in volume) due to small changes in their environment (pH, temperature, electric field).

Micro sized gel fibers contract in milliseconds, while thick polymers layers require minutes to react (up to 2 hours or even days). They have high strength and can deliver sizeable stress (approximately equal to that of human muscles).

The most common are polyvinyl alcohol (PVA), polyacrylicacid (PAA) and polyacrylonitrile (PAN). Many potential applications (e.g. artificial muscles, robot actuators, adsorbers of toxic chemicals), but presently, few of them have a commercial diffusion.

Page 24: Smart Materials

SHAPE MEMORY ALLOYS(SMA)

• Shape-Memory Alloys are metals that, after being strained, at a certain temperature revert back to their original shape. A change in their crystal structure above their transformation temperature causes them to return to their original shape.

SMA’s enable large forces (generated when encountering any resistance during their transformation) and large movements actuation, as they can recover large strains.

Page 25: Smart Materials

CONCLUSIONS

"Smart" materials respond to environmental stimuli with particular "Smart" materials respond to environmental stimuli with particular changes in some variables.changes in some variables.

Depending on changes in some external conditions, "smart" Depending on changes in some external conditions, "smart" materials change either their properties (mechanical, electrical, materials change either their properties (mechanical, electrical, appearance), their structure or composition, or their functionsappearance), their structure or composition, or their functions

Different types of Smart materials, like, Colour changing materials, Different types of Smart materials, like, Colour changing materials, Light emitting materials and Moving materials are available that are Light emitting materials and Moving materials are available that are used paints, inks, and mixed to mould or casting materials for used paints, inks, and mixed to mould or casting materials for different applications, making light stripes for decorating buildings, or different applications, making light stripes for decorating buildings, or for industrial and public vehicles safety precautions, for industrial and public vehicles safety precautions,

Page 26: Smart Materials

ANY QUERIES?

Page 27: Smart Materials

THANK YOU

Page 28: Smart Materials

A SEMINAR

ON

SMART MATERIALSBy

Divya lalitha Majji¾ CIVIL ENGINEERING

BAPATLA ENGINEERING COLLEGE

Page 29: Smart Materials

THANK YOU

Page 30: Smart Materials

QUERIES?