IIT Kharagpur

1

SMART SYSTEMSSMART MATERIALS & SMART STRUCTURES

JISHI P P14AE60R01

IIT Kharagpur

2

Content Smart Systems Classification of Smart materials Smart Composites Smart Structures and components Examples Importance for smart structures Applications Reference

IIT Kharagpur

3Smart Systems Smart systems consist of sensors and actuators that are either embedded in

or attached to the system containing central control and command unit to

form an integral part of it.

Smart or intelligent materials are materials that have the intrinsic and

extrinsic capabilities, first, to respond to stimuli and environmental changes

and, second, to activate their functions according to these changes. Stimulus —stress, strain, light, electric field, temperature and pressure, etc. Response —motion or change in optical properties, modulus, surface tension,

piezoelectricity etc.

IIT Kharagpur

4Classification of Smart Materials: Actively Smart

They posses the capacity to modify their geometric or material

properties under the application of electric, thermal or magnetic

fields, thereby acquiring an inherent capacity to transduce energy. Piezoelectric

Magnetostrictive

Shape memory alloys

Electro-Rheological fluid, etc.

They can be used as force transducers and actuators.

IIT Kharagpur

5

Passively Smart

Those smart materials that are not active are called passively smart

materials. Although smart, they lack the inherent capability to

transduce energy.

Optic fibres

These materials can act as sensors but not as actuators or transducers.

IIT Kharagpur

6

Fig: Common smart materials and associated stimulus response

IIT Kharagpur

7

Smart Composites

Combining two or more single smart materials to utilize the

best properties of their individual constituents is the objective of

any new smart composites.

IIT Kharagpur

8

IIT Kharagpur

9

Smart Structures A smart structure is a system that incorporates particular functions of

sensing and actuation to perform smart actions in an ingenious way.

The basic five components of a smart structure are

Data Acquisition (tactile sensing): the aim of this component is to collect the

required raw data needed for an appropriate sensing and monitoring of the

structure.

Data Transmission (sensory nerves): the purpose of this part is to forward the

raw data to the local and/or central command and control units.

IIT Kharagpur

10

Command and Control Unit (brain): 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.

Data Instructions (motor nerves): the function of this part is to transmit the

decisions and the associated instructions back to the members of the structure.

Action Devices (muscles): the purpose of this part is to take action by

triggering the controlling devices/ units.

IIT Kharagpur

11

Data Acquisition The sensing components of a smart structure are designed according to the

nature of the event to be sensed — radiation, magnetic, thermal, mechanical

or chemical — as well as according to the nature of the output required, such

as thermal, magnetic, electrical, optical or mechanical.

Example: Fibre optic sensing

They respond to a change in transmitted light. This change could

be in intensity, phase, frequency, polarization, wavelength or mode.

IIT Kharagpur

12

IIT Kharagpur

13

Command and Control Unit The command and control unit is the manager of day-to-day operations,

responsible for monitoring the health and integrity of the system by

means of a communication network which works in real time.

This is the brain of the smart structure and has two basic and distinct

functions

The Processing Function

The Analysis Function

IIT Kharagpur

14Actuating Units The actuating components are designed according to the nature of the

required actuation — optical, magnetic, thermal, mechanical or chemical

— as well as according to the nature of the driving energy, such as

thermal, magnetic, electrical or chemical.

Displacement and velocity control - LVDT and LVIT, accelerometers and

pneumatic/hydraulic actuators

Noise control application-microphone and loud speaker

IIT Kharagpur

15

IIT Kharagpur

16ExamplesSmart aircraft wing

IIT Kharagpur

17

Some possible locations where aircraft can become SMART

IIT Kharagpur

18

Noise reduction in vehicles : filaments of piezoelectric ceramic

fibres are used to counter noise in vehicles, neutralize shaking

in helicopter rotor blades, or nullify or at least diminish

vibrations in air conditioner fans and auto- mobile dashboards.

IIT Kharagpur

19

• Vibration reduction in sporting goods : a new generation of tennis

rackets, golf clubs, baseball bats and ski boards have been

introduced to reduce the vibration in these sporting goods,

increasing the user’s comfort and reducing injuries.

• Smart Skin or clothes

• Stealth applications

IIT Kharagpur

20

IIT Kharagpur

21

Importance for Smart Structures

Light weight Warnings on problems that can encounterPreventative maintenance Performance optimization Improved life cycle

IIT Kharagpur

22

Smart Structure Applications Aerospace

Damage detection Vibration control Shape control Adaptive structures

Defence Firing accuracy of weapons Vibration and noise reduction in submarines Smart missiles use smart fins which can warp to appropriate shapes

IIT Kharagpur

23

Automotive Passenger comfort (noise control in cabin) Vibration control (active engine mounts) Health monitoring (smart sensors)

Industrial Manufacturing (machine tool chatter control) Air conditioning and ventilation (noise control) Mining machinery (vibration control)

Medical Smart sensors Micro robotics Surgical tools

Civil Bridges Earthquake protection

IIT Kharagpur

24ReferencesCulshaw, B., Smart Structures and Materials, Artech House Inc,

1996 Bank, H. T., Smith, R.C. and Wang, Y., Smart Material Structures,

Modelling, Estimating and Control, John Wiley and Sons, 1996. Akhras, G., “Advanced Composites for Smart Structures”,

Proceedings, ICCM-12, 12th International Conference on Composite Materials, Paris, July 5-9, 1999.

See Akhras, G., “Smart Structures and their Applications in Civil Engineering”, Civil Engineering Report, CE97-2, RMC, Kingston, Ontario, Canada, 1997.

IIT Kharagpur

25

THANK YOU