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SMART MATERIALS SMART MATERIALS AND AND
STRUCTURES STRUCTURES
Presented by:Presented by:
SNEHAL PRASOONSNEHAL PRASOON
CONTENTSCONTENTS Introduction Introduction Smart MaterialsSmart Materials New Material RequirementsNew Material Requirements Classification Of Smart Materials Classification Of Smart Materials Properties Of Shape Memory AlloysProperties Of Shape Memory Alloys Smart StructureSmart Structure Components of Smart structureComponents of Smart structure Sensors and ActuatorsSensors and Actuators Structural Uses of SMA’SStructural Uses of SMA’S Case Study Case Study Conclusion Conclusion ReferencesReferences
INTRODUCTIONINTRODUCTION
Smart materials and structures technology represents an Smart materials and structures technology represents an
emerging field of study that is finding many applications emerging field of study that is finding many applications
in support of civil infrastructure systems.in support of civil infrastructure systems.
The potential benefit of this technology may be improved The potential benefit of this technology may be improved
system reliability, longevity enhanced system performance, system reliability, longevity enhanced system performance,
improved safety against natural hazards and vibrations, and a improved safety against natural hazards and vibrations, and a
reduction in life cycle costs in operating and managing civil reduction in life cycle costs in operating and managing civil
infrastructure systems. infrastructure systems.
SMARTSMART MATERIALSMATERIALS
Smart materials are materials that have the intrinsic and extrinsic capabilities , firstly to respond to stimuli and environmental changes and secondly to activate their functions according to these changes.
Depending on changes in some external conditions, "smart" materials change either their properties (mechanical, electrical, appearance), their structure or composition, or their functions.
REQUIREMENTSREQUIREMENTS
Technical properties Technological properties Economic criteria Environmental characteristics Sustainable development criteria, implying
reuse and recycling capacities.
CLASSIFICATION OF SMART MATERIALSCLASSIFICATION OF SMART MATERIALS
Actuator materials Piezoelectric Electrostrictive Magnetostrictive Shape Memory Alloys
The Sensors Optical fibers
PROPERTIES OF SMA’SPROPERTIES OF SMA’S
Repeated absorption of large amount of strain energy.
Usable strain range of 70%. Extraordinary fatigue resistance under large
strain cycle Their great durability and reliability in the
long run
SHAPE MEMORY ALLOYSSHAPE MEMORY ALLOYS
SHAPE MEMORY ALLOYSSHAPE MEMORY ALLOYS
SHAPE MEMORY ALLOYSSHAPE MEMORY ALLOYS
COMPONENTS OF A SMART STRUCTURESCOMPONENTS OF A SMART STRUCTURES
DATA ACQUISITION Collection of raw data required for appropriate sensing and monitoring of the structure.
DATA TRANSMISSION Forwards raw data to the local/central command and control units.
COMMAND AND CONTROL PROCESS Controls the whole systems by analyzing the
data , deriving the appropriate conclusion and determining the actions required .
DATA INSTRUCTIONS Transmits the decision and associated
instructions back to the member of the structure. ACTION DEVICE It takes the action by triggering the control
devices
Control systemControl system• monitors the sensor’s signalmonitors the sensor’s signal• processing the information in order to determine processing the information in order to determine
action required.action required.• If an action is required, then a signal is applied to the If an action is required, then a signal is applied to the
appropriate actuator.appropriate actuator.
SensorSensor• To monitor environmental changes To monitor environmental changes • and generate signals proportional to the changing and generate signals proportional to the changing
measured.measured.
ActuatorActuator• used to change the properties of the smart structure in used to change the properties of the smart structure in
order to achieve the desired responseorder to achieve the desired response
Sensors and ActuatorsSensors and Actuators
Mechanical Energy
Electrical Energy
Sensor Actuator
DisplacementVelocityAccelerationForcePressureTemperature
Current VoltageCapacitanceResistanceInductance
Sensors attached to columnsSensors attached to columns
Sensors attached to Deck slabsSensors attached to Deck slabs
Sensors attached to Deck slabsSensors attached to Deck slabs
Structural uses of SMA’sStructural uses of SMA’s
Active control of structures
Passive control of structures
Smart material tag
Retrofitting
Self healing
Structural health monitoring
Active control of structuresActive control of structures The structure adapts its dynamic characteristics
to meet the performance objectives at any instance
Test Setup of the Cantilevered Beam with SMA Wire Test Setup of the Cantilevered Beam with SMA Wire ActuatorActuator
Passive control of structuresPassive control of structures Special braces for framed structures
Isolation devices for buildings and bridges
Smart Material TagSmart Material Tag Used in composite structures
Can be monitored externally throughout the life of the structure
The internal material conditions like moisture, voids, cracks may be interpreted via sensing.
RetrofittingRetrofitting SMAs can be used as self stressing fibers and thus they can be
applied for retrofitting
Self-stressing fibers are the ones in which the reinforcement is placed into the composite in non stressed state
Prestressing force is introduced into the system by providing SMAs
Treatment can be applied at any time after hardening of the matrix instead of during its curing and hardening
Self-healing
The deformation beyond the first crack can be fully recovered and cracks can be fully closed.
Structural Health Monitoring
Use of piezo transducers, surface bonded to the structure or embedded in the walls of the structure can be used for structural health monitoring and local damage detection.
APPLICATION OF SMART MATERIALS
CARBON FIBER REINFORCED CONCRETE Its ability to conduct electricity and most
importantly, capacity to change its conductivity with mechanical stress makes a promising material for smart structure.
The high density coupled with choice of fibers ranging from stainless steel to carbon applied under high pressure gives the product with outstanding qualities.
SMART CONCRETE
A mere addition of 0.5% of specially treated carbon fibers enables the increase of electrical conductivity of concrete.
Addition of load reduces the conductivity of the concrete, on removing of load concrete regains its original conductivity.
Functions as a traffic sensing recorder when used as road pavement .
Used to lay smart highways to guide self steering cars which at present follow tracks of buried magnets.
Smart building materials remove Smart building materials remove pollutantspollutants
These are special construction materials and These are special construction materials and coatings containing titanium dioxide (TiO2) coatings containing titanium dioxide (TiO2)
They can “capture” organic and inorganic air They can “capture” organic and inorganic air pollutants after they have been exposed to pollutants after they have been exposed to ultra-violet and/or sun rays. ultra-violet and/or sun rays.
The degraded polluting substances can then be The degraded polluting substances can then be washed away by rainwater.washed away by rainwater.
Sensor Networking
Structure
Satellite
Telephone
RadioCellular
Fiber Optic
Communications
IP
Users
A Schematic view of a Smart BridgeA Schematic view of a Smart Bridge
Sensors atop flagpole measure movement, Dupont court
Sensor box mounted on flag pole
Rion Antirion Bridge, Greece
Rion Antirion Bridge, Greece
CONCLUSION
The technologies using smart materials are useful for both new
and existing constructions. Of the many emerging
technologies available the few described here need further
research to evolve the design guidelines of systems. Codes,
standards and practices are of crucial importance for the
further development.
With the benefits in sight , smart structures With the benefits in sight , smart structures technology is seeing quick moment into the civil technology is seeing quick moment into the civil engineering field. Civil infrastructures of the future engineering field. Civil infrastructures of the future will be integrated with sensors and control devices will be integrated with sensors and control devices through information networks to enhance their through information networks to enhance their performance at reduced life – cycle cost.performance at reduced life – cycle cost.
From an educational perspective it is desirable to From an educational perspective it is desirable to prepare the present and next generation of civil prepare the present and next generation of civil engineers for the advanced technologies which they engineers for the advanced technologies which they will use in the future.will use in the future.
ReferencesReferences Journal of professional issues in engineering education and practice ASCE / January 2008.Journal of professional issues in engineering education and practice ASCE / January 2008.
N.Krstulovic-Opara and A.E. Naaman, ACI Structural Journal, March – April 2000, pp 335-N.Krstulovic-Opara and A.E. Naaman, ACI Structural Journal, March – April 2000, pp 335-
344344
Web SitesWeb Sites
http://dbtindia.nic.inhttp://dbtindia.nic.in howstuffworks.comhowstuffworks.com rheonetic.comrheonetic.com sensortech.comsensortech.com google.comgoogle.com