SMART MATERIALS

ContentsWhat are smart materials?

The different types of smart materials

Applications of smart materials

Future of smart materials

INTRODUCTIONSome materials have the ability to change their 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 are materials that have one or more properties that can be significantly altered in a controlled fashion by external stimuli, such as stress, temperature, moisture, pH, electric or magnetic fields.

MAIN ADVANTAGES WITH RESPECT TO TRADITIONAL COMPONENTSThey Posses High DurabilityAct simultaneously as Sensors and ActuatorsHigh Level of MiniaturizationAre Adaptive with the environmental conditionsThey have good AccuracyThey reduce size and weight

TYPES OF SMART MATERIALSFig: Flow chart depicting the types of smart materials

Piezoelectric Materials:Piezoelectricity is the ability of the material to develop an electric charge when subjected to a mechanical strain (direct piezoelectric effect)Conversely develop mechanical strain in response to an applied electric field (indirect piezoelectric effect)They are often used to measure fluid compositions, fluid density, fluid viscosity, or the force of an impactAn example of a piezoelectric material in everyday life is the airbag sensor in the car.

SHAPE MEMORY ALLOYS:Shape memory alloys are materials where deformation can be induced and recovered through temperature changesAt a low temperature, the material is in its martensitic state. When heated, it will regain its original or memory shapeNitinol (Nickel-Titanium alloy) is the most commonly used SMASMA are applied to a wide variety of application such as . Antenna of a Mobile Phone . Aeronautical Applications . Eyeglass Frame . Robotic Muscles

Electro-rheological (ER) and Magnet-rheological(MR): These materials are fluids, which can experience a dramatic change in there viscosity.These fluids can change from a thick fluid to nearly a solid substance within the span of a millisecond when exposed to a magnetic or electric field.MR fluids are being developed for use in car shocks, dampers, prosthetic limbs, exercise equipment, and surface polishing of machine parts.ER fluids have mainly been developed for use in clutches and valves, as well as engine mounts designed to reduce noise and vibration in vehicles.

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

Electrostrictive and Magnetostrictive materials:

This refers to the material quality of changing size in response to either an electric or magnetic field, and conversely, producing a voltage when stretched

These materials show promise in applications such as:

Pumps and ValvesAerospace Wind TunnelLanding Gear HydraulicsAutomotive Fuel InjectorElectro Mechanical Transducer

APPLICATIONS OF SMART MATERIALS

Automotive:Smart Materials are being used in Automatic Light and Heat Control in the Automotive Industry (eg-Rear Windows).

Smart Materials are being used to reduce noise and vibration resulting in enhanced comfort and safety benefits.

Mechatronics:The mechatronics approach is familiar from systems already in existence such as ABS and active ride control in road vehicles and such an approach has already been employed in the vibration control of high rise Japanese buildings.

Examples include dams and aircraft and adaptive structures containing novel piezoceramic, electrostrictive, magnetostrictive and shape memory actuators for real time vibration and shape control.

Aerospace: Today the use of smart materials in the aerospace market is widespread, extending beyond Commercial and military aircraft to military jets, helicopters, space launchers and satellites.

Future Of Smart Materials The potential future benefits of smart materials, structures and systems are amazing in their scope.

This technology gives promise of optimum responses to highly complex problem areas , for example, providing early warning of the problems, thus enhancing the survivability of the system and improving its life cycle.

Moreover, enhancements to many products could provide better control by minimizing distortion and increasing precision.

Another possible benefit is enhanced preventative maintenance of systems and thus better performance of their functions.

GM Hopes New smart Materials to Modernize Car Designs General Motors has demonstrated a new technology, which it hopes to use in the cars in future. The materials such a shape memory alloys and polymers are intended to encourage many promising changeable features in cars.

GM Hopes to see these smart materials in production models by 2014. Some of the features might be buttons and handles that come out only when we need them or some sort of surfaces that pop out to assist aerodynamics.

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