Shape Memory Alloys

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  • Topic: Transducer, Magnetic field, Smart materials
  • Pages : 2 (275 words )
  • Download(s) : 98
  • Published : January 27, 2013
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SMART MATERIALS

Smart or intelligent materials form a group of new and state-of-the art materials now being developed that will have a significant influence on many of our technologies. The adjective “smart” implies that these materials are able to sense changes in their environments and then respond to these changes in predetermined manners—traits that are also found in living organisms.

The field of smart materials attempts to combine the

Sensor: that detects an input signal

Actuator: that performs a responsive and adaptive function and the

Control circuit: on as one integrated unit

Actuators may be called upon to change shape, position, natural frequency, or mechanical characteristics in response to changes in temperature, electric fields, and/or magnetic fields.

Usually, four types of materials are commonly used for actuators:

* shape memory alloys,
* piezoelectric ceramics,
* magnetostrictive materials,
* and electrorheological/magnetorheological fluids.

Shape memory alloys are metals that, after having been deformed, revert back to their original shapes when temperature is changed.

Piezoelectric ceramics expand and contract in response to an applied electric field (or voltage); conversely, these materials also generate an electric field when their dimensions are altered.

Magnetostrictive materials: the behaviour of magnetostrictive materials is analogous to that of the piezoelectric ceramic materials, except that they are responsive to magnetic fields.

Electrorheological and magnetorheological fluids are liquids that experience dramatic changes in viscosity upon the application of electric and magnetic fields, respectively.

The combined system of sensor, actuator and control circuit on as one IC unit, emulates a biological system.

Brain
Muscles
Actuators & motors
Control & computation
Sensors
Nerves & memory
`...
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