30-05-2013, 12:04 PM
INTRODUCTION TO SMART MATERIALS
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SMART MATERIALS
Sense and react to environmental conditions or stimuli such as those from mechanical, thermal,chemical,electrical,magnetic or other sources
In general, smart materials come in three distinct flavors:
(a) Passively smart materials that respond directly and uniformly to stimuli without any signal processing.
(b)Actively smart materials that can, with the help of a remote controller, sense a signal, analyze it, and then “decide” to respond in a particular way.
©Finally, the more powerful and autonomous intelligent materials that carry internal, fully integrated controllers, sensors, and actuators
HISTORY
Gold- Cadmium in1932
Copper-Zinc in1938
BEEHLER , Ni-Ti at the Naval Ordinance Laboratory – Nitinol (1962)
After the discovery of Nitinol, a number of other system with the ‘shape memory effect’ was found.
DIFFERENT TYPES OF SMART MATERIALS
Piezoelectric materials
Magneto restrictors
Shape Memory Alloys (SMAs)
Electro rheological Fluids
Thermo responsive materials
pH-sensitive materials
Electro chromic materials
Piezoelectric materials: produce an electrical field when subject to a mechanical strain
Magneto restrictors: respond to magnetic field. They produce a magnetic field when strained
Transformation Mechanism
When temp changes transformation between two phases occur
due to this transformation, SM have many special properties, such as shape memory effect and super elasticity
The future……
The emerging industrial applications are:
Active Vibration Control (AVC)
Active Noise Control (ANC)
Active Shape Control (ASC)
Active Health Monitoring (AHM)