3. Smart Materials - Introduction
• Intelligent materials or Responsive materials
• Respond to environmental stimuli with particular changes in some variables
• Depending on changes in some external conditions smart materials change either
their properties (mechanical, electrical, appearance) their structure or
composition or their functions
• These materials have one or more properties that can be significantly changed in
a controlled fashion by external stimuli, such as stress, temperature,
moisture, pH, electric or magnetic fields.
4. Smart Materials - Types
There are many types of smart materials. Some of the examples include
Piezo electric materials
Smart fluids
Electro-rheostatic (ER)
magneto-rheostatic (MR)
Magnetostrictive
Shape memory alloy, shape memory polymer
5. Common smart materials and associated stimulus-
response
Source: Susmita Kamila / American Journal of Applied Sciences 10 (8): 876-880, 2013
6. Piezo electric materials
• When deformed it gives a small but measurable electrical discharge
• Alternately, when an electrical current is passed thru’ a piezo electric material it
experiences a significant increase in size (up to 4% change in volume)
• Widely used as sensors in different environments
• Used to measure fluid composition, fluid density, fluid viscosity, or the force of an
impact
• Used as air bag sensor in vehicles
7. Smart Fluids
• Electro-rheostatic (ER) and magneto-rheostatic (MR)
• ER and MR are smart fluids, which can experience a dramatic change in their
viscosity
• 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
• The effect can be completely reversed just as quickly when the field is removed
• MR fluid experiences a viscosity change when exposed to magnetic field, while ER
fluid experiences similar change in an electric field
8. Magnetostrictive Materials
• Exhibit change in shape under the influence of magnetic field and also exhibit
change in their magnetization under the influence of mechanical stress
