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WELCOME

WELCOME. TECHNICAL SEMINAR ON “SMART MATERIALS”. INTRODUCTION HISTORY OF SHAPE MEMORY ALLOYS:. The first reported step towards discovery of shape memory effect were taken in 1930’s according to Otsuka and Wayman In a silver-cadmium alloy.

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WELCOME

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  1. WELCOME

  2. TECHNICAL SEMINAR ON “SMART MATERIALS”

  3. INTRODUCTIONHISTORY OF SHAPE MEMORY ALLOYS: The first reported step towards discovery of shape memory effect were taken in 1930’s according to Otsuka and WaymanIn a silver-cadmium alloy. Shape memory polymers have also been developed and become commercially available in late 1990’s. INTRODUCTION: Shape memory alloys or SMA's are metals that exhibit shape memory properties. It allows materials possessing shape memory properties to return to their original shape after having suffered some form of deformation after they are heated to temperatures above their transformation temperature.

  4. What are Smart Materials? • Senses a stimulus (eyes). • Takes an intelligent decision (brain). • Through electronic feedback it takes corrective/preventive measures to avoid catastrophic situations (arm).

  5. DEFINITION OF SMART MATERIALS: Smart materials are materials that 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.

  6. TYPES OF SMART MATERIALS • Shape memory alloys • Piezoelectric materials • Magnetostrictive materials • Active fluids • Ph and temperature sensitive polymers.

  7. SHAPE MEMORY EFFECTS TWO TYPES OF COMMON EFFECTS ARE: ONE WAY EFFECT TWO WAY EFFECT ONE WAY EFFECT: When a shape memory alloy is in its cold state, the metal can be bent or stretched and will hold those shapes until heated above transient temperature. Upon heating the shape changes to its original. TWO WAY EFFECT: A Material That Shows Shape Memory Effect During Both Heating And Cooling Is Called “Two Way Shape Memory” INITIAL STATE DEFORMED SHAPE HEATING BACK TO ORIGINAL SHAPE

  8. PIEZOELECTRIC MATERIALS • Expand and contract with the application of voltage. • Piezoceramics are the most widely used smart material. • Applications • Ink Jet Printers. • Medical Diagnostics. • High frequency stereo-speakers. • Computer Keyboards. • Microphones.

  9. MAGNETOSTRICTIVE MATERIALS • Expand and contract with the application of magnetic fields. • Applications • High-power sonar transducers. • Motors. • Hydraulic actuators.

  10. ACTIVE FLUIDS • Respond to an electric or a magnetic field with a change in viscosity. • Applications • Tunable dampers. • Vibration-isolation systems. • Clutches. • Brakes. • Resistance Controls

  11. pH AND TEMPERATURE SENSITIVE POLYMERS • pH-sensitive polymers are materials which swell/collapse when the pH of the surrounding media changes. • Temperature-responsive polymers are materials which undergo changes upon temperature. • Used as surface modifiers , drug delivery.

  12. APPLICATIONS : • Activate control inceptors using smart material motion control. • Remove toxic pollutant from water. • Advanced liquid crystal display. • Artificial muscles. • Hydraulic fitting. • To determine the defects in buildings and bridges. • To find stealth in aeroplanes and submarines.

  13. ADVANTAGES : • BIO-COMPATIBILITY • STRONG , CORROSIVE RESISTANT • PRODUCES VERY LARGE RECOVERY STRESSES • MATERIAL IS DUCTILE • VERY EFFECTIVE FOR LOW FREQUENCY VIBRATIONS

  14. DISADVANTAGES : • Expensive to manufacture. • Slow reaction time. • Non linear thermo-mechanical behavior can limit the accuracy. • Low energy efficiency conversion.

  15. CONCLUSION: “ Smart materials” are just starting to emerge from the laboratory but soon you can expect to find them in everything from laptops to concrete bridges.

  16. THANK YOU PRESENTED BY : ANANTH KR SHIVARAJ N

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