Shape Memory Alloy ppt
- 2. CONTENTS NAME 1.HISTORY OF SMA 2.INTRODUCTION 3.SCHEMATIC DIAGRAM UNDER TEMPERATURE 4.SUPERELASTIC SMAS 5.SHAPE MEMORY ALLOYS : MODELING 6.APPLICATIONS 7.FUTURE APPLICATIONS OF SMA 8.ADVANTAGES 9.DISADVANTAGES 10.CONCLUSION
- 3. 1.HISTORY OF SMA SMAs were first discovered in 1951 Further publicized after the discovery of Ni-Ti alloy in 1963 SMAs have two main phases: Austenite and Martensite Austenite phase is Symmetric,while martensite phase is less symmetric Phase transformation occur either thermally of mechanically
- 4. 2.INTRODUCTION Shape Memory Alloys (SMAs) are a unique class of metal alloys that can recover apparent permanent strains when they are heated above a certain temperature. The SMAs have two stable phases - the high-temperature phase, called austenite and the low-temperature phase, called martensite
- 6. 4.SUPERELASTIC SMAs Super elastic SMAs are characterized by: 1) Excellent recentering capability 2) Controlled level of force at moderate strain levels 3) Strain hardening at large strain levels 4) Hysteretic energy dissipation 5) Excellent corrosion resistance 6) High fatigue strength Casati, R., Passaretti, F., & Tuissi, A. (2011). Effect of electrical heating conditions on functional fatigue .
- 7. 5.SHAPE MEMORY ALLOYS : MODELING
- 8. 6.Applications: Various thermal actuators then came into existence as a part of electric appliances and automobile engineering. Automobile Aerospace application Bio medical Civil engineering of Mega structures
- 9. 7.FUTURE APPLICATIONS OF SMA Eliminate vibrations of read/write heads in hard disk drives Microstents Promote flow in tubular passages Reinforce weak blood vessels Microsurgery Cardiovascular applications Orthopedic applications microstents Simon filter Micro wrapper
- 10. 8. ADVANTAGES • High strength • Good elasticity • Fatigue Resistance • Wear resistance • Easy fabrication • Easy to sterilize • High Power/weight ratio • Light weight • Shape memory
- 11. Cont... Grab tiny foreign objects for removal from the body Facilitates access to intricate regions of the body Micro assembly for MEMS devices Intravascular Therapy
- 12. 9.DISADVANTAGES OF SMAs The main disadvantages of SMA’s are: Initial Expensive Sensitivity of material properties in fabrication. Residual Stress’s developed in thin films. Nonlinearity of actuation force. Lower maximum frequency compared to other micro actuator devices. • Poor fatigue Property.
- 13. 10
- 14. REFERENCE Casati, R., Passaretti, F., & Tuissi, A. (2011). Effect of electrical heating conditions on functional fatigue of thin NiTi wire for shape memory actuators Retrieved 06 2011, from ScienceDirect: http://www.sciencedirect.com/ de Haan, J. (1994, juli). Geheugenwerking bij NiTi-legeringen. Retrieved 06 2011, from alexandria.tue.nl: http://alexandria.tue.nl/repository/books/642146.pdf Detailed Introduction to Shape Memory Alloys. (n.d.). Retrieved 06 2011, from smart.tamu.edu: http://smart.tamu.edu/overview/smaintro/detailed/detailed.html Djavareshkian, M., Esmaeli, A., & Parsani, A. (2011). Aerodynamics of smart flap under ground effect Retrieved 07 2011, from ScienceDirect: http://www.sciencedirect.com Kanada, T. (2008, 05 05). A new drive system using a shape memory alloy (SMA). Retrieved 06 2011, from joam.inoe.ro/download.php?idu=1360