Aero495 01 introduction

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Introduction to smart structures

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Aero495 01 introduction

  1. 1. Smart Materials and theirApplications in Engineering Dr. Mohammad Tawfik
  2. 2. Smart Material: What?• Controlled change in properties – Change in mechanical properties (MR fluids, SMA) – Change in geometry (Piezoelectric, SMA)• Energy Converters! – Mechanical Electrical (Piezoelectric) – Heat  Mechanical (SMA) – Mechanical  Heat (Viscoelastic) – Etc…
  3. 3. Smart Materials: Why?• Vibration Damping• Shape Control• Noise Reduction• Vibration/Damage Sensing• Heat Sensing
  4. 4. Smart Structures: Classification Wada, Fanson, and Crawly
  5. 5. Magnetorheological Fluids
  6. 6. MR FluidsHow do they work?• Externally applied magnetic field in a direction normal to the fluid flow direction form dipoles in the iron particles• Magnetic poles start attracting each others to the direction of the field, hence forming chains• The chains then form a skeleton within the fluid, which gains the fluid controllable yield stress
  7. 7. Why MR technology? Required Materials to synthesize an MR fluid:  General purpose oil • Lithium grease Micron-sized iron particles Mix them and you are done!
  8. 8. MR Fluids
  9. 9. Rabinow and Winslow 1950’s
  10. 10. MR Damper FabricationPrototype Damper
  11. 11. Seat Shock Absorbers
  12. 12. Shape Memory Alloy
  13. 13. Shape Memory Alloy• Change mechanical properties with the change of temperature• Regain original shape when heated!
  14. 14. Shape Memory Alloys
  15. 15. Application
  16. 16. SMA Embedding
  17. 17. Other Applications• Dental Fillings• Artificial Joints• Heat Valves• Eye-glasses!
  18. 18. Piezoelectric Materials
  19. 19. Piezoelectric Material• Electric Field  Mechanical Strain : Actuator• Mechanical Stresses  Electrical Potential Field : Sensor
  20. 20. Basic Properties
  21. 21. Piezo-Fiber Composites
  22. 22. Active/Macro Fiber Composites
  23. 23. Energy Harvesters
  24. 24. MEMS Power Generation
  25. 25. Backpack Power Generator
  26. 26. Ionic Polymer Metal Composite IPMC
  27. 27. IPMC• New Material• Shape is controlled by electric field• Designed on the molecule level (NANO technology)
  28. 28. Slow and Fast!
  29. 29. Homework #1• Prepare a 2 page report on Piezoelectric materials• At least three different references• The report should reflect good understanding of the subject matter: Physics, applications, history• DO NOT copy sentences or paragraphs from references• Due 24/9/2012
  30. 30. Thank you for your attention! Mohammad.tawfik@gmail.com

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