This document summarizes smart materials and their applications in engineering. It discusses different types of smart materials like magnetorheological fluids, shape memory alloys, and piezoelectric materials. These materials can change their properties in response to external stimuli like magnetic fields, temperature changes, or electric currents. The document then explores various applications of smart materials in vibration damping, shape control, noise reduction, sensing, and energy harvesting. It provides examples of using these materials in seat shock absorbers, surgical implants, eyeglasses, and backpack power generators. In conclusion, the author assigns homework for students to write a report on piezoelectric materials and their physics, history, and applications.

1. Smart Materials and their
Applications in Engineering
Dr. Mohammad Tawfik

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. Smart Materials: Why?
• Vibration Damping
• Shape Control
• Noise Reduction
• Vibration/Damage Sensing
• Heat Sensing

4. Smart Structures: Classification
Wada, Fanson, and Crawly

5. Magnetorheological Fluids

6. MR Fluids
How 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. 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. MR Fluids

9. Rabinow and Winslow 1950’s

10. MR Damper Fabrication
Prototype Damper

11. Seat Shock Absorbers

12. Shape Memory Alloy

13. Shape Memory Alloy
• Change mechanical properties with the
change of temperature
• Regain original shape when heated!

14. Shape Memory Alloys

15. Application

16. SMA Embedding

17. Other Applications
• Dental Fillings
• Artificial Joints
• Heat Valves
• Eye-glasses!

19. Piezoelectric Materials

20. Piezoelectric Material
• Electric Field  Mechanical Strain : Actuator
• Mechanical Stresses  Electrical Potential
Field : Sensor

21. Basic Properties

22. Piezo-Fiber Composites

23. Active/Macro Fiber Composites

24. Energy Harvesters

25. MEMS Power Generation

26. Backpack Power Generator

27. Ionic Polymer Metal Composite
IPMC

28. IPMC
• New Material
• Shape is controlled by electric field
• Designed on the molecule level (NANO
technology)

29. Slow and Fast!

30. 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

31. Thank you for your attention!
Mohammad.tawfik@gmail.com