This document discusses smart materials and their applications in engineering. It begins by defining smart materials as materials that can change their mechanical properties or geometry in response to external stimuli like magnetic fields, temperature, or electricity. Examples provided include magnetorheological fluids, shape memory alloys, and piezoelectric materials. The document then explores various uses of smart materials in vibration damping, shape control, noise reduction, sensing, and more. It provides classifications of smart structures and delves into specific examples like MR fluids, shape memory alloys, piezoelectric materials, and IPMCs. In the end, it assigns homework for students to research and present on two chosen smart materials.

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 report and a presentation on tow
different smart materials of your choice
• At least three different references
• The report and presentation should reflect
good understanding of the subject matter
• DO NOT copy sentences or paragraphs from
references
• Due 27/9/2010