This document discusses smart materials and their applications in engineering. It begins with an introduction of the presenter and their background in smart materials and structures. It then defines smart materials as materials that can change properties in response to external stimuli like stress, temperature, or electric fields. Examples of smart materials discussed include magnetorheological fluids, shape memory alloys, and piezoelectric materials. Applications of these smart materials include vibration damping, shape control, noise reduction, sensing, and energy harvesting. Videos are also included to demonstrate some smart material applications.

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

2. Who am I?
• Aerospace Engineering Department
• Smart Materials and Structures
• American University in Cairo
• Communication and Leadership Skills

3. Why am I here?

4. To share the fun

5. And maybe … talk about
Smart Structures

6. 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…

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

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

9. Magnetorheological Fluids

10. 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

11. Why MR technology?
Mix them and you are done!
Required Materials to
synthesize an MR fluid:
• Lithium grease
 General purpose oil
 Micron-sized iron particles

12. Rabinow and Winslow 1950’s

13. • Some Videos

14. Seat Shock Absorbers

15. Shape Memory Alloy

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

17. Shape Memory Alloys
• Some Videos

18. Application

19. SMA Embedding

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

22. Piezoelectric Materials

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

24. Basic Properties

25. Piezo-Fiber Composites

26. Active/Macro Fiber Composites

27. Energy Harvesters

28. MEMS Power Generation

29. Backpack Power Generator

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