itw13 presentation

Smart Materials and their Applications in Engineering

Dr. Mohammad Tawfik

Who am I?

• Aerospace Engineering Department

• Smart Materials and Structures

• American University in Cairo

• Communication and Leadership Skills

Why am I here?

To share the fun

And maybe … talk about Smart Structures

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…

Smart Materials: Why?

• Vibration Damping

• Shape Control

• Noise Reduction

• Vibration/Damage Sensing

• Heat Sensing

Smart Structures: Classification

Wada, Fanson, and Crawly

Magnetorheological Fluids

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

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

Rabinow and Winslow 1950’s

• Some Videos

Seat Shock Absorbers

Shape Memory Alloy

Shape Memory Alloy

• Change mechanical properties with the change of temperature

• Regain original shape when heated!

Shape Memory Alloys

• Some Videos

Application

SMA Embedding

Other Applications

• Dental Fillings

• Artificial Joints

• Heat Valves

• Eye-glasses!

Piezoelectric Materials

Piezoelectric Material

• Electric Field Mechanical Strain : Actuator

• Mechanical Stresses Electrical Potential Field : Sensor

Basic Properties

Piezo-Fiber Composites

Active/Macro Fiber Composites

Energy Harvesters

MEMS Power Generation

Backpack Power Generator

Thank you for your attention!

Mohammad.tawfik@gmail.com

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