Send in Reinforcements
Background of composite materials
and usage
Composites are not recent innovations:
Wood Composites
Plywood (3500 BC)
Veneer
Composites are not recent innovations
• Fiber – reinforced composites
– Egyptians used straw and horsehair in mud bricks
– Asbestos fibers in cement paste (1890’s)
– Metal rods and stone fill in concrete
• Improved properties
– Toughness
– Ductility
– Crack resistance
4-point bending
Structural Composites are used in Building Construction
Name
Philadelphia City Hall (masonry)
Comcast Center
Year
1901
2008
Height
548 ft
975 ft
Cost
$27 million
$540 million
Aerospace Industry parts: less labor, less weight
http://curedcomposites.netfirms.com
http://igotech.ca
Name
P-51 Mustang (Best Fighter of WWII)
F-22 Raptor
Year
~1940’s
2000’s
Speed
490 mph
~1650 mph (Mach 2.5)
Cost
$54,000
$200 million
Range
1000 miles
2315 miles
Natural Composites and Biomechanics
• Xylem (plant cell wall)
• Bone (trabecular)
• Arteries (collagen and
elastin)
• Necessary because of
– function
– resistance to deformation
(mechanics)
http://journals.prous.com
What role do engineers play?
• Improve materials
(composites)
• Use mathematics to describe
how structures behave under
load.
• Computer simulations show
an end result based on the
mathematical description of
behavior.
Computer simulations used to model the
geometry and expected stress distribution