ORTA DOGU TEKNIK

1
COMPOSITE MATERIALS

• What are composite materials? Two or more
  materials bound together

• Example from civil engineering Concrete
  reinforced with steel bars

Reinforced concrete wall
2
COMPOSITE MATERIALS

• Fiber reinforced composite materials

Reinforcement Main load carrying member
Binding materialtransfers load to fibers, keeps
the fiber together
3
FIBER MATERIALS
4

• A Fiber (reinforcement) may be defined as an
  elongated stringy man-made material.
• A polymer (matrix) is a large molecule
  consisting of repeating units connected by
• covalent chemical bonds.
• Once the polymer is combined with the fibers,
  the polymerization process must take
• place in order to obtain a solid structural
  composite material.
• Another critical issue is the fiber-matrix
  bonding. When the composite material is
• loaded, both fibers and matrix must be
  strongly bonded so that they work as a solid
• rigid.

5
FABRIC ARCHITECTURES
Woven
Unidirectional
6
COMPOSITE LAMINATES
7
SANDWICH CONSTRUCTION

• When loads are applied to any beam, such as
  wing spar most stress occurs at the
• outer surfaces.
• Therefore, SANDWICH structure is commonly used
  in composite construction
• to increase the thickness without
  significant weight penalty

Core material Honeycomb Balsa wood Foam etc.
Valid for honeycomb cores
8
Typical SANDWICH structure
Bonding material between layers Epoxy resin
Core material Honeycomb, wood, foam etc.
Upper and lower layers Composite material
composed of suitable fiber matrix combination
Typical fiber materials E-Glass Standard fiber
glass workhorse of composites, moderate
strength, good bonding with epoxy, cheap Kevlar
Organic fibers, high impact resistance, high
strength, difficult to work, poor bonding with
epoxy, moderate prize Carbon 93-95 carbon
content, very high strength and fatigue
resistance, excellent bonding with epoxy,
expensive
9
Typical resin(matrix) materials Epoxy
Excellent adhesion to fibers, highest strength,
low shrinkage, will bond to dissimilar or already
cured materials Vinly ester Moderate
strength, more resistant to degradation from
water/moisture Polyester Low strength , fast
curing times, exhibit shrinkage, low weathering
resistance, cheapest (non adequate for advanced
composites poor adhesion to carbon and Kevlar)
10
COMPOSITE MANUFACTURING
11
COMPOSITE MANUFACTURING
12
COMPOSITE MANUFACTURING
INFUSION
13
COMPOSITE MANUFACTURING
INFUSION APPLICATIONS
14
COMPOSITE MANUFACTURING
VACUUM BAGGING
15
COMPOSITE MANUFACTURING
VACUUM BAGGING
16
COMPOSITE MANUFACTURING
VACUUM BAGGING
Release agent facilitates the extraction of
the part.
Peel ply leaves the part surface apt to be
bonded or painted.
Prepreg.
Release film prevents the resin to reach the
bleeder fabric but not the volatiles.
Bleeder fabric takes out the excess of resin
in order to get the desired fiber fraction.
Breather fabric makes the vacuum uniform along
the part.
Vacuum bag/seal seals the cavity to be
vacuumed.