Composite material is made from two or more constituent materials that have different physical or chemical properties. When combined, they create a material with properties unlike the individual elements. Composites can be very strong and stiff yet light, with better fatigue and toughness properties than metals. They do not corrode like steel and allow combinations of properties not possible with single materials. Composites are commonly used in aircraft due to their strength, stiffness, and light weight.

1. Composite material

2. Composite material is a material which is produced
from two or more constituent materials. These
constituent materials have notably dissimilar
chemical or physical properties and are merged to
create a material properties unlike the individual
elements. Within the finished structure, the
individual elements remain separate and distinct.
What is a composite Material?

3. • Composites can be very strong and stiff, yet very light in
weight, so ratios of strength -to - weight and
stiffness -to - weight are several times greater than steel or
aluminum.
• Fatigue properties are generally better than for common
engineering metals.
• Toughness is often greater too
• Composites can be designed that do not corrode like steel
• Possible to achieve combinations of properties not attainable
with metals, ceramics, or polymers

4. • The tensile strength of composite material is 4-6 times
higher than conventional materials such as steel,
aluminum, etc.
• They have better torsion and stiffness properties.
• They are 30-45% lighter than aluminum structures
designed for the same functional requirements.
• As they are lightweight, strong, stiff, and tough, Composites
are mainly used for making Fuselage and wings of an
aircraft
• Composites make less noise during operation and provide
less vibration.

5. 1. Traditional composites – composite materials that occur in
nature or have been produced by civilizations for many
years
Examples: wood, concrete
2. Synthetic composites - modern material systems normally
associated with the manufacturing industries, in which the
components are first produced separately and then
combined in a controlled way to achieve the desired
structure, properties, and part geometry

6. Nearly all composite materials consist of two phases:
1. Primary phase - forms the matrix within which the secondary
phase is imbedded
2. Secondary phase - imbedded phase sometimes referred to as a
reinforcing agent, because it usually serves to strengthen the
composite
The reinforcing phase may be in the form of fibers, particles, or
various other geometries

7. 7
:
-- Matrix - is continuous
-- Dispersed - is discontinuous and
surrounded by matrix
Fig.1

8. Composite Structural Organization: the design
variations

9. Functions of matrix
 Binds fibre
 Act as medium
 Protect fibre
 Prevent propagation of cracks.

10. Essentials of matrix phase
 It should be ductile
 Bonding strenth should be high
 Corrosion resistant

11. Classification of dispersed phase
 The dispersed phase can be fibre particle etc.
 Fibres:
1.Glass fibres
2.Carbon fibres
3.Aramid fibres(Aromatic)
 Particles (metallic or non metallic)
 Whiskers: thin crystals with high impact ratio e.g. graphite,
silicon carbide etc.

12. • It increases the mechanical properties of the composite.
• It provides strength and stiffness to the composite material
in one direction as reinforcement carries the load along the
length of the fiber
• It also increases the Co-efficient of thermal expansion and
the conductivity.

13. • Open Molding
•Closed molding
•Cast polymer molding

14. Open Molding / Hand layup
• Fiber reinforcements are placed by hand in a mold and resin is
applied with a brush or roller
• This process is used to make both large and small items, including
boats, storage tanks, tubs and showers.

15. Closed Molding
• Reinforcement material is loaded into a closed mold, the mold is
clamped, and resin is pumped in (through injection ports) under
pressure.
• This process produces complex parts with smooth finishes

16. Cast polymer Molding
• A mixture of resin and fillers are poured into a mold (typically without
reinforcements) and left to cure or harden.
• These molding methods sometimes use open molding and sometimes
use closed molding.

17. • Composites are more brittle than wrought metals and thus
are more easily damaged.
• Many of the polymer-based composites are subject to attack
by chemicals or solvents, just as the polymers themselves are
susceptible to attack.
• Composite materials are generally expensive
• Manufacturing methods for shaping composite materials are
often slow and costly

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