TE_Mechanical _composite materials

1. Composite materials.
Unit 1 : Introduction to Composites.
Presented by :-
Pune Vidhyarthi Griha's
College of Engineering and Technology-Pune 09
Prof. Rohan Panage
(7900155751)

2. Examination Scheme & CO

3. Syllabus
 Definitions , Need of composites, classification, Reinforcements
and matrices, Types of reinforcements and matrices, types of
composites.
 Natural composites, carbon fiber composites, Properties of
composites in comparison with standard materials.
 Advantages and disadvantages , natural composites, Hybrid
material and their difference with composites material, Application.

4. Definitions
 A composite is a structural material that consists of two or more combined constituents that
are combined at a macroscopic level and are not soluble in each other. One constituent is
called the reinforcing phase and the one in which it is embedded is called the matrix. The
reinforcing phase material may be in the form of fibers, particles, or flakes. The matrix
phase materials are generally continuous.
Examples of composite systems include concrete reinforced with steel and epoxy reinforced
with graphite fibers, etc.
 Only condition is that one of the material should retain its original physical identity after
processing.

5. Functions :-
a. Holds Fibers together
b. Protect the fiber from environment
c. Protect the fibers from abrasion
d. Provide the better finish.

6. Need of Composites
1. Weight Reduction (High Strength to Weight ratio)
2. Durability and maintenance
Don’t rust {e.g. marine }
3. Good thermal insulators.
4. Design Freedom. ( freedom for architectural form)

7. Reinforcement :- Anything that strengthens or increases a behavior.
The reinforcement material is embedded into matrix to enhance or reduce
their properties like wear resistance, hardness, density, porosity, mechanical strength,
thermal expansion, thermal and electrical conductivities.
In the case of high-performance structural composites, the normally continuous
fiber reinforcement is the backbone of the material, which determines its stiffness
and strength in the fiber direction.
The reinforcement can be either continuous or discontinuous.
Functions of a Reinforcement.
1. Contribute desired properties
2. Load carrying
3. Transfer the strength to matrix

8. Matrix:
 The matrix is the monolithic material into which the reinforcements is embedded
and is completely continuous.
 The matrix phase provides protection for the sensitive fibers, bonding, support
and local stress transfer from one fiber to another.
 In structural applications, the matrix is usually a lighter metal such as aluminum,
magnesium or titanium and provides a compliant support for the reinforcement.
In high temperature applications, Cobalt and Cobalt – nickel alloy matrices are
common.

9. Functions of a matrix
1. Holds the fibers together
2. Protects the fibers from environment
3. Protects the fibers from abrasion (with each other)
4. Helps to maintain the distribution of fibers.
5, Distributes the loads evenly between fibers
6. Enhances some of the properties of the resulting material and
structural component (that fiber alone is not able to impart) impart).
These properties are such as: transverse strength of a lamina &
Impact resistance.
7. Provides better finish to final product.

10. Role of Matrix and Reinforcement in Composite :
Matrix
 Gives shape to the
composite part
 Protects the reinforcements
from the environments.
 Transfers loads to there
reinforcements
 Contributes to properties
that depend upon both the
matrix and there
reinforcements, such as
toughness.
Reinforcement
 Give strength, stiffness,
and other mechanical
properties to the
composite.
 Dominate other properties
such as environment the
coefficient of thermal
expansion , conductivity,
and thermal transport.

11. Classification of Composite Material

12. Classification based on the Matrix (Types of Matrix )
A. Polymer matrix Composite
B. Metal Matrix Composite
C. Ceramic matrix Composite
A. Polymer matrix Composite :- Consist of a polymer ( eg. Epoxy, Polyester,
Poly Propylene ) which is reinforced by Fiber ( Eg. Graphite , Aramid,
boron, natural fiber)
Eg. Graphite epoxy polymer composite five times stronger than steel.
Thermoplastic Composites Thermoset Composites
1D -2D Molecular Structure. 3D Molecular Structure.
Tend to be at elevated temp. & show
exaggerated melting points.
Decompose instead of melting on
hardening.
Retained cured condition. Retained Partially cured condition.
Polyethylene (PE) Polypropylene epoxy, silicone, polyurethane and

13. B. Metal Matrix Composite :-
 Metal matrix composite are made by dispersing a reinforcing material into a
metal matrix.
 Matrix phase will be a metal whereas reinforcing material may be a different
metal or another material.
 Most commonly use used metallic matrix configurations are :
a. Aluminum base [AlMgSi, AlMg, AlCu]
b. Magnesium base
c. Titanium Base

14. C. Ceramic matrix Composite (CMC):-
 Ceramic material will be a matrix phase.
 They are brittle in nature.
 Widely use in aerospace sector [gas turbine ] and
energy sector [Heat exchanger fusion reactor walls]

15. Classification based on the Reinforcement.
A. Particle Reinforced
B. Whisker Reinforced
C. Fiber reinforced
D. Structural Reinforced
A. Particle Reinforced :- consists of particle of
one material dispersed in a matrix.
i. Large particle :- High- volume fraction of
large sized hard particles embedded in a
relatively soft matrix.
ii. Dispersion strengthened composite:- Small
size particle.

16. B. Whisker Reinforced :-
i. Single crystals grown with nearly zero defects are know as Whisker.
ii. Usually discontinuous and short fiber made from graphite silicon carbide ,
copper , iron etc,..
i. They have definite length to width ration grater than ONE.
ii. Having extraordinary strengths upto 7000 Mpa.

17. C. Fiber Reinforced :-
i. It is Engineered material, which exhibits high strength/ weight ratios
compared with some metallic materials.
Fiber Reinforced
Continuous Discontinuous
Unidirectional
Bidirectional
Aligned
Randomly
Oriented

18. D. Structural Reinforced :-
i. Engineered Products made from plastic , wood, glass, or carbon fiber materials.
ii. The formed or extruded products have applications as outdoor deck floors, railings,
fences , landscape timbers, cladding , sliding and window or door frames.
Classified as :-
a. Laminated :- It is a class of FRP composites consisting of several
layers of a composite mixture of fibers and matrix.
Each layer having similar and dissimilar material properties with
different fiber orientations.
 Fibre reinforced polymers (FRP) are composite material
made of polymer matrix reinforced with fibres.
FRP can be used for repair and strengthening of existing
structures. Externally bonded reinforcements can be used to
reinforce concrete, timber, steel and masonry structures.

19. b. Sandwich panel :-
Consist of two face sheet and core structure.
Core structure is to increases stiffness by increasing density to entire structure.

20. Natural Composites
Fibres :- A fibre is a thin thread of a natural or artificial substance,
especially one that is used to make cloth or rope. Fibre consists of the parts of
plants or seeds that your body cannot digest.
Examples of man-made fibers : Nylon. Polyester.
Fibres
Natural Fibres Synthetic Fibres

21. Natural fibres
Natural fibres are the fibres that are obtained from Plants, animals , or mineral
sources. Eg. Cotton, silk wool etc…
Advantages :-
i. Renewable resources
ii. Lower Production cost
iii. Good specific mechanical properties
iv. Loser density of composites
v. Biodegradability
vi. Lower risk to human being.
Limitations :-
i. Inhomogeneous structure
ii. Dimensional instability
iii. Lower thermal resistance
iv. Degradation and aging Problem

22. Synthetic fibres
Synthetic fibres are man made fibres, most of them are prepared from
raw material petroleum called Petrochemicals.
They consist of small unit or a polymer which is made from many
repeating units known as Monomers.
Eg. Nylon , acrylics, polypropylene etc…
Advantages ;-
i. Long Lasting
ii. Readily pickup to various dyes
iii. Stretchable
iv. Water proofing
v. Non- Biodegradability
Disadvantages ;-
i. Flammable
ii. Non- eco friendly

23. Classification of Fibres.

24. Carbon Fibre

25. Hybrid Composite Material