Composites are defined as the combination of two or more chemically different constituents which combines macroscopically to produce a useful material.
Natural composite materials are:
Wood, Granite and Bone
Artificial composite materials are:
Plywood, concrete, fibrous composites, fiber glass, plastic, alloys metals along with the impurities etc.,
Composite material usage:
In Sports they are used for the Bicycles, Golfing, Boats, badminton, Tennis and Hockey.Advertisement:
Transportation and Infrastructure
In Transportation and Infrastructure the composite materials are used for the bridges, ships, boats, dam’s railway coaches, floors, truck bodies and RV bodies.
In aircrafts, satellites, rockets and missiles they are used for the manufacturing of doors, nose, out boards, stabilizers, fuel tank, edges, elevators, inboard flaps, rudders, fin tips, pressure tanks, stators, turbo motor, antennae and structural parts etc.,
In automotive industries they are used in the process of manufacturing the car body, Drive shafts, fuel tank, hoods and spoilers.
In some stages they are used for consumer goods, Health care, Heavy machinery, Agriculture equipment, biomedical industry and computers etc.Advertisement:
Engineered Composites classification:
The engineered composites are classified into two types they are
- Particulates: In the binding matrix, the combination of one or more material particles is suspended. It is one dimensional.
- Fibrous: In the binding matrix, the combinations of fiber reinforcing materials are suspended.
The particulates are divided in to two types they are
- Random orientation: the particles are distributed randomly in all the directions
- Preferred orientation: in this case the particle orientation is aligned to single direction.
Fibrous are divided into two types they are
- Single layer: the composite is made up of several fiber layers and all are oriented in similar direction.
- Multi-layer: the composite is made up layer by layer and all of these are oriented in dissimilar direction.
Single layer are divided in to two types they are
- Continuous and long fibers
- Dis- continuous and short fibers
Continuous and long fibers are divided in to two types
- Bi directional
Dis- continuous and short fibers are divided in to two types
- Random orientation
- Preferred orientation
Multi- Single layer are divided in to two types they are
- Hybrid laminate
Advantages of composite materials:
- Compare to metals they exhibit high strength
- They are having low specific gravity
- Stiffness of the material is improved
- At high temperatures also they maintain the weight
- Toughness is also improved
- Production is lower
- Fabrication is also cheaper
- Fatigue strength and creep is better
- Oxidation and corrosion resistance
- Measured electrical conductivity is possible
Disadvantages of composite materials:
- Compare with the wrought metals, composites are more brittle and they are easily damaged
- Cast metals also tend to be brittle
- During the time of transportation material requires chilling.
- Special equipment’s are required and hot curing is also necessary
- For curing process it requires time for cold or hot process.
- After the completion of last rivet the process is done.
- The rivets are removed without causing any damage
- Pressure and tooling are required to repair at the original cure temperature
- Before starting the repair the composite must be cleaned