A composite material consists of two or more physically and/or chemically distinct, suitably arranged or distributed phases, with an interface separating them. It has characteristics that are not depicted by any of the components in isolation Most commonly, composite materials have a bulk phase, which is continuous, called the matrix, and one dispersed, non-continuous, phase called the reinforcement, which is usually harder and stronger. The arrangement of the fiber in the matrix critically influences the composite properties.
Composite materials can also be put into three main groups depending on their matrix: Polymer matrix composites (PMCs)
Metal matrix composites (MMCs)
Ceramic matrix composites (CMCs)
1.1.1 Advantages of composite materials
•Low inert mass
•Stiffness and strength tailored to application
•Reduced manufacturing cost and improved fatigue resistance compared to metal structure. •Corrosion resistance
•Availability for all tactical applications.
1.1.2Application of Composite Materials
The use of advanced materials, including composites, can result in significant weight and lifetime cost savings. Some of the applications as follows: •Composite power poles and cross arms
Composite power poles and cross arms Poles are produced from pultruded fibreglass-reinforced polymer composites
•Composite race car
Carbon fiber composites in all exterior door panels except the doors and roof
Sandwich structured composites are a special class of composite materials which have become very popular due to high specific strength and bending stiffness. Low density of these materials makes them especially suitable for use in aeronautical, space and marine applications. Concept of sandwich structured composite materials can be traced back to as early as the year 1849 AD  but potential of this construction could be realized only during Second World War.
Developments in aviation posed requirement of...