Composite Materials
From Swikipedia
Introduction
Composite materials or composites are complex materials made up of two or more complementary substances. These constituent materials, having significantly different physical or chemical properties do not dissolve or blend into each other. And, so, they can be difficult to recycle. Plastic laminates are an example. Composite materials are best applied in situations where they can be removed for reuse (not requiring remanufacture).
Brief Description
Wood is a natural composite of cellulose fibres in a matrix of lignin. Cellulose is also found in cotton and linen, but it is the binding power of the lignin that makes a piece of timber much stronger than a bundle of cotton fibres. The most primitive manmade composite materials were straw and mud combined to form bricks for building construction.
Composites are made up of individual materials referred to as constituent materials. There are two categories of constituent materials: matrix and reinforcement. At least one portion of each type is required. The matrix material surrounds and supports the reinforcement materials by maintaining their relative positions. The reinforcements impart their special mechanical and physical properties to enhance the matrix properties. A synergism produces material properties unavailable from the individual constituent materials, while the wide variety of matrix and strengthening materials allows the designer of the product or structure to choose an optimum combination.
Advantages of using composites
1. The greatest advantage of composite materials is strength and stiffness combined with lightness.
2. Composites are less likely than metals (such as aluminium) to break up completely under stress. A small crack in a piece of metal can spread very rapidly with very serious consequences. The fibres in a composite act to block the widening of any small crack and to share the stress around.
3. The right mix of constituent materials often results in composites which are heat and corrosion resistant.
4. Composite materials are also very durable.
5. They provide design flexibility, as they can be moulded into complex shapes.
6. The manufacturing processes are often more efficient when composites are used.
Disadvantage of using composites
The raw materials used for manufacturing composites are usually quite expensive. Also, composites will never totally replace traditional materials like steel, but in many cases they are just what we need.
References:
http://www.greenbuildingcookbook.info/Glossary.html
