Definition: A composite is a solid material, made out of two or more constituent, different and distinct substances that retain their physical characteristics, while contributing desirable properties to the whole.
Composites and composite fabricating is not new. Actually, it is one of man’s oldest engineering methods. Composites, like straw reinforced mud, were used for construction in prehistoric times. Today, composites are everywhere around us. For example, most buildings are composites, made out of newer materials like steel reinforced concrete or various kinds of panels. Likewise, glass fiber reinforced polyester is used extensively for the construction of many products like boats and yachts, tanks or piping.
Composite materials are the constituent materials that are used to fabricate composite products. Three types of materials are mostly used, or overwhelm the industry today:
- The matrix is a form of glue that surrounds, supports and keeps together in position the reinforcement.
- The reinforcement is usually some type fiber material in the form of fabric that exhibits some special physical characteristics (like mechanical or electrical).
- The core is usually some type of solid lightweight material used in-between the layers of fiber reinforced matrix forming a type of sandwich structure.
When matrix and reinforcement are combined in a laminate to form a new material, the imparting special characteristics of each are combined and enhanced by synergism (=working together.) Moreover, core can be utilized to improve the stiffness and strength of the product even further, resembling the effect of steel ‘I’ beam at a very low weight.
Growing demand for better performance on products and materials has led to continuous developments on the field of composites. Advanced, special fibers (like carbon or aramid) or resins (like epoxy) and cores (like PVC foam or honeycomb), and new fabricating methods were developed and utilized to construct other materials or products that have outstanding mechanical properties thought to be “exotic” a few decades ago. Those advanced composites are used in many industries like aerospace, automotive, energy, important sports/recreation and just about everywhere low weight and other special properties are needed.