The general definition of a composite is a combination of different components or elements. For your work on the Composite Materials merit badge, however, think of a composite as a material made from two or more dissimilar (not alike) materials that, when combined, are stronger than those individual materials by themselves. For this merit badge, composites is defined as “a combination of plastic resin and a fiber reinforcement.” Another term for composites is used in the past is reinforced plastics.
Today, the composites industry uses a more specific term: fiber reinforced polymer (FRP) composites. A polymer is a chemical compound made of many identical components linked together like a chain. “Polymer” and “resin” are interchangeable terms. The fiber reinforcement can be glass, carbon, or aramid (KevlarTM). These fibers are very strong.
The function of the fibers is to provide strength and stiffness to the composite product where the resin acts to bond and protect the fibers from chemicals and the environment, as well as transfer load between the fibers. Composites are different than other materials. For example, metals are isotropic, meaning they have equal strength in all directions. Composites are anisotropic, having different properties in different directions. This gives composites an advantage by allowing designers to make efficient use of materials for the design loads.