Fiber-reinforced composite (FRC) is a synthetic material combination of a polymeric (resinous) matrix and reinforcing fillers of high aspect ratio, i.e., the ratio between the diameter and length of the filler. High aspect ratio fillers are fibers. In general, a fiber is a rope or string used as a supporting/reinforcing component of composite materials. Fibers can be also as oriented fiber fabrics (a weave) of random fibers (a mat, a veil) into sheets (in plane) to make composite types of products such as felt or paper. Fibers can also be three-dimensionally oriented. The strongest engineering materials are generally made of continuous unidirectional fibers.