Fazzini's Rule

Fazzini's Rule states that the effective elastic modulus of a composite material—how stiff it is—is primarily determined by the properties and arrangement of its stiffest components, especially the fibers, when they are well-bonded within the matrix. In essence, the stiffness of the composite cannot be significantly greater than that of its strongest reinforcement, and good bonding ensures the load transfers efficiently. This rule helps in designing composites by emphasizing the importance of high-quality fibers and strong interfaces to achieve desired mechanical properties.