Normative Representation of Stress and Strain Applied to Fiber Reinforced Composites

A novel method of contracted notation to represent stress and strain in the form of normative representation has been employed in this article to describe the global mechanical behavior of fiber reinforced composite materials. A unified set of transforma tion equations governing orientational changes in stress and strain as well as that in stiffness and compliance was derived. A coordinate independent stress-strain law, the normal Hooke's law, was presented and several related concepts including the elastic eigenmodulus, elastic mode and modal stress were introduced. Considered also was the decomposition of the elastic strain-energy density mto irreducible, independent energy- orthogonal components which are related with distinct types of energy. Based on the nor mative representation approach and the various unique properties of the normal Hooke's law, a theory of material strength for anisotropic materials was established which encom passes the classical von Mises yield criterion for isotropic materials as its particular case.