ABSTRACT
The basic building block of composite structures is the unidirectional lamina. A composite lamina is a thin layer of resin reinforcing multiple fibers or fabrics. Many micromechanics models were developed by researchers for predicting properties of a composite lamina based on the percent of fibers in relation to resin either by weight or by volume. In general, those models can be classified into three main categories: (1) mechanics of materials, (2) theory of elasticity, and (3) numerical (finite element) methods. In numerical predictions, the lamina is modeled as though fibers are periodically spaced, infinitely long, and fully surrounded by matrix (no dry patch) in square or hexagonal arrays. Through the theory of elasticity approach, three fundamental laws of physics in a system are applied by satisfying (1) force equilibrium, (2) constitutive relations, and (3) strain compatibility. Likely, the compatibility equations may not be satisfied for models of mechanics of material approach because of approximations based on certain assumptions in developing these approaches. The lamina of the elastic model approach will be represented by the representative volume elements (RVEs). The details of the theory of elasticity approach or the numerical approach will not be discussed herein as they are beyond the scope of this textbook.
