ABSTRACT
A composite material is obviously heterogeneous at the constituent material level, with properties possibly changing from point to point. For example, the stress-strain relationships at a point are different for a point in the fiber material than for a point in the matrix material. If we take the composite lamina as the basic building block, however, the “macromechanical” stress-strain relationships of the lamina can be expressed in terms of average stresses and strains and effective properties of an equivalent homogeneous material [1]. This chapter is concerned with the development and manipulation of these macromechanical stress-strain relationships. The “micromechanical” relationships between the constituent material properties and the effective lamina properties will be discussed in more detail in Chapter 3, but the basic concept of an effective modulus will be discussed here.
