Composite Material Nomenclature and Definitions

The terminology used to describe and define composite materials and their behavior is introduced in this section. Many of the terms are familiar from earlier study of mechanics of materials, while other terms specific to composites may be unfamiliar. A collection of these terms in one location is provided for easy reference. 

Homogeneous body The material properties of a homogeneous body are independent of position in the body. Thus, physical properties from a representative material sample may be obtained from any location in a homogeneous body, provided the orientation of the sample is fixed relative to a set of axes attached to the body. In this chapter, the term material properties includes the mechanical properties discussed in Chapters 2 and 3 as well as typical material properties such as density and so on. 

Isotropic body The measured material properties of an isotropic body are independent of the orientation of the representative material sample taken to characterize 

Orthotropic body The mataM properties of an ortholropic material are different in three mutually perpendicular directions (material principal directions). The material properties for any other orientation in an orthotropic mataial can be obtained by appropriate transformation of the material povolies obtained for the principal material directions. Thus, the properties of an orthotropic material are a function of orientation. Planes perpendicular to the principal material directions are called planes of material symmetry. 

Anisotropic body The material properties at a point in an anisotropic body are different for each orientation of a material sample taken at this point. Thus, there are no planes of material symmetry in this type of material, and all material properties are a function of orientation. 

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