ABSTRACT
The mechanics of materials deal with stresses, strains, and deformations in
engineering structures subjected to mechanical and thermal loads. A common
assumption in the mechanics of conventional materials, such as steel and
aluminum, is that they are homogeneous and isotropic continua. For a homo-
geneous material, properties do not depend on the location, and for an iso-
tropic material, properties do not depend on the orientation. Unless severely
cold-worked, grains in metallic materials are randomly oriented so that, on a
statistical basis, the assumption of isotropy can be justified. Fiber-reinforced
composites, on the other hand, are microscopically inhomogeneous and non-
isotropic (orthotropic). As a result, the mechanics of fiber-reinforced composites
are far more complex than that of conventional materials.