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.