The analytical procedures mentioned so far yield approximate estimates of the exact solution of the micromechanics problem. These estimates must lie between lower and upper bounds for the solution. Since homogenization models are based on more or less accurate modeling of the microstructure, these models are also called micromechanics models, and the techniques used to obtain approximate values of the composite’s properties are called micromechanics methods or techniques. Micromechanics models can be classified into empirical, semiempirical, analytical, and numerical. The global model is used to compute the displacements and resulting strains, assuming that the material is homogeneous. The local model takes the inhomogeneities into account by modeling them with representative volume elements (RVE) and thus providing a better computation of stress, state variables, as well as secant and tangent constitutive tensors. Also, the computational cost may be too high to model the entire structure with the refinement that can be afforded inside the RVE.