Since the classical mixing theory was developed many extension or modification to complete this one have been done. A relevant modification was introducing of serial-parallel concept which gave as result the Serial/Parallel mixing theory. Afterward, the theory was extended to consider reinforcement like short fiber or carbon nanotubes. On the other hand, different non-linear constitutive equation for simples component was been developed. These constitutive models change the interaction between the components, then homogenized variables and behavior of the composite change too.

In this context, PLCd code incorporates all these phenomenological theory using a continuum mechanics formulation. Several constitutive models with the capacity to reproduce different material behavior (i.e., plasticity, damage) has already implemented in the code. Therefore, it is possible to simulate composites structures taking into account different failure modes in the composites (e.g. delamination, fiber debonding, etc.).