In SOLIDWORKS, the composites values we can only type in one set of material data for each layer, and because the matrix and lamina material in the composite have differing material properties, defining the material properties of either on their own is insufficient, therefore we need to use their effective properties. There is a couple of ways to do this.
Ideally, you could obtain physical test data for the material properties that you require (Young's Modulus etc.). Obviously this is fairly extensive so may not be possible for you?
There are several theories that exist to define different composite materials ( Tsukrov, Piat & Novak, “Micromechanical modelling of porous carbon/carbon composites”, Mechanics of Advanced Materials and Structures, 2005. is a good book to read on the subject.) One example would be the;
Rule of Mixtures (for unidirectional, continuous fibres and with transversely isotropic material)
Assuming the overall properties of the transversely isotropic fibre (Exf, Eyf, nxyf, nyzf, Gxyf) and isotropic matrix (Em, nm) individually are know, the rule of mixtures can be used to calculate the approximate effective properties of the unidirectional lamina. First, lets define some necessary terminology
Fibre Volume Fraction (Vf) - This is defined as the ratio of the total volume of fibre material divided by the total volume of the lamina.
Matrix Volume Fraction (Vm) - This is defined as the ratio of the total volume of matrix material divided by the total volume of the lamina.
If there is not anything else within the matrix (such as voids) then the sum of the Vf and Vm will be 1. The Rule of Mixtures then states that the equivalent properties will be;
Hope this helps