I need a question answered. If given the density of 2 materials in a composite, the fibres & the matrix, but not the over all density of the composite, how can one go about finding the thermal expansion coefficient, alpha of the composite? I have Youngs modulus, density of each individual material, & α's of each material. I can use Turners Formula when i have have the volume fraction, but can I get those (the volume fractions) without the overall density of the composite? Thanks for any help or insight.