· The elastic modulus of a composite material can be written in terms of the moduli of its fiber and matrix components and their volume fraction.
· For the uniaxial fiber reinforced composite shown: V_f = Volume fraction of fibers, 
V_m = Volume fraction of matrix, E_f = Fiber Young's modulus, E_m= Matrix Young's modulus.
· When this material is loaded in the longitudinal direction of the fibers, the fibers and the matrix experience the same strain: an Iso-strain situation.
· When the material is loaded transversely to the fiber direction, the fibers and the matrix experience the same stress: an Iso-stress situation.