1. The following data has been obtained experimentally for a composite based on an unidirectional carbon-epoxy prepreg (MR50 carbon fiber at 63% by volume in LTM25 epoxy). Determine if the restrictions on elastic constants are satisfied.
E1 = 156.403 GPa, E2= 7.786 GPa
v12 = 0.352, v21 = 0.016
G12 = 3.762 GPa
2. Select a matrix, fiber, and fiber volume fraction to obtain a material with E1 > 30 GP a, E1/E2 « 3.5.