Evaluation of the effective elastic properties of long fiber reinforced composites with interphases

► Composites with hexagonal fiber arrangement is transversely isotropic. ► Composites with square fiber arrangement is orthotropic. ► Rotational average of square fiber arrangement yield transversely isotropic behavior. ► Elastic constants derived from square and hexagonal fiber arrangements are different. ► Effects of interphase on effective elastic properties are discussed in details.