Based on the Gurtin–Murdoch interface model, a complex variable-based
approach is presented to study the longitudinal shear behavior of composites
containing unidirectional periodic nanofibers. For intuitive demonstration,
numerical results of the interfacial stress concentration and the effective
(longitudinal) shear moduli are calculated for composites containing circular and
(approximately) regular polygonal fibers. Graphic illustrations show that the
interaction among periodic nanofibers can be neglected in the prediction of the
interfacial stress field when the volume fraction of the fibers is less than 7%. For
reasonably given interface parameters, fiber volume fraction and fiber size, the
composite containing periodic circular fibers can achieve a lowest sensitivity of
effective shear moduli to the interface effect among all the aforementioned
fiber shapes. Moreover, we show that if the fibers are much harder than the
surrounding matrix (for example, the shear modulus of the fibers exceeds
twice that of the matrix), the corresponding interface effect can make only
negligible contributions to the effective longitudinal shear moduli of the
composites.