Stress Analysis of Unidirectional Fiber-Reinforced Composites

Part 1. Longitudinal Shear Loads

Abstract

The stress state in the unidirectional fiber-reinforced composites subjected to the longitudinal shear loading, τξz, is calculated with the point-matching technique. The square and the hexagonal array models are considered. The direction of the ξ-axis, in which τξz is defined, is arbitrarily taken in the transverse plane. The main results are that the maximum shear stress concentration is produced by τξz when the ξ-axis coincides with the direction in which the spacing between fibers is the thinnest and that it occurs at the fiber-matrix interface in any cases. It is also clarified that the maximum value of stress concentration factor is more dependent on geometrical parameters such as the closeness between fibers and the direction of the ξ-axis than on a material parameter, i. e., the shear moduli ratio of the constituents.