Explicit crack problem solutions of hybrid composites

Abstract

This paper examines the stress concentration problem in an idealized unidirectional continuous intraply hybrid fiber composite due to transverse multifilament failure. The boundary value problems are formulated based upon a two-dimensional elastic shear-lag model for a hybrid composite.Two types of crack in a brittle two-phase hybrid composite are analysed. By assuming that a crack extends when the stress in the first unbroken fiber reaches the average fiber strength, it is possible to predict when each type of crack will extend. A crack in the weak phase begins to spread when the stress in the material exceeds the critical stress. The growth of the crack is not accompanied by breakage of strong fibers. A developed crack, which breaks the material completely, spreads when the stress-intensity factor reaches the critical value. The analytical solution of boundary value problems for two types of semi-infinite cracks allows the critical stress intensity factor and critical stress to be estimated.