On the Prediction of Failure at a Fiber/Matrix Interface in a Composite Subjected to a Transverse Tensile Load

Abstract

This paper deals with the 3-D stress field of a cylindrical fiber which is embedded into a resin matrix. The composite is then subjected to a uniform tensile load so. The strain energy release rate is computed and the criterion is used to predict debonding initiation at the fiber/matrix interface. The analysis shows that this failure is most likely to occur at the free surface, i.e. the region where the fiber intersects a free surface, for example a hole, an edge, or a crack. Moreover, it will occur at approximately (1/10) the load value required for the same failure to commence at the center of the fiber length. The results are also extended to include a doubly periodic array of fibers which are embedded into a matrix. Based on 3-D considerations, the stiffness matrix is shown to increase as the volume fraction of the fibers increases. Similarly, the stress sr, in the matrix is shown to decrease as the volume fraction of the fibers increases.