Interfacial bond conditions and stress distribution in a two-dimensionally reinforced brittle-matrix composite

Abstract

A model has been developed for the stress distribution at the fibre/matrix interface in a brittle-matrix composite with a 2D woven reinforcement, which accounts for the interfacial bond conditions and is based on a shear-lag analysis. The modified shear-lag model equations fulfil the equilibrium condition between the interfacial regions exactly, incorporate the thermal stresses explicitly, and can cope with an interface under radial tension. The uniaxial shear-lag model is consecutively applied to the longitudinal tows with their surrounding intertow matrix and to the longitudinal fibres within their intratow matrix mantle. The presence of transverse tows and fibres can be adequately represented by attributing a normal tensile strength to the interface, associated to the restraining effect of the transverse reinforcement geometry. With material data from tensile tests on an Al 2O 3(f)/SiC composite the model parameters are determined, together with the in situ composite properties which are difficult to obtain experimentally. The model is subsequently incorporated into a numerical approach to describe a pull-out experiment.