Modification of the model for calculating the long SiC fibre-reinforced metal matrix composites transverse strength and study for interfacial influences

Abstract

The transverse strength of long SiC fibre-reinforced metal matrix composites is superior to its longitudinal strength owing to interface factors. To accurately predict the transverse strength of long SiC fibre-reinforced metal matrix composites, a micro-mechanics representative volume element (RVE) model was developed; periodic boundary conditions were applied to the model to ensure its displacement and stress continuity. Taking into account the influence of the stress concentration coefficient of the matrix, the failure strength of long SiC fibre-reinforced metal matrix composites under transverse tensile loads and compressive loads were calculated, where the error between the calculation results of the model and the test results was found to be large. A novel calculation method based on the interfacial cohesion model is proposed herein, to improve the accuracy of the RVE model. It was found that the accuracy of the corrected model calculation has been improved through a comparison with the experimental values. The stress/strain relationship between interfaces of different strengths under tensile and compressive loads was analysed, the failure index of interface strength was extracted, and the relationship between the influence of interface strength on failure was determined.