Matrix cracks around fibre breaks and their effect on stress redistribution and failure development in unidirectional composites

Despite the crucial significance of failure prediction in composites, such an objective remains challenging, even in unidirectional (UD) systems. A strength model for UD composites was used that has great versatility in handling various matrix and fibre behaviours. This model includes a simplified superposition principle that was found to be reliable in predicting stress concentration factors irrespective of the presence of matrix cracks. The model revealed the negligible influence of matrix cracks on stress concentrations, ineffective length, cluster development and failure strain. The presence of matrix cracks can therefore be safely neglected in models for UD composites. This information is important for experimental validations and for advancing the state of the art in strength models for UD composites.