Defect damage mechanics: broader strategy for performance evaluation of composites

Damage mechanics is a well established field wherein analyses and methodologies are developed to provide bases for evaluation of materials response and for structural design. Although this field has been very active for composites in the past two decades, the approaches taken still largely treat homogenised microstructures of composites, leaving out influences of manufacturing induced defects in initiation and progression of damage. The present paper illustrates the importance of accounting for such defects by taking examples of voids in unidirectional fibre reinforced composites and of fibre clusters in short fibre composites. The explicit incorporation of defects is suggested as a broader damage mechanics strategy by which failure analysis and the consequent performance evaluation of composite structures must be conducted.