Size effects in hybrid unidirectional polymer composites under longitudinal tension: A micromechanical investigation

Abstract

While fibre hybrid composites result in hybrid effects and improved ductility compared to non-hybrid laminates, it is unclear how material size influences hybrid properties (i.e. the so-called 'size effect'). This paper addresses this phenomenon in a carbon-carbon hybrid composite by means of micromechanical modelling using a progressive failure model. Results demonstrate that increasing either the length or the cross-section of the virtual Representative Volume Element (RVE) causes an earlier failure, slightly decreases ductility and significantly improves the hybrid effect. In addition, increasing the RVE volume results in a higher maximum cluster size, while the presence of ductility does not alter the magnitude of the size effects. Further, the presence of a larger hybrid effect does not necessarily translate into greater ductility