Failure modes of fibre reinforced composites: The effects of strain rate and fibre content

The many aspects of high speed response of fibre reinforced composite mater ials have received the attention of a large number of investigators. Nevert heless, the understanding of the mechanisms governing failure under high sp eed loadings remain largely unknown. The effect of rate and fibre content o n failure mechanisms was investigated by viewing fractured surfaces of tens ile specimens using a scanning electron microscope (SEM). Tensile tests wer e conducted on a woven glass/epoxy laminate at increasing rates of strain. A second laminate (with random continuous glass reinforcement) was tested i n tension at varying fibre volume fractions in order to ascertain the relat ionship between fibre content and failure mechanisms. The results suggest a brittle tensile failure in fibres of the woven laminate. In addition, the matrix was observed to play a greater role in the failure process as speed was increased, resulting in increased matrix damage and bunch fibre pull-ou t. The results also indicated that increasing the fibre volume fraction inc reased the likelihood of a matrix dominated failure mode. (C) 1998 Kluwer A cademic Publishers.