New Approaches to Quantifying Tensile Strength Variability and Size Effects in Unidirectional Composites

Abstract

Two methods were used to investigate the variability of tensile failure strain of unidirectional high strength carbon/epoxy. Scaled tests on glass/carbon hybrid specimens showed a significant size effect and reduction of failure strain with stressed volume consistent with a Weibull modulus of 25. Ply fragmentation tests were also carried out, producing multiple carbon fractures in a single specimen. Strains from these tests also fitted a Weibull distribution, and gave a similar Weibull modulus to the scaled tests.1