On the in-plane deformability of cross-plied unidirectional prepreg

Abstract

The work presented herein aims to investigate the in-plane properties of cross-plied unidirectional prepreg using the bias extension method. The study considers different generations of carbon fibre/epoxy material systems, and testing is performed at elevated temperatures to enhance the deformability. Using digital image correlation, the specimen deformation and fibre rotation is captured during testing. The study shows that most cross-plied unidirectional material deforms at different characteristic length scales as deformation continues: first seemingly continuous and later in the form of bands. Further, the different type of prepreg materials investigated behaves differently; for one type the pin-jointed net theory fit well, enabling simple estimation of the resulting fibre angle, while for the other two it did not. Different loading speeds and temperatures are investigated in order to pinpoint their influence on the deformability.