The high strain rate tension behaviour of pseudo-ductile high performance thin ply composites

In this study the effect of strain rate in tension on two different types of thin-ply pseudo-ductile laminates is reported. These comprised Unidirectional (UD) and quasi-isotropic (QI) hybrids made from low strain thin-ply carbon/epoxy and high strain glass/epoxy prepreg and all-carbon laminates made from thin-ply [±ϴ/0]s laminates referred to as angle-ply (AP) composites. Laminates were designed and subjected to a range of cross-head speeds from 2 mm/min (0.0003 s ⁻¹ ) to 10 m/s (100 s ⁻¹ ). The designed laminates were made from single or hybrids of low strain and high strain unidirectional prepregs, i.e. thin-ply Carbon/epoxy and Glass/epoxy, respectively. Dynamic stress-strain plots and details of the damage mechanisms were obtained for each sample and compared with the quasi-static test results. The investigated thin-ply UD and QI hybrid composite laminates showed excellent pseudo-ductility at different strain rates, whereas the AP laminates were strain rate dependent and pseudo-ductility decreased with increasing strain rate.