In-Situ Compressive Strength of Carbon/Epoxy AS4/3501-6 Laminates

An experimental program has been conducted to evaluate how changes in laminate lay-up can influence the compression behavior of fiber-dominated, resin-based composites. The testing utilized a cylindrical, 3.81 cm (1.5 in.) diameter test specimen because it provides inherent resistance to global buckling failure modes and lack of free edge effects. Seven different laminates representing 0° dominated lay-ups, axial bias lay-ups, and quasi-isotropic lay-ups were tested. The measured macroscopic stress strain failure data showed a strong in-situ dependence of the 0° failure strain on the lay-up. The quasi-isotropic laminate failure strains were nearly twice the 0° dominated laminate failure strains. Photomicrographs of the failure zone from sections of failed specimens showed the presence of fiber kinking in all the laminate failures.