Compressive strength determined for ultrahigh modulus fiber reinforced composites by [90/0]ns laminates

Abstract

Traditional ASTM D6641 standard is not suitable for ultrahigh modulus carbon fiber reinforced polymer (CFRP) composites under longitudinal compression due to the unacceptable failure mode of end crushing. Experiments and micro-mechanical finite element simulations are conducted for [90/0]ns laminates under compression to check if it is acceptable using results of [90/0]ns laminates to calculate longitudinal compressive strength. Experimental results show that failure modes in [90/0]ns laminates are acceptable. Fiber splitting, fiber breakage and kink band are found clearly in 0-degree lamina under SEM. Failure index distributions before peak load in simulation show that it is fiber failure in 0-degree lamina that causes the final failure which indicates that [90/0]ns laminates can be used to calculate compressive strength. Four different types of fibers with different modulus and [0/90]ns micro-mechanical model for ultrahigh modulus CFRP are also built for comparison. Results show that this method is also applicable for T800H CFRP composites, but not for T300 and T700 CFRP composites.