Three-dimensional measurement of CFRP deformation during high-speed impact loading

Abstract

The deformation of carbon fiber reinforced plastics (CFRPs) caused by projectile impact governs the absorption or dissipation of kinetic energy of the projectile. However, three-dimensional (3D) numerical information on CFRP deformations caused by projectile impact is not yet available. Therefore, we conducted 3D measurements to evaluate the deformation process and deformation behavior of CFRPs under high-velocity projectile impact, to subsequently evaluate the performance of CFRPs. We used CFRP specimens with two different stacking sequences. For measuring the deformation, we used a high-speed stereovision system comprising two high-speed video cameras. An SUJ-2 sphere projectile was impacted against a specimen plate using a light-gas accelerator at an impact velocity of approximately 175 m/s, and the deformation was recorded by synchronously capturing images using this system. The captured images were converted to stereo images by a 3D correlation method. The stereo images clearly revealed numerical differences in the deformations of the CFRPs with different stacking sequences. We verified the accuracy of results of the 3D measurement by comparing with results of another measurement methodology. Moreover, the stereo images corresponded to results of a numerical simulation of CFRP deformations, which confirms the validity of the simulations both qualitatively and quantitatively. This 3D measurement method is a powerful and useful tool for evaluating the performance of CFRPs during high-velocity projectile impact.