Symmetric and asymmetric intercalation effect on the low-velocity impact behavior of carbon/Kevlar hybrid woven laminates

Abstract

Hybrid fiber composite laminates with the same materials, manufacturing methods and molding processes may present different mechanical behaviors. In this paper, the effect of intercalation sequence on the mechanical performance of carbon/Kevlar plain laminates were studied. According to different intercalation methods, the hybrid layout was divided into symmetric and asymmetric configurations. It is found that the symmetric intercalation structures (KCCK and CKKC) possess better load-bearing and resilience capacity compared with asymmetric structures (CCKK and CKCK), even better than pure carbon structure (CCCC) under high energy impact. The impact damage volume of symmetric specimens was significantly smaller than that of asymmetric specimens by quantitative micro-CT analysis. The apparent damage index (df and dr) can be used to estimate the internal damage data (dCT, H and V). KCCK, a typical symmetric sandwich-like structure, presented the most slight damage among all symmetric and asymmetric configurations, with shear cracks observed at the brittle carbon fiber core layers, while the delamination cracks between Kevlar-carbon interlayers were away from the central damaged region. In CKCK, interlaminar cracks were formed at each carbon-Kevlar interlayers, which shared and relieved the primary interlaminar crack at the core layers compared with CCKK.