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This paper investigates the impact of hybrid fiber structures on the ballistic performance of columnar ceramic/interlayer hybrid fiber composites. Three hybrid fiber composites and one single fiber‐component composite were fabricated. The accuracy of the numerical model was validated through quantitative analysis of matching micro‐CT images with simulation results. The error of the back convex height (BCH) values between the numerical simulation and the micro‐CT was only 2.8%. The error of delamination area at four thickness positions is only 0.7%, 14.7%, 0.3%, and 5.3%, respectively. The quantitative study on the ballistic performance of ceramic/fiber composites indicates that all hybrid fiber composites provide enhanced penetration resistance, with the sandwich structure outperforming the rest. Compared with the C‐U sample, the bullet's remaining velocity and the BCH in the C‐(A/U/A) sample were significantly improved, with reductions of 195 m∙s−1 and 16.6 mm, respectively. During the penetration process, the ceramic/fiber composites mainly exhibited damage failure mechanisms such as ceramic crushing to form ceramic cones, shear failure, and shear‐tensile‐delamination mixed failure. The energy absorption rate (EAR) of ceramic failure was 54.1%–60.2%, the EAR of tension was 12.5%–20.9%, and the EAR of the tension‐delamination‐shearing mixed model was 21.9%–32.8%. Highlights: The numerical model is quantitatively validated with micro‐CT results.Ballistic resistance and EARs in six stages are quantitatively analyzed.C‐(A/U/A) composite has superior ballistic resistance compared to C‐U. [ABSTRACT FROM AUTHOR]

Obtaining a robust fiber/matrix interface is crucial for enhancing the mechanical performance of fiber-reinforced composites. This study addresses the issue by presenting a novel physical–chemical modification method to improve the interfacial property of an ultra-high molecular weight polyethylene (UHMWPE) fiber and epoxy resin. The UHMWPE fiber was successfully grafted with polypyrrole (PPy) for the first time after a plasma treatment in an atmosphere of mixed oxygen and nitrogen. The results demonstrated that the maximum value of the interfacial shear strength (IFSS) of the UHMWPE fiber/epoxy reached 15.75 MPa, which was significantly enhanced by 357% compared to the pristine UHMWPE fiber. Meanwhile, the tensile strength of the UHMWPE fiber was only slightly reduced by 7.3%, which was furtherly verified by the Weibull distribution analysis. The surface morphology and structure of the PPy in-situ grown UHMWPE fibers were studied using SEM, FTIR, and contact angle measurement. The results showed that the enhancement of the interfacial performance was attributed to the increased fiber surface roughness and in-situ grown groups, which improved the surface wettability between the UHMWPE fibers and epoxy resins. [ABSTRACT FROM AUTHOR]