Effect of tufting on the interlaminar bonding behavior of needled composite

Abstract The needled/stitched dual‐scale interlocking structure is a new fabric structure. However, the effect of stitching on the interlaminar bonding behavior of needled composite has not been elucidated. In this work, the needled/tufted dual‐scale interlocking composite was prepared, and experimental and numerical simulation of Mode I interlaminar property was carried out. The influence of stitching on the interfacial bonding behavior of needled composite was revealed. Results showed that the implantation of tufted fibers greatly improved the Mode I interlaminar property of the needled composite. The maximum experimental load of double cantilever beam (DCB) was 129.32 N, which increased by 248.53% compared to needled composites. And GIC increased by 3 times. Moreover，within a certain range, with the increase of the length of the head of the tufted fiber bundle, the interlaminar performance of Mode I was effectively improved. The typical failure mode of needled/tufted dual‐scale interlocking composite were matrix cracking, brittle fracture of needled fiber bundles, pulled out and brittle fracture of tufted fiber bundles. Moreover, the Tri‐cohesive zone models (TCZMs) was proposed, and DCB simulation of needled/tufted dual‐scale interlocking composite was conducted. The simulation of load–displacement curves was well closed to the experiment. The error range was within 7%.