Manufacturing and drop-weight impact properties of three-dimensional integrated-woven sandwich composite panels with hybrid core

This paper is concerned with the effect of core pile yarn hybridization on the low-velocity impact response of 3D integrated-woven sandwich composite panels. For this purpose, at first, hybrid yarn was produced by a co-wrapped technique that is composed of polyester and glass fibres as shell and core structure, respectively. Then, 3D-woven samples with glass and hybrid pile yarns were fabricated, and after the impregnation, the behaviour of fabricated samples under low-velocity impact was experimentally investigated. In order to characterize this new type of hybrid structure, the fabricated samples with different pile heights and pile distribution densities were subjected to low-velocity impact tests at an energy level of 8 J. The impact characteristics of all panels including the load–time and load–displacement curves, contact time, absorbed energy and extent of the damage have been studied. Also, the extent of damage is interpreted in terms of the compressive strength loss after the impact of samples. According to the results, in comparison with the homogeneous glass/epoxy composites, contact time and deflection increased in panels with hybrid pile yarn, whereas the impact load decreased for the hybrid one. On the other hand, hybrid samples have a lower impact index than the homogeneous glass/epoxy composites. The compression after impact test results showed that the residual strength in hybrid samples is higher than the glass/epoxy composites.