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The aim of this study is to characterize and assess the effect of fabric structure on the damage resistance subjected to low velocity impact. Composite panels reinforced by layered unidirectional (LU), layered woven (LW) and 3D orthogonal woven (OW) fabric were prepared respectively and the impact tests were carried out on a low-velocity testbench. Finite element models at yarn-level were established to numerically investigate the material deformation and failure mechanism. The impact tests showed that the OW composite possessed better impact resistance with respect to impact-induced deformation and inelastic energy absorption. The roles of the z-binder have also been identified through comparison of impacted morphology and numerical results. The z-binder serves as cracking trigger due to the weak debonding with resin pocket around it and its zig-zag configuration impedes the growth of delamination by damage deflection. Therefore, the discontinuous resin damage in 3D composite allows the enhancement of impact resistance instead of delamination failure in the 2D panel. In addition, the in-plane interlacement of woven fabric causes that primary yarn breaks in the high stress region and forms a circle damage area, whereas the penetrating cracking along the fiber orientation of superficial layer is induced in the unidirectional composite. [ABSTRACT FROM AUTHOR]

• The structural hybridization effect on low-velocity impact response of braided/unidirectional (UD) laminates was investigates. • Continuum shell finite element models based on the anisotropic constitutive relationship of braided and UD plies were established to reveal the damage onset and propagation. • The extensive delamination formed rapidly when impacted on the fabric side. • The damage characterized by severe fiber breakage occurs at the impact site when impacted on UD ply side. This work investigated the structural hybridization effect on the low-velocity impact response of braided/unidirectional(UD) laminate. Two groups of hybridization laminates, namely interleaving and clustering groups, were manufactured. The impact performance of the specimens was characterized by combining dropping testbench, optical camera and ultra-sound detector. A continuum shell finite element model was established to reveal the progressive damage behavior of hybridization laminate. The specimen in the interleaving group presented overwhelming performance than that in the clustering group. The impact side effect on failure modes was discussed in detail. When impacted on the braided fabric side, extensive delamination formed on the edge of the specimen due to bending deformation. It further resulted in-plane crushing failure of UD sub-laminate. In contrast, severe fiber breakage occurs at the impact site due to combination stress of tensile and shear when impacted on UD side. Therefore, the fabric-impacted specimen exhibits better impact resistance than that impacted on UD side with respect to higher peak load and lower absorbed energy. [Display omitted] [ABSTRACT FROM AUTHOR]