Quantitative Evaluation of Ply‐Level Hybridization on Impact Damage Resistance and Damage Characteristics of Laminated Composites

ABSTRACT Recent research on impact responses of hybrid laminates composed of thick and thin plies, in particular the quantitative analysis of impact damage characteristics, is limited. This study conducts extensive experiments to examine the influence of the ply‐level hybridization design on the low‐velocity impact (LVI) and compressive after impact (CAI) response, with a focus on the material valuations, such as quasi‐isotropic composite structure, and engineering applications, including the wing spars of the Boeing 787 aircraft. The impact damage characteristics are analyzed both qualitatively and quantitatively using ultrasound C‐scan inspections and de‐ply experiments. Results demonstrate the improvement of impact damage resistance of laminated composites using a ply‐level hybridization, as evidenced by increased damage threshold loads and reduced impact dent depths, and also indicate that the projected delamination area is not suitable as an indicator for evaluating the impact damage resistance of hybrid laminates. Meanwhile, the adaptability of ply‐level hybridization design in engineering has been revealed in terms of fiber breakages and residual properties. These findings suggest that ply‐level hybridization should be applied cautiously when fiber breakage critically affects the damage tolerance of laminated composites.