Energy-Dependent Response and Multiscale Damage of Hybrid Unidirectional-Tape/Woven-Fabric Composite Laminates Under...

Despite growing interest in hybrid unidirectional-tape/woven-fabric (UD/WF) composite laminates, the relationship between impact energy, macroscopic response, and multiscale damage evolution under low-velocity impact remains insufficiently understood. To address this issue, hybrid UD/WF composite laminates were investigated under low-velocity impacts of 10, 17, and 25 J through experiments and numerical simulations. Phased-array ultrasonic testing, micro-computed tomography (μCT), and cross-sectional microscopy were used to characterize multiscale damage, while a continuum-damage-mechanics-based progressive damage model was developed to capture intralaminar failure in the UD and woven-fabric plies and interlaminar delamination. The results showed a clear energy dependence of the impact response. The Hertzian failure load varied only slightly with impact energy, whereas the peak load, maximum displacement, and dissipated energy increased from 5.47 kN, 3.77 mm, and 1.91 J at 10 J to 10.08 kN, 5.51 mm, and 5.33 J at 25 J, respectively. Increasing impact energy intensified surface indentation and matrix cracking along the warp and weft directions. The projected delamination area increased from 484.15 mm² at 10 J to 923.78 mm² at 17 J and 987.70 mm² at 25 J, indicating a reduced rate of in-plane delamination growth at higher energies. Notably, from 17 to 25 J, the dissipated energy nearly doubled, whereas the projected delamination area increased by only 6.9%, indicating that the increase in energy dissipation was not accompanied by a proportional increase in the in-plane extent of delamination. At 25 J, internal damage was concentrated near the impact region and was dominated by delamination and matrix cracking, with no extensive fiber fracture in the UD plies. The numerical model reproduced the global impact response, indentation depth, and delamination extent with reasonable accuracy and further revealed nonuniform attenuation of delamination through the laminate thickness. These findings clarify the non-proportional evolution of energy dissipation and in-plane delamination growth with increasing impact energy and provide a basis for impact damage assessment and impact-resistant design of hybrid UD/WF laminates.