The Influence of Carbon Fiber Layer Position on the Low-Velocity Impact Characteristics of Biaxial Carbon/Glass Hybrid Laminates for Yachts

Objectives In consideration of the potential low-velocity impact risks faced by yachts during navigation, particularly in critical structural parts such as the bow and hull sides, higher requirements are imposed on the impact resistance of materials. The purpose of this study is to explore the mechanical response of different carbon/glass fiber hybrid laminates under low-velocity impact, in order to break the limitation of traditional single-material structures in terms of impact resistance, and provide a new idea for lightweight and high-strength design of yacht structures.

Methods In accordance with ASTM D7136M-05, carbon fiber and glass fiber commonly used in the actual yacht structures were selected to design and prepare carbon/glass fiber hybrid laminates with the size of 150 mm x 100 mm as test objects. A drop-weight impact tester was employed to conduct low-velocity impact tests, simulating the potential low-velocity impact scenarios that yachts may encounter in real-world operating environments. Furthermore, to gain a deeper understanding of the damage mechanisms during impact, a high-precision Vumat subroutine was developed by integrating the Hashin failure criterion and an energy dissipation evolution scheme. This subroutine was utilized to perform detailed numerical simulations of the low-velocity impact process of the laminates. Six laminates with different layup forms were designed, and their impact damage characteristics were analyzed in terms of peak impact force, absorbed energy, and damage morphology. The influence of carbon fiber position on the impact properties was specifically investigated.

Results Through a comparison of numerical simulations and experimental results, it was found that for the original laminate impact specimen, the peak impact force and absorbed energy were 5.54 kN and 8.98 J, respectively, with corresponding numerical simulation errors of 9.7% and 4.6%, which verified the validity of the simulation model. The analysis of the influence of carbon fiber position reveals that: the (C₂G₂)_S is found to exhibit significant advantages in impact resistance. Compared to other lay-up configurations, the (C₂G₂)_S has the highest absorbed energy value, with an increase of up to 34%, indicating its superior ability to absorb and dissipate impact energy during the impact process. Although its matrix damage volume is 1.4 times that of the (G₂C₂)_S, its maximum deformation is reduced by 8%, which further proves that (C₂G₂)_S has excellent deformation resistance while maintaining high toughness.

Conclusions Through the experimental-simulation synergy approach, this study not only validates the accuracy of the simulation model built for simulating the low-velocity impact behavior of carbon/glass fiber hybrid laminates, but also reveals the influence mechanism of different layup combinations on the impact resistance. These research findings provide a solid scientific basis for the optimal design of yacht composite structures, the formulation of impact protection strategies, and engineering applications. They hold significant theoretical guidance and practical application value for promoting innovation and development of yacht structural materials.