Low-Velocity Impact Characteristics and Impact Resistance Research of Biaxial Carbon/Glass Hybrid Laminates for Yachts: An Experimental-Simulation Synergy and Innovative Lay-up Design

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 150mm x 100mm 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. Based on this, six laminates with different layup forms were designed, and their impact damage characteristics, as well as the influence of carbon fiber position on the overall impact resistance of the laminates, were comprehensively analyzed from multiple dimensions, including lay-up sequence and interlayer interfaces. Results Through a comparison of numerical simulations and experimental results, it is found that the errors in terms of peak impact force and absorbed energy are both controlled at low levels, with the error in peak impact force being only 9.7% and the error in absorbed energy being 4.6%. This fully validates the effectiveness and accuracy of the simulation model. When comparing different lay-up configurations of the laminates, 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 lay-up 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.