This study investigates the repeated impact behavior and compression-after-impact (CAI) performance of triaxially braided carbon/glass fiber-reinforced polymer (C/GFRP) composite tubes. A two-stage experimental strategy was proposed to evaluate the synergistic effect of interlayer hybridization and axial yarn reinforcement on damage evolution and mechanical performance. In Stage I, six hybrid braided tubes with different carbon/glass stacking configurations—including pure carbon, pure glass, layered, and reversed-layered structures—were subjected to repeated low-velocity impacts at 31 J. Micro-CT was employed to reconstruct the internal damage morphology and assess damage accumulation. The optimal interlayer configuration was selected based on impact force, displacement, energy absorption, and internal failure characteristics. In Stage II, the selected structure was further reinforced with four types of axial yarns (none, carbon, glass, and carbon/glass alternating), and their axial compressive and CAI performance after 10 J impact was tested. Results revealed that reversed interlayer design effectively suppressed crack propagation and improved damage tolerance under cyclic impacts. Moreover, the inclusion of hybrid axial yarns significantly enhanced residual compressive strength without compromising energy absorption. This study establishes a lightweight, high-performance braided tube design strategy suitable for aerospace and transportation applications.

Synergistic design of intra- and inter-laminar fiber hybridization and axial yarn reinforcement in carbonglass hybrid braided tubes
    Abstract
    1 Introduction
    2 Experimental methodology
        2.1 Specimen preparation
        2.2 Low-velocity repeated impact testing
        2.3 Quasi-static compression and compression-after-impact (CAI) testing
    3 Experimental results and discussion
        3.1 Repeated low-velocity impact behavior
            3.1.1 Impact response history
            3.1.2 Damage morphology
        3.2 Damage mechanisms by Micro-CT
            3.2.1 Damage mechanisms
            3.2.2 Influence of repeated impact and fiber hybridization
            3.2.3 Influence of repeated impact and fiber hybridization
        3.3 Compression and post-impact performance of axial yarn-reinforced braided tubes
            3.3.1 Load–displacement characteristics
            3.3.2 Key parameter comparison
            3.3.3 Performance retention analysis
            3.3.4 Cost–performance analysis
            3.3.5 Assessment of engineering feasibility and application potential
    4 Conclusion
    Acknowledgements 
    References

• Hongjun Li(School of Mechanical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China)
• Zhenyu Wu(School of Mechanical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China, Zhejiang Provincial Innovation Center of Advanced Textile Technology, Shaoxing 312030, China)
• Yuhang Zhang(School of Mechanical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China, Zhejiang Provincial Innovation Center of Advanced Textile Technology, Shaoxing 312030, China)
• Lin Shi(School of Mechanical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China, Zhejiang Provincial Innovation Center of Advanced Textile Technology, Shaoxing 312030, China)
• Xiaoying Cheng(School of Mechanical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China, Zhejiang Provincial Innovation Center of Advanced Textile Technology, Shaoxing 312030, China)
• Zhi Yang(Zhejiang Provincial Innovation Center of Advanced Textile Technology, Shaoxing 312030, China)
• Duncan Camilleri(Faculty of Engineering, University of Malta, Msida MSD 2080, Malta)