Dai Yiqing, Chen Jiachun, Yu Chao, Almutairi Ahmed D, Yuan Yan
College of Civil Engineering, Fuzhou University, Fuzhou 350108, China.
Fujian Architecture & Light-Textile Design Institute Co., Ltd., Fuzhou 350001, China.
Materials (Basel). 2025 Sep 12;18(18):4290. doi: 10.3390/ma18184290.
Due to their high strength-to-weight ratio and corrosion resistance, glass fiber reinforced polymer (GFRP) composites have been used in various civil structures. However, the GFRP profiles may be perforated to allow bolting, wiring, and pipelining, causing stress concentration and safety concerns in load-carrying scenarios. A fundamental understanding of the stress concentration mechanisms and the efficacy of mitigation techniques in such anisotropic materials remains limited, particularly for the complex stress states introduced by perforations and mechanical fasteners. This study investigates the effectiveness of three techniques, adhesive filling, bolt reinforcement, and elliptical perforation design, in mitigating stress concentration and enhancing the strength of perforated GFRP plates. The effects of perforation geometry, filler modulus, bolt types, and applied preloads on the stress concentration and bearing capacity are investigated through experimental and finite element analysis. The results reveal that steel bolt reinforcement significantly improves load-bearing capacity, achieving a 13.9% increase in the pultrusion direction and restoring nearly full strength in the transverse direction (4.91 kN vs. unperforated 4.89 kN). Adhesive filling shows limited effectiveness, with minimal load improvement, while elliptical perforations exhibit the lowest performance, reducing strength by 38% compared to circular holes. Stress concentration factors (SCF) vary with hole diameter, peaking at 5.13 for 8 mm holes in the pultrusion direction, and demonstrate distinct sensitivity to filler modulus, with optimal SCF reduction observed at 30-40 GPa. The findings highlight the anisotropic nature of GFRP, emphasizing the importance of reinforcement selection based on loading direction and structural requirements. This study provides critical insights for optimizing perforated GFRP components in modular construction and other civil engineering applications.
由于其高强度重量比和耐腐蚀性，玻璃纤维增强聚合物（GFRP）复合材料已被用于各种土木结构中。然而，GFRP型材可能需要打孔以进行螺栓连接、布线和管道铺设，这在承载情况下会导致应力集中和安全问题。对于这种各向异性材料中的应力集中机制以及缓解技术的有效性，尤其是对于由穿孔和机械紧固件引入的复杂应力状态，人们的基本认识仍然有限。本研究调查了三种技术，即胶粘剂填充、螺栓加固和椭圆形穿孔设计，在减轻应力集中和提高穿孔GFRP板强度方面的有效性。通过实验和有限元分析，研究了穿孔几何形状、填料模量、螺栓类型和施加的预载荷对应力集中和承载能力的影响。结果表明，钢螺栓加固显著提高了承载能力，在拉挤方向上提高了13.9%，在横向方向上恢复了几乎全部强度（4.91 kN对未穿孔的4.89 kN）。胶粘剂填充效果有限，载荷提升最小，而椭圆形穿孔表现最差，与圆形孔相比强度降低了38%。应力集中系数（SCF）随孔径变化，在拉挤方向上8 mm孔处达到峰值5.13，并对填料模量表现出明显的敏感性，在30 - 40 GPa时观察到最佳的SCF降低。研究结果突出了GFRP的各向异性特性，强调了根据加载方向和结构要求选择加固方式的重要性。本研究为优化模块化建筑和其他土木工程应用中的穿孔GFRP部件提供了关键见解。
