Correlation between structural frequencies and bending fatigue life of CFRP laminates exposed in hygrothermal environment

doi:10.19936/j.cnki.2096-8000.20250228.013

Abstract

Abstract: The fatigue performance of fiber reinforced polymer (FRP) laminated structures can be degraded rapidly in a humid and warm environment, affecting the safety of the FRP structures and shortening their service life. To study the bending fatigue life of FRP structures in a humid and warm environment, water absorption under different temperatures were conducted on carbon fiber reinforced polymer (CFRP) laminates. Bending fatigue tests and modal testing were performed on the specimens that reached a state of moisture equilibrium. During the experiment, the fatigue loading was interrupted after a number of fatigue cycles, and modal testing were then conducted on the fatigue specimens to obtain the natural frequencies of the CFRP laminated plates. The results showed that fatigue failure occurred at the clamping end, mainly manifested as brittle fracture at the cross-section, with a serrated fracture surface. As the number of fatigue cycles increased, the vibrational frequencies of the CFRP specimens firstly dropped dramatically and then decreased gradually. The frequency reduction rate is following elevated temperature and wet condition (ETW)>room temperature and wet condition (RTW)>room temperature and dry condition (RTD). Compared with the RTD condition, the bending fatigue life of the FRP specimens under the RTW and ETW conditions decreased by 8.96% and 21.2% respectively, indicating that the combined effect of both temperature and humidity has a greater impact on the bending fatigue life of CFRP structures than a single factor, and the temperature has a greater impact than the humidity factor. A quantitative equation has been derived to correlate the structural frequencies and the bending fatigue life of FRP laminates. The outcomes of current work can provide a theoretical basis support for predicting the remaining bending fatigue life of FRP laminated plates through the structural frequencies.

Key words: hygrothermal effect, composite laminate, bending fatigue life, structural frequency

CLC Number:

TB332

LÜ Linze, ZHANG Zhifang, ZHENG Mingfeng, JIANG Jian. Correlation between structural frequencies and bending fatigue life of CFRP laminates exposed in hygrothermal environment[J]. COMPOSITES SCIENCE AND ENGINEERING, 2025, 0(2): 99-107.

References

[1] 刘晓军, 战丽, 邹爱玲, 等. 纤维增强复合材料层间增韧技术研究进展[J]. 复合材料科学与工程, 2022(1): 117-128.
[2] 叶列平, 冯鹏. FRP在工程结构中的应用与发展[J]. 土木工程学报, 2006(3): 24-36.
[3] 罗锐祺, 刘勇琼, 廖英强, 等. 碳纤维增强环氧树脂复合材料力学性能影响因素的研究进展[J]. 材料导报, 2021, 35(增刊2): 558-563.
[4] 郭静静, 张芝芳, 罗子微, 等. 含分层CFRP层合板结构的振动频率与剩余压缩强度的关联性研究[J]. 复合材料科学与工程, 2024(1): 38-44.
[5] LIU S, CHENG X, ZHANG Q, et al. An investigation of hygrothermal effects on adhesive materials and double lap shear joints of CFRP composite laminates[J]. Composites Part B: Engineering, 2016, 91: 431-440.
[6] 赵迅鹏, 孙双双, 王洋. 湿热环境下玻/碳纤维混杂复合材料弯曲强度的宏观力学分析[J]. 复合材料科学与工程, 2022(9): 41-47, 75.
[7] 卢敏, 唐先贺, 冯学斌, 等. 盐雾老化对风电叶片用环氧树脂性能的影响[J]. 玻璃钢/复合材料, 2012(1): 44-47.
[8] SIRIRUK A, PENUMADU D. Degradation in fatigue behavior of carbon fiber-vinyl ester based composites due to sea environment[J]. Composites Part B: Engineering, 2014, 61: 94-98.
[9] 陈琨, 张祥林, 安子乾, 等. 温度对碳纤维平纹布正交层合板拉伸疲劳性能的影响[J]. 材料导报, 2021, 35(16): 16195-16200.
[10] LI B, CHEN J, LV Y, et al. Influence of humidity on fatigue performance of CFRP: a molecular simulation[J]. Polymers, 2021, 13(1): 140-151.
[11] 牛一凡, 李璋琪, 朱晓峰. 全湿热场下碳纤维/环氧树脂复合材料弯曲性能及寿命预测[J]. 复合材料学报, 2020, 37(1): 104-112.
[12] MEJRI M, TOUBAL L, CUILLIÈRE J C, et al. Hygrothermal aging effects on mechanical and fatigue behaviors of a short- natural- fiber-reinforced composite[J]. International Journal of Fatigue, 2018, 108: 96-108.
[13] MA B-L, FENG Y, HE Y-T, et al. Effect of hygrothermal environment on the tension-tension fatigue performance and reliable fatigue life of T700/MTM46 composite laminates[J]. Journal of Zhejiang University-Science A (Applied Physics & Engineering), 2019, 20(7): 499-514.
[14] BEHERA A, DUPARE P, THAWRE M M, et al. Effects of hygrothermal aging and fiber orientations on constant amplitude fatigue properties of CFRP multidirectional composite laminates[J]. International Journal of Fatigue, 2020, 136: 105590.
[15] XU M, ZENG B, AN Z, et al. Experimental and numerical investigation on fatigue properties of carbon fiber cross-ply laminates in hygrothermal environments[J]. Polymers, 2022, 14(9): 1857-1870.
[16] KOSHIMA S, YONEDA S, KAJII N, et al. Evaluation of strength degradation behavior and fatigue life prediction of plain-woven carbon-fiber-reinforced plastic laminates immersed in seawater[J]. Composites Part A: Applied Science and Manufacturing, 2019, 127: 105645.
[17] KULKARNI P V, SAWANT P J, KULKARNI V V. Design and development of plane bending fatigue testing machine for composite material[J]. Materials Today: Proceedings, 2018, 5(5): 11563-11568.
[18] ASTM Standards. Standard test moisture absorption properties and equilibrium conditioning of polymer matrix composite materials: D5229-20[S]. West Conshohocken, PA: ASTM International, 2020.
[19] 张裕恒, 王继辉, 魏建辉, 等. 湿热环境下碳纤维增强乙烯基树脂复合材料长期力学性能[J]. 复合材料学报, 2023, 40(3): 1406-1416.
[20] 陈程, 李晨, 王岩, 等. 湿热环境对T800S/M21碳纤维复合材料基体主导力学性能的影响研究[J]. 复合材料科学与工程, 2024(5): 100-106.
[21] 廖兴升. 基于频率预测GFRP层合梁的剩余疲劳寿命[D]. 广州: 广州大学, 2021.
[22] 寇海霞. 复合材料风电叶片刚度退化模型研究[D]. 兰州: 兰州理工大学, 2019.
[23] 廖兴升, 梁智洪, 傅继阳, 等. 基于频率变化预测玻璃纤维增强树脂复合材料层合板的剩余疲劳寿命[J]. 复合材料学报, 2021, 38(10): 3323-3337.