Durability Study of Carbon/Glass Hybrid Fiber Reinforced Polymer Tubes Under Hygrothermal Environments

ABSTRACT Carbon/glass hybrid fiber reinforced polymer (C/GFRP) tubes, featuring a carbon fiber mat inner liner and an outer glass fiber winding structure, combine the high corrosion resistance of carbon fiber with the cost‐effectiveness of glass fiber, demonstrating significant potential in pipeline engineering. This paper systematically investigated the hygrothermal durability of C/GFRP tubes through accelerated aging tests (25°C, 40°C, and 60°C distilled water environments for 30–146 days). Results indicate that water absorption in C/GFRP follows a two‐stage diffusion model. After 146‐day aging, the water absorption rates reached 0.257%, 0.386%, and 0.537% at 25°C, 40°C, and 60°C, respectively, with elevated temperatures significantly accelerating water absorption. Fiber‐resin interface debonding occurred on both inner and outer surfaces under hygrothermal environments, leading to an 18.9% reduction in hoop tensile strength after 146 days at 60°C, while shear properties remain less affected. Hydrolysis and plasticization of the resin reduced the glass transition temperature ( T g ) by 2.4%–11.6% after 146 days of aging, while microcrack formation prolonged ultrasonic guided wave signal reception time by 8.0 μs. Based on Arrhenius theory, the service life of C/GFRP tubes was predicted for scenarios where tensile strength degrades to 50% at 5.4°C, 12.9°C, and 17.8°C.