Hydrothermal aging mechanisms and service life prediction of twisted bamboo fiber wound composites

Abstract

Twisted bamboo fiber (TBF) wound composites produced using filament winding exhibit excellent potential for applications in lightweight and high-strength rotary structural components. Hydrothermal aging crucially influences the durability of TBF-wound composites. The effects of hydrothermal aging on the microstructure, hygroscopic properties, and mechanical properties of TBF Naval Ordnance Laboratory (TBF-NOL) composites were examined in this study to elucidate the hydrothermal aging mechanisms of TBF-NOL composites and predict their service life. The moisture absorption behavior of the TBF-NOL composites conformed to Fick’s second law. After a 30 d water immersion test at 70 °C, the TBF-NOL composites exhibited a high moisture content, leading to a significant decrease in the tensile, bending, and shear properties. Hydrothermal aging significantly deteriorated the TBF/epoxy resin interface in the TBF-NOL composites. The effect of temperature on the hydrothermal aging of the TBF-NOL composites was more pronounced than that of humidity. This study predicts that the bending properties of TBF-NOL composites could be maintained at the 40–50% level for 5–10 years, depending on the degree of exposure to hydrothermal environments. The service-life prediction results can guide the practical application of TBF-wound composites.