Vacuum Prediction of Composites Cryogenic Pressure Vessels Based on Outgassing Behavior of Carbon Fiber Reinforced Polymer

Abstract Carbon Fiber Reinforced Polymer (CFRP) is widely employed in insulated cryogenic pressure vessels (ICPVs) due to their lightweight and superior thermal insulation properties. However, the outgassing behavior of CFRP accelerates interlayer vacuum degradation, compromising thermal insulation performance and the operational safety of these vessels. This study developed a theoretical vacuum outgassing model based on planar specimens and systematically investigated the outgassing characteristics of CFRP (resin volume fraction of 60%) and pure resin materials using the static pressure rise method. Results indicate that CFRP exhibits a lower diffusion coefficient than pure resin, validating the gas diffusion barrier effect of carbon fibers. The total ion current of CFRP represents 62.5% of that of pure resin over the same testing period, further confirming that outgassing originates solely from the resin, with no significant contribution from carbon fibers. Additionally, experiments on ICPV vacuum behavior identify composite outgassing as the primary factor contributing to interlayer vacuum degradation. Over a period of 10 hours, the interlayer pressure increased sharply from 10−1 Pa to approximately 1.5 Pa, highlighting the significant influence of CFRP outgassing on vacuum degradation and the need for effective mitigation strategies. This research provides a robust theoretical and experimental foundation for optimizing the design and maintenance of cryogenic pressure vessels, offering critical insights into improving the thermal insulation performance and reliability of cryo-compressed storage systems.