Currently, large-volume type IV composite vessel tube trailers garner significant attention and development within the hydrogen energy storage and transportation industry due to their cost-effectiveness and practicality. This study aims to assess the static strength and sealing performance of the boss structure in order to optimize its design. Firstly, a model of the mouth structure of type IV vessels was constructed to analyze the stress distributions in the boss and liner. Subsequently, innovative boss and liner structures were developed based on the primary mouth structure to investigate the impact of geometric dimensions through finite element analysis. This study revealed that changes in geometrical dimensions led to significant alterations in the stresses of the plastic liner in comparison to metallic bosses. Building upon these findings, the structural safety and sealing performance of the boss and liner structure were further validated through finite element analysis. The outcomes of this research can serve as a reference for guiding the structural design of bosses and aiding in the development of hydrogen storage vessels.

As one of the most important future energy solutions, liquid hydrogen has advantages in terms of high energy density, ease of storage and transportation, low cost, and high safety. Valves are critical components for liquid hydrogen systems; compared to other energy systems, liquid hydrogen systems require higher sealing performance for valves at working temperatures to ensure operational safety and efficiency. However, recent research either focuses on cryogenic valves for liquid nitrogen and higher temperature ranges or liquid hydrogen temperatures (−253 °C) with safety valves and small diameters (typically below DN50). In this work, the sealing performance of liquid hydrogen globe valves at design temperatures was investigated through the finite element method and experimental tests. The behavior of different sealing structures under liquid hydrogen conditions was observed by means of comparative numerical analysis. Furthermore, a test system for liquid hydrogen valves with diameters ranging from DN10 to DN100 was established, covering a size range that encompasses 80% of commercially available liquid hydrogen valve products. By employing an internal cooling method utilizing liquid helium to reach target temperatures, the valve leakage rates (both internal and external) were assessed using helium mass spectrometry. The test results indicated that valve leakage was recorded at only 25% of the maximum allowable leakage, thereby adhering to the standards set for liquid hydrogen valves. These test results provide actionable insights for optimizing valve design and advancing hydrogen energy infrastructure development.

The increasing use of lightweight fiber-wound composite pressure vessels in energy-storage and transportation applications has heightened the need to understand impact-induced structural damage and the associated degradation in residual load-bearing capacity. Despite their superior stiffness-to-weight ratio and corrosion resistance, these vessels are susceptible to low-velocity impacts (LVI) during handling and service, which may compromise their residual burst capacity. To address this issue, the present study adopts a sequential numerical procedure to examine the dynamic impact response and post-impact failure behavior of thin-walled composite vessels. The modeling approach uses ABAQUS/Explicit and ABAQUS/Standard sequentially with VUMAT and UMAT subroutines, incorporating the LaRC05-based damage model and a cohesive-zone interface model to capture both intralaminar and interlaminar degradation. With increasing impact energy, the peak impact displacement increases, indicating more pronounced deformation. The residual burst analysis further shows that higher impact energy reduces the vessel’s calculated burst pressure. The predicted burst pressure of an undamaged configuration is 22.95 MPa, serving as a reference for evaluating strength degradation under impact loading. The findings contribute to a deeper understanding of impact response and residual strength behavior in composite pressure vessels, providing a numerical reference for impact-related structural design and safety optimization in advanced energy systems.