Design Methodology and Engineering Validation of Thermoplastic Composite Pipelines for High-Pressure Hydrogen Transport

Hydrogen transport under high-pressure conditions poses significant challenges for pipeline materials and structural design. Existing studies on PA12-based systems are primarily limited to material-level characterization, with insufficient validation at the pipeline scale. To address this gap, this study presents the design and system-level experimental validation of an all-thermoplastic composite hydrogen pipeline. A full-scale DN50 pipeline, consisting of a PA12 liner and a ±54° filament-wound carbon fiber-reinforced layer, was fabricated and tested under hydrogen pressures up to 10 MPa, including long-term exposure and cyclic loading. The results indicate stable deformation behavior and low hydrogen permeation (~10−14 mol·m/(m2·s·Pa)) within the investigated pressure range, with a burst pressure exceeding 60 MPa. A transition from stable to accelerated deformation was identified at elevated pressure, indicating a structural operating limit. Post-test observations reveal that interlaminar damage, rather than primary interface failure, governs long-term degradation. Based on these findings, a design framework integrating stress-based, deformation-based, and damage-based criteria is proposed. This work extends PA12-based hydrogen pipeline research from material-level understanding to system-level validation and provides practical guidance for structural design and performance evaluation.