PSI - Issue 77

Niels Grigat et al. / Procedia Structural Integrity 77 (2026) 365–375 N. Grigat, B. Vollbrecht et. al. / Structural Integrity Procedia 00 (2026) 000 – 000

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act as preferred initiation sites for hydrogen-assisted cracking (HAC), which can compromise the structural integrity of the pipeline even under moderate operational stresses. To mitigate these risks, several countermeasures are employed, including the use of specialized steel alloys with controlled microstructures, post-weld heat treatments, and internal coatings or liners designed to reduce hydrogen permeation. However, these solutions increase both material and production costs, while the long-term durability of coatings under dynamic pressure and temperature conditions remains uncertain. Therefore, although steel-based hydrogen pipelines can serve as transitional solutions, their long-term feasibility is limited by the intrinsic susceptibility of metals to hydrogen-induced damage. These limitations underscore the necessity for alternative materials that inherently prevent hydrogen diffusion and corrosion — such as fibre-reinforced plastics (FRP) — to ensure sustainable and maintenance-free hydrogen transport systems. [3,5] 2.3. Use of Fibre-Reinforced Plastics as a Material for Hydrogen Applications Fibre-reinforced plastics (FRP) present a compelling alternative to conventional metallic materials for hydrogen related applications, exhibiting a synergy of high mechanical performance and exceptional corrosion and chemical resistance. These composites consist of high-strength fibres, such as glass, carbon, or aramid, which are embedded within a polymer matrix. This matrix provides structural cohesion and environmental protection. The anisotropic nature of FRP materials allows engineers to tailor their mechanical and barrier properties through precise control of fibre type, orientation, and volume fraction. This flexibility enables the design of lightweight yet structurally robust components specifically optimized for hydrogen transport and storage. The successful adoption of FRP composites in the field of composite pressure vessels (CPV) demonstrates their capability to safely withstand extreme pressures in hydrogen environments. In recent decades, there has been a notable transition in the design of storage vessels, with a shift from conventional steel constructions to the adoption of advanced Type IV composite tanks. These composite tanks feature polymer liners that are fortified with pre impregnated (towpreg) carbon fibres, representing a significant advancement in material science and engineering. The contemporary pressure vessels under consideration achieve burst pressures of up to 1500 bar, while concurrently exhibiting exceptional resistance to hydrogen embrittlement and corrosion. The employment of highly efficient multi filament winding (MFW) processes, in conjunction with the integration of pre-impregnated fibre systems, has facilitated reproducible, high-quality production on an industrial scale. Building upon these advancements, the underlying design and manufacturing principles from CPVs can be transferred to the development of FRP-based hydrogen pipelines. In contradistinction to pressure vessels, pipelines necessitate uninterrupted manufacturing processes that preserve uniform structural integrity over considerable lengths. It is evident that technologies such as filament winding and braiding offer effective methodologies for the scalable production of cylindrical composite structures, characterised by high dimensional accuracy and controlled fibre architecture. The combination of these processes with optimised resin systems — such as thermoset or thermoplastic matrices exhibiting low hydrogen permeability — enables FRP pipelines to achieve both mechanical reliability and diffusion resistance. Furthermore, the inherent non-conductivity and corrosion-free properties of FRP materials obviate the necessity for cathodic protection or costly anti-corrosion coatings that are required in steel systems. This approach not only facilitates maintenance but also fosters long-term sustainability and cost efficiency. As research progresses, the validation of FRP pipeline prototypes under realistic hydrogen conditions will be crucial to demonstrate their full potential as next-generation materials for safe, efficient, and durable hydrogen transport infrastructure. [9,11,12,13,l4] 3. Methodology The methodological approach of this research follows a structured sequence consisting of concept development, modelling and simulation, experimental validation, and prototype testing. The workflow guarantees the continuous verification of theoretical findings by experimental data, thereby ensuring the transferability of results from material level investigations to component-level applications.