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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1. Introduction The transition towards a hydrogen-based energy system is a fundamental element of Europe's strategy to achieve climate neutrality and energy independence The establishment of a reliable, safe and economically viable pipeline infrastructure is imperative for the successful implementation of large-scale hydrogen distribution. The primary composition of contemporary networks is steel, a material that has demonstrated efficacy in the transportation of natural gas. However, this material also presents substantial challenges for the transportation of hydrogen, primarily due to its vulnerability to hydrogen-induced embrittlement and corrosion. These material limitations result in diminished longevity, augmented maintenance expenditures, and heightened safety hazards, consequently necessitating the investigation of alternative pipeline materials. In this context, fibre-reinforced plastic (FRP) composites have emerged as a promising solution. The corrosion resistance, low weight, and tunable mechanical properties of these materials enable the design of durable and sustainable pipeline systems specifically suited for hydrogen environments. Furthermore, FRP pipelines can be customised in terms of fibre type, orientation, and resin system to meet specific strength and permeability requirements, thus opening new pathways for lightweight and durable infrastructure solutions. [4] At the Institute for Textile Technology (ITA) of RWTH Aachen University, research efforts are concentrated on the development and validation of fibre-reinforced polymer (FRP) pipeline systems for hydrogen transport. The institute's research encompasses material characterisation, diffusion testing and process optimisation through the utilisation of advanced filament winding technology. The overarching objective of this research is to design and manufacture composite pipelines that combine structural integrity with minimal hydrogen permeability, thereby ensuring both technical feasibility and long-term sustainability. The present paper expounds the motivation, methodological approach, and key findings from ongoing investigations into the development of FRP pipelines as a viable alternative to steel in hydrogen transport infrastructure. [1,2,3] 2. State of the Art The transportation of hydrogen via pipelines is considered to be a pivotal element in the future energy infrastructure. At present, the vast majority of extant hydrogen transport systems rely on modified steel pipelines. It is evident that such systems frequently employ high wall thicknesses as a means of compensating for the deleterious effects of hydrogen exposure on material degradation. However, despite their mechanical robustness, steel pipelines are inherently vulnerable to hydrogen-induced embrittlement, which can significantly reduce ductility and promote crack initiation and propagation. It is imperative to pay particular attention to welded joints, as they represent localised areas of microstructural inhomogeneity and residual stress. These factors increase the susceptibility of the material to hydrogen attack. [5, 6] In order to address the aforementioned challenges, it is possible to draw lessons from the development of composite pressure vessels (CPVs) for hydrogen storage. Historically, pressure vessels were manufactured from steel; however, recent advances in materials engineering have led to the widespread adoption of Type IV composite vessels, which employ fibre-reinforced polymer (FRP) structures with polymer liners. These vessels achieve burst pressures of up to 1500 bar while maintaining excellent resistance to hydrogen-induced degradation. The following technologies are pivotal in facilitating the process: the utilisation of pre-impregnated carbon fibres (Towpreg) and highly productive multi-filament winding (MFW) processes. These ensure precise placement of fibres and consistent structural quality. [7] The success of FRP-based storage technologies demonstrates the potential for transferring these materials and process principles to the domain of hydrogen pipelines. In contradistinction to discrete storage vessels, pipelines necessitate uninterrupted production processes and long-term operational reliability under cyclic loading conditions. Consequently, the adaptation of filament winding and braiding technologies for the purpose of scalable FRP pipeline manufacturing represents a promising route towards the creation of lightweight, corrosion-free, and hydrogen-resistant infrastructure. The transition from steel to composite systems has the potential to significantly enhance safety, reduce maintenance requirements, and facilitate the establishment of sustainable hydrogen distribution networks.