Localised Toughening of AFP Gaps in Cryogenic Hydrogen Tanks acm7 Tracking Number 40Presentation: Session: Session 9: Modelling and Characterisation of AFP Room: Main Session start: 10:50 Thu 16 Apr 2026 Jonas Appels jonas.appels@dlr.de Affifliation: Institute of Lightweight Systems, German Aerospace Center (DLR), Stade, Germany Daniel Stefaniak daniel.stefaniak@dlr.de Affifliation: Institute of Lightweight Systems, German Aerospace Center (DLR), Stade, Germany Clemens Dransfeld c.a.dransfeld@tudelft.nl Affifliation: Faculty of Aerospace Engineering, Delft University of Technology, Netherlands Topics: - Design for manufacturing of composite structures (All Topics) Abstract: During automated fibre placement in dome regions of hydrogen tanks, tow drops lead to triangular gaps, forming resin-rich regions that are prone to microcracking under cryogenic cycling. This research investigates a microscale toughening concept for linerless Type V cryogenic hydrogen tanks based on filling AFP gaps with polyetherimide (PEI). Tensile specimens made from HexPly 8552 with simplified gap regions showed that PEI/epoxy interphases formed around the insert, but the feature dimension depended on fibre packing and resin availability. The tensile properties did not improve, which is attributed to microstructural limitations of the gap and PEI arrangement. The results indicate that insert geometry and local contact conditions must be controlled more precisely before proceeding to a cryogenic validation of PEI-based gap filling. |