119 - EFFECT OF PLY THICKNESS ON INTERLAMINAR FRACTURE TOUGHNESS OF THINPLY THERMOPLASTIC COMPOSITES (CompTest 2025)
Motivated by the need to mitigate climate change, hydrogen as a CO2-free alternative to fossil fuels has been on the horizon for decades. While the successful solution to the future energy and climate crisis will obviously rely on multiple technologies and approaches, complementing each other to achieve continuous and grid-optimized energy supply [1], hydrogen-based technologies are essential as they are versatile enough for many applications, ranging from light personal vehicles, powering of habitation units as well as aerospace and aeronautical applications [2]. A main challenge in the hydrogen supply chain is the storage and transportation due to its high diffusivity and corrosivity to metals. Four storage vessel types are well developed, while the most efficient in use today is type IV, where carbon fiber composite (CFRP) is wrapped over a polymeric liner. Type V tanks, fully CFRP without liner, was proposed during the last decade as a lighter tank and overcome the challenges of type IV tanks that include the liner cavitation and collapse. Despite their advantage, the high permeation rate due to matrix cracks and first ply failure due to accumulation of hydrogen at the interface (similar phenomenon to the liner collapse) are still challenges that limit their application in ground vehicles and storage units [3]. In this work, we propose thin-ply thermoplastic composites that over come both challenges of type V tanks, where matrix cracking was supressed and the interlaminar fracture toughness of the laminate interfaces was enhanced by activating extrinsic dissipation mechanisms during propagation such as fiber and ply bridging. The material used in this study is CF reinforced polyamide 6 (CF/PA6) with ply 42 µm ply thickness. Three staking sequences were consolidated with different layer thickness at the delamination interface: [090/903/03//]𝑠 , [090/90/0/902/02//]𝑠, and [090/90/0/90/0/90/0//]𝑠. These configurations are composed of a core of cross plies and supporting layer of 0 plies to enable the double cantilever beam testing (DCB).
Date
21.05.2025.
Keywords
hydrogen, permeation, thermoplastic, thin-ply, composites
