Multi‐scale damage analysis of filament‐wound carbon fiber‐reinforced epoxy composites for hydrogen storage tanks under high strain rates

Abstract This study investigates the relationship between microstructure and mechanical properties of carbon fiber reinforced epoxy composites, specifically in the context of lightweight hydrogen storage pressure vessels manufactured by the filament winding process. The filament winding technique often introduces variability in fiber orientation and porosity which can lead to inconsistencies in mechanical properties. By investigating the influence of dynamic loading over a range of strain rates, from quasi‐static to 100 s −1 , this research aims to understand the effects of different fiber orientations (±15° and ±30°) and multilayer structures on the performance of these composites. Using a custom‐designed Interrupted Dynamic Tensile Test (IDTT) apparatus, we investigated how damage mechanisms evolve during rapid tensile deformation. The results showed that porosity has a significant impact on mechanical performance, particularly at high strain rates, where cracks initiate at pores and propagate via fiber/matrix decohesion and fiber breakage. These microstructural defects contribute to mesoscopic failure mechanisms such as transverse cracking and micro‐delamination between composite layers. The mechanical properties were found to be strain rate sensitive, with visco‐damage phenomena playing a critical role in determining the damage evolution under dynamic loading. These findings provide important insights into the design and optimization of hydrogen storage vessels, highlighting the importance of controlling porosity and understanding the response of the composite to varying strain rates for improved durability and performance. Highlights Comprehensive analysis of dynamic loading. Influence of fiber orientation and porosity on mechanical integrity. Visco‐damage and failure mechanisms under high strain rates.