Multiscale Experimental and Numerical Assessment of Filament-Wound Composite Pressure Vessel for Hydrogen Storage

Type IV composite overwrapped pressure vessels (COPVs) are widely used for high-pressure hydrogen storage. They require structural health monitoring techniques that provide accurate strain measurements without compromising structural integrity. This study presents an experimental and numerical investigation of filament-wound glass fiber/epoxy Type IV COPVs with embedded Fiber Bragg Grating (FBG) sensors. The FBG sensors were integrated into every hoop layer of the vessel during filament winding, and their placement was verified by computed tomography (CT). The influence of sensor integration on the composite microstructure was assessed by scanning electron microscopy (SEM), including quantitative evaluation of fiber volume fraction and void content. Hydrostatic burst tests and finite element analysis were performed to evaluate the structural response of the pressure vessel. CT confirmed the successful positioning and orientation of the embedded sensors, whereas SEM revealed that the optical fibers introduced only minor local disturbances comparable to typical manufacturing structural flaws. The numerical model predicted strains similar to those obtained experimentally. Embedded FBG sensors enabled through-thickness strain monitoring, revealing a non-monotonic strain distribution across the monitored hoop layers.