SUMMARY

A European project involving 19 industrial and academic partners called the Horizon Hydrogen Energy (H2E) progam is currently underway with the goal of building sustainable hydrogen-energy solutions. Composite Over-Wrapped Pressure Vessels (COPV) are envisioned to store hydrogen at high-pressures for hydrogen vehicles. Structural failure of the COPV is unacceptable, and thus Structural Health Monitoring (SHM) techniques are needed to give real-time updates on the structural integrity of the reservoirs. Ultrasonic techniques are one of the methods being investigated due to their non-destructive and cost-efficient attributes. This work focuses on addressing some of the fundamental concerns with implementing a SHM system based on the excitation and detection of Ultrasonic Guided Waves (UGW) in this novel environment. Most notably, this study uses experimental, analytical and numerical modeling techniques to consider the modal shapes and dispersive properties in this novel environment in order to make key decisions concerning frequency range, modal selection and emitter/receiver type and placement. UGW can be excited by permanently attached transducers on the exterior of the structure and signal analysis techniques can be used to determine if an excited wave packet has interacted with a defect within its propagation path. Wave packet interaction with damage can be quantified by mode conversion and/or mode reflection/transmission coefficients. These interactions are studied in a numerical environment via the finite element method for three specific damage types which were identified by our industrial partners as being critical. Some experimental results are presented as well to corroborate the findings of the numerical simulations.