High Pressure Composite Vessel With Integrated Optical Fiber Sensors: Monitoring of Manufacturing Process and Operation

The main purpose of the work was development of high-pressure composite vessel for hydrogen storage (type IV, CFRC) with an integrated Structural Health Monitoring (SHM) system, based on optical fiber sensors. It has been assumed that this NDE system should provide for continuous and reliable monitoring of the structure during its long operation and enable estimation of degradation degree of the composite vessel load-carrying layer, and by that determination of its safe operation period. Showing suitability of the system for control of the vessels manufacturing technology and fulfilling the requirements of vessel certification standards has been also considered essential. It has been expected, that reaching the work goals required application of measurement methods based at fibre optic sensors with particular consideration for the Fibre Bragg Gratings (FBG). These transducers allowed for integration with the monitored object and were embedded in the composite material structure without influencing its mechanical properties. The research object were prototype vessels for Hydrogen storage in automotive applications, with nominal working pressures up to 700 bars. FBG sensors were integrated with COPV during manufacturing process (winding by robot). It allowed for controlling of each manufacturing steps (winding each layer, curing, hydraulic test) and further use during vessel normal operation. Additional investigations were dedicated to evaluation of SHM strategy, which allows for detection of damages in the vessel structure from manufacturing process through the whole lifespan. The proposed SHM solution was validated during pressure cycle test, which were performed according to the current regulations (EC 406/2010).