Systems and methods for monitoring composite structure

A method comprising:

• detecting, by a plurality of broadband piezoelectric sensors connected to a composite cylinder having a laminate structure, deformation data associated with the composite cylinder, the broadband piezoelectric sensors being sensitive to an out-of-plane displacement of the laminate structure of the composite cylinder;
• determining, by a controller communicatively coupled to the plurality of broadband piezoelectric sensors, an estimated impact location on the composite cylinder based on arrival times from each broadband piezoelectric sensor of detected deformation data when the composite cylinder is impacted by an object;
• determining, by the controller, a direct wave energy from the object based on the detected deformation data when the composite cylinder is impacted by the object, the direct wave energy being determined based on a direct arrival time of a slowest moving wave component of interest from the estimated impact location and a voltage detected at each of the plurality of broadband piezoelectric sensors;
• normalizing, by the controller, the direct wave energy for propagation effect based on propagation distance to determine an impact energy corresponding to the impact of the object to the composite cylinder at the impact location, the normalization reducing false triggers by mitigating reflections and wrapping waves;
• communicating, by the controller, a notification when the impact energy exceeds a threshold;
• and
• communicating, by the plurality of broadband piezoelectric sensors to a filling controller, deformation data detected by the plurality of broadband piezoelectric sensors as the composite cylinder is filled with a fluid, causing a safety action to be performed when the filling controller detects damage to the composite cylinder based on the deformation data.

A monitoring system comprising:

• a housing for a composite cylinder, the housing configured to be coupled to a vehicle;
• a plurality of piezoelectric sensors connected to the composite cylinder located within the housing, and configured to detect deformation data associated with the composite cylinder;
• a controller communicatively coupled to the plurality of piezoelectric sensors and configured to:
• receive, from the plurality of piezoelectric sensors, a first detected deformation data associated with the composite cylinder when the composite cylinder is impacted by an object while being attached to the vehicle and during operation of the vehicle,
• determine a direct wave energy from the object based on the detected deformation data when the composite cylinder is impacted by the object, the direct wave energy determined based on a slowest moving wave component of interest from an estimated impact location and a voltage detected at each of the plurality of piezoelectric sensors, and
• communicate a notification when the direct wave energy exceeds a threshold;
• and
• a filling controller communicatively coupled to the plurality of piezoelectric sensors and configured to:
• detect, using a modal acoustic emission inspection, damage to the composite cylinder when the vehicle is being refueled and the composite cylinder is filled with a fluid, the detected damage being associated with the impact from the object and detected based on a second detected deformation data from the plurality of piezoelectric sensors, and
• perform a safety action when the damage to the composite cylinder is detected.