DAMAGE DETECTION AND FILTERING OF EOV EFFECTS BY MONITORING PIEZOELECTRIC COUPLING

This paper describes an innovative structural health monitoring approach for smart structures where piezoelectric elements are present and connected to the primary system to be monitored. The approach requires to measure and monitor the piezoelectric coupling trend for different modes of the system. Indeed, this quantity is shown to be sensitive to damage presence and its location, lowly affected by environmental (mainly thermal) and operational variability (which is an important point in structural health monitoring applications), and easy to be es timated. This makes the proposed approach reliable, robust and less expensive compared to already available structural health monitoring methods based on the use of piezoelectric ele ments (e.g., electromechanical impedance approaches). Numerical simulations are employed to highlight the capability of the newly proposed method to detect a damage and its location. Then, the final part of the paper proves the reliability of the approach by means of experimental tests on two different structures: a cantilever beam and a truss, using either piezoelectric patches or stacks. During the tests, particular attention was devoted to environmental variability effects, and the experimental activity confirms that the pro posed structural health monitoring method shows larger sensitivity to damage presence than to environmental variability effects.