Damage Detection of Beams by a Vibration Characteristic Tuning Technique Through an Optimal Design of Piezoelectric Layers

An advanced technique for damage detection in beam structures, using a vibration characteristic tuning procedure is developed by an optimal design of piezoelectric materials. Piezoelectric sensors and actuators are mounted on the surface of the host beam to generate excitations for the tuning via a feedback process. The excitations induced by the piezoelectric effect are used to magnify the effect of the damage in the vibration characteristics of the damaged structure to realize an effective damage detection process. To describe the detection process, theoretical models of the cantilevered beams with and without tuning induced by piezoelectric effect are built first, while the damage is represented by a crack at the fixed end. From the established models, the natural frequencies of the tuned beams with and without the crack are obtained to study the sensitivity of the proposed technique. As a result of the tuning process, more obvious changes on the natural frequencies due to the existence of a crack are observed. The results also indicate a shorter distance from the piezoelectric actuators to the crack leads to a higher detection sensitivity. An optimal length of the piezoelectric actuators is also obtained for better detection.