Structural Damage Monitoring and Localization with Longitudinal Wave Measuring Technique by PZT Patches.

This paper presents a practical and quantitative technique for assessment and localization of infancy damages in a structure by measuring the impedance change of piezoelectric patches which were glued on the structure. The consideration of longitudinal wave propagation in structures is introduced for quantitative assessment of damage characteristics because the corresponding frequency regions are easily determined with longitudinal wave propagation analysis. It is shown that the damage location can be simply estimated by measuring the PZT's electric impedance and comparing with the longitudinal strain mode shape functions in the healthy structure.