Wave localization due to material damping Original Research Article

A structural health monitoring technique developed at the Center for Intelligent Material Systems and Structures (CIMSS) relies on tracking the high frequency impedance characteristics of the structure to qualitatively detect incipient damage. This technique uses PZT actuator-sensors to obtain the structureʹs high frequency point electrical impedance, which is functionally compatible to its mechanical impedance. Due to the high frequency of excitation employed, the sensing region of the PZT actuator-sensor is highly localized in the presence of energy dissipation mechanisms, such as material damping and structural bolts. In this paper, a study of the structural damping effect, at high frequency, on the localization of the PZTs sensing region is presented. For this purpose, a long bolted beam has been simultaneously analyzed using numerical and experimental procedures to obtain a quantification of the energy dissipated through the structure. Firstly, the intrinsic material damping properties of the beamʹs material is experimentally obtained. Then, a theoretical model of the energy dissipation, using a wave propagation approach and the correspondence principle is derived to obtain the specific damping capacity.