An enhanced impedance-based damage identification method using adaptive piezoelectric circuitry

The piezoelectric impedance-based method for damage detection is a promising approach in structural health monitoring by virtue of its potential to detect small-sized damages with a low-cost measurement circuit that enables remote monitoring. The amount of available impedance data, however, is generally far less than the number of required system parameters, which results in a highly underdetermined inverse problem for identifying the location and severity of the damage. This numerical ill-conditioning undermines the accuracy and reliability of damage prediction, particularly in practical implementations in which measurement noise and baseline modeling error are unavoidable. In this research paper, we propose a new concept to enrich the impedance measurement by incorporating an adaptive piezoelectric circuitry in the structure. This circuitry alters the dynamics of the integrated system, and by systematically tuning the inductance value, one can significantly increase the number of measurement sets. Thus, the previous seriously underdetermined inverse problem can be notably improved. As a result, the new method yields significantly more accurate damage location and severity identification. A numerical example of the damage prediction of a fixed-fixed beam using the spectral element method demonstrates the effectiveness of the proposed approach. The concept is also verified via experimental investigations.