A multi-sensing electromechanical impedance method for non-destructive evaluation of metallic structures

Abstract

One of the problems with regard to the electromechanical impedance (EMI) method in the field of structural health monitoring is the relatively high cost requirement of the system. Since the EMI method utilizes a piezoelectric material in small sizes, numerous pieces of equipment are usually required to cover a large area. Thus, in order to compete for the increasing demand for structural health monitoring of components and structures, the technique must be cost effective and large areas need to be rapidly scanned with minimal disruption to the structure's operation. In this study, a technique is proposed for the EMI method to allow sensing of multiple areas with a single frequency sweep, minimizing both the time and the cost of the method. The principle of the proposed technique is the utilization of different resonance frequencies with the piezoelectric material, allowing one to find the location of the damage. Experiments show exceptional results, bringing the EMI method a step closer for real field application.