Ultra Low-cost Adaptations of Electro-mechanical Impedance Technique for Structural Health Monitoring

This article outlines new low-cost hardware set-ups as viable substitutes for conventionally employed cost-intensive impedance analyzers/LCR meters for implementation of the electro-mechanical impedance (EMI) technique for SHM/NDE. The proposed solutions warrant basic low-cost equipment, such as function generator and digital multimeter, which are commonly available in most laboratories. Unlike the case of impedance analyzers/LCR meters, only the absolute admittance (i.e., magnitude) is measured. A simple computational approach is outlined for effective utilization of the absolute admittance function for SHM after filtering the passive component. Comparison of results with LCR measurements shows that the measurement accuracy of the proposed set-up is fairly good, repeatability excellent, and the damage sensitivity comparable to that of the cost-intensive conventional hardware. The proposed adaptation is, therefore a suitable candidate for the widespread industrial applications of the EMI technique.