Experimental Evaluation of Miniature Impedance Chip for Structural Health Monitoring of Prototype Steel/RC Structures

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The electro-mechanical impedance (EMI) technique has been very successful so far in monitoring structural components made of both metals and nonmetals in the fields of civil, mechanical, and aerospace engineering. In the last two decades, researchers have reported fairly good results using the EMI technique through costly conventional hardware, such as impedance analyzer and LCR meter. This paper evaluates the performance of the low-cost miniature impedance chip AD5933 for structural health monitoring (SHM) of prototype structures. Most studies involving AD5933 have been restricted to miniature metal structures only, and in particular, no study has been reported so far on reinforced concrete (RC) structures. In this investigation, experiments are first performed on a real-life-sized RC beam, 150 × 210 × 4000 mm in size, instrumented with 19 pairs of piezoelectric-ceramic lead zirconate titanate (PZT) patches in embedded configuration, aiming to detect and locate incipient to severe damages. Experimental investigations are then extended to a large mild steel plate structure, 1200 × 970 × 8 mm in size, divided into 30 equal panels and instrumented with one PZT patch at each node. The results of the two studies confirm that the low-cost miniature impedance chip is suitable for level-one damage diagnosis in large prototype structures, both steel as well as RC. However it is not suitable for higher level analysis involving extraction of the structural impedance parameters.