PSI - Issue 70

Anubhav Kumar Singh et al. / Procedia Structural Integrity 70 (2025) 572–579

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2.2 PZT sensor placement The performance of the sensor, as well as the rigidity of the host structure, is the primary determinant of the electromechanical admittance. The surface of each specimen is surface-mounted by a piezoelectric sensor using epoxy resin. The PZT sensor electrodes are coupled to a measuring circuit that detects electrical signals when the sensor is subjected to mechanical stress caused by specimen vibration or strain. 2.3 Testing of Specimen An IM3536 LCR meter provides a 1V AC voltage signal to the PZT sensor to energize it. The voltage signal is applied to the sensor at a particular frequency. On providing controlled artificial damage using cutter machine at three locations: A (d1 to d6), B (d7 to d12), and C (d13 to d18) with depth increment of 0.5cm, the specimen's mechanical deformation, such as strain or vibration, generates an electric charge in the sensor. By altering the signal's frequency, the sensor's response can be evaluated during different modes of vibration or the specimen's resonant frequencies. The specimen was tested at healthy and damaged stages. The damage is applied using a controlled method of cutting in specimen to simulate different levels of damage. a. b

Fig. 1. Beam Specimen (a) At healthy state; (b) After Controlled damage.

2.4 Data Acquisition and Analysis Collected data from the LCR meter are fed into a data acquisition system, where the real and imaginary admittance signatures are stored for subsequent evaluation. Each EMI measurement was followed by the saving of data for analysis. Using an LCR meter, the PZT's electrical admittance was measured and displayed as a function of frequency, which showed both real and imaginary components. The admittance signature after processing was compared to estimate the extent of damage in terms of mass, and stiffness.

Fig. 2. Experimental setup showing data acquisition

2.5 Monitoring and Visualization over time Once the data is processed, the results are visualized on a computer screen or display system. Continuous monitoring provides early damage detection. By interpreting the impedance trends, engineers can make proactive decisions, ranging from localized repairs and preventive measures to, in more serious cases, complete replacement of damaged sections. In this way, proactive behavior allows for the safe preservation of the structure, the elongation of its lifespan, and the prevention of expensive repair work.