PSI - Issue 70

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

575

= ̅̅̅ + = + ̅̅̅̅̅

(1)

(2)

Equation (1) represents the direct piezoelectric effect, in which applied mechanical stress generates electrical charges, whereas Equation (2) illustrates the converse piezoelectric effect, where an applied electric field produces mechanical strain. Using the PZT fundamental expression, and integrating over the complete surface of the PZT transducer, we can arrive at an equation for the EM admittance (inverse of EMI) as y̅= V̅I̅ =iB+G=4ωjl 2 h [ ε 3T̅ 3 − 2d 32 1 Y̅ E ( 1−u ) + 2d 32 1 Y̅ E (1−u) ( Z a,eff Z a,eff +Z s,eff )( ta k n l kl )] The structural parameters will change as a result of any damage, altering their mass and stiffness characteristics. This causes a change in the structural impedance (Z s,eff ), which will change the admittance (y) in the equation above. This will serve as an indicator of the structure's overall health. The EMI technique utilizes the Root Mean Square Deviation value as a scalar damage indicator to evaluate the degree of variation between two signatures and assess the damage severity. Since the conductance signature interacts with structures more than the susceptance signature does, the conductance signature is typically utilized to detect deterioration. RMSD=√ Σ i N (G i −G i 0 ) 2 Σ i N (G i 0 ) 2 Thus, for proactive structural health monitoring, this electro-mechanical impedance approach appears to be a helpful tool. In order to provide greater safety factors, reduced maintenance costs, and longer lifespans for critical infrastructure, the approach depends on the interplay between electrical signals and mechanical characteristics. Technology will surely be incorporated into the smart infrastructure management system as soon as it is developed. 2. Experimental Setup The test arrangement is configured to evaluate the efficiency of the EMI method in identifying moderate and serious structural damages. Specimens are equipped with piezoelectric transducers as actuators and sensors, which measure dynamic impedance responses to controlled excitations. An impedance analyzer, in combination with a data acquisition system captures slight variations in the response for varying damage levels. Systematically, artificial damage situations are applied to calibrate and verify the sensitivity of the system.

2.1. Material and Specimens Beam (500mm x 100mm x 100mm) specimens were casted.

Table 1. Specifications of Mix proportion.

Characteristic compressive strength

M 30

Type of cement

OPC 43 20 mm 100mm

Maximum size of aggregate

Slump

S.G. of sand S.G. of C.A. Zone of F.A.

2.63 2.80

Zone II