PSI - Issue 70

Maheshwari Sonker et al. / Procedia Structural Integrity 70 (2025) 477–484

478

1. Introduction Composite fibre concrete is widely used for its high strength, durability, and resistance to environmental degradation. However, mechanical and environmental stressors can still lead to micro-cracks and damage over time. Traditional inspection methods are invasive and limited, highlighting the need for real-time, non-destructive monitoring techniques. The Electromechanical Impedance (EMI) technique, leveraging piezoelectric sensors, offers a non-destructive, real-time alternative capable of detecting minute structural changes through impedance variations. Previous studies have shown the effectiveness of the electromechanical impedance (EMI) technique for damage detection in composite materials. For instance, Salahaldein (2016) assessed damage detection in glass fiber composite plates using various PZT attachment methods to identify defects such as delamination and cracks through experimental analysis and finite element verification. Additionally, Shakir et al. (2008), H. Im et al. (2019) introduced a novel inverse algorithm for damage localization in unidirectional composite samples using the EMI technique, significantly improving localization accuracy. However, these studies primarily focus on fiber-reinforced polymer composites and do not specifically address the experimental evaluation of damage detection in composite fiber concrete using the EMI technique. This study aims to enhance the application of the Electro-Mechanical Impedance (EMI) technique for damage detection in composite fibre concrete structures, contributing to the field of structural health monitoring (SHM). Rather than limiting the scope to conventional concrete, this work focuses on the performance of the EMI method in detecting various damage levels in composite fibre concrete. A summary of the damage scenarios investigated is presented in Table 1. It introduces a technique designed to improve sensitivity and address challenges in identifying damage through variations in impedance signatures Peng (2013), Wandowski (2021), K. Chandramouli (2010) and Enfedaque et al. (2017). This study aims to detect, identify, and quantify multiple types of damage in concrete using the EMI technique. By calculating Root Mean Square Deviation (RMSD), Correlation Coefficient (CC), and Mean Absolute Percentage Deviation (MAPD) values from conductance signatures of different grade of concrete mix, we can effectively locate damages, assess their severity, and experimentally validate any structural changes Sonker (2025).

Table 1. Summary of different damages monitoring. Author & Year Method

Application

Key Result

Narayanan & Subramaniam (2017)

PZT sensors, EMI

Damage monitoring in concrete

EM peaks indicate load damage

AE, convolutional neural network (CNN) model Acoustic emission (AE), K Nearest Neighbors (KNN)

Online structural health monitoring (SHM)

99.6% accuracy, 0.555 mJ energy KNN effective for damage estimation

Zhang et al. (2023)

Real-time reinforced concrete (RC) monitoring

Inderyas et al. (2024)

Piezo sensors, EMI

Corrosion in prestressed concrete (PSC)beams

EMI tracks corrosion accurately

Bansal et al. (2024)

2. EMI Measurement Setup An LCR- meter was employed to measure electrical impedance of PZT sensors across a 30–400 kHz frequency range. Initial baseline signatures were recorded for undamaged specimens in eq. 1. = + = 4ω 2 ℎ [ 3 3 − 2d 2 3 1 (1− ) + 2d 2 3 1 (1− ) ( , , + , ) ] (1) Where, 3 1 = electrical admittance; ω represents the excitation frequency, l and h denote the half-length and the thickness of PZT patch, respectively ; 3 3 = 3 3 (1−δ ) is the complex dielectric constant at constant stress; = complex tangent ratio; ν = Poisson’s ratio . The impedance of mechanical structure is sensitive to the changes in its properties, such as stiffness, mass, and damping, which may occur due to damage, or environmental effects. By monitoring shifts in the electrical impedance spectra, damage can be identified and characterized.