Structural Health Monitoring (SHM) techniques aim to evaluate the structural integrity of civil, mechanical and aerospace systems. All these systems have a predicted service life which can be heavily reduced because of damage occurrence; their safety, serviceability and performance need to be ensured through the most suitable techniques. Once some damage emerges in the structures, the changes in the physical properties can cause detectable changes in modal parameters such as natural frequencies, modal damping and mode shapes, which can be used to detect, characterise and localise the damage itself. During the last few years, many techniques have been developed to identify suitable and reliable damage indices, and vibration-based structural health monitoring (VBSHM) has achieved great success and widespread adoption. The main goal is to remove or minimise environmental and operational influences such as temperature variations which can affect the quality and reliability of the analysis. Structures under investigation are typically laboratory ones representing plausible structures on a laboratory scale. This PhD thesis studies the possibility of implementing piezoelectric transducers for SHM techniques suiting a model-based approach. The structure under investigation is a laboratory truss girder specifically designed to develop VBSHM techniques. The possibility of exploiting the electromechanical coupling between the structure and piezoelectric transducer, specifically the variation of the so-called Modal Electro-Mechanical Coupling Factor (MEMCF) between undamaged and damaged conditions to evaluate the structural health status is investigated. This scalar parameter, which measures the effectiveness of the transducer’s sensing and actuating capabilities, has been proven to be sensible to structural alterations and not to temperature variations, being a reliable damage index. Moreover, it can be easily estimated by measuring the eigenfrequencies of the electromechanical system. This study provides numerical and experimental analysis: first, a Finite Element (FE) analysis of the electromechanical system, in different healthy conditions, has been performed to identify the best transducer and its best placement in the structure. After that, experimental tests were performed to validate the model and to estimate the variation of the MEMCF from undamaged to damaged condition of the structure. Ambient vibration excitation has been simulated with a shaker input signal control strategy to perform an Operational Modal Analysis (OMA) and properly estimate modal parameters such as eigenfrequencies. Different damage scenarios have been tested to evaluate the sensitivity of the damage indexes chosen to the damage’s entity and location.

Vibration-based damage detection strategies using piezoelectric sensors

Carlotta, Rossi
2025

Abstract

Structural Health Monitoring (SHM) techniques aim to evaluate the structural integrity of civil, mechanical and aerospace systems. All these systems have a predicted service life which can be heavily reduced because of damage occurrence; their safety, serviceability and performance need to be ensured through the most suitable techniques. Once some damage emerges in the structures, the changes in the physical properties can cause detectable changes in modal parameters such as natural frequencies, modal damping and mode shapes, which can be used to detect, characterise and localise the damage itself. During the last few years, many techniques have been developed to identify suitable and reliable damage indices, and vibration-based structural health monitoring (VBSHM) has achieved great success and widespread adoption. The main goal is to remove or minimise environmental and operational influences such as temperature variations which can affect the quality and reliability of the analysis. Structures under investigation are typically laboratory ones representing plausible structures on a laboratory scale. This PhD thesis studies the possibility of implementing piezoelectric transducers for SHM techniques suiting a model-based approach. The structure under investigation is a laboratory truss girder specifically designed to develop VBSHM techniques. The possibility of exploiting the electromechanical coupling between the structure and piezoelectric transducer, specifically the variation of the so-called Modal Electro-Mechanical Coupling Factor (MEMCF) between undamaged and damaged conditions to evaluate the structural health status is investigated. This scalar parameter, which measures the effectiveness of the transducer’s sensing and actuating capabilities, has been proven to be sensible to structural alterations and not to temperature variations, being a reliable damage index. Moreover, it can be easily estimated by measuring the eigenfrequencies of the electromechanical system. This study provides numerical and experimental analysis: first, a Finite Element (FE) analysis of the electromechanical system, in different healthy conditions, has been performed to identify the best transducer and its best placement in the structure. After that, experimental tests were performed to validate the model and to estimate the variation of the MEMCF from undamaged to damaged condition of the structure. Ambient vibration excitation has been simulated with a shaker input signal control strategy to perform an Operational Modal Analysis (OMA) and properly estimate modal parameters such as eigenfrequencies. Different damage scenarios have been tested to evaluate the sensitivity of the damage indexes chosen to the damage’s entity and location.
Vibration-based damage detection strategies using piezoelectric sensors
9-mag-2025
ENG
Structural Health Monitoring
Operational Modal Analysis
Piezoelectric elements
Electro-mechanical coupling factor
I-MIS/01-A
Marcello, Vanali
Università degli Studi di Parma. Dipartimento di Ingegneria dei sistemi e delle tecnologie industriali
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14242/213325
Il codice NBN di questa tesi è URN:NBN:IT:UNIPR-213325