Browsing by Author "DJEMANA Mohamed"

Now showing 1 - 7 of 7
  • Thumbnail Image
    Item
    Detection of unbalance and looseness faults in a ventilation turbine using vibration signature analysis
    (IOP Conference Series: Materials Science and Engineering Publishing, 2022) DJEMANA Mohamed
    Heavy industry, which generally uses turbomachines, often uses both technologies to perform high-performance vibration monitoring of its production tool. Vibration analysis is one of the means used to monitor the health of rotating machinery in operation. This is part of a policy of forecast maintenance of the industrial production tool. This work is part of the monitoring and diagnosis of rotating machines by vibration analysis taking as an example the X205 circulation fan. Numerical simulation was done to test the capabilities and limitations of a dynamic simulation. The modelling of vibratory phenomena is developed using SolidWorks software to perform a dynamic simulation of the 3D model. The numerical simulations were performed to find the effect of different types of defects, such as defect of unbalance fin fan and bolt joint looseness, on the output of system. The numerical results were confirmed either by experimentally using employing results available in the open literature that existent at factory of cement plant (SCHS) and a good agreement was observed. The proposed and derived model has demonstrated the viability of dynamic simulation approach to rotating machines by vibration analysis and serves as a significant alternative approach to the direct experimentation on the same systems in terms of cost and time
  • Thumbnail Image
    Item
    Improving Electromechanical Impedance Damage Detection Under Varying Temperature
    (Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 2022) DJEMANA Mohamed
    The field of structural health monitoring has seen a fundamental shift in recent years, as researchers strive to replace conventional non-destructive evaluation techniques with smart material-based techniques. Perhaps the most promising of smart material techniques for developing structural health monitoring (SHM) systems is electromechanical impedance (EMI) which can be used for real-time structural damage assessment. In EMI, mechanical resonances of structure can be seen in electrical characteristics of piezoelectric transducers due to electromechanical coupling of transducer with the structure. Existence of damage will cause a structural stiffness change and therefore the resonant characteristics of the structure will be altered. This article presents an experimental and numerical study to investigate the effects of notch damage with temperature on the electrical impedance of the piezoelectric sensor used in the EMI technique. The practical implementation of the compact EMI method utilizes as its main apparatus an impedance analyser (Model Agilent 4294A) that reads the in situ EMI of piezoelectric wafer active sensors (PWAS) attached to the monitored structure. The finite element modelling used ANSYS software three-dimensional (3D) capability to simulate an aluminium beam at varying temperatures. Real-time monitoring of the structure is achieved based on harmonic measurements. The results conclusively showed that the proposed temperature compensation technique eliminates the results ambiguity and enabled the EMI system to detect small damages that were otherwise indiscernible
  • Thumbnail Image
    Item
    Improving Electromechanical Impedance Damage Detection Under Varying Temperature
    (Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 2022) DJEMANA Mohamed
    The field of structural health monitoring has seen a fundamental shift in recent years, as researchers strive to replace conventional non-destructive evaluation techniques with smart material-based techniques. Perhaps the most promising of smart material techniques for developing structural health monitoring (SHM) systems is electromechanical impedance (EMI) which can be used for real-time structural damage assessment. In EMI, mechanical resonances of structure can be seen in electrical characteristics of piezoelectric transducers due to electromechanical coupling of transducer with the structure. Existence of damage will cause a structural stiffness change and therefore the resonant characteristics of the structure will be altered. This article presents an experimental and numerical study to investigate the effects of notch damage with temperature on the electrical impedance of the piezoelectric sensor used in the EMI technique. The practical implementation of the compact EMI method utilizes as its main apparatus an impedance analyser (Model Agilent 4294A) that reads the in situ EMI of piezoelectric wafer active sensors (PWAS) attached to the monitored structure. The finite element modelling used ANSYS software three-dimensional (3D) capability to simulate an aluminium beam at varying temperatures. Real-time monitoring of the structure is achieved based on harmonic measurements. The results conclusively showed that the proposed temperature compensation technique eliminates the results ambiguity and enabled the EMI system to detect small damages that were otherwise indiscernible.
  • Thumbnail Image
    Item
    Numerical Simulation of Electromechanical Impedance Based Crack Detection of Heated Metallic Structures
    (Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 2022) DJEMANA Mohamed
    Among the many health monitoring techniques for structures, one relatively new technique is based on electromechanical impedance (EMI) measurements. The goal of this investigation was to see if the EMI approach could be used to assess the health of metallic structures. In order to achieve this objective, the feasibility of numerical simulation of piezoelectric transducer – structure interaction in the field of the EMI technique to perform structural health monitoring using commercial finite element (FE) software, ANSYS was investigated. The numerical simulations were carried out to find the effect of different types of damage such as crack and to investigate the effect of temperature on the crack detection. When compared to experimental impedance responses found in the literature, where EMI is used to monitor different undamaged and damaged structures made of steel and aluminium, the developed FE models successfully obtained similar results with good agreement. This research revealed that the FEM could be a good alternative to experimentation for studying the EMI approach.
  • Thumbnail Image
    Item
    Numerical Simulation of Electromechanical Impedance Based Crack Detection of Heated Metallic Structures
    (The Eurasia Proceedings of Science, Technology, Engineering & Mathematics (EPSTEM), 2022) DJEMANA Mohamed
    Among the many health monitoring techniques for structures, one relatively new technique is based on electromechanical impedance (EMI) measurements. The goal of this investigation was to see if the EMI approach could be used to assess the health of metallic structures. In order to achieve this objective, the feasibility of numerical simulation of piezoelectric transducer – structure interaction in the field of the EMI technique to perform structural health monitoring using commercial finite element (FE) software, ANSYS was investigated. The numerical simulations were carried out to find the effect of different types of damage such as crack and to investigate the effect of temperature on the crack detection. When compared to experimental impedance responses found in the literature, where EMI is used to monitor different undamaged and damaged structures made of steel and aluminium, the developed FE models successfully obtained similar results with good agreement. This research revealed that the FEM could be a good alternative to experimentation for studying the EMI approach.
  • Thumbnail Image
    Item
    Real-Time Structural Damage Detection Using EMI under Varying Load a and Temperature Conditions
    (The Eurasia Proceedings of Science, Technology, Engineering & Mathematics (EPSTEM), 2023) DJEMANA Mohamed
    Structural Health Monitoring (SHM) is a critical aspect of maintaining the safety and integrity of infrastructure. In recent years, there has been a significant shift towards adopting innovative techniques, and one of the most promising methods is Electromechanical Impedance (EMI). EMI involves the utilization of piezoelectric transducers to assess the health of structures in real-time by examining changes in their electrical characteristics. The presence of load causes a change in structural stiffness, which alters the resonant characteristics of the structure. Understanding how external factors like load and temperature influence the electrical impedance of these sensors is essential for its reliable application in damage detection. This article presents an experimental and numerical study to investigate the effects of load and temperature on the electrical impedance of a piezoelectric sensor used in the electromechanical impedance (EMI) technique. The experimental setup uses an impedance analyzer (Agilent 4294A model) to measure the in-situ EMI of piezoelectric wafer active sensors (PWAS) attached to the monitored structure. The numerical model uses ANSYS software to simulate an aluminum beam at varying temperatures. The results show that the load and temperature have a significant effect on the impedance of the transducer. However, it is shown that it is still possible to detect damage using EMI even under varying load and temperature conditions. The results also show that the accuracy of EMI-based damage detection can be improved by using temperature and load compensation techniques.
  • Thumbnail Image
    Item
    Real-Time Structural Damage Detection Using EMI under Varying Load a and Temperature Conditions
    (The Eurasia Proceedings of Science, Technology, Engineering & Mathematics (EPSTEM), 2023) DJEMANA Mohamed ; HRAIRI Meftah (Co-Auteur)
    Structural Health Monitoring (SHM) is a critical aspect of maintaining the safety and integrity of infrastructure. In recent years, there has been a significant shift towards adopting innovative techniques, and one of the most promising methods is Electromechanical Impedance (EMI). EMI involves the utilization of piezoelectric transducers to assess the health of structures in real-time by examining changes in their electrical characteristics. The presence of load causes a change in structural stiffness, which alters the resonant characteristics of the structure. Understanding how external factors like load and temperature influence the electrical impedance of these sensors is essential for its reliable application in damage detection. This article presents an experimental and numerical study to investigate the effects of load and temperature on the electrical impedance of a piezoelectric sensor used in the electromechanical impedance (EMI) technique. The experimental setup uses an impedance analyzer (Agilent 4294A model) to measure the in-situ EMI of piezoelectric wafer active sensors (PWAS) attached to the monitored structure. The numerical model uses ANSYS software to simulate an aluminum beam at varying temperatures. The results show that the load and temperature have a significant effect on the impedance of the transducer. However, it is shown that it is still possible to detect damage using EMI even under varying load and temperature conditions. The results also show that the accuracy of EMI-based damage detection can be improved by using temperature and load compensation techniques.