Temperature Effects on Piezoelectric Wafer Active Sensors

2015 ◽  
Author(s):  
Linlin Ma ◽  
Xiaoyi Sun ◽  
Bin Lin ◽  
Lingyu Yu
Keyword(s):  
Analytical Model ◽  
Temperature Effects ◽  
Spent Nuclear Fuel ◽  
Pressure Vessels ◽  
Ultrasonic Waves ◽  
Final Report ◽  
Active Sensors ◽  
Sensing System ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer

This paper discusses the temperature effects of using piezoelectric wafer active sensors (PWAS) technologies for structural health monitoring (SHM) in pressure vessels and piping (PVP) applications, e.g. dry cast storage system (DCSS). The research into monitoring of DCSS health has experienced a dramatic increase following the issuance of the Blue Ribbon Commission (BRC) on America’s Nuclear Future Final Report in 2012. The interim storage of spent nuclear fuel from reactor sites has gained additional importance and urgency for resolving waste-management-related technical issues. PWAS have emerged as one of the major SHM technologies developed particularly for generating and receiving acousto-ultrasonic waves for the purpose of continuous monitoring and diagnosis. Durability and survivability of PWAS under temperature effects was first tested in experiments. The analytical model of PWAS based sensor and sensing system under temperature effects was then developed. This paper compared the analytical model and experimental results of PWAS under temperature changes. Since the environmental variability of a sensing system includes changes in both the sensors and the sensing methodology including acoustic emission (AE), guided ultrasonic waves (GUW), and electro-mechanical impedance spectroscopy (EMIS), we also performed several temperature exposure with different PWAS sensing configurations under a controlled oven. The potential of PWAS for DCSS applications has been explored. The paper ends with conclusions and suggestions for further work.

scholarly journals Analytical Model of Nuclear Environmental Effects With Piezoelectric Wafer Active Sensors

2014 ◽  
Author(s):  
Bin Lin ◽  
Lingyu Yu ◽  
Victor Giurgiutiu ◽  
Matthieu Gresil ◽  
Adrian E. Mendez Torres
Keyword(s):  
Analytical Model ◽  
Environmental Effects ◽  
Environmental Variability ◽  
Ultrasonic Waves ◽  
Analytical Models ◽  
Sensor Technology ◽  
Nuclear Facilities ◽  
Active Sensors ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer

The increasing number, size, and complexity of nuclear facilities deployed worldwide are increasing the need to maintain readiness and develop innovative sensing materials to monitor important to safety structures (ITS) for pipe and vessels (PVP) application. For example, nuclear dry cask storage system (DCSS) is a safety-critical facility in need of monitoring over prolonged periods of time. Technologies for the diagnosis and prognosis of PVP systems can improve verification of the health of the structure that can eventually reduce the likelihood of inadvertently failure of a component. The past two decades have witnessed an extensive sensor technology development using permanently installed piezoelectric wafer active sensors (PWAS) for structural health monitoring (SHM). PWAS have emerged as one of the major SHM technologies developed particularly for generating and receiving acousto-ultrasonic waves for the purpose of continuous monitoring and diagnosis. Durability and survivability of PWAS under nuclear environmental exposures has been tested preliminarily. However, the analytical model of PWAS based sensor and sensing system has not been developed with adequate solutions and guideline. This paper presents a study on an analytical model of nuclear environmental effects with PWAS. Environmental variability of a Nuclear-SHM system includes changes in both the sensors and the sensing methodology including acoustic emission (AE), guided ultrasonic waves (GUW), and electro-mechanical impedance spectroscopy (EMIS). We considered the environmental variability considers the effects of temperature changes and radiation. We superposed these changes on the analytical models and determined how much the structural sensing signals change is due to these environment effects for the DCSS system. The analytical modeling of various structural sensing methods to environmental disturbances was studied and the potential of PWAS as irradiation sensors for PVP applications was explored. The paper ends with conclusions and suggestions for further work.

Development of a Testing System for Piezoelectric Wafer Active Sensors Exposed to Extreme Temperatures

2015 ◽  
Author(s):  
William Roth ◽  
Banibrata Poddar ◽  
Jingjing Bao
Keyword(s):  
Elevated Temperatures ◽  
Electrical Contact ◽  
Pressure Vessels ◽  
Operating Conditions ◽  
Testing System ◽  
Active Sensors ◽  
Electromechanical Impedance ◽  
Piezoelectric Wafer Active Sensors ◽  
Wide Range ◽  
Piezoelectric Wafer

Piezoelectric Wafer Active Sensors (PWAS) are a viable option for monitoring the structural integrity of pressure vessels and piping systems. They are inexpensive, small and unobtrusive sensors which can be permanently attached to structures for long term monitoring without interfering with operations, such as operating in areas with limited head space. PWAS are used to inspect the structure through several methods which include; pitch catch or pulse echo wave propagation, and electromechanical impedance spectroscopy. Since the PWAS could be exposed to a range of environmental and/or operating conditions while attached to the structure, the change in the properties and electromechanical characteristics of the sensor must be known at a given condition. Accordingly, there is a need for a testing system which can measure the PWAS properties while exposing the sensor to a wide range of temperatures. The focus in this paper is on elevated temperatures, but the same methodology could be used for low temperature or environmental testing. The requirements which were imposed on the design include: providing an electrical connection from each electrode to the exterior of an industrial oven; allow the sensor to expand and contract both in plane and out of plane; withstand an extended duration at elevated temperatures; the equipment must not influence the measured quantities. The challenges include how to place the sensor in an oven and make electrical contact while allowing free motion, how to implement wiring and electrical connections at elevated temperatures, how to allow the thermal expansion of components and account for thermal mismatching, and how to maintain electrical isolation of the two electrodes. This paper discusses how these requirements were met and challenges overcome, as well as experimental validation of the system.

Structural Health Monitoring With Piezoelectric Wafer Active Sensors Exposed to Irradiation Effects

2012 ◽  
Author(s):  
Bin Lin ◽  
Matthieu Gresil ◽  
Victor Giurgiutiu ◽  
Adrian E. Mendez-Torres
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
High Energy ◽  
Pressure Vessels ◽  
Irradiation Effects ◽  
Nuclear Facilities ◽  
Active Sensors ◽  
Structural Health ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer

The increasing number, size, and complexity of nuclear facilities deployed worldwide are increasing the need to maintain readiness and develop innovative sensing materials to monitor important to safety structures (ITS) such as pressure vessels and piping (PVP) in a nuclear reactor. Technologies for the diagnosis and prognosis of PVP systems can improve verification of the health of the structure that can eventually reduce the likelihood of inadvertently failure. Recently investigated piezoelectric wafer active sensors (PWAS) open the possibilities to develop and deploy such system. Piezoelectric wafer active sensors are widely used in structural health monitoring (SHM) to determine the presence of cracks, delaminations, disbonds, and corrosion. Durability and survivability of PWAS under environmental exposures has been tested before. However the irradiation effects, pertinent to nuclear facilities for PWAS, have not been studied yet. This paper presents a study on PWAS that exposed to high energy gamma radiation. PWAS were irradiated using a Co-60 gamma source in an irradiator with different exposure times. The dose rate and total absorbed dose were calculated using Monte Carlo simulations (MCNPX). The PWAS material properties, electrical contact change were characterized through a series of tests. The electro-mechanical impedance spectrum (EMIS) of PWAS was measured before and after irradiation. This study not only provides the fundamental understanding of the PWAS irradiation survivability but also tests the potential of PWAS as irradiation sensors for nuclear applications.

Lamb Wave Tuning Between Piezoelectric Wafer Active Sensors and Host Structure: Experiments and Modeling

2006 ◽  
Author(s):  
Giola B. Santoni ◽  
Victor Giurgiutiu
Keyword(s):  
Lamb Wave ◽  
Integral Transform ◽  
Lamb Waves ◽  
Composite Plates ◽  
Ultrasonic Waves ◽  
Active Sensors ◽  
Piezoelectric Wafer Active Sensors ◽  
Isotropic Plates ◽  
Piezoelectric Wafer ◽  
Alternating Voltage

In structural health monitoring (SHM), a network of embedded sensors permanently bonded to the structure is used to monitor the presence and extent of damage. The sensors can actively interrogate the structure through ultrasonic waves. Among the ultrasonic waves, Lamb waves are quite convenient because they can propagate at large distances in plates and then interrogate a large area. Lamb waves in a plate can be produced with piezoelectric wafer active sensors (PWAS) that are small, inexpensive, unobtrusive transducers. PWAS can be surface-mounted on an existing structured or placed inside composite materials. PWAS sensors use the piezoelectric principle. An alternating voltage applied to the PWAS terminals produces an oscillatory expansion and contraction of the PWAS. An oscillatory expansion and contraction of the PWAS produces an alternating voltage at the PWAS terminals. PWAS are bonded to the structure through an adhesive layer; the coupling with the investigated structure is higher then conventional transducers. If the PWAS bonded to the structure is excited, it couples its in-plane motion with the Lamb wave particle motion on the material surfaces. In previous studies, the Lamb wave mode tuning between PWAS and isotropic plates has been observed experimentally and theoretically. Recently experiments have been performed to verify the presence of tuning between bonded PWAS and composite plates. In the present paper, it will be discussed a method, normal mode expansion (NME), for predicting the tuning frequencies of the PWAS-plate structure. This method can be used for both isotropic and non-isotropic material. Experimental values for the tuning frequencies in isotropic plates are compared with the theoretically data obtain with integral transform solution and NME.

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