scholarly journals A novel baseline-free approach for acousto-ultrasonic crack monitoring of rotating axles

2020 ◽  
pp. 147592172095305
Author(s):  
Tobias Reitz ◽  
Claus-Peter Fritzen
Keyword(s):  
Transverse Crack ◽  
Reference Method ◽  
Crack Size ◽  
Ultrasonic Waves ◽  
Bending Test ◽  
Transverse Cracks ◽  
Baseline Model ◽  
Active Sensors ◽  
Operational Conditions ◽  
Piezoelectric Wafer

Axles are widely used mechanical components in rotating machines. In many applications, axles are exposed to varying environmental and operational conditions, including for example, temperature, load and rotational speed. To apply acousto-ultrasonics–based structural health monitoring for axles, it is in some cases not economically feasible to collect data and to construct a baseline model for each combination of all possible environmental and operational conditions. In consideration of such a practical limit, a novel baseline-free method, called Dynamic Reference Method, is proposed in this article for the detection of transverse cracks in axles. Piezoelectric wafer active sensors are applied for exciting and sensing ultrasonic waves. In case a transverse crack is present in an axle, it is noticed that the crack will sequentially open and close within one revolution of the axle when it is mechanically loaded in the radial direction. Such an opening and closing phenomenon of the transverse crack will influence the propagation of the ultrasonic waves. During the short time of data acquisition, the environmental and operational conditions remain nearly constant and the changes in the propagation of the ultrasonic waves may indicate the appearance of a transverse crack on the axle, and a baseline model for the environmental and operational conditions is not needed. To validate the proposed baseline-free method, an axle is put on a rotating bending test rig to first initiate a fatigue crack on the surface of the axle and second to observe its growth. During the test, the ultrasonic waves are measured by piezoelectric wafer active sensor in situ and are analysed online using the proposed baseline-free method. According to the test results, not only can the crack be effectively detected, but also the progressive changes of the crack size can be differentiated. Such results demonstrate the potential of the proposed baseline-free method in condition-based maintenance and predictive maintenance for critical axle components.

Sensor Performance Assessment Based on a Physical Model and Impedance Measurements

2013 ◽  
Vol 569-570 ◽  
pp. 751-758 ◽  
Author(s):  
Inka Buethe ◽  
Claus Peter Fritzen
Keyword(s):  
Low Cost ◽  
Embedded Sensors ◽  
Strain Gauges ◽  
Bonding Layer ◽  
Temperature Dependent ◽  
Active Sensors ◽  
Operational Conditions ◽  
Sensor Performance ◽  
Piezoelectric Wafer Active Sensors ◽  
Piezoelectric Wafer

The employment of a large number of embedded sensors in advanced monitoring systems becomes more common, enabling in-service detection, localization and assessment of defects in mechanical, civil and aerospace structures. These sensors could be optical fibre sensors, accelerometers, strain gauges or piezoelectric wafer active sensors (PWAS). As the latter are quite popular, due to its multipurpose application as actuators and sensors and its low cost, this type will be investigated. Within this paper a possible approach of sensor performance is presented. The method uses the coupled electro-mechanical admittance to detect damage of the PWAS and its bonding layer. The help of a temperature dependent theoretical model provides for influences of changing environmental and operational conditions. The model will be compared with FEM-results, before showing the successful application on experimental results.

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.

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.

Analytical Buckling Loads of Columns Weakened Simultaneously with Transverse Cracks and Partial Delamination

2019 ◽  
Vol 19 (03) ◽  
pp. 1950027 ◽  
Author(s):  
Igor Planinc ◽  
Simon Schnabl
Keyword(s):  
Mathematical Model ◽  
Analytical Solution ◽  
Boundary Conditions ◽  
Parametric Study ◽  
Transverse Crack ◽  
Transverse Cracks ◽  
Buckling Loads ◽  
Crack Location ◽  
Benchmark Solution ◽  
First Time

This paper focuses on development of a new mathematical model and its analytical solution for buckling analysis of elastic columns weakened simultaneously with transverse open cracks and partial longitudinal delamination. Consequently, the analytical solution for buckling loads is derived for the first time. The critical buckling loads are calculated using the proposed analytical model. A parametric study is performed to investigate the effects of transverse crack location and magnitude, length and degree of partial longitudinal delamination, and different boundary conditions on critical buckling loads of weakened columns. It is shown that the critical buckling loads of weakened columns can be greatly affected by all the analyzed parameters. Finally, the presented results can be used as a benchmark solution.

Effects of Briquettes with Different Crack Structures on Propagation Characteristics of Ultrasonic Waves under Wetting Conditions

2020 ◽  
Author(s):  
Gang Wang ◽  
Jinzhou Li ◽  
Huaixing Li ◽  
Zhiyuan Liu ◽  
Yanpei Guo ◽  
...  
Keyword(s):  
Particle Size ◽  
Ultrasonic Velocity ◽  
Bituminous Coal ◽  
Ultrasonic Attenuation ◽  
Crack Size ◽  
Ultrasonic Waves ◽  
Ultrasonic Frequency ◽  
Propagation Characteristics ◽  
Sample Mass ◽  
Velocity Increase

Abstract In order to examine the effect of briquettes with different crack structures on ultrasonic characteristics under different wetting conditions, a series of ultrasonic testing are carried out on briquettes at different wetting heights and the ultrasonic characteristics in these coal samples are explored. The results show that ultrasonic amplitude is positively correlated with the emission voltage, whereas ultrasonic frequency is negatively correlated with the emission voltage. Changes in both are closely related to the particle size and density. The ultrasonic velocity is positively correlated with the wetting degree. Sample mass has the greatest effect on the ultrasonic velocity, followed by particle size, and pressure has the smallest effect. At dry stage, ultrasonic velocity in gas coal is less than that in bituminous coal. The opposite is true in the fully wet state. The influence of crack thickness on ultrasonic velocity gradually increases with the wetting degree increasing. At dry stage, the velocity gradually increases with the crack dip increasing, while as the wetting height increasing, magnitude of velocity increase gradually decreases with the dip increasing. The ultrasonic attenuation in the briquettes reduces with the emission voltage enhancing. The attenuation decreases with sample particle size, crack thickness and crack size decreasing and with sample mass, pressure and crack dip increasing. The ultrasonic attenuation shows a trend of increase before decrease with the wetting height increasing. The attenuation of ultrasonic wave increases with wave velocity increasing for intact samples and shows a trend of increase before decrease for cracked samples.

Sign in / Sign up

Export Citation Format

Share Document