scholarly journals Local Strand-Breakage Detection in Multi-Strand Anchorage System Using an Impedance-Based Stress Monitoring Method—Feasibility Study

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1054 ◽  
Author(s):  
Ngoc-Loi Dang ◽  
Thanh-Canh Huynh ◽  
Jeong-Tae Kim
Keyword(s):  
Dynamic Responses ◽  
Local Dynamic ◽  
Stress Monitoring ◽  
Monitoring Method ◽  
Stress Variation ◽  
Damage Indices ◽  
Anchorage System ◽  
Strand Breakage ◽  
Scale Experiment ◽  
Tomography Analysis

This study investigates the feasibility of impedance-based stress monitoring method for local-strand breakage detection in multi-strand anchorage systems. Firstly, stress fields of a multi-strand anchorage system are numerically analyzed to examine anchorage’s responses sensitive to local strand breakage. Secondly, an impedance-based stress monitoring technique via the PZT interface is outlined. Thirdly, a novel hoop-type PZT interface is designed for the multi-strands anchorage to monitor the stress variation induced by the strand breakage. Local dynamic responses of the hoop-type PZT interface are analyzed to predetermine the effective frequency ranges. Finally, the numerical feasibility of the proposed method is verified on a seven-strand anchorage system under various strand breakage cases. Variations in impedance responses are statistically quantified, and broken strands are localized by linear tomography analysis of damage indices. A lab-scale experiment is also conducted on a multi-strands anchorage to evaluate the realistic performance of the hoop PZT interface for impedance-based stress monitoring method.

Damage Detection Based on Adaptive Estimation of Amplitude and Phase

2008 ◽  
Author(s):  
Yousof Azizi ◽  
David M. McNamara ◽  
Alireza K. Ziarani ◽  
Ratneshwar Jha
Keyword(s):  
Experimental Data ◽  
Structural Health Monitoring ◽  
Damage Detection ◽  
Health Monitoring ◽  
Adaptive Estimation ◽  
Tracking Algorithm ◽  
Monitoring Method ◽  
Damage Scenarios ◽  
Damage Location ◽  
Damage Indices

This paper presents a novel structural health monitoring method that shows promise in identifying damage location within a structure while providing some means of indicating the severity of the damage. The proposed method is based on an adaptive sinusoid-tracking algorithm (STA), which is capable of tracking sinusoid parameters, namely amplitude, phase, and frequency. The proposed method makes use of the estimated amplitude and phase parameters obtained by processing strain recordings at individual sensors located along an excited structure to identify damage locations and severity. Damage indices have been developed that compare the tracked amplitude/phase from a baseline (or healthy) case to the tracked amplitude/phase from the structure under test at specific locations. The proposed methodology is applied to both simulated and experimental plates in a number of damage scenarios. The results of both simulated and experimental data indicate that the proposed method is promising in the detection of the damage, its location and its severity.

Damage detection in steel structures with semi-rigid connections using unscented Kalman filter

2017 ◽  
Vol 8 (2) ◽  
pp. 222-239
Author(s):  
Hasan Katkhuda ◽  
Nasim Shatarat ◽  
Khaled Hyari
Keyword(s):  
Kalman Filter ◽  
Damage Detection ◽  
Unscented Kalman Filter ◽  
Steel Structures ◽  
Least Square ◽  
Dynamic Responses ◽  
Optimum Number ◽  
Dynamic Force ◽  
Monitoring Method ◽  
Content Type

Purpose The purpose of this paper is to detect damages in steel structures with actual connections, i.e. semi-rigid connections. The method will detect the damages by tracking the changes in the stiffness of structural members using only a limited number of dynamic responses and without knowing the type or time history of the dynamic force applied on the structure. Design/methodology/approach The paper proposes a technique that combines the iterative least-square and unscented Kalman filter (UKF) methods to identify the stiffness of beams and columns in typical two-dimensional steel-framed structures with semi-rigid connections. The detection of damages is by using nonlinear time-domain structural health monitoring method. Findings The technique is verified by using numerical examples using noise-free and noise-included dynamic responses from two different types of dynamic forces: harmonic and blast loads. The results showed that the UKF method with iterative least-square is a powerful approach to identify and detect damages in structures that have nonlinear behavior and the method was able to detect the damages in beams with a very high accuracy for noise-free and noise-included dynamic responses. In addition, the optimum number and locations of dynamic responses (accelerometer sensors) required for damage detection were determined. Originality/value This paper fulfills an identified need to detect damages in steel structures using only a limited number of accelerometer sensors.

Development on Stress Monitoring Method for Measurement of Cyclic Stress of Railway Axles

2005 ◽  
Vol 297-300 ◽  
pp. 84-89
Author(s):  
Seok Jin Kwon ◽  
Kazuhiro Ogawa ◽  
Tetsuo Shoji
Keyword(s):  
Electrical Resistance ◽  
Stress Measurement ◽  
Cyclic Stress ◽  
Railway Vehicle ◽  
Strain Gages ◽  
Stress Monitoring ◽  
Monitoring Method ◽  
Use Of Data ◽  
Copper Electroplating ◽  
Long Time

In general, the S-N curve in railway axles was mainly carried out under 107-108 cycles, while the service area of a railway axle is 108-109 cycles. The strain gages using electrical resistance have been used to measure stresses in railway vehicle wheelsets. However, there are some problems with strain gages using electrical resistance for railway axles. For example, the measured data is for special or limited intervals only. Strain gage installation is complicated, that is, it requires lead wires for measurement. The design of railway axles makes use of data that was obtained many years ago. The applied stresses in wheelsets running for a long time and in new railway vehicle wheelsets have not been studied clearly yet. It is necessary to carry out stress monitoring for more than 108 cycles to evaluate the safety of railway wheelset. Therefore, it is necessary to develop new stress monitoring techniques that can easily measure the working stress of the wheelset. In the present paper, the stress measurement technique of copper electroplating is considered because of its high potential for this purpose.

Theoretical Study on Coal Mine In Situ Stress’s Monitoring Method

2013 ◽  
Vol 446-447 ◽  
pp. 1113-1117 ◽  
Author(s):  
Hong Biao Wang ◽  
Chao An ◽  
Shan Dong Zhang
Keyword(s):  
Coal Mine ◽  
In Situ Stress ◽  
Mining Engineering ◽  
Stress Monitoring ◽  
Working Process ◽  
Monitoring Method ◽  
Deformation And Failure ◽  
The Stability ◽  
Dynamic Phenomena

For mine mining, In-situ stress is the fundamental force that causes the deformation and failure of surrounding rock in the mining engineering and supporting, and produces mine dynamic phenomena. Among many factors which affecting the stability of mining engineering, In-situ stress is the main and one of the most fundamental factors. According to the In-situ stress monitoring method some coal mine adopted, this paper introduces the concrete principle and working process.

scholarly journals Tension Monitoring of Wedge Connection Using Piezoceramic Transducers and Wavelet Packet Analysis Method

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 364
Author(s):  
Xiaoyu Zhang ◽  
Liuyu Zhang ◽  
Laijun Liu ◽  
Linsheng Huo
Keyword(s):  
Energy Transfer ◽  
Stress Wave ◽  
Wavelet Packet ◽  
Active Sensing ◽  
Analysis Method ◽  
Wavelet Packet Analysis ◽  
Monitoring Method ◽  
Anchorage System ◽  
Steel Strand ◽  
Contact Surfaces

A steel strand is widely used in long span prestressed concrete bridges. The safety and stability of a steel strand are important issues during its operation period. A steel strand is usually subjected to various types of prestress loss which loosens the anchorage system, negatively impacting the stability of the structure and even leading to severe accidents. In this paper, the authors propose a wavelet packet analysis method to monitor the looseness of the wedge anchorage system by using stress wave-based active sensing. As a commonly used piezoceramic material, lead zirconate titanate (PZT) is employed with a strong piezoelectric effect. In the proposed active sensing approach, PZT patches are used as sensors and actuators to monitor the steel strand looseness. The anchorage system consists of the steel strand, wedges and barrel, which forms two different direct contact surfaces to monitor the tension force. PZT patches are pasted on the surface of each steel strand, corresponding wedge and barrel, respectively. Different combinations of PZTs are formed to monitor the anchoring state of the steel strand according to the position of the PZT patches. In this monitoring method of two contact surfaces, one PZT patch is used as an actuator to generate a stress wave and the other corresponding PZT patch is used as a sensor to detect the propagated waves through the wedge anchorage system. The function of these two PZTs were exchanged with the changing of transmission direction. The wavelet packet analysis method is utilized to analyze the transmitted signal between PZT patches through the steel strand anchorage system. Compared with the wavelet packet energy of received signals under different PZT combinations, it could be found that the wavelet packet energy increased with the increasing of anchorage system tightness. Therefore, the wavelet packet energy of received signal could be used to monitor the tightness of the steel strand during operation. Additionally, the wavelet packet energy of the received signals are different when the same PZT combination exchanges the energy transfer direction. With the comparison on the received signals of different combinations of PZTs, the optimal energy transfer path corresponding to different contact surfaces of the steel strand could be determined and the optimal experimental results are achieved.

scholarly journals Impedance based service life assessment of corroded structures with Cross correlation analysis

2021 ◽  
Vol 309 ◽  
pp. 01207
Author(s):  
N. Naga Sai Pravallika ◽  
V. Mallikarjuna Reddy ◽  
B. Siva Konda Reddy
Keyword(s):  
Service Life ◽  
Correlation Analysis ◽  
Life Span ◽  
Cross Correlation ◽  
Dynamic Responses ◽  
Life Assessment ◽  
Smart Devices ◽  
Monitoring Method ◽  
Cross Correlation Analysis ◽  
Impedance Technique

Electro mechanical impedance technique has garnered major significance in structural health monitoring field by integrating with information and sensing technology. Technical advancements in automated smart devices improved the diagnostic evaluation of this monitoring method by incorporating piezoelectric materials. The optimistic coupling property of these materials enhanced the life span of structural members by detecting damages at incipient stage. The intervention of piezoelectric transducers has created potential applications for impedance approach in assessing the structural performance with high feasibility. The present work aims at estimating the service life of simply supported smart beam using piezoelectric sensors in Abaqus Simulia software. Corrosion is deployed at a uniform rate in reinforced concrete beam with impressed current flow and the loss in diameter of rebar is calculated using Faraday’s electrochemical equation. With frequency domain based impedance technique numerical analysis is conducted on the modeled beams by exciting the sensor with an external harmonic force and the output electric responses of different piezoelectric locations are captured. The steady state dynamic responses for different cases are compared and quantified with a statistical damage algorithm in MATLAB. The resulted cross correlation indices are analyzed to prevent further deterioration of the corroded beams by setting a limit value. The proposed simulation technology is capable of estimating the residual life span of damage structures with cross correlation analysis.

Monitoring of stress variation of strands in prestressed concrete by second harmonic generation measurements based on piezoelectric sensors

2021 ◽  
Author(s):  
JUN CHEN ◽  
Xiaohan Wan ◽  
Quanquan Guo
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Contact Force ◽  
Prestressed Concrete ◽  
Second Harmonic ◽  
Nonlinear Parameter ◽  
Tension Stress ◽  
Stress Monitoring ◽  
Stress Variation ◽  
Nonlinear Ultrasonic

Abstract The stress loss of prestressed concrete may cause the ultimate failure of structures and the monitoring of stress variation of prestressed structures is therefore important to ensure the service safety. This paper developed a nondestructive evaluation (NDE) method of nonlinear ultrasonic second harmonic generation (SHG) based on piezoelectric (PZT) sensors and applied for the distinction of different stress level of post-tensioned steel strands in concrete. The nonlinear ultrasonic behavior of both free strand and embedded strand having different length is studied with the developed SHG technique and a defined nonlinear parameter is introduced in SHG experiments to correlate with the tension stress in the strand. It is found that the nonlinear parameter has a negative correlation with the increasing stress of strand in both free and embedded case, indicating the nonlinear ultrasonic behavior is getting weak corresponding to the increasing contact force among strand wires. In addition, the decreasing ratio of nonlinear parameter is very close to each other regardless of the length of steel strand, indicating the possibility of replacing the large-scale on-site testing with scaled down samples in laboratory. The experimental results of this research demonstrate that the SHG technique based on PZT sensors could be useful for the stress monitoring of prestressed reinforced concrete with consideration of the relatively high sensitivity of nonlinear parameter to the variation of contact force of strand wires.

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