A structural health monitoring method based on magneto-optic imaging technology

2012 ◽  
Author(s):  
Yu Hua Cheng ◽  
Yi Ming Deng ◽  
Li Bing Bai ◽  
Gui Yun Tian
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Monitoring Method ◽  
Imaging Technology ◽  
Structural Health ◽  
Magneto Optic

scholarly journals Structural Health Monitoring Method of Pantograph–Catenary System Based on Strain Response Inversion

2021 ◽  
Vol 9 ◽  
Author(s):  
Sheng Liu ◽  
Yibo Wei ◽  
Yongxin Yin ◽  
Tangzheng Feng ◽  
Jinbao Lin
Keyword(s):  
Structural Health Monitoring ◽  
Contact Force ◽  
Health Monitoring ◽  
Data Consistency ◽  
Inversion Method ◽  
Maximum Speed ◽  
Strain Response ◽  
Monitoring Method ◽  
Structural Health ◽  
Catenary System

Pantograph-catenary system provides electric energy for the subway lines; its health status is essential to the serviceability of the vehicle. In this study, a real-time structural health monitoring method based on strain response inversion is proposed to calculate the magnitude and position of the dynamic contact force between the catenary and pantograph. The measurement principle, calibration, and installation detail of the fiber Bragg grating (FBG) sensors are also presented in this article. Putting this monitoring system in use, an application example of a subway with a rigid overhead catenary is given to demonstrate its performance. The pantograph was monitored and analyzed, running underground at a maximum speed of 80 km/h. The results show that the strain response inversion method has high measurement accuracy, good data consistency, and flexibility on sensor installation. It can accurately calculate the magnitude and location of the contact force exerted on the pantograph.

scholarly journals Effect of Adhesive Debonding on the Performance of Piezoelectric Sensors in Structural Health Monitoring Systems

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5070 ◽  
Author(s):  
Liu ◽  
Xu ◽  
Li ◽  
Wang ◽  
Zhang
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Research Work ◽  
Piezoelectric Sensor ◽  
Systematic Investigation ◽  
Monitoring Method ◽  
Structural Health ◽  
Negative Effect ◽  
Inherent Frequency ◽  
Slow Rise

Piezoelectric (PZT) ceramic elements are often subjected to complex loads during in- service lifetime in structural health monitoring (SHM) systems, and debonding of both excitation actuators and receiving sensors have a negative effect on the monitoring signals. A first systematic investigation of debonding behaviors by considering actuators and sensors simultaneously was performed in this paper. The debonding areas of actuators were set in different percentage range from 0% to 70%, and sensors in 0%, 20%, 40% and 60%. The signal-based monitoring method was used to extract the characteristic parameters of both the amplitudes and phases of received signals. Experimental results revealed that as the debonding areas of the actuators increase, the normalized amplitude appears a quick decrease before 35% debonding area of actuators and then a slow rise until 60% of debonding reached. This may be explained that the 35% debonding turning point correspond to the coincidence of the excitation frequencies of peripheral actuators with the inherent frequency of the central piezoelectric sensor, and the 60% be the result of the maximum ability of piezoelectric sensor. The degrees of debonding of actuators and sensors also have significant influence on the phase angle offset, with large debonding of actuators increases the phase offset sharply. The research work may provide useful information for practical monitoring of SHM systems.

Structural Health Monitoring of Composite Plates Subjected to Impacts Using the Electromechanical Impedance Technique

2008 ◽  
Author(s):  
Karina M. Tsuruta ◽  
Leandro R. Cunha ◽  
Raquel S. L. Rade ◽  
Domingos A. Rade
Keyword(s):  
Structural Health Monitoring ◽  
Impact Energy ◽  
Health Monitoring ◽  
Fiber Composite ◽  
Composite Plates ◽  
Carbon Fiber Composite ◽  
Monitoring Method ◽  
Electromechanical Impedance ◽  
Structural Health ◽  
Functional Relations

The aim of this paper is to evaluate the use of the Structural Health Monitoring (SHM) technique based on the concept of electromechanical impedance for the assessment of low-energy impact damage in laminated carbon-fiber composite plates. The experiments were carried-out by using an especially designed pendulum, and were planned in such a way to accommodate a range of test conditions, such as impact energy and dimension of the impacting piece. Also, it was investigated the influence of the frequency band in which the impedance functions are measured. Additionally, statistical metamodels were built aiming at establishing functional relations between the values of the damage metric and impact energy for single and multiple impacts. The obtained results demonstrate the capability of the monitoring method to identify various damage levels corresponding to different impact conditions.

Nonlinear ultrasonic detection for evaluating fatigue crack in metal plate

2018 ◽  
Vol 18 (3) ◽  
pp. 869-881 ◽  
Author(s):  
Rong Wang ◽  
Qi Wu ◽  
Fengming Yu ◽  
Yoji Okabe ◽  
Ke Xiong
Keyword(s):  
Fatigue Crack ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Lamb Wave ◽  
Fatigue Cracks ◽  
Crack Model ◽  
Monitoring Method ◽  
Cycle Number ◽  
Structural Health ◽  
Nonlinear Ultrasonic

In engineering structures, metal materials always endure fatigue cracks under long-term service. There has been a demand for developing a structural health monitoring method to evaluate micro-sized fatigue cracks, as cracking is considered as a precursor to structural failure. However, conventional linear-ultrasound-based technology is not sensitive to crack when it is barely visible in a metal medium. In this article, we present a nonlinear ultrasonic technology based on crack–wave interaction to investigate the growth of a fatigue crack. A breathing-crack model with a plastic zone around it was precisely established to reveal the change in the Lamb wave. The relative nonlinear parameter calculated from the fundamental and harmonic components of the Lamb wave showed linearly increasing with the growth of the fatigue crack. The relative nonlinearity was related to ultrasonic parameters, such as the cycle number and the excited frequency of the tone-burst signal. In addition, it was also related to the angle between the sensor and the crack rather than their distance. A set of experiments were conducted, demonstrating that the increasing trend of ultrasonic nonlinearity fits very well to the finite element analysis results. In conclusion, the nonlinear ultrasonic method that can be applied to the detection of micro fatigue cracks in metal plates is an effective structural health monitoring technique.

scholarly journals Structural health monitoring of two-way slabs based on random decrement technique

2021 ◽  
Author(s):  
Azita Pourrastegar
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Failure Modes ◽  
Ambient Vibration ◽  
Experimental Investigations ◽  
Monitoring Method ◽  
Structural Health ◽  
Random Decrement Technique ◽  
Random Decrement ◽  
Extent Of Damage

The current research attempts to explore the feasible use of a Structural Health Monitoring method for a two-way slab system through the effective vibration based damage diagnostic technique of Random Decrement (RD). Experimental investigations have been conducted on a total of four reinforced concrete two-way slab specimens. The slabs behaviour was examined under static loading. The results were presented in terms of load-deflection relationship at service and ultimate load, crack pattern and failure modes. At each stage of loading, the ambient vibration excitation test has been performed to investigate the extent of damage at the cracking, yield, and ultimate states through changes in dynamic parameters obtained from RD signatures. Additional applications of RD technique were performed on two-way slabs, first, to explore the location of damage by Multi-Channel Random Decrement using FBG sensor arrays. Secondly, RD technique was utilized to evaluate the extent of damage under successive equal dynamic impacts.

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