Application of Marginal Spectrum in Active Lamb Wave Damage Monitoring of Plate Structure

2014 ◽  
Vol 490-491 ◽  
pp. 1698-1701 ◽  
Author(s):  
Bao Chun Xu ◽  
Mu Lan Wang ◽  
Qian Jia
Keyword(s):  
Health Monitoring ◽  
Lamb Wave ◽  
Monitoring Technology ◽  
Plate Structure ◽  
Damage Monitoring ◽  
Before And After ◽  
Marginal Spectrum ◽  
Scattering Signal

In this study, the marginal spectrum based on instantaneous parameter is applied to the active Lamb wave-based health monitoring of plate structure to investigate the marginal spectrum variation of the signals after being added with damage scattering signal. First,the active Lamb wave monitoring technology is employed to obtain the Lamb wave signals of the plate before and after damage. Then the marginal spectra of the signals before and after damage are obtained using the HHT technology and compared with the spectrum of the signals. The results show that the marginal spectrum can better describe the variation of the signals before and after damage.

Impedance Analyzer Design Based on EMI and Lamb Wave

2014 ◽  
Vol 529 ◽  
pp. 506-510 ◽  
Author(s):  
Yu Xiang Zhang ◽  
Xin Zhang ◽  
Shi Yi Chen ◽  
Jia Zhao Chen
Keyword(s):  
Health Monitoring ◽  
Lamb Wave ◽  
Detection Method ◽  
Specific Structure ◽  
Impedance Analyzer ◽  
Wave Technology ◽  
Damage Monitoring ◽  
Single Method ◽  
Active Detection

EMI and the Lamb Wave technology are two kinds of mainstream active detection method in health monitoring , which have a long-term development. Health monitoring based on the combination of the EMI technology and Lamb wave, can be either a single method to conduct monitoring and analysis of specific structure ,or two methods together to conduct more comprehensive damage monitoring.

Selection of Materials and Sensors for Health Monitoring of Composite Structures

2003 ◽  
Vol 785 ◽  
Author(s):  
Seth S. Kessler ◽  
S. Mark Spearing
Keyword(s):  
Health Monitoring ◽  
Lamb Wave ◽  
Composite Structures ◽  
Structural Damage ◽  
Performance Metrics ◽  
Full Range ◽  
Transportation Systems ◽  
Health Monitoring Systems ◽  
The Relationship ◽  
Selection Of

ABSTRACTEmbedded structural health monitoring systems are envisioned to be an important component of future transportation systems. One of the key challenges in designing an SHM system is the choice of sensors, and a sensor layout, which can detect unambiguously relevant structural damage. This paper focuses on the relationship between sensors, the materials of which they are made, and their ability to detect structural damage. Sensor selection maps have been produced which plot the capabilities of the full range of available sensor types vs. the key performance metrics (power consumption, resolution, range, sensor size, coverage). This exercise resulted in the identification of piezoceramic Lamb wave transducers as the sensor of choice. Experimental results are presented for the detailed selection of piezoceramic materials to be used as Lamb wave transducers.

Development of PZT fiber rosette to locate acoustic source

2021 ◽  
pp. 1045389X2199192
Author(s):  
Bao Chi Ha ◽  
Kevin Gilbert ◽  
Gang Wang
Keyword(s):  
Lead Zirconate Titanate ◽  
Health Monitoring ◽  
Lamb Wave ◽  
Lead Zirconate ◽  
Acoustic Source ◽  
Mechanical Coupling ◽  
Monitoring Applications ◽  
Commercial Off The Shelf ◽  
Lamb Wave Propagation ◽  
Strain Direction

Because of their electro-mechanical coupling property, Lead-Zirconate-Titanate (PZT) materials have been widely used for ultrasonic wave sensing and actuation in structural health monitoring applications. In this paper, a PZT rosette concept is proposed to conduct Lamb wave-based damage detection in panel-like structures by exploring its best directional sensing capability. First, a directivity study was conducted to investigate sensing of flexural Lamb wave propagation using a PZT fiber having d33 effects. Then, commercial off-the-shelf PZT fibers were polarized in-house in order to construct the PZT rosette configuration, in which three PZT fibers are oriented at 0°, 45°, 90°, respectively. Since Lamb wave responses are directly related to measured PZT fiber voltage signals, a simple interrogation scheme was developed to calculate principal strain direction in order to locate an acoustic source. Comprehensive tests were conducted to evaluate the performance of the proposed PZT rosette using an aluminum plate. It is shown that the PZT rosette is able to sense Lamb wave responses and accurately locate an acoustic source. We expect to further evaluate the PZT rosette performance when damages are introduced.

scholarly journals A Vibration-Based Structural Health Monitoring System for Transmission Line Towers

Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 515 ◽  
Author(s):  
Long Zhao ◽  
Xinbo Huang ◽  
Ye Zhang ◽  
Yi Tian ◽  
Yu Zhao
Keyword(s):  
Structural Health Monitoring ◽  
Transmission Line ◽  
Natural Frequency ◽  
Health Monitoring ◽  
Structural Changes ◽  
Natural Frequencies ◽  
Transmission Tower ◽  
Health Monitoring System ◽  
Wind Speeds ◽  
Before And After

In this paper, we present a vibration-based transmission tower structural health monitoring system consisting of two parts that identifies structural changes in towers. An accelerometer group realizes vibration response acquisition at different positions and reduces the risk of data loss by data compression technology. A solar cell provides the power supply. An analyser receives the data from the acceleration sensor group and calculates the transmission tower natural frequencies, and the change in the structure is determined based on natural frequencies. Then, the data are sent to the monitoring center. Furthermore, analysis of the vibration signal and the calculation method of natural frequencies are proposed. The response and natural frequencies of vibration at different wind speeds are analysed by time-domain signal, power spectral density (PSD), root mean square (RMS) and short-time Fouier transform (STFT). The natural frequency identification of the overall structure by the stochastic subspace identification (SSI) method reveals that the number of natural frequencies that can be calculated at different wind speeds is different, but the 2nd, 3rd and 4th natural frequencies can be excited. Finally, the system was tested on a 110 kV experimental transmission line. After 18 h of experimentation, the natural frequency of the overall structure of the transmission tower was determined before and after the tower leg was lifted. The results show that before and after the tower leg is lifted, the natural frequencies of each order exhibit obvious changes, and the differences in the average values can be used as the basis for judging the structural changes of the tower.

Load testing and health monitoring of monolithic bridges with innovative reinforcement

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kexin Zhang ◽  
Tianyu Qi ◽  
Dachao Li ◽  
Xingwei Xue ◽  
Zhimin Zhu
Keyword(s):  
Health Monitoring ◽  
Construction Process ◽  
Content Type ◽  
Continuous Rigid Frame Bridge ◽  
Rigid Frame ◽  
Steel Strand ◽  
Before And After ◽  
Load Tests ◽  
Rigid Frame Bridge ◽  
Strengthening Method

PurposeThe paper aims to investigate effectiveness of the strengthening method, the construction process monitoring, fielding-load tests before and after strengthening, and health monitoring after reinforcement were carried out. The results of concrete strain and deflection show that the flexural strength and stiffness of the strengthened beam are improved.Design/methodology/approachThis paper describes prestressed steel strand as a way to strengthen a 25-year-old continuous rigid frame bridge. High strength, low relaxation steel strand with high tensile strain and good corrosion resistance were used in this reinforcement. The construction process for strengthening with prestressed steel strand and steel plate was described. Ultimate bearing capacity of the bridge after strengthening was discussed based on finite element model.FindingsThe cumulative upward deflection of the second span the third span was 39.7 mm, which is basically consistent with the theoretical value, and the measured value is smaller than the theoretical value. The deflection value of the second span during data acquisition was −20 mm–10 mm, which does not exceed the maximum deflection value of live load, and the deflection of the bridge is in a safe state during normal use. Thus, this strengthened way with prestressed steel wire rope is feasible and effective.Originality/valueThis paper describes prestressed steel strand as a way to strengthen a 25-year-old continuous rigid frame bridge. To investigate effectiveness of the strengthening method, the construction process monitoring, fielding-load tests before and after strengthening and health monitoring after reinforcement were carried out.

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