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.

SHM System Based on Modal Filtration

2012 ◽  
Vol 518 ◽  
pp. 289-297 ◽  
Author(s):  
Krzysztof Mendrok ◽  
Tadeusz Uhl ◽  
Wojciech Maj ◽  
Paweł Paćko
Keyword(s):  
Structural Health Monitoring ◽  
Damage Detection ◽  
Health Monitoring ◽  
Structural Modification ◽  
Structural Changes ◽  
Environmental Changes ◽  
Practical Implementation ◽  
Health Monitoring System ◽  
Structural Health ◽  
Changes Detection

The modal filter has various applications, among the others for damage detection. It was shown, that a structural modification (e.g. drop of stiffness due to a crack) causes an appearance of peaks on the output of the modal filter. This peaks result from not perfect modal filtration due to system local structural changes. That makes it a great indicator for damage detection, which has fallowing advantages: low computational afford due to the data reduction, the structural health monitoring system based on it, is easy to automate. Furthermore the system is theoretically insensitive to environmental changes as temperature or humidity variation (global structural changes do not cause a drop of modal filtration accuracy). In the paper the practical implementation of the presented technique is shown. The developed structural health monitoring (SHM) system is described as well as results of its extensive simulation and laboratory testing. Finally the application of the system for the structural changes detection on the airplane parts is presented..

A Structural Health Monitoring System for Composite Beams With Coupled Bending-Torsion

2012 ◽  
Author(s):  
Zeaid Hasan ◽  
Ghassan Atmeh
Keyword(s):  
Structural Health Monitoring ◽  
Damage Detection ◽  
Natural Frequency ◽  
Health Monitoring ◽  
Composite Beam ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Current Time ◽  
Structural Health ◽  
Area Of Interest

Structural health monitoring (SHM) is the process of damage identification in structural systems which have been an area of interest and a well-recognized field of technology in the past decade. Such systems involve the integration of smart materials, sensors and decision-making algorithms into the structure to detect damage, evaluate the structural integrity and predict the remaining life time. These systems have the potential to replace traditional non-destructive evaluation (NDE) of structures. This study focuses on presenting an automated structural health monitoring (SHM) system based on detecting shifts in natural frequencies of the structure. The damage detection technique is implemented on a cracked composite beam vibrating in coupled bending-torsion where the crack is assumed open. Modal analysis is conducted on the composite beam in order to predict the natural frequency and the associated mode shapes. Based on this analysis, a database of information related to the specific composite beam being analyzed such as layups and natural frequencies are stored. The natural frequency will be measured and compared to that database for damage detection. A finite element model is also presented and compared with the analytical results. It is observed that the variation of natural frequencies in the presence of a crack is affected by the crack ratio, crack location and fiber orientation. In particular, the variation pattern is different as the magnitude of bending-torsion coupling changes due to different fiber angles. A simple circuit containing a microcontroller is implemented to simulate the automated SHM concept. The microcontroller serves as the data storage device as well as the decision maker based on the instantaneous comparison between the healthy and the damaged structure. The proposed system may be implemented in many structural components such as aircraft frames and bridges. This SHM technology may help replace the current time-based maintenance scheme with a condition-based one. The condition-based maintenance scheme relies on the ability to monitor the condition of the system and supply information of damage detection to allow a corrective action to be taken.

scholarly journals Application of MEMS accelerometer of smartphones to define natural frequencies and damping ratios obtained from concrete viaducts and footbridge

2022 ◽  
Vol 15 (2) ◽  
Author(s):  
Jorge Dalmas Braido ◽  
Zacarias Martin Chamberlain Pravia
Keyword(s):  
Structural Health Monitoring ◽  
Natural Frequency ◽  
Health Monitoring ◽  
Natural Frequencies ◽  
Sampling Rate ◽  
Concrete Bridges ◽  
Dynamic Parameters ◽  
Research Attention ◽  
Mems Accelerometer ◽  
Mems Accelerometers

Abstract The continuous development of smartphones has garnered considered research attention owing to the possibility of its use in different engineering applications. MEMS accelerometers available on smartphones are useful for structural health monitoring. This study is aimed at determining the use of smartphones in the calibration and correction of the sampling rate for natural frequency and damping identification. Three concrete bridges were used in the case studies. The results indicate that smartphones can be used to understand some dynamic parameters.

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