Degradation of Sensor Systems in Multifunctional Composites

2010 ◽  
Author(s):  
Mohammad Mehdizadeh ◽  
Sabu John ◽  
Chun Wang ◽  
Michael Bannister ◽  
Viktor Verijenko
Keyword(s):  
Electrical Properties ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Structural Changes ◽  
Reliability Assessment ◽  
Fatigue Loading ◽  
Piezoelectric Sensors ◽  
Multifunctional Composites ◽  
Aerospace Structures ◽  
Sensory Data

Structural health monitoring (SHM) systems are increasingly being considered for implementation in aerospace structures. As the application of SHM systems increase, it will be important to define standardized procedures to test durability, reliability, and longevity of the systems. The work presented in this paper is some preliminary work on the integrity of Piezoelectric sensors itself when used to monitor the strains in structures. This study involved the measurements of pertinent electrical properties of these sensors over 100,000 cycles of fatigue loading. Marked changes in the capacitance and inductance of these sensors highlighted deleterious structural changes in the sensor itself without any discernible change in the structure it is supposed to monitor. This might have significant implications in the reliability assessment of sensory data from SHM systems.

Distinguishing the Degradation of the Interdigital Piezoelectric Fibre Transducers From Structural Damage in Multifunctional Composites

2012 ◽  
Author(s):  
Mohammad Mehdizadeh ◽  
Sabu John ◽  
Chun H. Wang ◽  
Kamran Ghorbani ◽  
Wayne S. T. Rowe
Keyword(s):  
Electrical Properties ◽  
Structural Damage ◽  
Structural Changes ◽  
Fatigue Loading ◽  
Operational Environment ◽  
Multifunctional Composites ◽  
The Status ◽  
Safety And Reliability ◽  
Thermal Features ◽  
Sensor Degradation

The next-generation design of structural components involves combining multiple functions. The goal of such Multi-functional structures (MFS) is to incorporate various tasks and functions such as structural, electrical and thermal features within a structural housing. The performance and behaviour characteristics of the multi-functional structures can be affected by degradation of any of the sub-components. This can have consequences on the safety, cost, and operational capability. Therefore, the timely and accurate detection, characterization and monitoring of the degradation in these sub-components are major concerns in the operational environment. This calls for Structural Health Monitoring (SHM) as a possible method to improve the safety and reliability of structures and thereby reduce their operational cost. As the application of SHM systems to monitor the status of the MFS increase, it will be increasingly important to determine the durability, reliability, and reparability of the components of SHM system such as sensors. The sensors themselves must be reliable enough so that they do not require replacement at intervals less than the economic lifetime of the structures and components they are monitoring. This is especially important when the deleterious structural changes in the sensor occurs without any discernible change in the structure being monitored In the present work, an assessment is carried out to quantify the degradation in the electric and electromechanical characteristics of polymer composite PZT sensors, under fatigue loading. Changes in the electrical properties of these sensors such as capacitance and inductance have been measured. The strain measurements of the sensor have also been compared to the theoretically calculated strain. The results show that the delineation of structural damage from sensor degradation is possible by monitoring the changes in the key electrical properties of the sensor components such as electrodes and PZT fibers as well as the comparison of experimentally measured and theoretically calculated strain values.

Differentiating Structural Damage From Piezo-Fibre-Based Sensor Damage in Multifunctional Composites

2011 ◽  
Author(s):  
Mohammad Mehdizadeh ◽  
Sabu John ◽  
Chun H. Wang ◽  
Viktor Verijenko ◽  
Wayne Rowe ◽  
...  
Keyword(s):  
Structural Damage ◽  
Energy Production ◽  
Structural Changes ◽  
Fatigue Loading ◽  
Piezoelectric Sensors ◽  
Civil Infrastructure ◽  
Sensor Failure ◽  
Multifunctional Composites ◽  
Wide Range ◽  
Health Monitoring Systems

Structural health monitoring systems (SHMS) are increasingly being considered for implementation in a wide range of industries, including transport, civil infrastructure, and energy production. As the application of SHM systems increase, it will be increasingly important to quantify the durability, reliability, and reparability of the SHM system. This paper investigates the electrical and electro-mechanical characteristics of piezoelectric sensors in an attempt to distinguish sensor failure from structural damage. This study involved the measurements of pertinent electrical properties for three various types of advanced piezoelectric sensors under fatigue loading. Changes in the capacitance and inductance of these sensors have been recorded, highlighting the deleterious structural changes in the sensor itself without any discernible change in the structure being monitored.

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.

scholarly journals Structural reliability assessment based on optical monitoring system: case study

2016 ◽  
Vol 9 (2) ◽  
pp. 297-305 ◽  
Author(s):  
E. Mesquita ◽  
P. Antunes ◽  
A. A. Henriques ◽  
A. Arêde ◽  
P. S. André ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Structural Reliability ◽  
Extreme Values ◽  
Low Cost ◽  
Reliability Assessment ◽  
Water Reservoir ◽  
Optical Systems ◽  
Structural Health

ABSTRACT Optical systems are recognized to be an important tool for structural health monitoring, especially for real time safety assessment, due to simplified system configuration and low cost when compared to regular systems, namely electrical systems. This work aims to present a case study on structural health monitoring focused on reliability assessment and applying data collected by a simplified optical sensing system. This way, an elevated reinforced concrete water reservoir was instrumented with a bi-axial optical accelerometer and monitored since January 2014. Taking into account acceleration data, the natural frequencies and relative displacements were estimated. The reliability analysis was performed based on generalized extreme values distribution (GEV) and the results were employed to build a forecast of the reliability of the water elevated reservoir for the next 100 years. The results showed that the optical system combined with GEV analysis, implemented in this experimental work, can provide adequate data for structural reliability assessment.

scholarly journals Smart Sensing Technologies for Structural Health Monitoring of Civil Engineering Structures

2010 ◽  
Vol 2010 ◽  
pp. 1-13 ◽  
Author(s):  
M. Sun ◽  
W. J. Staszewski ◽  
R. N. Swamy
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Smart Materials ◽  
Civil Engineering ◽  
Piezoelectric Sensors ◽  
Sensors And Actuators ◽  
Engineering Structures ◽  
Structural Health ◽  
Civil Engineering Structures ◽  
Smart Sensing

Structural Health Monitoring (SHM) aims to develop automated systems for the continuous monitoring, inspection, and damage detection of structures with minimum labour involvement. The first step to set up a SHM system is to incorporate a level of structural sensing capability that is reliable and possesses long term stability. Smart sensing technologies including the applications of fibre optic sensors, piezoelectric sensors, magnetostrictive sensors and self-diagnosing fibre reinforced composites, possess very important capabilities of monitoring various physical or chemical parameters related to the health and therefore, durable service life of structures. In particular, piezoelectric sensors and magnetorestrictive sensors can serve as both sensors and actuators, which make SHM to be an active monitoring system. Thus, smart sensing technologies are now currently available, and can be utilized to the SHM of civil engineering structures. In this paper, the application of smart materials/sensors for the SHM of civil engineering structures is critically reviewed. The major focus is on the evaluations of laboratory and field studies of smart materials/sensors in civil engineering structures.

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