Information Granularity With the Self-Emergence Mechanism for Event Detection in WSN-Based Tunnel Health Monitoring

2020 ◽  
Vol 20 (15) ◽  
pp. 8265-8275 ◽  
Author(s):  
Gang Li ◽  
Bin He ◽  
Yanmin Zhou ◽  
Zhongpan Zhu ◽  
Hongwei Huang
Keyword(s):  
Health Monitoring ◽  
Event Detection ◽  
The Self ◽  
Information Granularity

scholarly journals Response of a Tensegrity Simplex in Experimental Tests of a Modal Hammer at Different Self-Stress Levels

2020 ◽  
Vol 10 (23) ◽  
pp. 8733
Author(s):  
Leszek Małyszko ◽  
Andrzej Rutkiewicz
Keyword(s):  
Stress Level ◽  
Health Monitoring ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Experimental Tests ◽  
Rotational Frequency ◽  
The Self ◽  
The Finite Element Method ◽  
Recorded Data ◽  
The Relationship

The natural frequencies and eigenmodes of the tensegrity simplex are determined experimentally in impact hammer tests. To study an effect of prestressing, the tests are carried out on a physical model 1.2 m high and 0.5 m diameter with build-in transducers for measuring actual values of forces in cables at 13 prestress levels. The recorded data for each pre-stress level from three three-axial accelerometers are combined to extract the first five natural frequencies and modes by means of the method of experimental modal analysis. It was experimentally confirmed that the first rotational frequency depends on the pre-stress level and its sensitivity to the self-stress state is high enough to be successfully used in vibrational health monitoring. A proprietary formula was proposed for the relationship between frequency and the pre-stress level to control the dynamic properties of the simplex. An excellent comparison between the experimental results of the frequency and the formula was obtained. A comparison of numerical results of the finite element method with truss element and experiment is also shown.

scholarly journals Health Monitoring of Single Lap Joint of Woven Glass Fibre Reinforced Epoxy Composites Modified with MWCNTs

2016 ◽  
Vol 25 (3) ◽  
pp. 096369351602500
Author(s):  
Fatih Turan ◽  
Alaattin Aktaş ◽  
Koray Gürkan ◽  
Mehmet Güçlü ◽  
Yener Taşkin ◽  
...  
Keyword(s):  
Health Monitoring ◽  
Glass Fibre ◽  
Joint Strength ◽  
The Self ◽  
Epoxy Composites ◽  
Thickness Effect ◽  
Lap Joint ◽  
Single Lap Joint ◽  
Glass Fibre Reinforced ◽  
Sensing Sensitivity

In this study, in situ monitoring of single lap joint of woven glass fabric reinforced epoxy composites modified with multi-walled carbon nanotubes (MWCNTs) is presented. Woven glass fibre reinforced/epoxy composite plates modified with 3% wt. highly electrically conductive MWCNTs were manufactured by hand lay-up process for obtaining adherends. MWCNTs were used in 1% and 2% by weight in order to investigate the effect of the MWCNTs level on the shear lap joint strength and the self-sensing sensitivity of bonded area. One, four, and seven plies of adhesive woven cloths were employed for bonding adherends to examine the thickness effect on both the shear lap joint strength and the self-sensing sensitivity of bonded area. In order to provide low electrical contact resistance, woven carbon fibres were placed on the top and bottom of the glass fibre layer during production. Results indicate that the health monitoring of lap joints in the woven glass reinforced epoxy composites can be successfully achieved.

Influence of Cracks on Frequency of the Self-Vibration of Reinforced Concrete T Beam of Road Bridges

2019 ◽  
Vol 828 ◽  
pp. 9-13 ◽  
Author(s):  
Artashes Sargsyan ◽  
Grigor Sargsyan ◽  
Boris Resnik
Keyword(s):  
Reinforced Concrete ◽  
Health Monitoring ◽  
Theoretical Calculations ◽  
Health Condition ◽  
The Self ◽  
Correct Evaluation ◽  
Bridge Health Monitoring ◽  
Structure Vibration ◽  
Different Characteristics ◽  
T Beam

The main goal of bridge health monitoring is to show the condition of structure in real time mode with using special sensors, which can measure different characteristics, which can indicate about the changes in structure. One of the easier measured indicators what can be used is frequency of structure vibration. The diagnostic of the health condition of structure is dependent of correct evaluation of changes range of measured indicators. This paper presents the theoretical calculations to study the effect of cracking on the frequency response of typical reinforced concrete T type beams which has widespread in road bridges construction.

Reference-Free Transducer Self-Diagnosis Scheme Development

2006 ◽  
Author(s):  
Sang Jun Lee ◽  
Hoon Sohn
Keyword(s):  
Lead Zirconate Titanate ◽  
Health Monitoring ◽  
Input Signal ◽  
Mechanical Response ◽  
Lead Zirconate ◽  
The Self ◽  
Specific Input ◽  
Host Structure ◽  
Aluminum Beam ◽  
Simultaneous Sensing

A self-sensing scheme, which allows using Lead Zirconate Titanate (PZT) materials for simultaneous sensing and actuation, has been developed in the context of structural health monitoring (SHM). Based on the self-sensing scheme developed, a time response of the PZT transducer coupled with a mechanical response of the host structure is successfully extracted while the same PZT transducer is excited by a specific input signal. Then, the measured PZT response is used for detecting transducer defects such as PZT cracking and debonding. In order to improve the reliability of transducer diagnosis, the reference-free transducer self-diagnosis scheme based on the developed self-sensing scheme is proposed. Finally, the effectiveness of the proposed self-diagnosis scheme is examined using PZT wafers instrumented on a fixed-free aluminum beam.

Self-Diagnostics of Piezoelectric Transducers

2014 ◽  
Vol 613 ◽  
pp. 204-212
Author(s):  
Vladimir N. Kostyukov ◽  
Alexey V. Kostyukov
Keyword(s):  
Health Monitoring ◽  
Temperature Sensors ◽  
Technical Condition ◽  
Piezoelectric Transducers ◽  
The Self ◽  
Monitoring Systems ◽  
Practical Implementation ◽  
Reliability Growth ◽  
State Monitoring ◽  
Measuring Converter

Equipment technical state monitoring systems contain hundreds of vibration and temperature sensors for real-time health monitoring of machinery. Monitoring systems reliability should significantly exceed the units stock reliability, being protected from accidents and incidents.The paper considers the approach to monitoring systems reliability growth, primarily by means of providing control (monitoring) of measuring-converter path technical condition. Sensors are the weakest point, due not only to wear, but also to damage, caused by repair personnel when servicing equipment. The self-diagnostics method for channels with piezoelectric transducers and the choice of optimal self-diagnostics circuits parameters have been suggested. The results of practical implementation have been provided as well.

scholarly journals Characterization of Six-Degree-of-Freedom Sensors for Building Health Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3732
Author(s):  
Louisa Murray-Bergquist ◽  
Felix Bernauer ◽  
Heiner Igel
Keyword(s):  
Health Monitoring ◽  
Degree Of Freedom ◽  
The Self ◽  
Effect Of Temperature ◽  
Interstory Drift ◽  
Power Spectral ◽  
External Reference ◽  
Building Motion ◽  
Six Degree Of Freedom ◽  
Building Health Monitoring

Six-degree-of-freedom (6DoF) sensors measure translation along three axes and rotation around three axes. These collocated measurements make it possible to fully describe building motion without the need for an external reference point. This is an advantage for building health monitoring, which uses interstory drift and building eigenfrequencies to monitor stability. In this paper, IMU50 6DoF sensors are characterized to determine their suitability for building health monitoring. The sensors are calibrated using step table methods and by comparison with earth’s rotation and gravity. These methods are found to be comparable. The sensor’s self-noise is examined through the power spectral density and the Allan deviation of data recorded in a quiet environment. The effect of temperature variation is tested between 14 and 50 °C. It appears that the self-noise of the rotation components increases while the self-noise of the acceleration components decreases with temperature. The comparison of the sensor self-noise with ambient building signal and higher amplitude shaking shows that these sensors are in general not sensitive enough for ambient signal building health monitoring in the frequency domain, but could be useful for monitoring interstory drift and building motion during, for example, strong earthquake shaking in buildings similar to those examined here.

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