scholarly journals Dielectric and Electrical Properties of WS2 Nanotubes/Epoxy Composites and Their Use for Stress Monitoring of Structures

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
A. Sedova ◽  
S. Khodorov ◽  
D. Ehre ◽  
B. Achrai ◽  
H. D. Wagner ◽  
...  
Keyword(s):  
Health Monitoring ◽  
Epoxy Composites ◽  
Electrical Characteristics ◽  
Structural Components ◽  
Stress Monitoring ◽  
Strain Measurements ◽  
Three Point Bending ◽  
Stress Sensors ◽  
Monitoring Applications ◽  
As Stress

The dielectric and electrical characteristics of the semiconductive WS2 nanotubes/epoxy composites were studied as a function of the nanotubes concentration and the pressure applied during their molding. In addition, the ability of WS2 nanotubes to serve as stress sensors in epoxy based nanocomposites, for health-monitoring applications, was studied. The nanocomposite elements were loaded in three-point bending configuration. The direct current was monitored simultaneously with stress-strain measurements. It was found that, in nanocomposites, above the percolation concentrations of the nanotubes, the electrical conductivity increases considerably with the applied load and hence WS2 nanotubes can be potentially used as sensors for health monitoring of structural components.

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.

Cryogenic Interlaminar Properties of PBO Fiber/Epoxy Composites

2011 ◽  
Vol 391-392 ◽  
pp. 1445-1449
Author(s):  
Chun Hua Zhang ◽  
Shi Lin Luan ◽  
Xiu Song Qian ◽  
Bao Hua Sun ◽  
Wen Sheng Zhang
Keyword(s):  
Liquid Nitrogen ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Epoxy Composites ◽  
Bending Test ◽  
Test Results ◽  
Sem Images ◽  
Three Point Bending ◽  
Pbo Fiber ◽  
Interlaminar Shear

The influences of low temperature on the interlaminar properties for PBO fiber/epoxy composites have been studied at liquid nitrogen temperature (77 K) in terms of three point bending test. Results showed that the interlaminar shear strength at 77 K were significantly higher than those at room temperature (RT). For the analysis of the test results, the tensile behaviors of epoxy resin at both room temperature and liquid nitrogen temperature were investigated. The interface between fiber and matrix was observed using SEM images.

scholarly journals Hybrid Carbon Microfibers-Graphite Fillers for Piezoresistive Cementitious Composites

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 518
Author(s):  
Hasan Borke Birgin ◽  
Antonella D’Alessandro ◽  
Simon Laflamme ◽  
Filippo Ubertini
Keyword(s):  
Percolation Threshold ◽  
Health Monitoring ◽  
Cementitious Materials ◽  
Strain Sensing ◽  
Composite Matrix ◽  
Hybrid Fillers ◽  
Monitoring Applications ◽  
Conductive Fillers ◽  
Carbon Microfibers ◽  
Hybrid Carbon

Multifunctional structural materials are very promising in the field of engineering. Particularly, their strain sensing ability draws much attention for structural health monitoring applications. Generally, strain sensing materials are produced by adding a certain amount of conductive fillers, around the so-called “percolation threshold”, to the cement or composite matrix. Recently, graphite has been found to be a suitable filler for strain sensing. However, graphite requires high amounts of doping to reach percolation threshold. In order to decrease the amount of inclusions, this paper proposes cementitious materials doped with new hybrid carbon inclusions, i.e., graphite and carbon microfibers. Carbon microfibers having higher aspect ratio than graphite accelerate the percolation threshold of the graphite particles without incurring into dispersion issues. The resistivity and strain sensitivity of different fibers’ compositions are investigated. The electromechanical tests reveal that, when combined, carbon microfibers and graphite hybrid fillers reach to percolation faster and exhibit higher gauge factors and enhanced linearity.

scholarly journals Energy Efficiency of Fog Computing Health Monitoring Applications

2018 ◽  
Author(s):  
Ida Syafiza M. Isa ◽  
Mohamed O. I. Musa ◽  
Taisir E. H. El-Gorashi ◽  
Ahmed Q. Lawey ◽  
Jaafar M. H. Elmirghani
Keyword(s):  
Energy Efficiency ◽  
Health Monitoring ◽  
Fog Computing ◽  
Monitoring Applications

scholarly journals A Review of Passive RFID Tag Antenna-Based Sensors and Systems for Structural Health Monitoring Applications

Sensors ◽  
2017 ◽  
Vol 17 (2) ◽  
pp. 265 ◽  
Author(s):  
Jun Zhang ◽  
Gui Tian ◽  
Adi Marindra ◽  
Ali Sunny ◽  
Ao Zhao
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Rfid Tag ◽  
Structural Health ◽  
Monitoring Applications ◽  
Passive Rfid
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