Electric field and radio frequency measurements for rocket engine health monitoring applications

1992 ◽  
Vol 8 (5) ◽  
pp. 943-947
Author(s):  
Elizabeth L. Valenti
Keyword(s):  
Electric Field ◽  
Radio Frequency ◽  
Health Monitoring ◽  
Rocket Engine ◽  
Frequency Measurements ◽  
Monitoring Applications

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 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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