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Monitoring of beam deflection subjected to bending load using Brillouin distributed optical fiber sensors
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Monitoring of fatigue crack growth of cracked thick aluminum plate repaired with a bonded composite patch using transmission-type extrinsic Fabry-Perot interferometric optical fiber sensors
No full textRecently, optical fiber sensors have been increasingly applied to monitor various engineering and civil structural components. These fiber optic smart structures allow engineers to add nervous systems to their designs, giving structures capabilities that would be very difficult to achieve by other means, including continuous assessment of damage processes. Several studies associated with crack monitoring using optical fiber sensors have been reported. In this study, we used recently developed transmission-type extrinsic Fabry-Perot interferometric (TEFPI) optical fiber sensors for the monitoring of fatigue crack growth behavior of cracked thick aluminum plate repaired with a bonded composite patch. The TEFPI optical fiber sensor has both the advantages of reflection-type EFP1 optical fiber sensors and a simpler and more effective function to distinguish strain direction than do reflection-type EFP1 optical fiber sensors. The objective of this study is to evaluate the potentiality of the application of TEFPI optical fiber sensors to the monitoring of the fatigue crack growth behavior of composite patch repaired structures. The sensing principle and the sensor construction of the TEFPI optical fiber sensor are presented. The experimental results from fatigue tests of center cracked tension aluminum specimens repaired with a bonded composite patch are presented and discussed. TEFPI optical fiber sensors are embedded and surface bonded to the composite patch at several locations. The experimental results show that it is possible to monitor the fatigue crack growth behavior of composite patch repaired structures using TEFPI optical fiber sensors
Guided wave generation and sensing system using a single laser source and optical fibers
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Structural monitoring of a bending beam using Brillouin distributed optical fiber sensors
No full textDue to the large measurement range, distributed optical fiber sensors are very effective in the monitoring of large structures. Brillouin distributed optical fiber sensors, which measure strain by using Brillouin frequency shift, show some measurement error for non-uniformily distributed strain because of their spatial resolution characteristics. They require compensation of measured values and positions in the end-parts of the measurement range because measured values are not distributed over all the positions of the spatial resolution range. In this paper, we present the strain measurement characteristics of Brillouin distributed optical fiber sensors and the compensation method in the end-parts of the measurement range. A deflection measurement method for a beam subjected to a bending load using Brillouin distributed optical fiber sensors is also presented. This is verified by a three-point bending experiment employing an 8 m aluminum beam. The experimental results showed that the measured value agrees with the one expected by Brillouin measurement theory
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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