scholarly journals Study of a Long-Gauge FBG Strain Sensor with Enhanced Sensitivity and Its Application in Structural Monitoring

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3492
Author(s):  
Jing Yang ◽  
Peng Hou ◽  
Caiqian Yang ◽  
Ning Yang

A long-gauge fiber Bragg grating (FBG) strain sensor with enhanced strain sensitivity is proposed, which is encapsulated with two T-shaped metal blocks. Its fabrication method is described briefly, and the strain sensitivity can be flexibly adjusted through changing its packaging method. A series of experiments are carried out to study the packaging and its sensing properties. The experimental results show that the strain and temperature sensitivity coefficient of the sensor are three times larger than the common FBG sensors. The linearity coefficients of the FBG sensor are larger than 0.999, and the relative error of the repeatability of all sensor samples is less than 1%. Through the stability test on the actual bridge, it is revealed that the long-term stability of the sensor is excellent, and the maximum error is less than 1.5%. In addition, the proposed FBG strain sensors are used to conduct a shear strengthening experiment on a reinforced concrete (RC) beam to verify its working performance. The experimental results show that the strain change and crack propagation of the RC beam are well monitored by the sensors during the loading process.

2019 ◽  
Vol 10 ◽  
pp. 475-480 ◽  
Author(s):  
Jian Lv ◽  
Chuncai Kong ◽  
Chao Yang ◽  
Lu Yin ◽  
Itthipon Jeerapan ◽  
...  

A stable and highly sensitive graphene/hydrogel strain sensor is designed by introducing glycerol as a co-solvent in the formation of a hydrogel substrate and then casting a graphene solution onto the hydrogel in a simple, two-step method. This hydrogel-based strain sensor can effectively retain water in the polymer network due to the formation of strong hydrogen bonding between glycerol and water. The addition of glycerol not only enhances the stability of the hydrogel over a wider temperature range, but also increases the stretchability of the hydrogel from 800% to 2000%. The enhanced sensitivity can be attributed to the graphene film, whereby the graphene flakes redistribute to optimize the contact area under different strains. The careful design enables this sensor to be used in both stretching and bending modes. As a demonstration, the as-prepared strain sensor was applied to sense the movement of finger knuckles. Given the outstanding performance of this wearable sensor, together with the proposed scalable fabrication method, this stable and sensitive hydrogel strain sensor is considered to have great potential in the field of wearable sensors.


Author(s):  
Ji Liu ◽  
Pengyu Nan ◽  
Qin Tian ◽  
Xiaokun Sun ◽  
Hangting Yang ◽  
...  

Author(s):  
Enea Mustafaraj ◽  
Yavuz Yardim

In this paper, it is presented the experimental results of a campaign on diagonal compression tests, as of ASTM E519-02, to assess and compare the in-plane behavior of standard size of 1200 × 1200 × 250 mm, for three unreinforced and three reinforced wall panels by glass fiber reinforced polymer (GFRP) embedded in an inorganic matrix.From the diagonal compression test results, were determined some of the main mechanical parameters such as: shear strength, modulus of rigidity and ductility, before and after application of the reinforcement.The experimental results showed that the GFRP reinforced panels exhibited a significant increase of 127% in shear resistance, 1100% in ductility and 650% in modulus of rigidity when compared to unreinforced panels.It was concluded that this technique provided satisfactory results and can be considered a suitable method for repair of masonry structures.


Author(s):  
Yalcin Yuksel ◽  
Marcel van Gent ◽  
Esin Cevik ◽  
H. Alper Kaya ◽  
Irem Gumuscu ◽  
...  

The stability number for rubble mound breakwaters is a function of several parameters and depends on unit shape, placing method, slope angle, relative density, etc. In this study two different densities for cubes in breakwater armour layers were tested to determine the influence of the density on the stability. The experimental results show that the stability of high density blocks were found to be more stable and the damage initiation for high density blocks started at higher stability numbers compared to normal density cubes.


1989 ◽  
Vol 4 (5) ◽  
pp. 1209-1217 ◽  
Author(s):  
K. Maex ◽  
G. Ghosh ◽  
L. Delaey ◽  
V. Probst ◽  
P. Lippens ◽  
...  

The thermodynamic equilibrium of structures consisting of a thin film silicide (TiSi2 or CoSi2) on doped Si (with As or B) is investigated. Isothermal sections of the ternary phase diagrams for Ti–Si–B, Co–Si–B, Ti–Si–As, and Co–Si–As have been evaluated, indicating the stability of high B concentrations in Si underneath a CoSi2 layer, the instability of high As concentrations in Si underneath a CoSi2 layer, and of B and As concentrations underneath a TiSi2 layer. The obtained thermodynamic predictions agree very well with experimental results (i) on the redistribution of dopants during silicide formation, (ii) on the diffusion of dopants from an ion implanted silicide, and (iii) on the stability of highly doped regions underneath the silicide, both for the case of TiSi2 and CoSi2. It is shown that even though the inaccuracy of reported thermodynamic data is substantial, thermodynamic calculations provide a useful guidance and are consistent with the experimental results.


1977 ◽  
Vol 14 (02) ◽  
pp. 265-275
Author(s):  
Carl A. Scragg

This paper presents a new method of experimentally determining the stability derivatives of a ship. Using a linearized set of the equations of motion which allows for the presence of a memory effect, the response of the ship to impulsive motions is examined. This new technique is compared with the traditional method of regular-motion tests and experimental results are presented for both methods.


Author(s):  
Eldar Mehraly Gojayev ◽  
Gulshan Nuraddin Mammadova

In this work, single crystals of TlIn[Formula: see text]Ga[Formula: see text]Se2 solid solutions were grown by the methods of zone recrystallization, technologies for the manufacture of strain gauges based on them were developed and the tensoresistive properties of these phases were studied, the coefficient of strain sensitivity was determined by the static method depending on the temperature, the magnitude of mechanical deformation and optical illumination. Revealing that the single crystals have a high strain sensitivity coefficient, by the variation of the composition, quantity of mechanical deformation and the optical illumination, it is possible to control the phase coefficients investigated tensosensitivity.


2011 ◽  
Vol 189-193 ◽  
pp. 3153-3157
Author(s):  
Yan Zhen Zhang ◽  
Yong Hong Liu ◽  
Ren Jie Ji ◽  
Bao Ping Cai

In this paper, the EDM performance of water-in-oil (W/O) emulsions dielectric with different surfactant concentration is investigated by correlated to its physical properties, such as viscosity and droplets size, which is predominantly determined by the surfactant concentration. Experimental results show that the stability of the W/O emulsions increases with increasing surfactant concentration, whereas the EDM performance deteriorates with increasing surfactant concentration. So, taking a comprehensively consideration of the emulsion stability and EDM performance, the concentration of surfactant must be appropriately selected.


In a previous paper the interaction between two coplanar dislocation-type cracks was studied, the crack openings being described by continuous distributions of dislocations. A similar approach is used here to examine the stability of an infinite periodic sequence of coplanar dislocation-type cracks, each dislocation being such that its associated extra material is pointing in the same direction. Primary consideration is given to the criterion for the cracks to join up thereby causing complete fracture of the solid, and the characteristics of the model are applied to a very brief discussion of some experimental results on the deformation of magnesium oxide single crystals.


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