New Type Of Fiber Research Articles

Application of advances in the development and production of optical fiber in the development and design of fiber optic devices.

The dimensions of devices based on optical fiber are limited by the sensitivity of the optical fiber to macrobending, which leads to an increase in optical losses at small bending radii. New types of fibers with low macrobending losses make it possible to significantly tighten the dimensions. However, there may be a risk of fiber failure at bending points during the life of the product due to mechanical fatigue. In the article, based on the use of a static fatigue model of silica glass, a simple expression is obtained to estimate the probability of fiber failure under long-term bending stress depending on the length of the bent section, bend radius and humidity, taking into account the result of a proof-test carried out by the fiber manufacturer. The possibility of increasing the mechanical reliability of silica fiber by applying a hermetical carbon coating is discussed. The use of the obtained expressions in design makes it possible to reduce the dimensions of fiber optic products without the risk of reducing their reliability.

Experimental study on static performance of ballastless track slabs reinforced by new FRP trusses

The main objective of this study was to overcome the problem of the closed-loops created in the steel truss of the ballastless track slabs. In this paper, a new type of Fiber Reinforced Polymer (FRP) truss was fabricated and expected to overcome the above problem due to the excellent insulation performance of FRP. However, the static performance of the ballastless track slab reinforced by the new FRP trusses has not been studied. Therefore, five ballastless track slabs (one traditional slab and four new FRP trusses reinforced slabs) were constructed and tested under four-point loading. The test results indicate that: (1) the shear failure of the new FRP truss reinforced ballastless track slab was observed due to the high strength of the FRP bar, which is different from the bending failure of the traditional slab; (2) the new FRP truss has sufficient bearing capacity, stiffness and ductility, and can meet various mechanical requirements in its service stage; (3) the proposed modes can be well used to predict the bearing capacity, deflection and the crack width of this type of ballastless track slab.

Destructive and nondestructive tests formulation for concrete containing polyolefin fibers

Abstract Polyolefin fiber is a new type of fiber that was used in concrete to improve some of the poor properties of concrete including; tensile strength, ductility, and fracture energy. In this research, the contribution of Polyolefin fiber in improving the properties of hardened concrete was examined by adding polyolefin fibers to mix with different fiber content. The polypropylene fibers were added as a ratio of 0.5, 0.75, 1.0, 1.5, and 2% of concrete volume. Destructive and non-destructive tests were carried out: slump, compression, splitting, and bending, Schmidt Hammer, and ultrasonic pulse velocity tests. The results showed that, as the polyolefin fiber content increases, the workability of concrete reduces dramatically. The experimental findings demonstrate that the concrete tensile strength and ductility were improved by a small improvement in overall compressive strength. The results show that the compressive strength increased gradually with the increase in fiber content of up to 1.5%, and then, the compressive strength starts to decrease. However, the tensile strength increases continuously with the fiber content increasing. A good relationship was obtained between the destructive and nondestructive tests.

Fiber cladding dual channel surface plasmon resonance sensor based on S-type fiber

Fiber cladding surface plasmon resonance (SPR) sensors have few structures, and a clad SPR sensor based on S-type fiber is proposed in this paper. This new type of fiber cladding SPR sensor was formed by electrofusing an S-shaped structure on the fiber to couple the light in the fiber core to the cladding. In this paper, the effects of fiber parameters on the performance of the sensor were studied by simulation and experiment. Based on the conclusion that the smaller the core diameter is, the closer the working band of the SPR resonance is to long wavelengths, and that the geometric characteristics mean that a multimode fiber can receive the fiber cladding light from a small core diameter few-mode fiber, a dual channel SPR sensor with a double S-type fiber cascade was proposed. In the refractive index detection range of 1.333–1.385 refractive index units (RIU), the resonant working band of channel I is 627.66 nm–759.78 nm, with an average sensitivity of 2540.77 nm/RIU, and the resonant working band of channel II is 518.24 nm–658.2 nm, with an average sensitivity of 2691.54 nm/RIU. The processing method for the S-type fiber cladding SPR sensor is simple, effectively solving the problem of this type of SPR sensor structure and the difficult realization of a dual channel. The sensor is expected to be used in the fields of medical treatment and biological analysis.

Experimental study and finite element analysis on impact resistance of large-rupture-strain FRP reinforced civil air defense wall

In order to study the impact resistance of civil air defense wall strengthened with large-rupture-strain FRP and improve its explosion resistance, the pendulum impact test and ANSYS/LS-DYNA finite element simulation were used to study the influence of the reinforcement area, pendulum impact height and impact times of large-rupture-strain FRP on the impact resistance of civil air defense wall. Large-rupture-strain FRP is a new type of fiber reinforced plastics, which has the advantages of large tensile fracture strain and high strength. It is pasted on the back of the civil air defense wall to improve the overall ductility and flexural stiffness of the civil air defense wall. In this paper, large-rupture-strain FRP is firstly applied to the reinforcement of civil air defense wall resist out-of-plane impact load to improve the impact resistance of civil air defense wall. The advantages of large-rupture- strain FRP reinforcement of civil air defense wall to improve the impact resistance are analyzed from the parameters of civil air defense wall damage degree, mid-span horizontal maximum displacement and residual displacement, concrete cracks and steel strain. The pendulum impact test results show that the civil air defense wall bonded with large-rupture-strain FRP can well coordinate with the wall, restrain the cracking of the back concrete, and avoid the overall collapse of the civil air defense wall due to local damage. The residual displacement is significantly reduced, and the crack width of the concrete is reduced by 25%–76%. Even if the civil air defense wall is subjected to multiple impacts, there is no fracture of large-rupture-strain FRP. The large-rupture-strain FRP can still play a role in strengthening and restrain the stripping of the back concrete fragments. The advantage of large tensile fracture strain of large-rupture-strain FRP makes up for the shortcomings of small tensile fracture strain of FRP commonly used at present, and finally provides a new reinforcement material for improving the explosion resistance of civil air defense wall.

Ultralow loss hollow-core negative curvature fibers with nested elliptical antiresonance tubes.

Hollow-core negative curvature fibers can confine light within air core and have small nonlinearity and dispersion and high damage threshold, thereby attracting a great deal of interest in the field of hollow core fibers. However, reducing the loss of hollow-core negative curvature fibers is a serious problem. On this basis, three new types of fibers with different nested tube structures are proposed in the near-infrared spectral regions and compared in detail with a previously proposed hollow-core negative curvature fiber. We used finite-element method for numerical simulation studies of their transmission loss, bending loss, and single-mode performance, and then the transmission performance of various structural fibers is compared. We found that the nested elliptical antiresonant fiber 1 has better transmission performance than that of the three other types of fibers in the spectral range of 0.72-1.6 µm. Results show that the confinement loss of the LP01 mode is as low as 6.45×10-6 dB/km at λ = 1.06 µm. To the best of our knowledge, the record low level of confinement loss of hollow-core antiresonant fibers with nested tube structures was created. In addition, the nested elliptical antiresonant fiber 1 has better bending resistance, and its bending loss was below 2.99×10-2 dB/km at 5 cm bending radius.

Review on high capacity transmission with multi core fibers

This paper describes cases where the new type of fiber called Multi-core fiber that can resolve the current Internet capacity transmission problems with low crosstalk and attenuation. India is a data-hungry country, and with the help of the Internet, it's moving towards a strong economy and a digital India. A few years ago, no one knew that such a type of digitalization would occur and India would participate in it so rapidly. Currently, the world is moving towards basic phones to Smart Phones, Broadband, Wi-Fi equipment, Over the Top Platforms, IT Hub formation, and much more internet traffic is ongoing, so transmission with standard single-core cable is very tough. Multi Core Fiber (MCF) can resolve this problem. This article, looks at all of the options for multi-core fibers, particularly trench-assisted multi-core fibers.

Topological photonic crystal fibers based on second-order corner modes.

Photonic crystal fibers represent one of the most active research fields in modern fiber optics. The recent advancements in topological photonics have inspired new fiber concepts and designs. Here, we demonstrate a new, to the best of our knowledge, type of topological photonic crystal fiber based on second-order photonic corner modes from the Su-Schrieffer-Heeger model. Different from previous works where the in-plane properties at kz=0 have been mainly studied, we find that in the fiber configuration of kz>0, a topological bandgap exists only when the propagation constant kz along the fiber axis is larger than a certain threshold and the emergent topological bandgap at large kz hosts two sets of corner fiber modes. We further investigate the propagation diagrams, propose a convenient way to tune the frequencies of the corner fiber modes within the topological bandgap, and envisage multi-frequency and multi-channel transmission capabilities of this new type of fiber. Our work will not only have practical importance, but could also open a new area for fiber exploration where many existing higher-order topological photonic modes could bring exciting new opportunities for fiber designs and applications.

Shape memory alloy tufted composites combining high delamination resistant and crack closure properties

A new type of fibre reinforced polymer composite is presented that uniquely combines high delamination resistance with crack closure properties via the use of tufted shape memory alloy (SMA) filaments. A carbon-epoxy laminate was tufted in the through-thickness direction using thin SMA filaments of Ni-Ti alloy (nitinol). The SMA tufts increase the mode I interlaminar fracture toughness of the laminate by forming a large-scale bridging process zone along the delamination crack. Following crack growth, electrical heating of the SMA tufts activates a shape memory effect that partially closes the delamination. Finite element (FE) analysis reveals that complete crack closure occurs when the SMA tufts are not deformed above the shape memory strain limit. The use of SMA tufts offers the important opportunity to produce a new class of damage tolerant composite material that both resist the opening and aid the closing of delamination cracks formed by overloading, impact or other damaging events.

Characterization the Properties of Blended Single Jersey Fabrics using Different Microfiber Yarn Cross-sections and Gauges Machine

Since the last few decades, a development of new types of fibers were appeared in order to improve the mechanical properties of fabrics besides its comfort properties, Cotton material was used as a blended material to enhance the properties of the manufactured products. The main purpose of this article is to investigate the influence of different polyester yarn cross-section and gauges on the mechanical properties of blended knitted samples. In this study two groups of knitted samples were manufactured, using gauge 24 and gauge 20, the samples were implemented with single jersey knitted structure by two different polyester microfiber cross-sections and blended cotton ratio. Some of mechanical properties were carried out for all samples such as air permeability, spray test, bursting strength and roughness. The result values recorded and tabulated, as well as statistically analysis using ANOVA Two-way Measurements were executed. The results illustrate that tests properties of blended knitted samples were significantly affected by variables except the spray test. In the same context the results clarify that trilobal cross-section improves UPF property for knitted samples. Finally, due to study the performance of each sample the radar chart was occurred, as the results revealed that Polyester Trilobal samples recorded the best sample radar area with different gauges.

Microwave absorption performance of hexagonal nano boron nitride doped basalt fabric-reinforced epoxy composites

PurposeThe purpose of this paper is to investigate the effect of doping element on the microwave absorption performance of hexagonal nano boron nitride (h-nBN)-reinforced basalt fabric (BF)/epoxy composites. A new type of hybrid composite that will be produced by the use of boron nitride as an additive that leads to increased radar absorption capability will be developed and a new material that can be used in aeronautical radar applications.Design/methodology/approachThis study is focused on the microwave absorption properties of h-nBN doped basalt fabric-reinforced epoxy composites. Basalt fabric (BF)/epoxy composites (pure composites) and the BF/h-nBN (1 Wt.% h-nBN doped composites) hybrid composites were fabricated by vacuum infusion method. Phase identification of the composites were performed using X-ray diffraction (XRD), the 2θ scan range was from 10 to 60 with the scanning speed of 3°/min and surface morphologies of the composites were investigated using scanning electron microscopy (SEM). Microwave properties of samples were investigated through transmission/reflection measurements in Agilent brand 2-Port PNA-L Network Analyzer in the frequency range of 3–18 GHz. The prepared sample is positioned between two horn antennas with and without metal plate.FindingsExperimental results show that h-nBN doped composite was synthesized successfully and the produced hexagonal nano boron nitride-added fiber laminated composite material has good absorption behavior when they are used with metallic sheets and good for isolation applications at many points in the 3–18 GHz band.Originality/valueThis paper will contribute to the literature on the use of basalt fabric, which are new types of fibers, and hexagonal nano boron nitride and the effects of boron nitride on radar absorption properties of composite material. It presents detail characterization of each composite by using XRD and scanning electron microscopy.

Experimental Study on Dynamic Properties of UHMWPE and PVA Fibers Concrete

The purpose of this paper is to examine the dynamic three-point bending performance of UHMWPE and PVA fiber concrete specimens by means of density variation (0, 0.6, 1.2, 1.8, 2.4 kg/m3). Additionally, the difference in performance between UHMWPE and PVA fiber concretes, as well as the impact characteristics and the damage evolution law exhibited by these fiber concretes under repeated dynamic loading were studied and discussed. A Split Hopkinson pressure bar (SHPB) apparatus was used to determine the concrete behavior at different strain rates; the accuracy of which was achieved by conducting a structural transient dynamic response analysis. The dynamic failure strength and strain rate of the specimen were derived to investigate the rate effect with different quantities of UHMWPE and PVA fiber concretes. The experimental results were then compared with those predicted from available equations, verifying the validity of the results obtained. A theoretical model for analyzing the transient elastic response of the specimen was then proposed. This paper concludes by proposing an analytical equation for predicting the dynamic compression and tensile properties of these new-type fibers.

Experimental study on dynamic properties of BFRP laminates used for structural strengthening under high strain rates

Fiber reinforced polymer (FRP) has been widely used for structural strengthening due to its outstanding mechanical properties and excellent chemical resistance. Basalt fiber is a new type of fiber which has greater failure strain than the commonly used carbon fiber and higher tensile strength than the E-glass fiber. At the same time, it shows good resistance to chemical attack, impact load and fire with less poisonous fume. Therefore, application of basalt fiber reinforced polymer (BFRP) as a strengthening material to retrofit structural components against seismic and blast loads is very promising. Currently the quasi-static properties of BFRP composites have been extensively studied, however, researches on their dynamic properties are rather limited. In this study, mechanical properties of unidirectional BFRP composites under the strain rate ranging from 0.00006 s−1 to 260 s−1 are derived from quasi-static and dynamic tensile tests. A universal testing machine was used to conduct the quasi-static and low-speed tensile tests and a high-speed servo-hydraulic testing machine (INSTRON VHS 160/100-20) was applied to conduct the high-speed tests, respectively. Test results showed that the mechanical properties of BFRP are strain rate dependent. Strain rate effects on tensile strength, Young’s modulus, and failure strain are analyzed and discussed. Based on the testing data of present study and data collected from other literatures, empirical equations of dynamic increase factors (DIFs) in terms of strain rate are derived to estimate the dynamic mechanical properties of BFRP within the strain rate range considered.

Bending Properties of Short‐Cut Basalt Fiber Shotcrete in Deep Soft Rock Roadway

To study the effect of short‐cut basalt fiber (BF) on the bending and toughening properties of shotcrete, bending toughness tests of short‐cut BF shotcrete slabs with different volume fractions were carried out. A transparent soil model and Scanning Electron Microscopy (SEM) were used to observe the distribution of BF with different volume fractions and analyze the toughness enhancement mechanism of basalt fiber shotcrete. The supporting effect of basalt fiber shotcrete with different volume fractions was verified by an underground engineering test. The test results show the following: (1) when the fiber content is within 3∼4.5 kg/m3, the distribution of BF in transparent soil is uniform, and it does not easily agglomerate, which is beneficial to improving the bending toughness of shotcrete. (2) The shotcrete slab with 4.5 kg/m3 fiber content had the best reinforcing effect. Compared with the control group, the peak load and absorption capacity increased by 56.67% and 636.96%, respectively, and the maximum crack width decreased by 32.10%. (3) The SEM analysis indicated that the basalt fibers distributed randomly and evenly in the concrete, which can form a three‐dimensional spatial skeleton with a stable structure. Excessive fiber incorporation can increase fiber agglomeration during stirring and spraying. (4) The support results of an underground engineering test show that, in 35 days, short‐cut basalt fiber shotcrete with 4.5 kg/m3 fiber content is better at restraining the surrounding rock than shotcrete with other fiber contents. BF has the properties of crack resistance, bridging, and toughening for shotcrete and can significantly improve the ability of shotcrete to restrain surrounding rock deformation. As a new type of fiber, BF has great significance in deep soft rock underground engineering.

Single-frequency fibre laser with a cavity formed by Bragg gratings written in the core of an active composite fibre using KrF laser radiation (248 nm)

The possibility of producing a single-frequency fibre laser using a new type of fibre made by sintering phosphate glass in a silica glass tube (composite fibre) is demonstrated. In a fibre of this type, photosensitivity to laser radiation with a wavelength of 248 nm is detected. A fibre laser cavity is fabricated by writing fibre Bragg gratings directly in the core of the composite optical fibre activated by erbium ions. Stable single-frequency linearly polarised lasing regime is obtained at a wavelength of 1559.5 nm with a maximum output power of ∼3 mW.

Bragg gratings and Fabry-Perot interferometers on an Er-MgO-doped optical fiber

In this paper, the fabrication of fiber Bragg gratings (FBGs) and intrinsic Fabry-Pérot interferometers (IFPIs) on an Er-MgO-doped silica optical fiber is reported. The inscription of both sensing devices was performed by means of a femtosecond laser, using the phase mask method to inscribe the FBG and a micromachining platform for the IFPI. Thermal and strain characterizations were performed for both devices, achieving the maximum sensitivities of 12.57 pm/°C and 0.85 pm/µε for the FBG case, and 10.2 pm/°C and 0.91 pm/µε for the IFPI. A high temperature experiment was conducted to assess the thermal behavior of the inscribed FBG, revealing sensing capabilities for temperatures up to 700 °C. The results confirm that this new type of fiber will have an important role on the development of new optoelectronic devices, such as fiber lasers, optical amplifiers and sensors.

Fracture toughness of concrete with basalt fiber

The analysis of fracture mechanics parameters of concrete with new types of fibers is essential for the dissemination of their application and development of new methods of structural design.Fracture mechanics parameters are widely used to analyze the material behaviour and also in the design process of selected structures. The paper reports the results of an experimental programme focused on the effect of non-metallic (basalt) fibers on the fracture properties of concrete investigated in Mode I conditions. The changes in concrete properties were analysed on the basis of the critical stress intensity factor KIc, the critical value of crack tip opening displacement (CTODc) and the fracture energy GF. The addition of the basalt fibers had a slight effect on the strength properties of concrete but, at the same time, it had a significant influence on the fracture parameters by the modification of pre-cracking and particularly post-cracking behaviour of the concrete. Results of measuring the toughness and energy-absorption characteristics showed that the specimens reinforced with basalt fibers acquired a great ductile behaviour and energy absorption capacity, compared to ordinary concrete specimens.

Investigation on Concrete Reinforced with Two Types of Hooked Fibers under Flexure

Steel fiber reinforced concrete (SFRC) is a material widely used for structural applications. The effectiveness of the steel fibers in the concrete matrix is strongly affected by the shape of the fibers. Because the steel fibers with various geometrical parameters are currently available, the knowledge about their influence on concrete response is needed. The paper presents the investigation on concrete reinforced with new type of fibers which are crimped along the length with additional hooks at the ends. To estimate the effect of this kind of fibers on the mechanical parameters of SFRC the typical hooked fibers were also investigated. The compressive and three-point flexural tensile tests were performed on specimens where three fiber contents were applied: 0.32%, 0.45% and 0.57%. The results indicate that the fracture energy did not differ apparently, whereas in the equivalent tensile strengths some differences were noted due to the change of fiber shape. The difference was only observed in the shape of the load-deflection curves obtained from the tests with a use of two fiber types. However, the compressive strength and flexural tensile strength at the limit of proportionality were more affected by crimped and hooked fibers than typical hooked ones. It shows that the new type of fiber may delay the formation of the cracks in the SFRC.

Melt-spun polymer fibers with liquid core exhibit enhanced mechanical damping

We demonstrate the continuous production of liquid-filled polymeric fibers in a stable melt-spinning process at the pilot plant scale. Different polymers and liquids could successfully be combined over a wide range of core-sheath dimensions. The ability to produce a continuous liquid-core fiber (LCF) is attractive since post-filling of a hollow fiber with similar dimensions is not practical. We characterized the mechanical properties of the LCF's with particular attention to their damping properties. A LCF can exhibit significantly enhanced damping properties compared to plain polymeric filaments of same dimensions. Some possible damping mechanisms are discussed. This new type of fiber could find future applications in the enhancement of the damping factor of fiber-reinforced lightweight structures.

Structural and Antibacterial Properties of PP/CuO Composite Filaments Having Different Cross Sectional Shapes

AbstractTextile scientists make researches for producing new types of fibers as well as modifying the existing fibers to provide new raw materials for technical textile applications. The easiest way of modifying fiber physical properties is to change the cross sectional shape of a synthetic fiber. Also, composite fibers loaded with different kinds of additives attracted the attention of researchers in the last decades for functionalizing fibers. Some other methods like coating, exhausting, padding or other novel methods can be used for the same purpose. But in these methods, the functional effect is generally not durable enough against several times of washing and abrasion. Also, these methods usually require higher consumption of water and heat when compared to composite fiber production. As a result, in this work the effect of cross sectional modification and composite fiber production were combined in the same fiber. One of the most important functional properties which can be provided by composite fiber production is antibacterial activity. Only a few research papers were published on antibacterial additive doped polypropylene fibers. In this work cupric oxide (CuO) doped antibacterial composite polypropylene (PP) fibers having different cross sectional shapes (circular, trilobal and triangular) were produced and the effect of cross sectional shape and CuO on the antibacterial activity, structural and mechanical properties of the fibers were investigated for the first time. Cross sectional and longitudinal images of composite fibers were evaluated by using optical microscope and scanning electron microscope (SEM). As the released content of active agent is an important parameter for the activity, durability, environmental and health effect of the product, the copper release from the fibers into the water media was investigated by inductively coupled plasma optical emission spectrometry (ICP-OES). Thermal analysis results showed that PP/CuO composite filaments having three different cross sectional shapes can be produced without any significant changes on thermal behavior of fibers. With the increasing content of cupric oxide, tenacities of fibers slightly decreased. Cupric oxide particles also led to some crystallinity changes. All of the composite fibers showed good antibacterial activity against Gram-negative bacterium Escherichia coli.