Wire Core Research Articles

Intensification of auxetic effect in high stiffness auxetic yarns with potential application as the reinforcing element of composite

Helical auxetic yarn (HAY) is a newly developed composite yarn with negative Poisson’s ratio. HAYs offers advantageous merits as a reinforcing element in composite materials. In this paper high stiffness HAYs composed of Nylon filament core and fine steel wire wrap yarns were developed. The importance of the stiffness ratio of the wrap to the core components in the resultant auxetic yarn was examined. The differences between instantaneous and engineering Poisson’s ratio analyses in the understanding of the strain-dependent behavior of HAY was investigated. Results revealed that the utilization of the fine steel multifilament in the developed HAY samples enormously improves the stiffness of HAY. It was possible to obtain an elastic modulus of 9 GPa and a maximum auxetic effect of –16.82 in the samples. It was concluded that such highly stiff auxetic yarn can successfully be used as reinforcement in various composite materials such as cementitious composites.

Corrosion resistance of hoisting ropes

Abstract In this study, the goal is to determine the types of steel rope best used in environments such as harbors and on ships, by examining the behavior of different types of steel wire hoisting ropes used in cranes with respect to corrosion. Initially, hemp and steel wire core ropes were taken from 6 × 19 Standard, 8 × 19 Seale and 6 × 36 Warrington Seale rope groups that have the same diameter. Corrosion resistance was compared in these ropes through the application of three methods. According to the first method, corrosion resistance was examined via change in material mass. For this purpose, ropes were subjected to an accelerated aging test in an aging test cabin in accordance with ASTM B117 standard for one month for each aging process. 3 different 30-day processes were followed with 24-hour cycles. Corrosion exposure rates differed for each process. After going through the aging process, the damage suffered by the ropes was determined via visual inspection and the impact left by corrosion was evaluated by examining the mass changes seen in the ropes before and after aging for each process. The Tafel extrapolation, which is an electrochemical test, was applied in the second method. Ecorr and Icorr values of the ropes as well as their corrosion rates were determined and compared. Corrosion behavior was investigated in the third method through the application of mechanical experiments on aged steel ropes. In conclusion, corrosion resistant hoisting ropes were identified by comparing the results attained from the three methods.

Corrosion resistance of hoisting ropes

Abstract In this study, the goal is to determine the types of steel rope best used in environments such as harbors and on ships, by examining the behavior of different types of steel wire hoisting ropes used in cranes with respect to corrosion. Initially, hemp and steel wire core ropes were taken from 6 × 19 Standard, 8 × 19 Seale and 6 × 36 Warrington Seale rope groups that have the same diameter. Corrosion resistance was compared in these ropes through the application of three methods. According to the first method, corrosion resistance was examined via change in material mass. For this purpose, ropes were subjected to an accelerated aging test in an aging test cabin in accordance with ASTM B117 standard for one month for each aging process. 3 different 30-day processes were followed with 24-hour cycles. Corrosion exposure rates differed for each process. After going through the aging process, the damage suffered by the ropes was determined via visual inspection and the impact left by corrosion was evaluated by examining the mass changes seen in the ropes before and after aging for each process. The Tafel extrapolation, which is an electrochemical test, was applied in the second method. Ecorr and Icorr values of the ropes as well as their corrosion rates were determined and compared. Corrosion behavior was investigated in the third method through the application of mechanical experiments on aged steel ropes. In conclusion, corrosion resistant hoisting ropes were identified by comparing the results attained from the three methods.

Development of 7-Segment Numeral Display Using Electrochromic Yarns for Advanced Functional Textiles

Development of electrochromic yarns opens up a high-tech option for the development of next-generation fashion textiles. Previous work has introduced electrochromic yarns comprising a metal wire core wrapped with organometallic compounds and conjugated polymers, but has reported unsatisfying colour-changing contrast and weavability. Here we report a tungsten trioxide (WO3)-electroplated high-contrast electrochromic filament suitable for weaving, and a 7-segment display embroidered with such filaments. The electroplating conditions have been optimised through elemental analysis via X-ray photoelectron spectroscopy (XPS), with the aid of coating morphology observation via scanning electron microscopy (SEM). We have learnt that sufficient WO3 for an evident change of colour can be deposited on the filament surface at -0.5V (vs. AgCl) in 30s. This low voltage and short coating duration have shown possibility for up scaled production of the electrochromic filament. Connecting the 7-segment display with ESP8266 Wi-Fi micro-controller unit, through remote signal input on ‘Blynk’ (an open-access mobile platform), we have demonstrated a double-digit ‘chance of rainfall’. Our study offers guidance on the design of textile-based information displays.

Vibration of buckled sandwich beam with self-deployable SMA core and heat treated SMA reinforced hybrid composite faces

Shape memory effect is the key factor in the design of self-reconfigurable core using origami. Effects of heat treatment on transformation temperatures and stress-strain curve of shape memory alloys using differential scanning calorimetry and tensile testing is presented. Moreover, vibration of pre/post-buckled sandwich beam with self-deployable shape memory alloy (SMA) core and SMA wires reinforced hybrid composite faces is investigated. The Boyd and Lagoudas SMA constitutive model is utilized in ABAQUS UMAT subroutine. Extensive numerical studies presented for pre-strain, volume fraction, location, time and temperature of heat treatment depends on the properties of SMA fibers, along with core and hybrid composite temperature dependency. As can be seen from results, vibration behaviors, thermal stability and total thickness of self-foldable sandwich structure can be efficiently controlled by adjusting the values of SMA wires volume fraction, pre-strain and core type, respectively. Mechanical properties of SMA are decreased, as a result of increase in heat treatment time and temperature. Increasing heat treatment temperature leads to lower transformation temperatures of SMA. In contrast, higher transformation temperatures are the results of increasing heat treatment time.

Implosion dynamics and radiation characteristics of preconditioned hybrid X-pinch driven by double pulse current

Preconditioned hybrid X-pinch (HXP) experiments have been performed on the Qin-1 facility to investigate the effect of the prepulse current on the implosion dynamics and radiation characteristics. HXPs with molybdenum wires of ∼1.2 mm in length and 25 to 50 μm in diameter have been tested. Driven by the prepulse current, the molybdenum wire is heated to a core-corona structure with a Joule energy deposition of 0.5–4.8 eV/atom, which is smaller than its atomization enthalpy. The radial expansion velocity of the wire core is 0.5–3 km/s. The main current of 450 kA/400 ns is applied ∼610 ns after the prepulse current. The implosion dynamics of the preconditioned HXP is characterized by two-shell structure implosion. Immediately after the main current starts, the current mainly passes through the corona plasma located in a large radius, and the implosion of corona plasma lasts for ∼100 ns until the corona plasma collides with the wire core. Then, the current distribution switches from the corona plasma to the wire core, which results in the onset of implosion of the wire core. The implosion of the wire core generates hot spots and x-ray radiation. The calculated inductance and radius of the current sheath agree with the experimental results. The corona plasma performs as a current switch, which allows the main current passing through the wire core after 100 ns. It indirectly contributes to sharpening the main current used for implosion of the wire core. A single hot spot with x-rays over 2.5 keV is measured using the preconditioned HXP.

Stratification and filamentation instabilities in the dense core of exploding wires

We report experiments characterizing the stratified and filamentary structures formed in the dense core of nanosecond electrical explosion of aluminum wires to understand the physical scenario of electrothermal instability. Direct experimental observations for stratification and filamentation instabilities, as well as the coexistence state of azimuthal strata and vertical filament in the dense plasma column, are presented. The wire core exhibits remarkable different patterns of instability with the decreasing wire length. The shadowgram of shorter wires demonstrates that the instability is transformed from stratified structures to filamentary structures. According to a radial magnetohydrodynamic computation, the wire enters a phase state of negative temperature dependence of resistivity before voltage breakdown. However, filamentary structures are only observed in exploding wires of 1 cm and 0.5 cm in length. The analyses based on experimental and computational results indicate that the increase in internal energy determines the manifestation of instability in the dense core. Filamentation instability occurs when the total energy input is no less than 1.5 times the vaporization energy at the moment of voltage breakdown. The lower limit of energy deposition ensures that the increase in internal energy covers vaporization energy.

RLS Impedance Intelligence Control Algorithm for Wire Peeler of Robot in Complex Power Networks

Considering the wire core which is easily damaged because of the instability of the power distribution robot during the process of peeling the insulation layer, we have proposed a cutting force tracking control algorithm based on impedance control that is suitable for the end peeling instrument. At present, the task requirement of sudden changes about environment stiffness cannot be accomplished by many impedance control approaches due to the complexity of working environment stiffness about power distribution robot; then, the Recursive Least Square (RLS) method was introduced into the impedance control algorithm to identify the cable insulation layer and cable core stiffness online to achieve accurate and stable tracking of the cutting force. Furthermore, the impedance control of peeling cable insulation layer and the proposed RLS method were simulated and tested contrastively, and the high-voltage cable peeling experiment was performed. The results of simulation and experiment showed that the force control algorithm based on RLS parameter identification still has good force tracking performance during the environment stiffness changes suddenly, and the steady-state error approaches zero, demonstrating the feasibility and effectiveness of the RLS impedance control algorithm, which has important practical significance for improving power distribution efficiency.

Development of 3D hollow woven fabrics with superior mechanical properties by using nitinol and steel wire core hybrid yarns

In this study, nitinol and steel wire core hybrid yarns were produced from wires having two different diameters and used as warp yarns to weave 3D woven fabrics in two different fabric constructions. The steel bars with two different diameters were placed into the gaps between fabric layers to create a hollow form after fabric production. The fabrics produced with cold-worked nitinol wire were exposed to heat treatments at high temperatures to provide them shape memory property according to data obtained from DSC analysis. Conventional textile fibers are not durable to these temperatures; for this reason, carbon fiber was used both as sheath material of hybrid yarns and additionally as warp and weft carbon fiber yarns. All yarn and fabric tests were carried out simultaneously to evaluate the mechanical properties of nitinol and steel wire core hybrid yarns, and wire-reinforced fabrics. Tensile tests were applied to all wire and hybrid yarn samples, DSC and DMA analyses were conducted for only heat-treated nitinol wires. Low-velocity impact, tensile and pull-out tests were applied to fabric samples. Reference fabrics with no wire were produced and evaluated by comparing with wire-reinforced samples to provide a point of comparison to the data from the mechanical properties of wire-reinforced 3D fabrics. The study's results were analyzed with regression analysis using the backward method, and the parameters such as wire type, wire diameter, and fabric gap width for optimum fabric production were determined. Data obtained from all mechanical tests demonstrate that fabric samples with steel wire, thinner wire, and narrow gaps have better results than others. The effect of wire thickness was also found the same for the nitinol wire. DMA analyses show that the thinner nitinol wire is better than, the thicker one. Finally, an innovative technique has been developed in this study to weave carbon fiber on a conventional automatic sample loom without fiber breakage by twisting PVA yarn around the wire core hybrid and twisted carbon fiber yarns.

Strengthening of PCCP with broken wires using prestressed CFRP

With increasing years of service, prestressed concrete cylinder pipes (PCCP) can be damaged due to wire breakage. Burst can then occur in the pipeline, resulting in loss of water resources. For main water diversion projects, water supply in pipelines cannot be interrupted, and as such repair for damaged pipe segments can become difficult. This study proposes an innovative retrofitting technique of using externally bonded prestressed carbon fiber reinforced polymer (CFRP) to repair damaged PCCP with broken wires. A three-dimensional (3D) PCCP model is established. Upon the successful reproduction of experimental measurements, the numerical model is used to simulate the effects of prestress level, number of CFRP layers, and wire breakage ratio. The results show that the developed approach could strengthen the resistance of PCCP by at least 28.6%, 36.7%, 19.8% and 16.1% as an interpretation of the stress–strain analyses for inner concrete core, outer concrete core, steel cylinder and steel wires, respectively. A damaged PCCP with a wire breakage ratio of less than 25% can remain in service, after it is strengthened by four layers of CFRP at a prestress level of 40%.

Effect of heat transfer through wire core toward unburned region on the extinction of spreading flame over electric wires

Effect of heat transfer through wire core toward unburned region on the extinction of spreading flame over electric wires

Effect of transverse flow on flame spread and extinction over polyethylene-insulated wires

The spread of flames over solid combustible surface in a transverse flow (perpendicular to the flame spread direction) is common in real fire scenarios, but has not been well quantified yet. In this paper, we systematically investigate the effect of transverse flow on flame spread and extinction over electrical wire insulation by using eight types of polyethylene (PE)-insulated wire of various configurations (core diameter; insulation thickness) and two representative core material (Copper: high-conductivity, Nickel-chrome: low-conductivity). The experiment is conducted in a combustion tunnel providing a uniform transverse flow. Results demonstrate that the flame spread rate (FSR) shows non-monotonic behavior with increasing transverse flow velocity until extinction, where four regimes can be identified with different controlling mechanisms. Flame spread faster over Copper (Cu)-core wires than that over Nickel-chrome (NiCr)-core wires, but is easier to extinguish in high flow region, revealing simultaneous dual effect of the “heat source” and “heat sink” due to wire core conduction. A theoretical model is developed based on two characteristic lengths (flame base width Wf and average gas-phase thermal length Lg¯), and a proposed mixed-flow velocity Vmix coupling transverse flow velocity and buoyancy-induced flow velocity. The model well predicts the experimental FSR. Moreover, an extinction limit is proposed in terms of heat loss factor Rloss as a function of strain rate am, where the coupling effects of gas-phase blow-off and condensed-phase quenching are well integrated. The present work facilitates understanding of flame spread mechanism in mixed-transverse flow condition over cylindrical fuels not only on the electric wires, but also on the branches in wildland fires.

Template-Free Electrochemical Deposition of t-Se Nano- and Sub-micro Structures With Controlled Morphology and Dimensions.

Selenium, depending on its crystal structure, can exhibit various properties and, as a result, be used in a wide range of applications. However, its exploitation has been limited due to the lack of understanding of its complex growth mechanism. In this work, template-free electrodeposition has been utilized for the first time to synthesize hexagonal-selenium (t-Se) microstructures of various morphologies at 80°C. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) revealed 5 reduction peaks, which were correlated with possible electrochemical or chemical reaction related to the formation of selenium. Potentiostatic electrodeposition using 100 mM SeO2 showed selenium nanorods formed at−0.389 V then increased in diameter up to −0.490 V, while more negative potentials (-0.594 V) induced formation of sub-micron wires with average diameter of 708 ± 116 nm. Submicron tubes of average diameter 744 ± 130 nm were deposited at −0.696 V. Finally, a mixture of tubes, wires, and particles was observed at more cathodic potential due to a combination of nucleation, growth, dissolution of structures as well as formation of amorphous selenium via comproportionation reaction. Texture coefficient as a function of applied potential described the preferred orientation of the sub-microstructures changed from (100) direction to more randomly oriented as more cathodic potentials were applied. Lower selenium precursor concentration lead to formation of nanowires only with smaller average diameters (124 ± 42 nm using 1 mM, 153 ± 46 nm using 10 mM SeO2 at −0.389 V). Time-dependent electrodeposition using 100 mM selenium precursor at −0.696 V explained selenium was formed first as amorphous, on top of which nucleation continued to form rods and wires, followed by preferential dissolution of the wire core to form tubes.

Optimization of Process Parameter by using CNC Wire Electrical Discharge Machine through Taguchi Method

Wire Electrical Discharge Machining (WEPSPDM) is utilizedin industries to manufacture components of conductive strong metal with complicated shape, greater tolerance and precision. A review of the literature exposes that most of the research work has been intended for towards the optimization of WEDM operation and modeling of the process. Conventional wire electrode has been developed to a brass wire from a copper wire and finally to zinc coated wire on the brass, steel or copper wire core, by which more advanced WEDM, is realized in terms of better machining speed and accuracy. To examine the parameters likePeak Current (Ip ), Time of Pulse ON (Ton), Time of Pulse OFF (Toff), etc. by the optimization of WEDM operation and modeling of the process during micro slit machining. Analyzed the results and optimize the process parameter conditions for maximum MRR (g/min), and surface roughness based on Taguchi’s Methodology. The ANOVA analysis indicates the significant factors for maximization of MRR, improvement of Surface Roughness and regression analysis. By the research work, it has been concluded that the MRR reduces with raise in Time of Pulse OFF (Toff) and Set Voltage of spark gap (SV) besides Material Removal Rate (MRR) increases with escalating in Time of Pulse ON (Ton) and PC (IP).

Estimation of the cable effect in megavoltage photon beam by measurement and Monte Carlo simulation.

Ionization chambers are widely used for dosimetry with megavoltage photon beams. Several properties of ionization chambers, including the cable effect, polarity effect, and ion recombination loss, are described in standard dosimetry protocols. The cable effect is categorized as the leakage current and Compton current, and careful consideration of these factors has been described not only in reference dosimetry but also in large fields. However, the mechanism of Compton current in the cable has not been investigated thoroughly. The cable effect of ionization chambers in 6MV X-ray beam was evaluated by measurement, and the mechanism of Compton current was investigated by Monte Carlo simulation. Four PTW ionization chambers (TM30013, TM31010, TM31014, and TM31016) with the same type of mounted cable, but different ionization volumes, were used to measure output factor (OPF) and cable effect measurement. The OPF was measured to observe any variation resulting from the cable effect. The cable effect was evaluated separately for the leakage current and Compton current, and its charge per absorbed dose to water per cable length was estimated by a newly proposed method. The behavior of electrons and positrons in the core wire was analyzed and the Compton current for the photon beam was estimated by Monte Carlo simulation. In OPF measurement, the difference in the electrometer readings by polarity became obvious for the mini- or microchamber and its difference tended to be larger for a chamber with a smaller ionization volume. For the cable effect measurement, it was determined that the contribution of the leakage current to the cable effect was ignorable, while the Compton current was dominant. The charge due to the Compton current per absorbed dose to water per cable length was estimated to be 0.36±0.03pC Gy-1 cm-1 for PTW ionization chambers. As a result, the contribution of the Compton current to the electrometer readings was estimated to be 0.002%cm-1 for the Farmer-type, 0.011%cm-1 for the scanning, and 0.088%cm-1 for microchambers, respectively. By the simulation, it was determined that the Compton current for MV x-ray could be explained by not only recoil electrons due to Compton scattering but also positron due to pair production. The Compton current estimated by the difference in outflowing and inflowing charge was 0.45pC Gy-1 cm-1 and was comparable with the measured value. The cable effect, which includes the leakage current and Compton current, was quantitatively estimated for several chambers from measurements, and the mechanism of Compton current was investigated by Monte Carlo simulation. It was determined that the Compton current is a dominant component of the cable effect and its charge is consistently positive and nearly the same, irrespective of the ionization chamber volume. The contribution of Compton current to the electrometer readings was estimated for chambers. The mechanism of Compton current was analyzed and it was confirmed that the Compton current can be estimated from the difference in outflowing and inflowing charge to and from the core wire.

Mechanical properties of ultrathin gold nanowires from first principles: Interdependencies between size, morphology, and twin boundaries

The mechanical behavior of $\ensuremath{\langle}111\ensuremath{\rangle}$ ultrathin gold nanowires (NWs) and their dependence on the correlated parameters of size (i.e., diameter $\ensuremath{\sim}1--1.6$ nm), morphology (rectangular and hexagonal prism), and ultrahigh density twin boundaries was investigated using density functional theory calculations. The parameters of size, morphology, and the presence of twins all significantly influence the mechanical behavior of Au NWs, and their effects are interdependent. Importantly, an ultrahigh density of twins in NWs enhances their strength in both morphologies, and across all sizes studied. Our calculations reveal a remarkable range of Young's modulus (60--158 GPa) and ultimate tensile strengths (3.7--14.0 GPa), suggesting that the scatter observed in experimental research involving ultrathin gold nanowires is a feature of intrinsic complexity. In particular, a ``wrinkling'' of the atomic planes along the wire axis due to a combination of anisotropic surface stresses and wire core response, is demonstrated to be largely suppressed by the presence of high-density twins. The high tensile strengths of the studied nanowires with twins is attributed to a combination of the suppression of this anisotropic phenomena and slip plane disruption. This work demonstrates that precise control of these parameters is required during synthesis to achieve target mechanical behaviour in industrial device applications. Moreover, the work demonstrates that this system has the potential to be tuned for access to a vast range of materials design space.

Experimental study of flame spread over PE‐insulated single copper core wire under varying pressure and electric current

SummaryIn this study, the flame spread over a thin wire with overload current (0‐16 A) has been experimentally investigated at both normal pressure (Hefei: altitude 50 m, 100 kPa) and reduced pressure (Lijiang: altitude 2400 m, 76 kPa; Lhasa: altitude 3650 m, 64 kPa). Polyethylene‐insulated single‐core wires, comprising Cu as the inner core of diameter 0.30, 0.50, and 0.80 mm and insulation thickness 0.15 and 0.30 mm, are used as samples. The experimental results clearly indicate that the height of the flame increases with the electric current and ambient pressure, but the flame width changes only slightly. At identical conditions, the finer the wire, the faster the flame spreads. The flame spread rate increases with the electric current and ambient pressure. A simplified thermal balance analysis concerning the load current is developed to calculate the flame spread rate, and the calculated flame spread rates are shown to be fairly consistent with the experimental values at different electric currents for different wires at both ambient pressures. In addition, the coupled effect of electric current and ambient pressure on the flame spread is discussed. These results may be meaningful for promoting the research process of wire fire safety.

Influence of the elastic modulus of a conveyor belt on the power allocation of multi-drive conveyors.

The implementation of multiple drives for belt conveyors can solve the problems associated with motor overpower and the excessive tension of conveyor belts powered by a single drive. However, multiple drives can suffer from uneven driving power allocation. Among various factors, the selection of the type of conveyor belt particularly affects the power allocation. The current study aims to investigate the influence of the elastic modulus of a conveyor belt on the power allocation of multi-drive conveyors. Based on the Kelvin-Voigt viscoelastic model, a discrete model of an entire machine is established. Kelvin-Voigt software is used to simulate the working conditions of conveyor belts with different elastic moduli under full loads. The driving forces of individual rollers are obtained and then compared. Compared to other types of belts, a steel wire core conveyor belt, whose elastic modulus is relatively high, effectively improves the stability of the conveyor belt under a full load after start-up to achieve a reasonable power allocation. The results of this study provide a foundation for conveyor belt selection for multi-drive conveyors.

Role of wire core in extinction of opposed flame spread over thin electric wires

Theoretical and experimental works have been carried out to clarify the effect of core material on the extinction characteristics of the flame spreading over electric wires. Additionally, an attempt has been made to explain previous experimental results (Takahashi et al., 2013 [1]) which found that Limiting Oxygen Concentration (LOC) of copper (Cu) wire is higher than that of nickel-chrome (NiCr) wire. A theoretical model is developed to discuss the heat loss mechanism in the unburned zone ahead of the gas-phase preheat zone and its validity is confirmed by measured temperature profiles along Cu, iron (Fe), and NiCr wires insulated by low-density polyethylene (LDPE). The theoretical analysis reveals that the flame spread rate is a crucial value to assess the extinction characteristics of the flame spreading over electric wires because it controls heat loss in the unburned zone. The reduction of the flame spread rate increases heat loss in the unburned zone and induces the quenching extinction as a result of extended thermal diffusion length along the electric wire. It is also found that a highly conductive wire increases heat loss rather than poorly conductive wire even under the same flame spread rate. Such characteristics are well described by a newly introduced parameter, ηf, which is a dimensionless flame spread rate derived by the present study. By using ηf, previous experimental findings [1] are successfully explained.

LineSpyX: A Power Line Inspection Robot Based on Digital Radiography

Most of the current power line inspection robots use cameras and LiDARs to inspect the power line surfaces and the surrounding environment. But it is still difficult to detect the internal defects of the power lines. In this letter, the design and implementation of LineSpyX, a novel power line inspection robot based on digital radiography (DR), is introduced to solve the problem of non-destructive testing (NDT) of the overhead Aluminum Conductor Composite Core (ACCC) wires. The proposed robot has a stable wrapped mechanical structure with a moving system, a live work system, and a NDT system. The wheeled moving system enables the robot to move on the wires and cross obstacles such as vibration dampers. The NDT system consists of a portable X-ray generator and a DR detection panel. When the robot performs the inspection task, the X-ray goes up through the ACCC wire to the panel, where the X-ray images of the internal carbon fiber cores are recorded. A deep learning based defect diagnosis method combined with manual diagnosis is proposed to detect potential defects. The main functionalities of the developed robot are verified by lab experiments and field tests.