Wire Thickness Research Articles

Finite element failure analysis of wires for civil engineering applications with various crack-like laminations

This paper presents the finite element (FE) failure predictions and analyses of a typical wire for civil engineering applications with various crack-like lamination types (Single and double), geometries (straight-end and inclined-end) and orientations (longitudinal, lateral and transverse). FE prediction and analysis of the failure of notched pre-cracked wires with a surface across-the-thickness crack-like lamination validated with experimental results are also presented. The FE predicted fracture shape for the notched pre-cracked wires that consists of a cup and cone fracture shape below the bottom tip of the surface across-the-thickness crack-like lamination agrees with the experimental fracture shape. Wires with the double straight-end and double inclined-end crack-like/line-type laminations exhibit a “slant-middle W” and a “zigzag” fractures respectively. Above and below the lateral mid-width across-the-thickness lamination, the wires with the lateral mid-width across-the-thickness lamination exhibit a combination of a transverse mid-thickness flat fracture that is perpendicular to the lateral mid-width across-the-thickness lamination and negatively inclined slant fractures on each side of the mid-thickness flat fracture at the remaining outer edges of the wire's thickness. On both the front and back sides of the transverse mid-thickness across-the-width lamination, the wires with the transverse mid-thickness across-the-width lamination exhibit a combination of transverse flat fractures parallel to the transverse mid-thickness across-the-width lamination and positively inclined slant fractures at the outer edges of the wire's thickness. FE failure analysis reveals that fracture initiations do not always begin at the termini of every longitudinal crack-like/line-type lamination as reported in a published fractographic failure analysis report of wires with longitudinal crack-like laminations. Fracture initiation only begins at the termini/tip of longitudinal inclined-end crack-like laminations and at the termini/tip of transverse and lateral laminations. FE failure analysis also reveals that wires with single straight-end, double straight-end and double inclined-end longitudinal crack-like/line-type laminations do not exhibit cup and cone fractures as reported. This work further demonstrates the need to employ FE failure analysis as a complimentary or alternative failure analysis approach where the destruction/alteration of the fracture markings by corrosion could affect the accuracy of fractographic failure analysis.

Investigation of strain sensors based on thin graphite wires

In this study, the electrical properties of thin graphite wires were investigated for strain sensors. The thin graphite wires were simply and easily fabricated from pyrolytic graphite sheet, which can be formed by firing a polymer film (such as a polyimide film) at high temperatures. The resistance of the thin graphite wires increased under increasing tensile bending strains and decreased under increasing compressive bending strains. Notably, the sensitivity of the sensors increased when the thickness of the thin graphite wires was reduced. This property was investigated via modeling of the strain-induced changes in the overlap area and conduction pathways of the graphite flakes. Multiple-cycle tests were carried out to evaluate the long-term stability of the thin graphite wires; specifically, the electrical response was monitored under repeated cycling, for approximately 1000 cycles. The thin graphite wires were assembled on ultrathin gloves to fabricate data gloves that could detect finger motions. The results of this study indicate that the thin graphite wires that were simply and easily fabricated from pyrolytic graphite sheet have great potential for a wide range of applications, including human motion detectors.

Dynamic Trajectory and Capture of Fine Dust by Magnetic Mesh Filters Based on a Particle Velocity Model

The particle velocity model developed in this study described the dynamic motion of fine dust particles along the magnetized mesh wires in a low Stokes regime. The numerically evaluated velocity contour of the particles modeled the critical path lines indicating the threshold positions for magnetic collection. The velocity contour was determined using the parameters such as particle size, magnetic intensity, flow velocity, and mesh configuration including wire thickness and packing density. Particle size was one of the most significant parameters to determine the magnetic collection. The theoretical estimation matched well with the lab experiments, but the discrepancy increased for large particles with a fine filter. In consequence, application of magnetized mesh filters could contribute to the collection of the ferromagnetic dust or aerosols to a certain extent without any additional power or pressure resistance.Copyright 2015 American Association for Aerosol Research

Thermodynamics of the adsorption of flexible polymers on nanowires.

Generalized-ensemble simulations enable the study of complex adsorption scenarios of a coarse-grained model polymer near an attractive nanostring, representing an ultrathin nanowire. We perform canonical and microcanonical statistical analyses to investigate structural transitions of the polymer and discuss their dependence on the temperature and on model parameters such as effective wire thickness and attraction strength. The result is a complete hyperphase diagram of the polymer phases, whose locations and stability are influenced by the effective material properties of the nanowire and the strength of the thermal fluctuations. Major structural polymer phases in the adsorbed state include compact droplets attached to or wrapping around the wire, and tubelike conformations with triangular pattern that resemble ideal boron nanotubes. The classification of the transitions is performed by microcanonical inflection-point analysis.

Effects of Edge Taper on Domain Wall Structure and Current-Driven Walker Breakdown in a Ferromagnetic Thin Film Wire

Domain walls in a ferromagnetic thin film wire with rectangular cross section adopt transverse wall (TW) or vortex wall (VW) geometries depending on the magnetic material and the wire width and thickness. However, experimentally wires can have a trapezoidal cross section if they are made by liftoff using an undercut resist profile. Micromagnetic modeling shows that tapering of the wire not only promotes the formation of a TW over a VW, but also increases the critical current value and the domain wall velocity at which Walker breakdown occurs, providing a potential route to higher speed domain wall devices.

Process Parameter Optimization of Scanning Probe Lithography for Anodic Oxidation of Nanowire

Because consumer electronic products, such as notebook computers or digital cameras, are becoming increasingly popular, product design is moving toward the trend of lightweight and compact size. Therefore, how to produce nanosized patterns on silicon wafer becomes the key technology to reducing electronic modules. In terms of the scanning probe lithography proposed in this paper, wire thickness was defined directly on the surface of silicon wafer using anodic oxidation of atomic force microscope (AFM), improving on the optical diffraction of traditional optical lithography. The control factor and level value were planned using the Taguchi method, and the quality characteristics were specified. The Taguchi method designs one single quality, in terms of process, the overall quality characteristic seldom being optimized. Therefore, this paper combined grey relational generating with the fuzzy inference system to integrate multiple quality characteristics. Finally, the back-propagation neural network was combined with the quasi-Newton method to build the process prediction system to simulate the experimental results. After multi-quality optimization design, silicon oxide wire of width 68 nm was produced. Results showed marked uniformity on the silicon wafer and could become a useful technology in reducing electronic modules.

Analysis of the Quality of the Weld Metal Obtained with Alloyed Flux-Cored Wire

Abstract. The main aim of this paper is to assess the quality of newly produced, alloyed flux-cored wire with increased thickness of the steel cover compared to traditional according to AWS A5.29 standard, alloyed with Ni and Mo, and designed for welding of fine-grained HSLA steel. Flux-cored wire was produced on a pilot production line that allows calibration of steel band of higher thickness and production of flux-cored wire. Quality assessment of the alloyed flux-cored wire was based on the analysis of the results of tests of mechanical properties and microstructure mainly of the weld metal. Variation of chemical composition and microstructure were analyzed along weld metal (for each welding pass) and heat affected zone (HAZ) using SEM and EDS. Based on the results of the quality assessment of flux-cored wire, the conclusions about the feasibility of industrial application of selected metallurgical grade of flux-cored wire designed for welding of fine-grain HSLA steel were presented.

Optical response of anisotropic silver nanostructures on polarized light

Treatment of absorbing polymer (polyethyleneterephthalate) with pulse KrF excimer laser causes formation of laser induced periodic surface structures (LIPSS). Silver nanowires were prepared on the surface of laser treated polymer using vacuum evaporation at glancing angle geometry (70°). The wires were observed with Scanning Electron Microscope equipped with Focused Ion Beam module (FIB-SEM). Relations between size and spacing of wires and morphology of polymer template were observed from those images. Optical response of prepared wires with different cross-sections and spatial parameters was investigated. The effect of polarizer on measured UV–vis absorption spectra showed anisotropy in optical properties of 1D metal nanostructures. The excitation of Localized Surface Plasmon Resonance (LSPR) was achieved only with an appropriate arrangement of the wire axis to the plane of polarization. Influence of wire width on position of absorption band was detected. Wire thickness was found to be a crucial parameter resulting in plasmon peak intensity.

Growth and characterization of horizontal GaN wires on silicon

We report the growth of in-plane GaN wires on silicon by metalorganic chemical vapor deposition. Triangular-shaped GaN microwires with semi-polar sidewalls are observed to grow on top of a GaN/Si template patterned with nano-porous SiO2. With a length-to-thickness ratio ∼200, the GaN wires are well aligned along the three equivalent 〈112¯0〉 directions. Micro-Raman measurements indicate negligible stress and a low defect density inside the wires. Stacking faults were found to be the only defect type in the GaN wire by cross-sectional transmission electron microscopy. The GaN wires exhibited high conductivity, and the resistivity was 20–30 mΩ cm, regardless of the wire thickness. With proper heterostructure and doping design, these highly aligned GaN wires are promising for photonic and electronic applications monolithically integrated on silicon.

Strain effects on the optical properties of compressively-strained InGaAs/InP multiple quantum wires

Strain effects on the optical properties of compressively-strained InGaAs/InP multiple quantum wires (QWRs) are investigated as functions of the wire thickness along the x direction, Lx, by using a six-band strain-dependent k·p Hamiltonian. In the case of QWRs with the same initial strains, the transition energy decreases with increasing number of wire layers, and its rate of decrease is shown to increase with increasing Lx. On the other hand, in the case of QWRs with different initial strains, the transition energy slightly increases with increasing number of wire layers and its rate of increase is nearly independent of Lx. The z-polarized optical matrix element for QWRs with different initial strains is shown to be much larger than that for QWRs with the same initial strains, irrespective of Lx. This can be explained by the fact that the confinement of the wavefunction in the conduction band is enhanced due to the strain effect.

Performance-based assessment and design of FRP-based high damping rubber bearing incorporated with shape memory alloy wires

This study deals with two new generation smart high damping rubber bearings (HDRBs) incorporated with shape memory alloy (SMA) wires. Due to the superelastic effect and the re-centering capability of SMAs, the residual deformation in SMA-based elastomeric isolators is reduced. Two different configurations of SMA wires incorporated in rubber bearings are compared by changing the aspect ratio of base isolator, the type of SMA, the thickness of wires, and the pre-strain in wires where the isolator is subjected to a vertical pressure and unidirectional cyclic lateral displacement. A performance-based design flowchart is also provided along with a design example for determining the pre-strain and the radius of cross section of wires in the SMA wire-based rubber bearings. Results demonstrated that using ferrous SMA wires (FeNCATB) with 13.5% superelastic strain in the cross configuration leads to the best performance since the strain induced in wires is significantly decreased. Seismic performance evaluation of a three-span continuous bridge isolated by smart HDRBs shows that using SMA wires with cross configuration leads to the highest energy dissipation during earthquake. However, implementing SMA wires into HDRBs has negligible effect and in some cases no effect on the pier displacement and peak deck acceleration. It was also observed that neither of the HDRBs nor the SMA-HDRBs experienced any residual deformations when they were subjected to three different ground motions scaled by Vancouver design response spectrum.

Thermopower Peculiarities of Uniaxial-Strained Bismuth Nanowires

We present the results of the investigations of the thermopower and electrical resistance of Pyrex-coated Bi nanowires. Here we show that there is a critical thickness of wire below which structural defects can strongly influence the charge transport in Bi nanowires, fabricated by the melt spinning method. At low temperature the contribution of holes to the thermopower dominates the electron contribution. Thermoelectric parameters of Bi nanowires may be controlled by applying a thermal treatment and/or a uniaxial pressure. A fairly high value of thermoelectric power factor was found under strain in the temperature range of 80–300 K, where the dominant mechanism contributing to the thermopower is diffusive thermoelectric generation with electrons as the majority carrier.

Mechanical Behaviors of Wire-woven Metals Composed of Two Different Thickness of Wires

Wire-weaving is virtually only a practical method to fabricate multi-layered truss type cellular metals, except for stacking multiple single layered structures. To date, the wire-woven metals have been fabricated of wires of a uniform thickness. In this work, variations of wire-woven metals fabricated of two different thickness wires in out-of-plane and in-plane directions are introduced. The mechanical properties subjected to compressive or shear loading are investigated.

Fast Moving Multiple Magnetic Bits in Permalloy Cylindrical Nanowires

Controlling the movement of domain walls in magnetic nanowires is important due to the impact on the viability of data storage devices. A series of micromagnetic simulations of multiple current-induced domain walls motion (CIDWM) have been performed. Multiple CIDWM in the cylindrical permalloy nanowires display outstanding dynamic properties. In cases of different domain bits, we observed the motion of transverse domain walls (TDWs) did not show oscillatory behavior. The domain walls only changed their positions in the same direction as they propagated and kept the distance between the walls almost the same, with their internal magnetic structure unchanged. Furthermore, we have found that the TDW velocity in cylindrical thin wires was closely related to the wire thickness and showed a strong dependence on the Gilbert damping factor.

Monolithic carbon structures including suspended single nanowires and nanomeshes as a sensor platform

With the development of nanomaterial-based nanodevices, it became inevitable to develop cost-effective and simple nanofabrication technologies enabling the formation of nanomaterial assembly in a controllable manner. Herein, we present suspended monolithic carbon single nanowires and nanomeshes bridging two bulk carbon posts, fabricated in a designed manner using two successive UV exposure steps and a single pyrolysis step. The pyrolysis step is accompanied with a significant volume reduction, resulting in the shrinkage of micro-sized photoresist structures into nanoscale carbon structures. Even with the significant elongation of the suspended carbon nanowire induced by the volume reduction of the bulk carbon posts, the resultant tensional stress along the nanowire is not significant but grows along the wire thickness; this tensional stress gradient and the bent supports of the bridge-like carbon nanowire enhance structural robustness and alleviate the stiction problem that suspended nanostructures frequently experience. The feasibility of the suspended carbon nanostructures as a sensor platform was demonstrated by testing its electrochemical behavior, conductivity-temperature relationship, and hydrogen gas sensing capability.

Microfabricated environmental barrier using ZnO nanowire on metal mesh

In this study, a waterproof environmental barrier for microsensor package has been developed using metal mesh covered with zinc oxide (ZnO) nanowire. A near superhydrophobic surface with two-dimensional array of holes has been fabricated by hydrothermal growth of ZnO nanowire on an off-the-shelf steel use stainless (SUS) mesh. For a twill-woven SUS wire mesh having wire thickness of 30 µm and gap of 33 µm, a maximum contact angle of 160.40° and a minimum contact angle hysteresis of 15.23° have been achieved using ZnO nanowire grown on the wire surface and further deposition of FC film. The mesh was able to withstand a maximum water pressure of 2,459.8 Pa. The measured height of ZnO nanowire was approximately 2–3 µm. The fabricated SUS mesh covered with ZnO nanowire has been assembled with a microphone package, and waterproof characteristics have been measured by cyclic dipping test at various water levels. For a microphone package having two acoustic ports on top and bottom covered with fabricated mesh, no visible change in acoustic characteristics has been observed up to 1,372.9 Pa of water pressure. Total volume of the package was 6.8 × 9.8 × 1.9 mm3.

Design and Optimization of a Shape Memory Alloy-Based Self-Folding Sheet

Origami engineering—the practice of creating useful three-dimensional structures through folding and fold-like operations on two-dimensional building-blocks—has the potential to impact several areas of design and manufacturing. In this article, we study a new concept for a self-folding system. It consists of an active, self-morphing laminate that includes two meshes of thermally-actuated shape memory alloy (SMA) wire separated by a compliant passive layer. The goal of this article is to analyze the folding behavior and examine key engineering tradeoffs associated with the proposed system. We consider the impact of several design variables including mesh wire thickness, mesh wire spacing, thickness of the insulating elastomer layer, and heating power. Response parameters of interest include effective folding angle, maximum von Mises stress in the SMA, maximum temperature in the SMA, maximum temperature in the elastomer, and radius of curvature at the fold line. We identify an optimized physical realization for maximizing folding capability under mechanical and thermal failure constraints. Furthermore, we conclude that the proposed self-folding system is capable of achieving folds of significant magnitude (as measured by the effective folding angle) as required to create useful 3D structures.

Parametric Study of Losses in Cross-Bonded Cables: Conductors Transposed Versus Conductors Nontransposed

Conductor transposition, for cross-bonded cables, is recommended in the ANSI/IEEE Standard 575-1988 as a means to reduce interference with communication systems. In this paper, it is shown that reduced interference comes at the price of increased cable losses, which is an issue not addressed in the 1998 edition of the IEEE Standard 575. Analytical formulas are obtained for the calculation of the positive-sequence resistance for transposed and not transposed conductors to shed light on the reasons why the losses increase when the conductors are transposed. It has been found that for cross-bonded cables installed in flat formations, the positive-sequence resistance of transposed conductors is always larger than that of nontransposed conductors. Parametric studies are performed by varying all of the construction and installation parameters that affect the value of the positive-sequence resistance. In particular, we have changed the separation distance between cables, the insulation thickness, the number and resistance of the concentric wires, and the resistivity of the soil among other parameters. Examples on transmission and distribution cables are discussed.

Transport model for homogenized uniaxial wire media: Three-dimensional scattering problems and homogenized model limits

A transport-based formulation is used to model three-dimensional objects made of a uniaxial wire medium. The resulting drift-diffusion equation is used to calculate the extinction/scattering cross section of various uniaxial wire medium objects. A comparison is made with measurement and full wave simulation results. This method is faster than full wave simulation and provides physical insight into electrodynamic processes within the homogenized medium. The effect of wire period and thickness on the homogenized model is investigated, and a Debye length parameter is used to access the effect of wire length.

Electrical burns of the abdomen

A 35-year-old male farmer came in contact with 11,000 volts high tension electric wire and sustained full thickness burn wounds over scapula, upper limb and anterior abdominal wall along with perforation of the intestine. Patient was initially managed conservatively in general surgery ward and was referred to us after 3 days with necrosis of the burned skin and muscles over the shoulder and abdomen. Patient was initially managed conservatively and then thorough debridement of the necrotic skin over the left shoulder and upper arm was done and the area was split skin grafted. Patient developed enterocutaneous fistula, which healed over a period of 8 weeks. The granulating wound over the abdomen was also skin grafted and patient was discharged after 18 days. About 4 months, after the discharge patient presented with ventral hernia. Repair of ventral hernia by synthetic mesh application and reconstruction of the abdominal wall with a free tensor fascia lata flap was done over the mesh, but the flap failed. Then after debridement two random pattern transposition skin flaps, one from the right upper and another from the left lower abdomen were transposed over the abdominal wound and donor area was skin grafted. Patient was discharged after 17 days.