Wire Strands Research Articles

A New Signal Processing Method Based on Notch Filtering and Wavelet Denoising in Wire Rope Inspection

Wire rope is a necessary tool in practical applications especially in crane, elevator and bridge construction, which plays an important role in the national economy and daily life, and safety inspection for wire rope is the key to ensure people’s life and property. However, detection signals are usually complicated due to the twining structures, which make the wire rope defect signal and strand signal mix together. What’s more, no reports and studies have appeared to solve this problem. In view of the situation and challenges above, this paper proposes a combined signal processing method based on notch filtering and wavelet denoising to process detected wire rope signals. Basic time domain, frequency domain and joint time–frequency analysis are first conducted, thereafter, conventional signal processing methods such as lowpass filtering and adaptive analysis are presented according to the signal characterizations. These comparisons and results demonstrate that a conventional single method is incapable of wire-rope-detection signal identification and differentiation. Nonetheless, after the notch filter design and calculation, the processing results for the typical wire rope inspection signals in the experiments indicate that the combined methods can not only distinguish steel wire rope defect signal and strand signal effectively but also with high detection accuracy, even for the inner defect. Finally, the feasibility and reliability are verified by a series of signal processing results and comparisons, which demonstrate that this new method has great application potential and is of vital significance to the development of wire rope safety inspection.

Tribo-fatigue behaviors of steel wire rope under bending fatigue with the variable tension

Tribo-fatigue behaviors of steel wire rope under bending fatigue with the variable tension were presented in this study. A self-made bending fatigue test apparatus of steel wire rope under the variable tension was introduced. Fracture and wear mechanisms of steel wires in the rope were investigated employing the VW-9000E high speed camera. The total wear depth of both contacting wires was calculated in cases of distinct rope segments and different pulley diameters. The finite element method was employed to analyze three-dimensional contact behaviors between the rope and friction pulley in order to validate test results. The results show that the number of broken wires in the rope decreases in the order: the outer layer in the core strand, outer layer in the outer strand, inner layer in the core strand and center wire in the core strand. The tribo-fatigue damage between core and outer strands is larger than that between outer strand and friction pulley. Severe wear in the rope is located at the outer layer wire in the outer strand contacting the friction pulley, at contacting wires between neighboring outer strands, and at contacting wires between core and outer strands. The outer layer wire of core strand contacting with the outer strand presents several consecutive wear scars. The total wear depth of steel wire decreases with increasing pulley diameter and presents the fluctuating change with increasing bending fatigue cycles, which is the same case at various contact regions. Contact and damage locations in finite element analyses coincide well with the test results.

Detection Prestress Loss in Prestressed Concrete Slab using Modal Analysis

The paper presents numerical results of prestress loss in the prestressed hollow core slabs by using few natural frequencies. Loss of prestress has been investigated by the 3D finite element method, by using ANSYS software. Loss of prestress is modelled by decreasing of prestressing forces in the 7 wire strand that simulated damage or severing of prestress strands. The prestressing force in the strands is applied as an initial stress. The effectiveness of using frequency percentage changes as an indicator of the loss of prestress and effectiveness of the proposed method are investigated using the planning of experiments and response surface technique. After selection of equation of regression, the parametric studies are carried out in order to determine the influence of the slab length, concrete strength and initial stress on the frequency percentage changes and study the dependence of the percentage changes on these parameters. The present study shows that natural frequencies percentage change is dependent on the span of slab and compressive strength of concrete.

Testing, numerical simulation and design of prestressed high strength steel arched trusses

The structural behaviour of prestressed high strength steel arched trusses is studied in this paper through experimentation and numerical modelling. Four 11 m span prestressed arched trusses fabricated from S460 hot finished square hollow section members were loaded vertically to failure. Three of the tested trusses were prestressed to different levels by means of a 7-wire strand cable housed within the bottom chord, while the fourth truss contained no cable and served as a control specimen. Each truss was loaded at five points coinciding with joint locations along its span, and the recorded load-deformation responses at each loading point are presented. Inclusion and prestressing of the cable was shown to delay yielding of the bottom chord and enhance the load carrying capacity of the trusses, which ultimately failed by either in-plane or out-of-plane buckling of the top chord. For the tested trusses, around 40% increases in structural resistance were achieved through the addition of the cable, though the self-weight was increased by only approximately 3%. In parallel with the experimental programme, a finite element model was developed and validated against the test results. Upon successful replication of the experimentally observed structural response of the trusses, parametric studies were conducted to investigate the effect of key parameters such as prestress level, material grade and the top chord cross-section on the overall structural response. Based on both the experimental and numerical results, design recommendations in the form of simple design checks to be performed for such systems are provided.

Transverse load influence on tensile fatigue resistance of high-strength steel wires for structural applications in civil engineering

Cold-drawn duplex stainless steel is an alternative to cold-drawn eutectoid steel to prevent the stress corrosion cracking risk in strands for structural uses as concrete prestressing and strand-tendons of cable stayed bridges. These possible applications create uncertainty concerning the fatigue behaviour of strand wires when subjected to the combined action of cyclic tensile loads and transverse loads that occur at the contact with the other strand wires or at the anchorages, couplers and deviators. This research compares the experimental behaviour of two cold-drawn wire types, manufactured from a lean duplex stainless steel and an eutectoid steel, when simultaneously subjected to transverse static and axial fatigue loads. The results show that the fatigue endurance required by the standards in force for prestressing steel wires, free from transverse loads are maintained by the two wire types even under transverse loads as high as 40% of their tensile strength.

Effects of Teeth Length and Magnet Material on Characteristics and Effects on Conductor Eddy Current Loss due to Changes in the number of Strands of Litz Wire of Low Voltage Drive High-Speed Motorp

High-speed motor driven in low voltage are used in equipment such as electric reel and handy vacuum cleaner. If a motor with a general structure used in an operating range of several thousand revolutions is used as it is in a high-speed range of several tens of thousands of revolutions, efficiency will decrease due to a large amount of iron loss. In this paper, we proposed models in which the stator teeth length and the magnet material were changed in order to suppress the iron loss that causes the efficiency reduction of the high-speed PM motor. In this case, since the eddy current loss occurs in the armature conductor, the effect of reducing the conductor eddy current loss by using the Litz wire was also examined. As a result, it was shown that the proposed model improves the efficiency compared to the conventional structure.

Effect of Structure Parameters on Polycal Wire Rope Isolator Stiffness‐Damping Characteristics

Wire rope isolators are mainly used to isolate vibration and protect precise equipment. However, the issue of regulation of vibration isolators taking into account the nonlinearity of their characteristics was poorly understood in the modern literature. In this paper, the influence of structural parameters (diameter ratio and lay pitch of the single strand, and lay pitch and bending radius of the wire rope) on stiffness‐damping characteristics of the Polycal WRI was investigated by the simplified finite element analysis method. The stiffness and damping prediction models including structural parameters and material properties were established. The results showed that the stiffness‐damping characteristics were the best; when the diameter ratio of wire strand was 1.1, the inside layer wire pitch length was 6 times the diameter of the wire strand, the outside layer wire pitch length was 11 times the diameter of the wire strand, the pitch length of the wire rope was 7.5 times its diameter, and the bending radius was equal to 46.5 mm. The errors of the prediction for prestiffness and softened stiffness were within 5%, and the errors of prediction for the energy dissipation coefficient were within 10%.

Finite Element Analysis of a Newly Designed Straight Three-layered Seale Wire Strand

Finite Element Analysis of a Newly Designed Straight Three-layered Seale Wire Strand

Technical Innovation of Ultra-Deep Well Drilling Rig and Its Development Trend

8000-meter drilling rig and quadruple joint 9000-meter drilling rig have been developed for ultra-deep and complex wells of the complicated geological structure area in Tarim Basin, China. The key components of the drilling rigs are redesigned and innovated, including optimization of the high bearing capacity derricks and substructures and a completely new design of integrated single shaft drawworks with the compacted strand wire rope. The rotary table and its driving device with larger torque and load capacity, the high-pressure drilling pump with a high power, intelligent top drive system, casing running device with good compatibility, and automated pipe handling system are equipped. Field application shows that 8000 meters drilling rig, compared with the conventional 9000-meter drilling rig, can save equipment procurement costs by about 20%, reduce drilling operational costs 37%. In addition, the quadruple joint 9000-meter drilling rig can reduce the tripping time by more than 20%, and that the pressure is difficult to control in the complicated formation by conventional drilling rigs can be avoided to a certain extent. At the end of this paper, the advantages and the problems to be solved urgently of the ultra-deep well drilling rigs are expounded.

Multi-view wire art

Wire art is the creation of three-dimensional sculptural art using wire strands. As the 2D projection of a 3D wire sculpture forms line drawing patterns, it is possible to craft multi-view wire sculpture art --- a static sculpture with multiple (potentially very different) interpretations when perceived at different viewpoints. Artists can effectively leverage this characteristic and produce compelling artistic effects. However, the creation of such multi-view wire sculpture is extremely time-consuming even by highly skilled artists. In this paper, we present a computational framework for automatic creation of multi-view 3D wire sculpture. Our system takes two or three user-specified line drawings and the associated viewpoints as inputs. We start with producing a sparse set of voxels via greedy selection approach such that their projections on the virtual cameras cover all the contour pixels of the input line drawings. The sparse set of voxels, however, do not necessary form one single connected component. We introduce a constrained 3D pathfinding algorithm to link isolated groups of voxels into a connected component while maintaining the similarity between the projected voxels and the line drawings. Using the reconstructed visual hull, we extract a curve skeleton and produce a collection of smooth 3D curves by fitting cubic splines and optimizing the curve deformation to best approximate the provided line drawings. We demonstrate the effectiveness of our system for creating compelling multi-view wire sculptures in both simulation and 3D physical printouts.

Effect of friction on the mechanical behavior of wire rope with hierarchical helical structures

The effect of friction on the mechanical behavior of wire rope with hierarchical helical structures under tensile and bending loads is studied. A typical 7×7 wire rope with an independent wire rope core is considered. It is assumed that friction only occurs between adjacent helical wires in the core strand, and between the core wire and the double-helix wires in the outer strands. Based on Love’s thin rod theory, the mechanical responses of the rope under tensile and bending loads are analyzed, as well as the contact force. The effects of the chirality of rope and the initial helix angle of the wire on the distribution of the contact force are analyzed. It is shown that the effect of the chirality on the contact force of wires and stresses in the rope is insignificant. The global stiffness of the rope can be enhanced by the friction effect. The contact force of wires changes periodically with the winding angle of the centerline around the axis of the strand. The current model provides an effective method to assess the local deformation and stresses of the wire rope with consideration of the inter-wire friction.

BOND STRESS-SLIP OF STRAND IN PRESTRESSED CONCRETE SLEEPERS

Continuous vertical force on sleepers gradually degrades the bonding between the concrete and the prestressing strands. In particular, the vertical wheel loads can be significantly amplified due to irregularities on the wheel or on the track. This can eventually result in cracking or splitting of concrete along the strands leading to the structural failure of concrete sleepers. The bond between strand and concrete is an important factor which can directly or indirectly influence the cracking and splitting failure of the sleeper. This paper reports a series of pullout tests undertaken on specimens with 85 MPa concrete (nominal strength) and 7-wire prestressing strands replicating typical prestressed concrete sleepers produced in New Zealand. The results are discussed and compared in terms of the loads causing the first strand slip and also the bond stress-slip relationship. The results show that longer water curing time does not necessarily increase the bond between strand and concrete in prestressed concrete sleepers. This behaviour can be attributed to the effect of shrinkage and the trade-off between strength and shrinkage influenced by water curing. The obtained results can contribute to determining optimum sleeper curing time to achieve required strength and bonding and is valuable for concrete sleeper manufacturers where curing process is associated with considerable cost and logistical issues.

Improvement in the Transmission Efficiency of EV Wireless Power Transfer System Using a Magnetoplated Aluminum Pipe

The wireless power transfer (WPT) system in an electric vehicle charger uses a litz copper wire (LCW) in the transmission coil to reduce the high-frequency loss at 81–90 kHz. The litz wire improves the performance of the WPT system by increasing the number of strand wires and reducing the diameter while simultaneously increasing the cost. Using a solid wire coil reduces cost, but it causes a high frequency loss that reduces the efficiency. Therefore, this paper proposes the use of a magnetoplated aluminum pipe (MAP) in a transmission coil. Compared to the solid wire, the MAP is light and cheap to manufacture. In our prototype, the transmission efficiencies between coils were 95.67%, 94%, and 92.6% for the LCW, MAP, and aluminum pipe coils, respectively. Therefore, the MAP coil can effectively be used as a replacement for the LCW coil in the transmission coil.

Induction Heating Technology for Steel Wire Processing

This article discusses the induction heating application features in metallurgical industry for previously unused objects, such as wire coils and wire rod bundles. The analysis of international trends and a forecast of the induction heating application shows a steady expansion of the induction technologies in the metallurgical industry. The article considers the advantages of induction heating in comparison to other competitive technologies. Heat treatment in electrotechnological induction plants is determined by the interconnected electric and thermophysical processes taking place in them, the complex nature of the internal heat sources distribution, the dependence of the distribution pattern of the induction plant on the temperature of the products being processed. It is shown that the investigation results of the induction heating method influence the temperature and time factors in the formation of the structure, the increase in the uniformity of heating, and the quality of the heat treatment of steel wire and wire rod buntle, taking into account the stated technological task. The efficiency estimation of application of medium and high-frequency induction heating of steel wire of various diameters is given. Evaluation of the efficiency improving of the induction heating device, when the heat treatment simultaneous multiple strands of steel wire of equal diameter, united in a bundle, is given.

PERENCANAAN GELAGAR BETON PRATEGANG PADA JEMBATAN KEUDE RANTO PEUREULAK KABUPATEN ACEH TIMUR

Keude Ranto Peureulak Bridge a bridge connecting Keude Ranto Panjang with Keude Geurobak village and other villages in Ranto Peureulak Sub-district, East Aceh District. Keude Ranto Peureulak Bridge is planned with a span length of 20.8 meters and width of 7 meters. The longitudinal axis planned for the bridge is the posttractive pretreat type concrete girder. The girder plan includes gelagar dimensioning, stress calculation, prestress loss, cross-sectional capacity, deflection control, and drawing. The quality of concrete used is fc = 40 Mpa, the tendon used is seven wire strand diameter ½ inch with 51 mm diameter tendon sheath. Tendon fpu voltage = 1860 Mpa, fy threaded steel reinforcement = 320 Mpa, plain steel reinforcement fy = 240 Mpa, and efficient cross-sectional height is 0.9 meters. From the calculation results obtained the moment that occurred on the girder of 2563,439 kNm on the calculation of the third combination. The number of tendons obtained from the calculation is 3 pieces with 7 pieces of strand on each tendon. Losing the total prestress force is 380,694 Mpa. The principal reference is used D13 mm, the shear reinforcement is used Ø10-100 mm at the support area and Ø10-600 mm in the field area. The ultimate moment capacity of the prestress beam is 5575.60 kNm from the calculation of the third combination. The largest deflection of 0.0247 meters due to a combination of two loads. All the results of the calculations obtained are safe to use.Keywords: girder, prestress, tendon, reinforcement, deflection

Application of electromagnetic forming in terminal crimping using different types of field shapers

Mechanical crimping is the most used method of pressure connection for permanent electrical contact in electrical and electronic equipment. Terminal plastic deformation on multi-wire strands is carried out to achieve mechanical strength and electrical conductivity. Electromagnetic (EM) is assumed to be an alternative method to overcome the challenges of spring back in the terminal on tool relaxation, cracks, non-uniform deformation, reduced strength, decreased the durability of joints in conventional crimping tool. Implementation of the field shaper (FS) has been proposed to enhance the magnetic field to concentrate the magnetic pressure at the required location for the effective terminal crimping over the wire strands. In this work, crimping was carried out using FS as a tool. Experiments were carried out utilizing tapered FS, single step FS and double step FS on aluminum terminal over seven strands aluminum wire strands that are commercially utilized for making interconnections. Results like contact length, contact resistance, terminal deformation, surface hardness, cross-section hardness and pull-out tests were found out and compared simultaneously. Also, the test results were compared with the samples crimped using a conventional crimping tool. From the results single step FS was found to be the most efficient FS than double step FS whereas the tapered FS was the least efficient. The results will be helpful in determining the geometry for the field shapers in similar applications.

Thermal Analysis for Underground Power Cables with Different Arrays in Hot Places

In this paper, the electrical cables have been studied numerically and the effect of soil on its cooling has been investigated. The thermal conditions applied for hot climate temperature such as in south of Iraq data. Different cables arrays for three phase connections of electricity were done (horizontal, vertical and inclined (Which is new compared to previous researches) arrays). The arrangement of cables was buried and passed underground level for mechanical and electrical protection in addition to cooling them by conduction of low soil temperature. The cables of 19 strand wire (7mm diameter for each) homogeneously distributed inside a layer of insulation according to standards. The cables were placed at the centre of soil domain to utilized from a uniform temperature distribution due to the cold soil temperature in hot places. Heat flux assumed to flow from the outer surface of cable insulation to determine the temperature distribution in the domain and cables for selection of good insulation at peak electrical loads and hot weather conditions. The results showed that the maximum temperature was for the medium cable and that the electrical cables in hot areas should be buried underground at a depth of approximately 4 m to keep them from mechanical and electrical damage

TINJAUAN PERENCANAAN GELAGAR BETON PRATEGANG PADA JEMBATAN BAKONGAN KECAMATAN PERMATA KABUPATEN BENAR MERIAH

Bakongan bridge located in Bakongan village, Permata Subdistrict, Bener Meriah District. Based on the characteristics of the river, the bridge isplanned to Bakongan spans 13,6 meters long and 6 meters width. Girder longitudinal direction planned for the bridge is prestressed concrete girder type of post­ tension with the imposition of standard rules RSNI T-02-2005, RSNI T-12-2004 and Construction Manual 021/BM/201 J . Jn the early stages of planning done preliminary design to determine the dimensions of the main bridge, the calculation of the secondary structure are used as load analysis that occurs, the control voltage that occurs in the structure, post-tensile prestressing loss, sectional capacity, control deflection, and depiction. Quality of concrete used was Jc = 45 MPa, tendon used is seven strand wire with a diameter of 9,3 mm inch diameter 51 mm shells tendon. Voltage tendonfpu = 1860 MPa, quality threaded steel reinforcement isfY = 320 MPa, and quality plain steel reinforcement isfY = 240 MPa. Moments that occur in the calculation of girder 1502,0967 KNM combination III. Number of tendons obtained from the calculation is 5 to 35 pieces offruit on each strand tendons. Total loss of prestressing force obtained at 817,54 MPa or 34 %. Principal reinforcement used Æ13 mm, Æ10-shear reinforcement used in the staging area 100 mm and g 10-600 mm in thefield area. Ultimate moment capacity of prestressed beams 3629664KN/m combination Ill of calculation. Greatest deflection is 0.0151 meters caused by a combination JV. Keywords: Concrete prestressed, Post-tension girder, tendons, reinforcement

Corrosion Study of Galvanized Ultra High Strength Steel Reinforced Overhead Transmission Conductors

Overhead high voltage transmission conductors used worldwide are produced in several configurations. A multi-strand conductor of the type ACSR330 is typically used for 275 kV overhead transmission lines. The conductor is composed of 7 inner strands of Ultra High Strength Galvanized Steel for the mechanical support of the conductor and 26 strands of high conductivity Aluminum wires meant for power transfer over long distances. During the use, weather conditions and power fluctuations tend to degrade the properties of these conductors. In the present work, study of the state of galvanization and oxidation of an ACSR330 conductor is undertaken with a view to understand the effectiveness of the loss in corrosion protection and changes in the zinc coating on the galvanized steel strands after use for 25 to 30 years. The Scanning Electron Microscopy (SEM), X Ray Diffraction (XRD) and Energy Dispersive Analysis through X rays (EDAX) provide a very useful insight into the state of the conductor and gives important information to the strategic decision maker, whether or not to replace the conductor. It was observed in the present study that the zinc coating diffuses inside the steel strand under temperature and time effect. This unique study on the used conductors also reveals that the morphology of the coating and its interface structure changes significantly compared to an unused conductor of the same age.

The Analysis of 91-Wire Strand Tensile Behavior Using Beam Finite Element Model

Due to its complex geometry and high nonlinearity of inter-wire contact, the efficient prediction of the mechanical properties of a 91-wire strand is difficult by using the conventional three-dimensional solid finite element model (FEM). In this paper, a beam FEM for efficient analysis of the mechanical behavior of multilayered wire strands is applied to study the tensile behavior of the 91-wire strand. The beam FEM has a small model size and can be capable of taking into account the nonlinear factors such as the uneven wire bending, contact deformation and wire material plasticity etc. (International Journal of Perfomability Engineering (2017). By using the beam FEM, the axial tensile properties of the 91-wire strand have been predicted efficiently. The finite element analysis results have a good agreement with the experimental test results. Moreover, the contact behavior between contacted wires and the influences of above factors on the strand axial properties have also been analyzed effectively.