Independent Wire Rope Core Research Articles

Analysis and design of compacted IWRC meshed model under axial strain

Wire ropes are one of the most complex shapes due to the helical coiling of wires. It is difficult to generate a meshed model of even the classical circular wire rope. In this paper a more complex form which is known as compacted wire rope is modeled in 3D. The originality of this work is that, it is the first time a multi-layered compacted wire rope is generated and brought to the literature. The written code permits to create any length of compacted independent wire rope core geometry and to change wire radiuses and pitch lengths easily. Meanwhile flexibility of the code makes it easier to generate different kind of compacted independent wire rope core which is ready for numerical analysis. Compacted wire ropes have increased wear resistance and tensile strength. Due to its flattened surface their usage on a sheave or a pulley provides less wearing and breaking of wires while more tensile strength and increased lifetime. With the compaction process diameter of the wire rope decreases which results a decrease on the reaction moment also. This modeling issue can be used to create new type of complex wire rope models in the future.

A precise mathematical model for geometric modeling of wire rope strands structure

Based on the Frenet frame, this paper proposes a general mathematical spiral model with an arbitrary smooth space curve as the center path, which can accurately build complex skeleton lines of wire rope strands. From the aspect of geometry, all the wires are spatial cylinders and must meet the actual geometric requirements: 1. The center cylinder is tangent or separated from the spiral cylinder; 2. The adjacent spiral cylinders do not overlap each other. For requirement 1, Costello’ conclusion is referenced and extended universally to suit an arbitrary smooth space central curve case with rigorous proofs. For requirement 2, the overlapping problem is described as obtaining the minimum distance between the two adjacent spatial path curves, which is deduced by a novel cross section method (SCM) with rigorous proofs and solved by the General Particle Swarm Optimization (PSO) algorithm. Based on the above models, the geometric modeling of wire rope strands procedure is proposed and implemented on the platforms of MATLAB and SolidWorks. Validations are conducted through geometric graphical representations, compared with those from some previous researches. For the simple straight strand case, when the number of spiral cylinders and spiral radius are given, the critical relationship between the ratio of spiral wire radius to spiral radius and the spiral angle is firstly obtained, which can be a precise dimension design reference of simple straight strand for eliminating initial geometric overlap. Further, to show the advance, some precise graphical examples of complex wire rope strands like independent wire rope core (IWRC) and multilayered rope are presented. The wire rope strands geometric modeling method proposed in this paper is precise enough averting initial geometric overlap between the wires for the benefit of subsequent mechanical computation accuracy and efficiency.

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.

Key Innovations and Technologies in Vertical Transportation Systems since 1980

Vertical transportation systems have been rapidly evolving since the 1990’s. Lifts without machine rooms have become common, many buildings of 100 or more floors have been built or are planned and new technologies for lifts are being introduced.The common types of lifts produced in 1990 are explained as a baseline for explaining the innovations that have revolutionized lifts since then. These innovations include Variable Voltage Variable Frequency (VVVF) technology, the Insulated Gate Bipolar Transistors (IGBT), Permanent Magnet Alternate Current Motors (PMAC), Independent Wire Rope Core (IWRC) ropes, and Machine Room Less (MRL) lift technologies.Two novel suspension means, coated steel belts and coated carbon belts, are new technologies that are changing lift designs are reviewed.Systems that employ more than one lift per hoistway are explained. These systems can use ropes or they can be rope-less and employ magnetic levitation.Two interesting new technologies that are profoundly changing the lift industry, Machine Learning and Robots are also examined.

Performance evaluation of an independent wire rope core in a cage winder of a mechanized coal mine using nondestructive testing instrument

Nondestructive testing is an important means for assessment of performance of winder ropes. The visual method produces a possibility for inadequate inspection due to its subjectivity. Wire ropes wear out eventually, gradually losing work capability throughout its useful life making periodic inspections, lubrication and tensioning necessary. Magnetic flaw detectors are used to determine rope wearing. They measure loss of metallic area and detect the local faults like broken wires and other faults of the ropes. An attempt has been made in this paper to evaluate the performance of one cage winder rope in a mechanized coal mine in India using nondestructive testing instrument.

PS09 ワイヤロープ疲労破壊メカニズムの有限要素法解析

Recently in Japan, IWRC (Independent Wire Rope Core) wire ropes are widely used on crane. Comparing with traditional fiber core rope, IWRC is known to be prone to undetectable internal damage. Although a number of fatigue tests on IWRC have been done with the aim of life prediction and investigation of fracture characteristic, the mechanism of fracture has not been proved for the reason that it is difficult to observe where and when the internal damage occurs. In this study, to visualize the stress state of inner wires, we performed FEM analysis on two kinds of widespread IWRC rope, 6×WS(31) and 6×Fi(29), bent and dragged along sheave. The method of zooming analysis was introduced to this analysis for dealing with computational difficulty caused by the geometrical complexity of IWRC. The result of this analysis shows qualitative agreement with the result of S-type bending fatigue test that inner wires of Fi(29) rope has stronger tendency than those of WS(31) to break prior to visible damage.

GS24 ウォリントン・シール形鋼心ワイヤロープの疲労損傷に及ぼす張力の影響

GS24 ウォリントン・シール形鋼心ワイヤロープの疲労損傷に及ぼす張力の影響

A finite element model for independent wire rope core with double helical geometry subjected to axial loads

Due to the complex geometry of wires within a wire rope, it is difficult to model and analyse independent wire rope core accurately (IWRC). In this paper, a more realistic three-dimensional modelling approach and finite element analysis of wire ropes are explained. Single helical geometry is enough to model simple straight strand while IWRC has a more complex geometry by inclusion of double helical wires in outer strands. Taking the advantage of the double helical wires, three-dimensional IWRCs modelling is applied for both right regular lay and lang lay IWRCs. Wire-by-wire based results are gathered by using the proposed modelling and analysis method under various loading conditions. Illustrative examples are given for those show the accuracy and the robustness of the present FE analysis scheme with considering frictional properties and contact interactions between wires. FE analysis results are compared with the analytical and available test results and show reasonable agreement with a simpler and more practical approach.

Efektifitas Wire Rope Sebagai Perkuatan padaDaerah Momen Negatif Balok Beton Bertulang Tampang T

<p>The loss due to collapsing structure includes not only materialsbutalso take lives. In thecase of structure function changing that may cause increasing loads, it is required to put efforts instrengtheningthe structure elements in order to increase the capacity and hence to avoid the possibility of collapsing. The objective of this research was to study thebehavior of T-sectional reinforced concrete beamstrengthenedin the negative momentregionwithwire rope and mortar composite. The test was carried out to three T-sectional beams: without wire rope reinforcement (BK), with 2 wire rope reinforcements (BP1), and with 4 wirerope (BP2) reinforcements. The type of wire rope was Independent Wire Rope Core (IWRC) with10 mm diameter. The testing method used was two points static loading with flens positions below (the flens part experienced tensile stress). Results showed that the maximum load carryingcapacity of BP1 and BP2 specimens increased by ratios of 1.59 and 2.03 to the BK specimen respectively. However, the increase was achievedafter the development and propagation of highcracking. Ductility of BP1 and BP2 specimens decreased by ratios of 0.62 and 0.36 to the BK specimen respectively. The initial stiffness of BP1 and BP2 increased byratios of 1.09 and 1.08 to the BK specimen respectively.The effective stiffness ofBP1 and BP2 specimensdecreased by ratios of 0.88 and 0.92 to the BK specimenrespectively. Stress occurred in the wire rope based on the analysis results of Response-2000 and the layer method have not reached 50% ofthe ultimate stress resulted from the preliminary test. In general, unless improvement was given to the stiffness characteristics of thewire rope, its contribution would not become optimum.</p>

On the Problem of Wire Rope Model Generation with Axial Loading

Independent wire rope core (IWRC) is one of the fundamental components of complex wire ropes. It is a complex geometry and constructed by wrapping wire strands over a straight wire strand. The outer wires of the IWRC are double helical shaped feature which can be only modeled using special treatment. The aims of this paper are to introduce a new technique of modeling wire rope with IWRC and to compare numerical results obtained from this model with available results in the literature. Therefore the model generation for a simple straight strand is explained and accuracy of this model is validated. Furthermore this modeling procedure is adapted to whole wire rope structure considering double helical geometry concept. The proposed rope model gives remarkable results by means of wire by wire analysis scheme. This model is found easier and more effective. The results show good agreement with other available results but with a simpler and more practical approach.Independent wire rope core (IWRC) is one of the fundamental components of complex wire ropes. It is a complex geometry and constructed by wrapping wire strands over a straight wire strand. The outer wires of the IWRC are double helical shaped feature which can be only modeled using special treatment. The aims of this paper are to introduce a new technique of modeling wire rope with IWRC and to compare numerical results obtained from this model with available results in the literature. Therefore the model generation for a simple straight strand is explained and accuracy of this model is validated. Furthermore this modeling procedure is adapted to whole wire rope structure considering double helical geometry concept. The proposed rope model gives remarkable results by means of wire by wire analysis scheme. This model is found easier and more effective. The results show good agreement with other available results but with a simpler and more practical approach.

In situ assessment of independent wire rope core ropes in cage winders by a nondestructive method

The most widely used method to study the condition of winder ropes is the magnetic nondestructive method. Localized and distributed flaws in winder ropes can be detected by this method. This paper is intended to highlight the findings using such a technique in the case of independent wire rope core rope in two cage winders in a coal mine.

Theoretical approach to the solutions of axially loaded complex ropes

A rational analysis procedure consisting of a complete cycle of systematic calculations has been developed for the theoretical solutions of problems in describing the behavior of axially loaded complex ropes consisting of wires and strands, which were simulated as particle‐motion models. In essence, axial and rotational strains of a rope were specified. Constitutive relations of the loaded wires and strands were obtained through compatibility of motion requirements. Material law was then imposed to determine the internal force of each wire. Nonlinear equilibrium relations of wires were applied to describe the relationship among sectional stresses and external forces. The theory is used in the analysis of a 6 × 7 wire rope with an independent wire rope core (IWRC). Some solutions and comparisons to other research results have been provided. Results show that the recursive nature of the wire in the model enhanced the calculation of constitutive relations and made it easier to apply to the analysis of complex ropes having multiple orders.

The mechanical behavior of a wire rope with an independent wire rope core

A new model for simulating the mechanical response of a wire rope with an independent wire rope core is presented. The rope is subjected to both an axial load and an axial torque. In contrast with previous models that consider the effective response of wound strands, the present model fully considers the double-helix configuration of individual wires within the wound strand. This enables to directly relate the wire level stress to the overall load applied at the rope level. The model assumes a fiber response of individual wires. Two alternative kinematics of the wires are considered, and are used to predict the elastic response of the rope. The postulated kinematics are theoretically validated and the predicted rope response is in agreement with new experimental data. The new model enables the extraction of the stress at the wire level that can be used in turn to estimate global features of the rope such as force interaction between wires, rope stiffness, strength, and fatigue life.

Simple determination of the axial stiffness for largediameter independent wire rope core or fibre core wire ropes

Raoof and Kraincanic recently developed two somewhat different theoretical models for analysing large-diameter wire ropes with either an independent wire rope core (IWRC) or a fibre core. Most importantly, unlike all of the previously available theories (with their often very lengthy mathematical formulations), very encouraging correlations have been found between Raoof and Kraincanic's theoretical predictions of wire rope axial stiffnesses and a fairly large body of experimental data from other sources, hence providing ample support for the reliability of both theoretical models. Raoof and Kraincanic's original models were, however, computer based and involved certain iterative procedures. This potential drawback for practical applications (in an area where, by tradition, the rule of thumb reigns supreme) is overcome in the present paper, which reports details of some simplified (but still accurate) procedures for predicting the no-slip and/or full-slip axial stiffnesses of wire ropes with either an independent wire rope core or a fibre core, with the proposed formulations being amenable to simple hand calculations using a pocket calculator, which is of value to busy practising engineers.

Frictional performance of wire and fibre ropes bent over sheaves

The frictional behaviour of heavily loaded wire ropes bent over relatively small sheaves has been investigated with 6 × 36, 28 mm and 35 mm diameter, IWRC (independent wire rope core) and FC (fibre core), bright and galvanized ropes being tested, over sheaves with D/d ratios between 12 and 20. The groove profiles used were plain U and undercut U, with groove diameters 2.5 per cent smaller than the rope nominal diameter. Some pilot studies were also run on high-strength synthetic fibre ropes. The measurements showed that the effective friction coefficient increased with decreasing line tension and increasing sheave diameter for unused surfaces but became almost constant for used surfaces. It was shown that the undercut U groove had a higher frictional hold than the plain U groove but gave rise to early erratic slip. Galvanized rope had a lower friction coefficient while increased speed of sliding decreased friction.

Fatigue of wire ropes bent over small sheaves

The fatigue performance of heavily loaded wire ropes bent over rather small sheaves has been investigated. A selection of 28 and 35 mm diameter ropes of 6 x 36 construction was tested over sheaves with D/ d ratios between 12 and 20. Three different groove profiles with diameters 2.5% less than the nominal rope diameter and mean loads of up to 65% of the rated axial strength of the rope were used. Under the conditions examined, a 28 mm independent wire rope core bright wire rope had the best fatigue life and a 28 mm fibrecore galvanized rope the worst. One of the three grooves employed severely decreased fatigue life.

On the Design of Wire Rope

In recent work, a design methodology for multi-lay wire strands has been developed. The current paper expands on this earlier work to study wire ropes in which the strand is a basic component. Wire ropes with the three types of cores, independent-wire-rope-core (IWRC), fiber-core (FC), and wire-strand-core (WSC), are considered. This work further generalizes the previously developed linearized theory which, through substantiation with experiment, is felt to be reasonably accurate for most wire rope behavior. The theory is then utilized to examine various parameters in the design of wire ropes.

General nonlinear theory for complex wire rope

A general nonlinear theory has been developed to analyze complex wire rope. The rope is considered to consist of several strands each comprised of a collection of helical wires and the nonlinear equations of equilibrium for bending and twisting of thin rods are applied. The resultant theory is used in the analysis of a 6 × 19 Seale wire rope with an independent wire rope core. Dimensionless results are presented for both the total wire rope and the individual strands of which it is comprised. The results of the current theory are compared to the recently developed linear theory for complex wire rope.

Wire Rope with Complex Cross Sections

A theory is developed to predict the static response of a wire rope with complex cross sections. The solutions of the nonlinear equations of equilibrium are linearized, and the results are applied to a 6 × 19 Seale rope with an independent wire rope core. The linearization permits a considerable simplification in the theory so that the results can readily by applied to other types of cross sections. Expressions are presented for the stresses in the rope, and the maximum tensile stress is also determined. A load-deformation curve of a Seale rope is obtained experimentally, and the results are compared with the theory.