Rope Type Research Articles

Study on friction and wear behavior of braided wire rope for traction

In this paper, the friction and wear properties of braided wire rope for cable traction engineering are studied. Through the observation of the wear morphology of the rope at different contact locations by VHX-5000, it is found that the rope between strands is in point contact state, which leads to stress concentration, so the wear is the most serious. The second is the “rope-wheel” contact rope, while the rope in the strand is only slightly worn. On this basis, by means of the analysis of scanning electron microscope (COXEMEM-30), it is revealed that the main wear types of braided wire rope in actual working conditions are adhesive wear and composite wear formed by fatigue wear and corrosion wear.

Loads borne by a tie-in point (TIP) during arboricultural climbing operations

Failure of a tie-in point (TIP) in tree climbing can have severe consequences, yet few studies have quantified the loads borne by and load-bearing capacity of TIPs. In two separate experiments, loads borne by the TIP during (i) abrupt stops while a climber descended and (ii) simulated climber falls were quantified for a variety of TIPs, rope types, and rope lengths (distance between the TIP and the application of the load). Peak load ratios (measured load divided by the weight of a simulated or actual climber) up to 10.6 were recorded, a potentially dangerous value with respect to both TIP failure and personal injury. Peak load ratios decreased as the length of rope between the TIP and the location of the simulated fall increased, and when trees were in leaf. Minimizing the potential fall distance during ascents is the surest way to reduce the likelihood of TIP failure and personal injury.

About features of management of mobile robots with stepping movers of a rope type in a water environment

The methods of moving robotic platforms having in their arsenal either an anchor-rope or an anchor-rope-tracked mover are analyzed. The algorithms of operation of caterpillar-anchor-cable movers of various designs and gait algorithms for a platform with an anchor-cable mover are determined.

Flume tank evaluation of the hydrodynamic lift and drag of helix ropes compared to conventional ropes used in midwater trawls

The hydrodynamic properties of ropes can significantly affect the underwater performance of midwater trawls, including their geometry, drag, fuel consumption, and rate of gear setting and hauling activities. In this study, we investigate the hydrodynamic properties of helix ropes compared to conventional polyethylene (PE) and nylon (PA) ropes. Flume tank tests were conducted using 17 different braided and twisted ropes of varying diameter (6 mm, 8 mm, 9 mm, and 14 mm). Samples of each rope type were subjected to a series of water velocities (0.5 m/s, 0.7 m/s, and 0.9 m/s) and angles of attack (0°, 12°, 20°, 45°, 61°, and 90°) in order to measure drag and lift forces. To understand how hydrodynamic coefficients vary with increasing Reynolds number (Re), we also evaluated a wider range of water velocities (0.3 m/s to 0.9 m/s) for 14 mm ropes. Our results showed that, when compared to conventional ropes of the same diameter, helix ropes produced increased lift force (L), verifying their description as self-spreading ropes. To our knowledge, these findings represent the first known evidence of its kind published in scientific literature with direct application to midwater trawling operations.

Global Energetics of Solar Flares. IX. Refined Magnetic Modeling

A more accurate analytical solution of the {\sl vertical-current approximation nonlinear force-free field (VCA3-NLFFF)} model is presented that includes besides the radial $(B_r)$ and the azimuthal $(B_\varphi)$ magnetic field components a poloidal component $(B_{\theta} \neq 0)$ also. This new analytical solution is of second-order accuracy in the divergence-freeness condition, and of third-order accuracy in the force-freeness condition. We re-analyze the sample of 173 GOES M- and X-class flares observed with the {\sl Atmospheric Imaging Assembly (AIA)} and {\sl Helioseismic and Magnetic Imager (HMI)} onboard the {\sl Solar Dynamics Observatory (SDO)}. The new code reproduces helically twisted loops with a low winding number below the kink instability consistently, avoiding unstable, highly-twisted structures of the Gold-Hoyle flux rope type. The magnetic energies agree within $E_{VCA3}/E_W=0.99\pm0.21$ with the Wiegelmann (W-NLFFF) code. The time evolution of the magnetic field reveals multiple, intermittent energy build-up and releases in most flares, contradicting both the Rosner-Vaiana model (with gradual energy storage in the corona) and the principle of time scale separation ($\tau_{flare} \ll \tau_{storage}$) postulated in self-organized criticality models. The mean dissipated flare energy is found to amount to $7\%\pm3\%$ of the potential energy, or $60\%\pm26\%$ of the free energy, a result that can be used for predicting flare magnitudes based on the potential field of active regions.

Modelling of locally damaged steel wire ropes

ABSTRACT This work examines various approaches proposed during the last fifty years, intended for the study of the scattering fields of topology (spotting the exact location) in the magnetic flaw detectors of steel wire ropes caused by damage in various types of wire ropes. In this study, the known steel wire rope models and their damages are compared. The preservation of low degree of reliability in the modelling of wire ropes with complex and closed structures is observed. New volumetric numerical models of the wire rope structure elements are proposed, taking into account design features such as the number and the profile of the wires, coiling mode and steepness of the strands in a single wire, and the number of layers. In spotting the location of a local magnetic field defect, principal differences of various details were identified by observing the case of simplified models and comparing it with the example of a real model of a steel wire rope, in the area of the local defect location. The results demonstrate the importance of reliable modelling of the steel wire rope structure when studying the magnetic field topology in the area of wire rope defects.

Methods to prevent and treat biofouling in shellfish aquaculture

Fouling organisms in bivalve aquaculture cause significant economic losses for the industry. Husbandry strategies to reduce biofouling can involve avoidance, prevention, and treatment. In this way, the type of rope used to collect spat or grow bivalves may prevent or reduce fouling by particularly harmful species but remains largely untested. Further, while a range of eco-friendly control methods exist, their effect on widespread, common biofoulers is poorly known. We tested biofouling accumulation and spat collection for seven commercially used ropes, and evaluated treatments of ambient and heated seawater, acetic and citric acid, and combinations of both applied across a range of exposure times to two commercially grown shellfish (Mytilus galloprovincialis and Ostrea angasi) and three biofouling species (Ectopleura crocea, Ciona intestinalis and Styela clava). Rope types differed significantly in terms of fouling rates and spat collection, with specific rope types clearly advantageous, despite not being used commercially in our study area. Treatments proved variably successful, with E. crocea highly susceptible to all treatments, Ciona intestinalis moderately susceptible, and Styela clava relatively resistant. Excluding S. clava, efficacious treatments were attainable that did not adversely affect shellfish. Combining heat and acid treatments were more successful than individual treatments and provide a useful avenue for further trials. This study provides baseline evidence for treatment efficacy that will tailor longer-term, field trials to validate and streamline biofouling treatments in shellfish aquaculture.

Evaluation of Composite Wire Ropes Using Unsaturated Magnetic Excitation and Reconstruction Image with Super-Resolution

Estimating the exact residual lifetime of wire rope involves the security of industry manufacturing, mining, tourism, and so on. In this paper, a novel testing technology was developed based on unsaturated magnetic excitation, and a fabricating prototype overcame the shortcomings of traditional detection equipment in terms of volume, sensibility, reliability, and weight. Massive artificial discontinuities were applied to examine the effectiveness of this new technology with a giant magneto resistance(GMR) sensor array, which included types of small gaps, curling wires, wide fractures, and abrasion. A resolution enhancement method, which was adopted for multiframe images, was proposed for promoting magnetic flux leakage images of a few sensors. Characteristic vectors of statistics and geometry were extracted, then we applied a radial basis function neural network to achieve a quantitative recognition rate of 91.43% with one wire-limiting error. Experimental results showed that the new device can detect defects in various types of wire rope and prolong the service life with high lift-off distance and high reliability, and the system could provide useful options to evaluate the lifetime of wire rope.

Coronal Magnetic Structure of Earthbound CMEs and In Situ Comparison

AbstractPredicting the magnetic field within an Earth‐directed coronal mass ejection (CME) well before its arrival at Earth is one of the most important issues in space weather research. In this article, we compare the intrinsic flux rope type, that is, the CME orientation and handedness during eruption, with the in situ flux rope type for 20 CME events that have been uniquely linked from Sun to Earth through heliospheric imaging. Our study shows that the intrinsic flux rope type can be estimated for CMEs originating from different source regions using a combination of indirect proxies. We find that only 20% of the events studied match strictly between the intrinsic and in situ flux rope types. The percentage rises to 55% when intermediate cases (where the orientation at the Sun and/or in situ is close to 45°) are considered as a match. We also determine the change in the flux rope tilt angle between the Sun and Earth. For the majority of the cases, the rotation is several tens of degrees, while 35% of the events change by more than 90°. While occasionally the intrinsic flux rope type is a good proxy for the magnetic structure impacting Earth, our study highlights the importance of capturing the CME evolution for space weather forecasting purposes. Moreover, we emphasize that determination of the intrinsic flux rope type is a crucial input for CME forecasting models.

Mooring Design Selection of Aquaculture Cage for Indonesian Ocean

Fish production is important for the economy in fishing community and for ensuring food security. Climate change will lead a threat to fish productivity. Therefore, a solution offered is to cultivate certain fish, especially those with high economic value by using offshore aquaculture technology. A Sea Station cage is one of the offshore aquaculture cage model that has been used in some locations. As a floating structure, the Sea Station cage need a mooring system to maintain its position. This paper presents the selection analysis of the mooring system designs of the Sea Station cage model that it is suitable with Indonesia Ocean. There are 3 mooring configurations that are linear array, rectangular array, and 4 points mooring type. The nylon mooring rope type has been selected to be used on the 3 mooring configurations and the rope has a diameter of 104 mm with a breaking force of 2.3 MN. Based on results from comparing the 3 mooring configurations, the best mooring configuration is linear array with the tension on the rope of 217 KN and has the safety factor of 0.2 based on DNVGL OS-E301

Research of different types of ropes and choosing optimal for designs of rope-profile conductor

Research of different types of ropes and choosing optimal for designs of rope-profile conductor

Synthetic Fiber Capstan Drives for Highly Efficient, Torque Controlled, Robotic Applications

This paper describes the design and performance of a synthetic rope on sheave drive system. This system uses synthetic ropes instead of steel cables to achieve low weight and a compact form factor. We demonstrate how this system is capable of 28-Hz torque control bandwidth, 95% efficiency, and quiet operation, making it ideal for use on legged robots and other dynamic physically interactive systems. Component geometry and tailored maintenance procedures are used to achieve high endurance. Endurance tests based on walking data predict that the ropes will survive roughly 247,000 cycles when used on large (90 kg), fully actuated bipedal robot systems. The drive systems have been incorporated into two novel bipedal robots capable of three-dimensional unsupported walking. Robot data illustrate effective torque tracking and nearly silent operation. Finally, comparisons with alternative transmission designs illustrate the size, weight, and endurance advantages of using this type of synthetic rope drive system.

Non-Destructive Detection of Wire Rope Discontinuities from Residual Magnetic Field Images Using the Hilbert-Huang Transform and Compressed Sensing.

Electromagnetic methods are commonly employed to detect wire rope discontinuities. However, determining the residual strength of wire rope based on the quantitative recognition of discontinuities remains problematic. We have designed a prototype device based on the residual magnetic field (RMF) of ferromagnetic materials, which overcomes the disadvantages associated with in-service inspections, such as large volume, inconvenient operation, low precision, and poor portability by providing a relatively small and lightweight device with improved detection precision. A novel filtering system consisting of the Hilbert-Huang transform and compressed sensing wavelet filtering is presented. Digital image processing was applied to achieve the localization and segmentation of defect RMF images. The statistical texture and invariant moment characteristics of the defect images were extracted as the input of a radial basis function neural network. Experimental results show that the RMF device can detect defects in various types of wire rope and prolong the service life of test equipment by reducing the friction between the detection device and the wire rope by accommodating a high lift-off distance.

Determining the Intrinsic CME Flux Rope Type Using Remote-sensing Solar Disk Observations

A key aim in space weather research is to be able to use remote-sensing observations of the solar atmosphere to extend the lead time of predicting the geoeffectiveness of a coronal mass ejection (CME). In order to achieve this, the magnetic structure of the CME as it leaves the Sun must be known. In this article we address this issue by developing a method to determine the intrinsic flux rope type of a CME solely from solar disk observations. We use several well known proxies for the magnetic helicity sign, the axis orientation, and the axial magnetic field direction to predict the magnetic structure of the interplanetary flux rope. We present two case studies: the 2 June 2011 and the 14 June 2012 CMEs. Both of these events erupted from an active region and, despite having clear in situ counterparts, their eruption characteristics were relatively complex. The first event was associated with an active region filament that erupted in two stages, while for the other event the eruption originated from a relatively high coronal altitude and the source region did not feature the presence of a filament. Our magnetic helicity sign proxies include the analysis of magnetic tongues, soft X-ray and/or EUV sigmoids, coronal arcade skew, filament emission and absorption threads, and filament rotation. Since the inclination of the post-eruption arcades was not clear, we use the tilt of the polarity inversion line to determine the flux rope axis orientation, and coronal dimmings to determine the flux rope footpoints and, therefore, the direction of the axial magnetic field. The comparison of the estimated intrinsic flux rope structure to in situ observations at the Lagrangian point L1 indicated a good agreement with the predictions. Our results highlight the flux rope type determination techniques that are particularly useful for active region eruptions, where most geoeffective CMEs originate.

Damage-Induced Stresses and Remaining Service Life Predictions of Wire Ropes

Wire ropes in marine applications often encounter relatively fast and noticeable wear, a result of the fatigue to which they are exposed coupled with harsh operational conditions. This paper addresses some of the aspects of fatigue damage that occur in wire ropes. Using the finite element method, stress and fatigue analysis of three different design types (6 × 7, 7 × 7, 8 × 7) of wire rope is performed. The size of the wire rope cross-section area is varied in order to simulate the progressive damage of the wires so that consequential stress levels and remaining fatigue life can be numerically predicted. The aim was to provide a better understanding of the mechanical behavior of damaged wire ropes under various conditions, since an appropriate choice of wire rope design could then be made from engineering and economic points of view. Additionally, potential failures can be predicted, resulting in effective maintenance and the avoidance of potential risks of rope failure, especially important regarding economical and safety aspects of transportation in the marine industry.

高強度化学繊維によるワイヤ駆動のための基礎的検討

Synthetic fiber ropes, which are lightweight and have high tensile strength and flexibility, have attracted attention as an alternative to stainless steel wire rope. This study clarifies various physical characteristics of synthetic fiber ropes to design a tendon-driven mechanism and this paper focuses on creep of ropes. We first designed and constructed a creep testing machine for ropes. Second, we performed experiments with three types of synthetic fiber ropes and one stainless steel wire rope. As a result, in stainless steel wire rope, creep was not observed. In addition, Polyarylate(PAR) fiber rope and Poly-phenylene-Benzobisoxazole(PBO) fiber rope have much higher creep resistance than Ultra High molecular weight Polyethylene(UHPE) fiber rope.

スパイラル推進機構を用いたロープ型宇宙エレベーター実験用クライマーの開発

スパイラル推進機構を用いたロープ型宇宙エレベーター実験用クライマーの開発

Observation of ultrasonic guided wave propagation behaviours in pre-stressed multi-wire structures

Ultrasonic guided wave (UGW) is a promising technique for nondestructive testing of pre-stressed multi-wire structures, such as steel strand and wire rope. The understanding of the propagation behaviours of UGW in these structures is a priority to applications. In the present study, first the properties of the UGW missing frequency band in the pre-stressed seven-wire steel strand is experimentally examined. The high correlation between the observed results and the previously published findings proves the feasibility of the magnetostrictive sensor (MsS) based testing method. The evolution of missing frequency band of UGW in slightly tensioned steel strand is discussed. Two calibration equations representing the relationship between the missing band parameters and the tensile force are given to derive a new tensile force measurement method, which is capable of measuring an incremental of stress of approximately 3MPa. Second, the effects of tensile force on the UGW propagation behaviours in three types of complicated steel wire ropes are alternatively investigated based on the short time Fourier transform (STFT) results of the received direct transmission wave (DTW) signals. The observed inherent missing frequency band of the longitudinal mode UGW in the pre-stressed steel wire rope and its shifting to a higher frequency range as the increases of the applied tensile force are reported for the first time. The influence of applied tensile force on the amplitude of the DTW signal and the unique UGW energy jump behaviour observed in a wire rope of 16.0mm, 6×Fi(29)+IWRC are also investigated, despite the fact that they cannot yet be explained.

Mechanical Analysis of the Arm Lifting Rope of the Dynamic Compaction Machine

In this paper, the mechanics equation of the dynamic compaction machine arm frame is established based on the theory of statics, the arm lifting rope force is given, the influence of the wire rope force with relative position parameters changing is also discussed. The critical factors that affect the arm lifting rope force are identified. Compared the simulation and the test results, the major forces errors are less than 8%. The correctness of the theoretical study and simulation are verified. The research results could be used for the arm wire rope type selection of the dynamic compaction.

What gets left behind for future generations? Reproduction and the environment in Spey Bay, Scotland

What gets left behind for future generations? Reproduction and the environment in Spey Bay, Scotland