Catenary Cables Research Articles

Analysis of Tow Cables

Hydrodynamic analysis of tow cable has an important role in the design of towed system. Cable catenary, cable depth attained for a given cable length, cable tension and angle of cable with the body are the parameters that affects the towed system related to tow cable. This paper deals with analysis of a set of commercially available cables of different properties using Orcaflex software. The cables were analysed for different payouts at different speeds. A comparative study was performed on the results obtained relating the cable properties (diameter and buoyancy). This provides a rough idea on the catenary profiles that reflects the depth and trail achieved by the cable given payout and speed.

INCREASING ROBUSTNESS OF REINFORCED CONCRETE STRUCTURES UNDER COLUMN LOSS SCENARIO

This paper presents a simple technique to enhance robustness of reinforced concrete (RC) plane frames to progressive collapse under column loss scenario. The response of the enhanced/mitigated RC frames is analyzed using fiber force-based finite element analysis and applying displacement-controlled nonlinear static pushdown at the location of failed column. The technique involves addition of external unbounded steel cables to the continuous beam in each floor at anchorage and deviator locations. The cables transfer the loads above the failed column to the anchorages and deviators that are assumed to perform as rigid arms, which in turn redistribute the loads to adjacent columns. The numerical model computes the frame progressive collapse robustness using push-down analysis to simulate a column elimination and estimate the effects of cable catenary action on the frame. Two-dimensional RC frame of six stories and four bays was adopted in the study. The numerical results demonstrate the prospect of increasing robustness of RC frames to progressive collapse using presented technique.

Application of Template Matching for Improving Classification of Urban Railroad Point Clouds.

This study develops an integrated data-driven and model-driven approach (template matching) that clusters the urban railroad point clouds into three classes of rail track, contact cable, and catenary cable. The employed dataset covers 630 m of the Dutch urban railroad corridors in which there are four rail tracks, two contact cables, and two catenary cables. The dataset includes only geometrical information (three dimensional (3D) coordinates of the points) with no intensity data and no RGB data. The obtained results indicate that all objects of interest are successfully classified at the object level with no false positives and no false negatives. The results also show that an average 97.3% precision and an average 97.7% accuracy at the point cloud level are achieved. The high precision and high accuracy of the rail track classification (both greater than 96%) at the point cloud level stems from the great impact of the employed template matching method on excluding the false positives. The cables also achieve quite high average precision (96.8%) and accuracy (98.4%) due to their high sampling and isolated position in the railroad corridor.

Improving the robustness of reinforced concrete framed structures under sudden column losses

Recent guidelines have addressed provisions to improve structure integrity to accommodate progressive collapse due to failure of an interior support. This article presents novel technique and numerical model to enhance and evaluate reinforced concrete frame robustness to progressive collapse triggered by an interior or edge column failure in any floor. The presented technique enhances the structure robustness to progressive collapse by providing sufficient ductility, continuity, and redundancy. The technique involves placing external unbounded steel cables attached to the continuous beam in each floor at anchorage and deviator locations to bridge over a damaged column of any floor of the frame. The cables transfer the loads above the failed column to the anchorages and deviators that are assumed to perform as rigid arms, which in turn redistribute the loads to adjacent columns. The numerical model computes the frame building progressive collapse robustness using push-down analysis to simulate a column elimination and estimate the effects of cable catenary action on the frame. Two-dimensional reinforced concrete frame of six stories and four bays was adopted in the study. The numerical results demonstrate the prospect of resisting progressive collapse of reinforced concrete structures by implementing the presented technique.

ПОДСИСТЕМА МОНИТОРИНГА ВИБРАЦИОННЫХ ВОЗДЕЙСТВИЙ НА ПРОВОДА И ТРОСЫ КОНТАКТНОЙ ПОДВЕСКИ

ПОДСИСТЕМА МОНИТОРИНГА ВИБРАЦИОННЫХ ВОЗДЕЙСТВИЙ НА ПРОВОДА И ТРОСЫ КОНТАКТНОЙ ПОДВЕСКИ

СПОСОБ НЕПРЕРЫВНОГО МОНИТОРИНГА МЕХАНИЧЕСКОГО УСИЛИЯ В ПРОВОДАХ И ТРОСАХ КОНТАКТНОЙ ПОДВЕСКИ

СПОСОБ НЕПРЕРЫВНОГО МОНИТОРИНГА МЕХАНИЧЕСКОГО УСИЛИЯ В ПРОВОДАХ И ТРОСАХ КОНТАКТНОЙ ПОДВЕСКИ

Optimization of Mooring Systems for Floating Offshore Wind Turbines

The paper deals with the optimum design of mooring systems, with chain cable catenary line configuration, for Floating Offshore Wind Turbines with tri-floater support structure in deep waters. Operational and extreme climate conditions are assessed for a candidate location in southern Tyrrhenian Sea, determining wind, wave and current loads. The platform response is assessed in terms of static loads due to turbine thrust, wind, current and steady drift forces. The platform dynamic offset is determined considering both wave-frequency linear and low-frequency second-order motions. Two different mooring systems with 9 (equally spaced) and 11 (non-uniformly spaced) lines are selected in order to minimize the total mass; the incidence of both line number and pattern is appreciable and there is wide space to achieve considerable weight reductions, so increasing the overall wind farm cost-performance trade-off.

Automated Recognition of Railroad Infrastructure in Rural Areas from LIDAR Data

This study is aimed at developing automated methods to recognize railroad infrastructure from 3D LIDAR data. Railroad infrastructure includes rail tracks, contact cables, catenary cables, return current cables, masts, and cantilevers. The LIDAR dataset used in this study is acquired by placing an Optech Lynx mobile mapping system on a railcar, operating at 125 km/h. The acquired dataset covers 550 meters of Austrian rural railroad corridor comprising 31 railroad key elements and containing only spatial information. The proposed methodology recognizes key components of the railroad corridor based on their physical shape, geometrical properties, and the topological relationships among them. The developed algorithms managed to recognize all key components of the railroad infrastructure, including two rail tracks, thirteen masts, thirteen cantilevers, one contact cable, one catenary cable, and one return current cable. The results are presented and discussed both at object level and at point cloud level. The results indicate that 100% accuracy and 100% precision at the object level and an average of 96.4% accuracy and an average of 97.1% precision at point cloud level are achieved.

3차원 정적 집중하중을 받는 복합 탄성 케이블의 정적 해석

An elastic cable with piecewise constant properties under the action of concentrated static loads is studied analytically. Analytic solutions for catenary cables are combined at the discontinuous points caused by the discontinuous elastic properties or concentrated loads. The application of the boundary conditions at both ends of the multi-component cable results in three algebraic non-linear equations for three unknown parameters, which are determined numerically. The solutions for the shape, tension, elongation, and cross-sectional contraction of the cable are expressed in closed forms. Some examples are given for cases of two- and three-dimensional loads.

Dynamic response of floating substructure of spar-type offshore wind turbine with catenary mooring cables

The station keeping and the rotational oscillation control are important to secure the dynamic stability of spar-type floating offshore wind turbine subject to irregular wind and wave excitations. Those are usually evaluated in terms of rigid body dynamic response of floating substructure which supports whole offshore wind turbine. In this context, this paper addresses the numerical investigation of dynamic response of a spar-type hollow cylindrical floating substructure moored by three catenary cables to irregular wave excitation. The upper part of wind turbine above wind tower is simplified as a lumped mass and the incompressible irregular potential wave flow is generated according to the Pierson–Moskowitz spectrum. The wave-floating substructure and wave-mooring cable interactions are simulated by coupling BEM and FEM in the staggered iterative manner. Through the numerical experiments, the time- and frequency-responses of a rigid spar-type hollow cylindrical floating substructure and the tension of mooring cables are investigated with respect to the total length and the connection position of mooring cables.

Nonlinear analysis of cable structures under general loadings

In this paper, two new elements for three-dimensional finite element analysis of cable structures are proposed. The tangent stiffness matrices of the cable elements are derived under spatially concentrated and distributed static and thermal loads. The first element, which is called Continuous Catenary Cable (CCC) element and extends the classic catenary cable element, presents the explicit forms of the stiffness matrix and internal force vector of the cable. The second element, Discrete Catenary Cable (DCC) element, is introduced by transforming the continuous equations of the CCC element into discrete formulation, giving the capability of dividing the cable into several straight elements with axial behavior. The DCC element, having all the features of the CCC element, has the advantages of including more three-dimensional loadings such as point loads along the member and non-uniform distributed lateral loads, and incorporating various geometrical and material nonlinearities such as cable cross-section variation and cable material yielding. Thereafter, employing the proposed elements, we have presented a simple algorithm for the analysis of pretensioned cables. The proposed elements are then used for nonlinear analysis of cable structures, and the response is compared with those obtained by other researchers. The results of numerical examples indicate the capability and robustness of the proposed elements in predicting the deformation response of cable structures.

계류장치 연결 위치가 Spar Type 부유식 해상풍력 발전기의 동적 응답에 미치는 영향 해석

This paper deals with the analysis of dynamic characteristics of mooring system of floating-type offshore wind turbine. A spar-type floating structure which consists of a nacelle, a tower and the platform excepting blades, is used to model the floating wind turbine and connect three catenary cables to substructure. The motion of floating structure is simulated when the mooring system is attached using irregular wave Pierson-Moskowitz model. The mooring system is analyzed by changing cable position of floating structure. The dynamic behavior characteristics of mooring system are investigated comparing with cable tension and 6-dof motion of floating structure. These characteristics are much useful to initial design of floating-type structure. From the simulation results, the optimized design parameter that is cable position of connect point of mooring cable can be obtained.

Analysis of a dual-arm mobile robot dynamics and balance compensation

The kinematic and dynamic behaviours of a robot manipulator on an elastic catenary cable were investigated. The dynamic equations of the robot and the cable were derived based on the Newton-Euler principle and Hamilton principle respectively. The recursive formulations describing the nonlinear and coupling dynamics relationship between the robot and the cable were presented. Based on the rigid-flexible coupling model proposed in this paper, a dynamic compensation technique with complementary control strategy was discussed which was implemented to adjust the posture of the robot and restrain the vibration that arise the flexible characteristics of the cable. The simulation and experiment results shown in this paper validate the effectiveness of the dynamic compensation.

Development of hurricane resistant traffic signal structures

Performance of traffic signal support systems during hurricanes has indicated that the current dual cable system used in Florida often experiences substantial damage. Because there is widespread use of single cable support systems in hurricane-prone regions of other states, this project investigated the performance of both dual cable and single cable support systems in high velocity winds. The weight, orientation, and type of signal support hardware were modified to show the effects of various signal configurations. Test results indicate that (1) the difference in signal rotation is insignificant between dual cable and single cable systems, (2) the tension in the catenary cable does not significantly increase for either system; however, in the dual cable system, the increase in tensile force is substantial in the messenger cable resulting in increased flexural loading in the pole support structure, and (3) the cable supported traffic signals should be designed using both the drag and lift coefficients rather than just the drag coefficient to account for signal rotation. The single cable configuration was found to be the preferred option for structural response to wind.

Nonlinear dynamic analysis of spatially suspended elastic catenary cable with finite element method

This paper investigates the dynamic behavior of a cable considering geometrical nonlinearity due to the sagging effect, based on the elastic catenary cable thoery. The finite element method has been limited in application to the dynamic analysis of a cable element because its displacement interpolation function can not be obtained from the boundary conditions. This paper proposes a derivation of the interpolation function for spatially suspended catenary cable, using the flexibility matrix. Equations for the compatibility conditions of a catenary cable are derived under mutiple concentrated loads within an element. Also, self-weight and other vairous types of distributed load imposed within an element are discritized with equivalent concentrated loads at multiple Gaussian points. Dynamic inertia and damping forces along the cable profile are assumed to be distributed according to the developed interpolation functions so that internal forces are evaluated directly from the compatibility equations and flexiblity matrix. The proposed element is verified through an experiment testing the free vibration of a suspension cable, and the dynamic bahevior of a suspension cable is compared with the ABAQUS beam element where three-dimensional support excitations are imposed.

Evaluation of membrane structure designs using boundary web cables for uniform tensioning

A design challenge in large membrane space structures is to apply pretension as uniformly as possible throughout the membrane, without increasing structural mass and volume. The present paper begins with a brief review of existing designs of membranes surrounded by catenary cables and shear compliant borders. The paper then introduces weblike cables that surround the membrane, and analyzes the consequent reduction in mass and volume. In addition, a series of quasi-static finite element analyses demonstrates the attenuation of wrinkles by the web cables when support points are perturbed. The paper concludes that the proposed design preserves a biaxially prestressed membrane even in disturbed conditions, with a minimal suspension-cable mass and volume.

3827 鉛直方向加振を受ける懸垂ケーブル構造物の動的安定性と数値シミュレーション(J15 マルチボディダイナミクスの新展開,J15 マルチボディダイナミクスの新展開)

3827 鉛直方向加振を受ける懸垂ケーブル構造物の動的安定性と数値シミュレーション(J15 マルチボディダイナミクスの新展開,J15 マルチボディダイナミクスの新展開)

Three-Dimensional Large Deformation Analysis of the Multibody Pantograph/Catenary Systems

To accurately model the nonlinear behavior of the pantograph/catenary systems, it is necessary to take into consideration the effect of the large deformation of the catenary and its interaction with the nonlinear pantograph system dynamics. The large deformation of the catenary is modeled in this investigation using the three-dimensional finite element absolute nodal coordinate formulation. To model the interaction between the pantograph and the catenary, a sliding joint that allows for the motion of the pan-head on the catenary cable is formulated. To this end, a non-generalized arc-length parameter is introduced in order to be able to accurately predict the location of the point of contact between the pan-head and the catenary. The resulting system of differential and algebraic equations formulated in terms of reference coordinates, finite element absolute nodal coordinates, and non-generalized arc-length and contact surface parameters are solved using computational multibody system algorithms. A detailed three-dimensional multibody railroad vehicle model is developed to demonstrate the use of the formulation presented in this paper. In this model, the interaction between the wheel and the rail is considered. For future research, a method is proposed to deal with the problem of the loss of contact between the pan-head and the catenary cable.

21207 周期的な加振を受けるカーテンケーブルの動的安定性と数値シミュレーション(振動・騒音(2))

This paper deals with the dynamic stability and numerical simulation of catenary cables subjected to periodic excitation. In this paper, the analysis model is constructed by using multi-body dynamics formulation. The dynamic behavior of the catenary cables subjected to the periodic excitation is examined numerically and experimentally. The numerical results are verified by the experiments. Moreover, it is found that parametric vibrations occur to the system in out-of-plane direction.

파랑 중 계류된 스파 플랫폼의 시간영역 해석

The Spar platform with deep draft is characterized as effective structure in extreme wave condition, which has larger natural period than that of waves in sea. In this paper, the time domain simulation of motion responses of Spar with catenary mooring line is presented in irregular waves. The memory effect is modeled by added mass at infinite frequency and convolution integrals in terms of wave damping coefficients. The added mass, wave damping coefficients and wave exciting forces are obtained from three-dimensional panel method in the frequency domain. The motion equations are consisted of forces for inertia, memory effect, hydrostatic restoring, wave exciting and mooring line. The forces of mooring line are modeled as quasi-static catenary cable.