Behavior Of Cables Research Articles

Reconfigurable cable-driven parallel mechanism design: physical constraints and control

Abstract The cable-driven parallel mechanism (CDPM) is known as an interesting application in industry to pick and place objects owing to its advantages such as large workspaces. In addition to the advantages of this mechanism, there are some challenges to improving performance by considering constraints in different components, such as the behavior of cables, shape, size of the end effector and base, and model of pulleys and actuators. Moreover, the impact of online geometry reconfiguration must be analyzed. This paper demonstrates the impact of these constraints on the performance of reconfigurable CDPM. The methodology is based on the systematic review and meta-analysis guidelines to report the results. The databases used to find the papers are extracted from Scopus and Google Scholar, using related keywords. As a result, the impact of physical constraints on system performance is discussed. A total of 90 and 37 articles are selected, respectively. After removing duplicates and unrelated papers, 88 studies that met the inclusion criteria are selected for review. Even when considering the physical constraints in modeling the mechanism, simplifications in designing a model for the reconfigurable CDPM generate errors. There is a gap in designing high-performance controllers to track desired trajectories while reconfiguring the geometry, and the satisfaction of physical constraints needs to be satisfied. In conclusion, this review presents several constraints in designing a controller to track desired trajectories and improve performance in future work. This paper presents an integrated controller architecture that includes physical constraints and predictive control.

Numerical Investigation of Burial Depth Effects on Tension of Submarine Power Cables

To protect submarine power cables from damage caused by anchoring and fishing, submarine power cables in shallow water areas are buried to a certain depth through a cable laying machine. However, limited attention has been paid to studying the stress behavior of submarine power cables while considering the effects of burial depth. In this research, static and dynamic analyses are carried out using three-dimensional numerical models performed by the OrcaFlex v11.0 to investigate the effects of burial depths on cable tension during the cable installation under various conditions. Numerical simulation results show that the peak tension of the submarine power cable increases linearly with the increase in burial depth. In addition, the burial depth can also change the tension state at the endpoint of the submarine power cable. The endpoint of the cable is in a compressed state when h < 2 m and the cable turns into a tensile state when h ≥ 2 m. Finally, genetic programming (GP) is used to analyze numerical simulation results to propose a prediction model that can be used to estimate the peak tension of the submarine power cable during cable installation under various burial depths in shallow sea areas. It should be noted that the proposed GP model is based on the analyses of numerical results; therefore, the GP model is open for further improvements as more experimental data become available.

Advanced finite element modeling methods for tensile and bending analysis of arresting gear cables

This study addresses the gap in understanding the dynamic bending behavior of multi-layer twisted steel cable, pivotal in various industrial applications such as naval aircraft arresting systems. Utilizing advanced finite element modeling, the research explores the mechanical responses of these cables under macroscopic bending scenarios. By integrating beam elements and connectors within the finite element framework, the study simulates complex inter-strand interactions under various loading conditions. Results indicate that this method significantly enhances the prediction accuracy of the cables’ mechanical properties, thus offering substantial improvements in design and performance analysis of arresting gear systems. This study’s value lies in its potential to refine mechanical modeling of complex cable systems, thereby optimizing operational efficiency and safety in engineering applications.

Experimental study on vortex-induced vibrations of double-hanger cable: Upstream wake flow induces downstream vibrations

This study is inspired by an experimental observation for vortex-induced vibrations (VIVs) of a double-hanger cable system, in which a smaller vibration of the downwind hanger cable is re-excited over a narrow range of wind speeds beyond the “lock-in” range. This phenomenon is known as the wake vortex-induced vibrations (WVIVs), where the upstream wake flow induces downstream vibrations. To further investigate the characteristics and reasons for WVIVs, a refined wind tunnel test of double-hanger cable was conducted to consider the influence of aerodynamic interaction. The double-hanger cable was modeled by the tandem-arranged spring-mounted cylinders vibrating in two dimensions. The vibration responses of hanger cables were obtained under various wind speeds to reproduce the lock-in phenomenon. In addition, the vibration trajectory, phase relationship, damping ratio, inter-cable correlation, and the wind pressure on the surface of cables were analyzed. Finally, the Stockbridge dampers were designed to suppress the vibrations. The results show that under the aerodynamic interaction of the cables, the onset wind speed of VIVs in the double cables increases, and the downstream cable WVIVs closely follow the VIVs. During the WVIV phase, the downstream cable behavior is characterized by increased negative aerodynamic damping and an inverse displacement correlation between the cables. The phase relationships between the cables are time-varying due to the aerodynamic interaction. The first proper orthogonal decomposition mode of wind pressure dominates the cross-wind of motions and is crucial in vibrations. Stockbridge dampers can effectively reduce the amplitude of VIVs and eliminate WVIVs in cables.

A study on the mechanical behavior of umbilical cables under impact loads using experimental and numerical methods

Accidental impacts affect the structural integrity of umbilical cables during their life cycle. This study investigates the impact behavior of a steel tube umbilical cable using both experimental tests and numerical simulations. A series of impact tests are carried out to elucidate the failure modes and deformation responses of non-bonded multi-layer components. A three-dimensional finite element model is established and verified to capture time-history responses. Through the analysis of time-history responses, the impact energy dissipation mechanisms are investigated, and the impact resistance of armor layers is further evaluated. It is found that the armor layers and polymer sheaths dissipate only approximately one-third of the impact energy, demonstrating limited protection capability, while more impact energy is absorbed by internal functional components. The steel tube may have sustained severe damage, even though the armor layer and polymer sheath exhibit only minor damage. This work has provided a reference for the damage assessment and protection design of umbilical cables.

Lateral buckling of umbilical cable armour under compression and bending

ABSTRACT With the increasing exploration and extraction of offshore oil and gas resources in deep-sea environments, the occurrence of lateral buckling has emerged as a predominant failure mode for umbilical cable armour. In this paper, a finite element model is developed to simulate the lateral buckling behaviour of umbilical cables. Additionally, the model test is conducted to compare and analyse the lateral buckling behaviour. The results demonstrate that the critical buckling load obtained from the numerical simulation closely corresponds to the experimental findings, affirming the reliability of the finite element model. This study investigates the wire shapes during lateral buckling process and examines the influence of various factors on lateral buckling. Notably, the formation of extrados and intrados resulting from umbilical cable bending significantly influences lateral buckling. This research provides valuable insights for the design and assessment of umbilical cables intended for deep-sea applications.

A study of XLPE insulation failure in power cables under electromagnetic stress

Underground cables with cross-linked polyethylene (XLPE) insulation are integral to medium voltage (MV) power transmission systems, ensuring continuous electricity supply amidst operational challenges and environmental conditions. However, the reliability of these cables can be compromised over time due to aging and installation-related factors, particularly at joints and terminations. This study offers a comprehensive analysis of how various defects, including spherical air voids, pinholes, and irregularities in semiconducting layers, affect electric field and potential distributions within cable end terminations using COMSOL Multiphysics software. Through detailed simulations, the study identifies significant variations in electric field strength caused by these defects, highlighting critical stress concentration areas. In this study, it assumed that the cable and termination have the same cross-section. By analyzing these simulations, the study provides insights into optimizing cable design and installation practices to enhance the reliability and lifespan of underground power transmission systems. This study introduces a novel approach by combining advanced COMSOL Multiphysics simulations with a detailed analysis of defect impacts on electric field distributions, offering new insights into stress concentrations and degradation at cable terminations. Simulation outcomes reveal significant variations in electric field strengths due to air voids and pinholes in cables and terminations: for 2 mm voids, up to 2.45×106 V mm−1 near the conductor and 56.5 V mm−1 at termination. These findings enhance the understanding of XLPE-insulated cable behavior under electromagnetic stress, providing a basis for mitigating failures and improving overall system performance.

Cyclic response and stability of shape memory alloy cables considering training, displacement history, and prestrain effects

Superelastic shape memory alloy (SMA) cables have been considered in the development of various seismic protection technologies. The cyclic nature of seismic loads necessitates a comprehensive understanding of the mechanical behavior of SMA cables under repeated loading conditions. As SMAs undergo repeated phase transformation cycles, alterations in their properties occur due to defects generated and modified during the transformation. When utilizing superelasticity, this response can be stabilized after numerous transformation cycles. In various applications, components made of SMAs undergo a stabilization process referred to as training to enhance the predictability of the alloy’s response. Despite the widespread acceptance of training cycles to achieve stable cyclic response, a well-defined protocol is lacking. This study investigates the effects of various factors, including training strain amplitude, repeated loading, low-cycle fatigue loading, loading at high strain amplitudes, displacement loading history, and prestrain on the cyclic response of a large-diameter SMA cable. A total of 14 SMA cable specimens are tested under various tensile loading conditions. The experimental results, including stress-strain curves and various response parameters such as peak stress, residual strains, energy dissipation capacity, and equivalent viscous damping are examined in detail. The results indicate that training SMA cables at a strain amplitude near the end of phase transformation plateau leads to a highly stable cyclic response. However, it is worth noting that, in comparison to untrained cables, training induces a softening effect in the cable response.

Simulation and parameterization of nonlinear elastic behavior of cables

AbstractThis work contributes to the simulation, modeling, and characterization of nonlinear elastic bending behavior within the framework of geometrically nonlinear rod models. These models often assume a linear constitutive bending behavior, which is not sufficient for some complex flexible slender structures. In general, nonlinear elastic behavior often coexists with inelastic behavior. In this work, we incorporate the inelastic deformation into the rod model using reference curvatures. We present an algorithmic approach for simulating the nonlinear elastic bending behavior, which is based on the theory of Cosserat rods, where the static equilibrium is calculated by minimizing the linear elastic energy. For this algorithmic approach, in each iteration the static equilibrium is obtained by minimizing the potential energy with locally constant algorithmic bending stiffness values. These constants are updated according to the given nonlinear elastic constitutive law until the state of the rod converges. To determine the nonlinear elastic constitutive bending behavior of the flexible slender structures (such as cables) from the measured values, we formulate an inverse problem. By solving it we aim to determine a curvature-dependent bending stiffness characteristic and the reference curvatures using the given measured values. We first provide examples using virtual bending measurements, followed by the application of bending measurements on real cables. Solving the inverse problem yields physically plausible results.

Impact of thermal aging temperatures on the combustion behavior and mechanical properties of flame-retardant electrical cables

Impact of thermal aging temperatures on the combustion behavior and mechanical properties of flame-retardant electrical cables

Investigation of Mixed-Mode Crack Quantification with Distributed Fiber Optic Sensors

The development of high-resolution distributed fiber optic sensing (DFOS) technologies, particularly optical frequency domain reflectometry (OFDR), has proven effective in measuring crack widths. However, most existing research assumes that the crack opening direction is perpendicular to the cable direction, with limited studies addressing mixed-mode cracks using distributed fiber optic sensors. This research aims to create a novel method for quantifying mixed-mode cracks using DFOS, combining experimental investigations and numerical simulations. A calibration rig was designed and fabricated to simulate mixed-mode crack conditions in a 2D plane, allowing for the reproduction of various crack opening scenarios. Multiple fiber optic cable types with distinct strain transfer mechanisms were used, crossing the artificial crack surface at varying angles. The mechanical behavior of fiber optic cables in mixed-mode crack situations was further examined through numerical simulations. Based on findings from both experimental and numerical studies, an algorithm was developed to determine crack width and crack opening direction using DFOS data. As mixed-mode cracks frequently occur in reinforced concrete structures under complex stress conditions, this research enhances the understanding of fiber optic sensor performance in realistic cracking situations and offers valuable insights for more precise damage assessment using DFOS.

Modeling of contact resistivity and simplification of 3D homogenization strategy for the H formulation

The finite element method (FEM) provides a powerful support for the calculations of superconducting electromagnetic responses. It enables the analysis of large-scale high-temperature superconducting (HTS) systems by the popular H formulation. Nonetheless, modeling of contact resistivity in three-dimensional (3D) FEM is still a matter of interest. The difficulty stems from the large aspect ratio of the contact layer in numerical modeling. Nowadays, an available solution is to model the contact layer with zero thickness but requires the discontinuity conditions of the magnetic field. In this paper, the energy variational method is utilized to incorporate the contribution of contact resistivity into the H formulation. From the perspective of energy transfer, the contact resistivity is related to the energy dissipation of the radial current flowing through the contact interface. In terms of applications, this method can be employed to calculate the charging delay of no-insulation coils and the current sharing behaviors of CORC cables. One advantage of this model is that the magnetic field is continuous and hence can be easily implemented in FEM. Additionally, it requires fewer degrees of freedom and hence presents advantages in computational efficiency. Moreover, this method can be employed to simplify the 3D H homogeneous model for insulated coils. The above discussions demonstrate that the proposed model is a promising tool for the modeling of contact resistivity.

Cyclic and uniaxial tensile properties of superelastic niti shape memory alloy cables

This study investigates the impact of various factors, including annealing duration, strain amplitude, cyclic loading, loading rate, and pre-training, on the mechanical properties of Nickel–Titanium shape memory alloy (SMA) cable. The primary focus is on evaluating their recovery ability and energy dissipation capabilities. The tested SMA cable has an outer diameter of 9 mm and a 7 × 7 configuration. The variation of strength, stiffness, residual strain, hysteretic energy, and equivalent viscous damping ratio of SMA cable with the loading cycle is analyzed. Furthermore, the impact of various annealing durations on the tensile strength and elongation of both SMA cables and wires was examined through monotonic tensile tests. The results indicate that the annealing duration considerably affects the superelastic behavior of SMA cables by shifting the stress-strain loops down and widening them. The recovery ability of SMA cable degrades more progressively with increasing loading amplitude and the number of loading cycles. The mechanical properties gradually stabilized after 20 times of constant strain amplitude loading and unloading training. The strain selection for cyclic training should not make the SMA cable in the martensite hardening stage. The recovery ability and peak stress of SMA cable can be significantly improved by pre-training. With the increase of annealing duration, the tensile strength of the SMA cable decreases gradually. Compared with SMA wire, SMA cable has better ductility and robustness and provides sufficient restoring force under large deformation.

Mechanical behavior of multi-layer CORC cable in high external field with 3D numerical model

The degradation of critical current due to mechanical deformation in a high field has a profound impact on the performance of high-temperature superconducting (HTS) structures. The multi-layer conductor on round core (CORC) cable is a widely-applied HTS structure in engineering. Due to the complexity of the multi-layer CORC cable, the contact between the tapes should be considered when simulating the mechanical behavior in high field. In this paper, 3D electromagnetic and mechanical models were developed to investigate the mechanical behavior of the multi-layer CORC cable. Under the same electromagnetic force, the comparisons of mechanical models of a 5-layer CORC cable with different contact methods are presented. Subsequently, the effects of the loading path of the external magnetic field and transport current, the bending geometry of the CORC cable, the winding direction of the HTS tape in the CORC cable, and the shielding current on the mechanical behavior are discussed, respectively. The numerical results are useful for the design and operation of CORC cable in high field.

Taut cables with hanging masses: A metamaterial-like dynamic behavior

We inspect the dynamic behavior of suspended cables presenting a periodic array of scatter elements, consisting of a discrete set of masses that are hanging by means of elastic or rigid connections. By introducing some approximations, we show that the problem in the continuous domain can be brought back to an equivalent discrete problem, whose solutions depend on the variation of an effective mass. We find that the essential spectrum of the problem presents band gaps. By considering boundary conditions, eigenmodes can only be found at frequencies belonging to pass bands for the propagation problem of the unbounded system. This is no more true when a defect of periodicity is inserted, leading to the formation of localized modes. We provide a quantitative validation of these theoretical results by means of comparison with experimental tests.

Fatigue assessment of suspended inter-array power cables for floating offshore wind turbines

The present paper aims to investigate the fatigue behavior of suspended inter-array power cables connecting two floating offshore wind turbines (FOWTs). Two spar FOWTs interconnected with a dynamic power cable are chosen as the base configuration for the present investigation. The base configuration is modeled in the dynamic analysis software OrcaFlex. The relationship between the axial tensions and curvatures of the power cable and its stresses is obtained by cross-section analysis in UFLEX (special purpose Finite Element program for nonlinear stress analysis of complex umbilical and cable cross-sections). Several different environmental conditions and load directions are applied. A fatigue life of 85 years is determined for the base configuration, with curvature-induced stresses being identified as the main contributor to the fatigue damage. Effects of marine growth on the fatigue life of the power cable are investigated. It is observed that marine growth negatively affects the fatigue life of the power cable. A parametric study on the effect of the number of buoys attached to the cable on the fatigue life is performed. Decreasing the number of buoys below the optimal value leads to an increase in fatigue life due to lower curvatures. In addition to the base configuration, an alternative configuration using semi-submersible floaters is investigated under the same metocean conditions and cable geometry. The power cable fatigue life is higher for semi-submersible floaters compared to the spar floaters. The present findings reveal that the main reason is the reduced number of large amplitude curvature cycles. The critical component prone to fatigue failure for all evaluated cases is the armor layer, and the largest fatigue damage always occurs at buoy-cable connection points. The critical direction of environmental load resulting in the highest fatigue damage is found to be the load case where waves, wind and current approach the suspended cable in a crossflow direction.

Thermal State Effects on Potential Augmentation of the Ampacity of a Medium Voltage Underground Cable in Power Distribution: A Case Study

Thermal State Effects on Potential Augmentation of the Ampacity of a Medium Voltage Underground Cable in Power Distribution: A Case Study

Application of suspended inter-array power cables in floating offshore wind farms

The aim of the present study is to propose an engineering approach of designing suspended inter-array power cable configuration for offshore wind farms. To achieve this, a spar type and a semi-submersible type floating offshore wind turbines (FOWTs) are modeled in the dynamic analysis software OrcaFlex. The accuracy of these models is validated against reference studies. Several different cable configurations connecting two spar FOWTs are assessed based on Fitness Factors using static and dynamic analyses. The non-linear bending behavior and the marine growth effects are considered in the analyses. The number of buoys is found to be the main parameter affecting the maximum effective tension and the minimum bending radii of the cables. The buoy spacing determines whether the cable touches the seabed, floats fully submerged, or floats at the sea surface. The influence of the cable length and the marine growth on the observed cable tensions and curvatures is small for the investigated configurations. The optimum cable configuration found for the two spar FOWTs is employed to connect two semi-submersible FOWTs. The influence of the floater type on the suspended power cable tension and curvature is found to be negligible. Analysis of power cable behavior in an offshore wind farm layout shows that a two-turbine setup with different environmental load directions can be used as a representative case for the suspended power cables design of the entire wind farm.

A Method for Assessing the Degradation of PVC-Insulated Low-Voltage Distribution Cables Exposed to Short-Term Cyclic Aging

The distribution grid comprises cables with diverse constructions. The insulating material used in low-voltage (LV) distribution cables is predominantly PVC. Furthermore, the presence of cables with different structures in the grid poses challenges in detecting the aging of the cable network. Finding a universal and dependable condition-monitoring technique that can be applied to various types of cables is indeed a challenge. The diverse construction and materials used in different cables make it difficult to identify a single monitoring approach that can effectively assess the condition of all cables. To address this issue, this study aims to compare the thermal aging behavior of different LV distribution cables with various structures, i.e., one cable contains a PVC belting layer, while the other contains filler material. The growing adoption of distributed generation sources, electric vehicles, and new consumer appliances in low-voltage distribution grids can lead to short, repetitive overloads on the low-voltage cable network. Hence, these cable samples were exposed to short-term cyclic accelerated aging in the climate chamber at 110 °C. The cable’s overall behavior under thermal stress was evaluated through frequency and time domain electrical measurements (including tan δ and extended voltage response) and a mechanical measurement (Shore D). The tan δ was measured in the frequency range of 20 Hz–500 kHz by using the Wayne-Kerr impedance analyzer. The extended voltage response measurement was conducted using a C# application developed in-house specifically for laboratory measurements in the .NET environment. The study observed a strong correlation between the different measurement methods used, indicating that electrical methods have the potential to be adopted as a non-destructive condition-monitoring technique.

Experimental and Mechanical Analysis of the Yielding Support Behavior of a Novel Compact Yielding Anchor Cable

Experimental and Mechanical Analysis of the Yielding Support Behavior of a Novel Compact Yielding Anchor Cable