Cable Structures Research Articles

Identification of Tension Force in Cable Structures Using Vibration-Based and Impedance-Based Methods in Parallel

For cable structures, the tension force is one of the main factors showing the structure’s health. If the tension force falls below a safe level during construction or operation, it can lead to partial or complete the structural failure, posing a risk to the people’s safety. In this study, a parallel structural health monitoring approach of the vibration-based and impedance-based methods is proposed to identify the tension force in cable structures. Firstly, a cable structure including the anchorage is simulated using a finite element model to obtain the vibration and impedance responses. The numerical results are verified with the experimental ones of the previous studies. Then, the parallel approach combining the above two methods is presented to determine the tension force. For the vibration-based method, the tension force is estimated by the natural frequencies. For the impedance-based method, the tension force is estimated by the mean absolute percentage deviation (MAPD) index and the artificial neural network (ANN). Finally, the tension force estimation results are compared and assessed. By using the parallel approach, the reliability and accuracy of the tension force identification results are guaranteed.

Analysis and Evaluation of the Progressive Collapse of Cable Dome Structures Induced by Joint Damage

The current literature lacks an effective progressive collapse analysis of a cable dome structure induced by joint damage. In this study, a dynamic analysis was performed using actual construction cases, an ANSYS LS-DYNA analysis platform, and a fully dynamic equivalent load instantaneous removal method. First, the structure’s dynamic responses and collapse modes induced by different joints with different types of damage were explored. Subsequently, joint importance coefficients were proposed depending on the structure’s displacement before and after joint removal, and the relationships between the joint importance coefficients and the joint properties and collapse modes, respectively, were then identified. Finally, the relationship between the joint damage and the connected component damage was explored. The results revealed that different joints and identical joints with different types induced a variety of dynamic responses. However, the dynamic response induced by the discontinuous joint damage was more apparent than that induced by the continuous joint damage. When a continuous joint model was used, the damage on all joints did not result in the progressive or local progressive collapse of the structure. Thus, all these joints were considered as common joints. However, when a discontinuous joint model was used, the failure of the joints resulted in three distinct collapse modes, namely a progressive collapse, a local progressive collapse, and a nonprogressive collapse, corresponding to the key joints, the important joints, and the common joints, respectively. These three types of joints corresponded to different importance coefficients. When damage occurred in the discontinuous joints separately linked to the key components, the important components, and the common components, the joints resulted in the progressive collapse, local progressive collapse, and nonprogressive collapse, respectively, of the structure.

Accurate Modeling of CCS Combo Type 1 Cable and Its Communication Performance Analysis for High-Speed EV-EVSE Charging System

This paper addresses the issue of electromagnetic interference (EMI) in electric vehicle supply equipment (EVSE) charging cables, which can disrupt the communication signal for the real-time monitoring of the charging status, leading to the termination of charging. We propose a dedicated measurement jig for the Combined Charging System Combo Type 1 (CCS-CT1) cable structure and models its electrical characteristics of the jig using the impedance peeling technique for de-embedding. The obtained pure S-parameters of CCS-CT1 are then used to conduct a simulation of the signal integrity problem caused by Gaussian noise, which is the worst-case scenario that can occur in a typical charging system. This paper suggests that the root cause of this problem may be related to the high-power AC/DC conversion device included in the EVSE, which uses a switch-mode power conversion (SMPC) method that involves nonlinear operation and can result in increased harmonic noise and a more complex signal protocol for precise control. Finally, this study provides insights into the challenges of implementing high-speed charging systems and offers a solution for obtaining the accurate electromagnetic characteristics of charging cables.

Experimental Analysis of the Magnetic Leakage Detection of a Corroded Steel Strand Due to Vibration.

The self-magnetic flux leakage (SMFL) detection technique has great potential in the corrosion detection of bridge stay cables due to its advantages of small testing equipment, high accuracy, and fast testing rate. However, the vibration effect in the cable's SMFL detection is unclear. To address this, the influence of vibration on the magnetic field distribution of cable structure is analyzed theoretically. According to the theoretical model, the effect of vibration on SMFL detection primarily manifests as displacement changes (displacement-added magnetic field) and defect shape changes (deformation-added magnetic field). SMFL detection experiments are conducted on steel strands. The results demonstrate that the displacement-added magnetic field exhibits statistical characteristics in the form of a normal distribution, fluctuating around the zero value. The impact of the deformation-added magnetic field on SMFL is linearly correlated with the corrosion ratio c. Moreover, a corrosion characterization index A was proposed and has an excellent linear fit with the corrosion ratio c. The index A effectively improves the accuracy of corrosion detection and provides early warning for the maintenance of cable structures.

On the Plane Geometry Design Method of the Loop-free Hyperbolic Single-layer Cable Structures

The plane geometry design of the cable-net structure is the basis for the form-finding and structural design. The loop-free single-layer cable-net structure is a new cable-net scheme, but due to its special and complex shape, it is difficult to determine its plane geometry according to architectural requirements. In this paper, the moving support node method is proposed, which can quickly get the plane geometry of a loop-free single-layer cable-net structure. The form-finding is proceeded based on the existing small elastic modulus method. There are two constraints when using the moving support node method. One is that the projection of all cables is straight line, and the other is that the distance between the two cables of each support node and the inner boundary of the target is equal. The aim is to minimize the sum of the distances from all cables to the inner boundary of the target. Using the plane geometry control parameters and the plane coordinates of the support nodes as decision variables, the plane geometry closest to the target inner and outer boundaries is get through optimization analysis. According to the derivation of the formula, the plane projection shape of a loop-free single-layer cable-net structure is mainly related to three parameters, including the number of supports, the difference between the node numbers of the supports at both ends of each cable, and the target curve equations of the inner and outer boundaries. Finally, taking the roof structure of Linyi Olympic Stadium as an instance, the feasibility of the plane geometry design method of the loop-free single-layer cable-net structures based on the moving support node method is verified.

Design and Analysis of Buffer Device for Interstage Pyrotechnic Separation

Buffer device for interstage pyrotechnic separation is the key part to achieving electrical connector plug separation. This paper carries out research on the buffer structure in different working conditions and finally designs two kinds of buffer devices, which are respectively applied to the stage separation structure of large mass SLMB (Shingle-Like Mass Blocks) and the stage separation structure of the small mass SLMB. Both can control the energy absorption size of the device through structural parameters to adapt to different working conditions. Compared with the original structure, the buffer effect after optimization is very obvious. The time domain peak value and frequency domain peak value of the buffering device suitable for small mass SLMB are reduced by 79.90% and 85.67%, respectively. The buffering device suitable for large mass SLMB changes the energy absorption mode of the buffering structure, and the steel cable structure will not break. Compared with the original structure loaded with small mass SLMB, the response in the time domain and frequency domain also decreased. The application range of buffer devices for interstage pyrotechnic separation is greatly expanded.

Development of Cu-Nb Reinforced Nb3Sn Wires Appropriate for Large Multi-Stage Stranded Cables With Short-Pitch Twisting and Low-Void Ratio

The strength of the conventional Cu/Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn wires may be too low to be applied to much larger cable-in-conduit (CIC) conductors with the multi-stranded cable structure of short-pitch twisting and low-void ratio applied for ITER-CS conductors. In this study, the Nb-rod-method Cu-Nb reinforced ITER-type Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn wire was developed by using a bronze-process not only to realize superior superconducting properties under high electromagnetic stresses but also to mitigate damage to the superconducting wires during the cable manufacturing process. The critical current properties of the Cu-Nb/Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn wire were significantly higher performance under both tensile stress and transverse compression stress compared to a conventional non-reinforced Cu/Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn wire. The Cu-Nb reinforcement had no detrimental effect on the AC losses of the wire. The trial production of short-pitch sub-cables was conducted, and it was confirmed that the Cu-Nb/Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn wires can improve the manufacturability of multi-stage stranded cables co-twisted with copper wires.

Study on the Dynamic Response of the Component Failure of Drum-Shaped Honeycomb-Type III Cable Dome with Quad-Strut Layout

The drum-shaped honeycomb-type cable dome departs from traditional concepts and incorporates the idea of multiple strut configurations. It is the most diverse type of cable dome structure. Both cables and struts serve as the main load-bearing components. Analyzing the effects of local component failure is crucial for designing large-scale cable domes able to resist continuous collapse. A numerical analysis model using the ANSYS finite element method with a 120 m span is established. Dynamic analysis methods are employed to study the response of structural internal forces and displacements during the failure of different component types. By defining the internal force dynamic coefficient and change coefficient, the structural continuity collapse resulting from component failure is determined based on computational results and observation of structural deformations. Furthermore, the importance of the various components within the overall structure is classified. The research findings indicate that the failure of individual components does not cause overall instability of the structure. The importance level of the ring cables and some upper chord ridge cables is higher than that of the inclined cables. Class a struts have a higher importance level than class b struts. Additionally, the importance level of outer ring components is higher than that of inner ring components.

Approximate analytical solution of a (V,m,h) reduced system for backpropagating action potentials in sparsely excitable dendrites

We derive an approximate analytical solution of a nonlinear cable equation describing the backpropagation of action potentials in sparsely excitable dendrites with clusters of transiently activating, TTX-sensitive Na+ channels of low density, discretely distributed as point sources of transmembrane current along a continuous (non-segmented) passive cable structure. Each cluster or hot-spot, corresponding to a mesoscopic level description of Na+ ion channels, included known cumulative inactivation kinetics observed at the microscopic level. In such a reduced third-order system, the ‘recovery’ variable is an electrogenic sodium-pump and/or a Na+-Ca2+ exchanger imbedded in the passive membrane, and a high leakage conductance stabilizes the system. A nonlinear cable equation was used to investigate back-propagation and repetitive activity of action potentials, exhibiting characteristics of the modified Hodgkin-Huxley kinetics (in the presence of suprathreshold input). In particular, a time-dependent analytical solution was obtained through a perturbation expansion of the non-dimensional membrane potential (Φ) for all voltage dependent terms including the voltage dependent Na+ activation μ) and state-dependent inactivation (η) gating variables and then solving the resulting system of integral equations. It was shown that back-propagating action potentials attenuate in amplitude with the frequency following experimental findings and that the discrete and low-density distributions of transient Na+ channels along the cable structure contribute significantly to their discharge patterns. A major significance of integrative modelling is the provision of a continuous description of the non-dimensional membrane potential (Φ) as a function of position.

A novel integrated sleeve-wedge anchorage system for multi-tendon CFRP cable utilized in cable roof structures: Concept and numerical investigation

Carbon fiber-reinforced polymer (CFRP) cables demonstrate exceptional mechanical properties and offer significant potential for utilization in large-span cable roof structures. However, the implementation of efficient CFRP cable anchorage systems specifically designed for cable roofs remains an urgent necessity. In this paper, a novel integrated sleeve-wedge anchorage system (NISWAS) consisting of two components, a multi-channel integrated sleeve-wedge (MCISW) and a barrel, has been proposed to achieve the anchorage of CFRP cable with multiple tendons. Compared to the traditional wedge-type anchorage system (WTAS), which can only clamp a single CFRP tendon, the use of the novel integrated steel wire anchorage system (NISWAS) reduces both the volume and self-weight of the cable anchorage end, significantly improving construction efficiency. The design concept of NISWAS was validated through finite element method (FEM) as an example of a 6-Φ5 CFRP cable, and its anchor performance was systematically evaluated. Three key factors affecting the anchor performance were analyzed: the slope angle of MCISW, the anchor length and the differential angle between barrel and MCISW. The results show that the NISWAS is an effective way of anchoring multiple CFRP tendons, and the design of the MCISW can prevent excessive transverse stress on the CFRP cable at the loaded end of the anchorage. The slope angle of the MCISW exerts the most significant impact on the anchor performance. The optimal choice of angle is 3°, beyond which the effect of the anchorage system on the sliding of CFRP cable becomes less significant, while excessive transverse stress may cause premature failure of the cable. The differential angle between barrel and MCISW has a secondary influence on the anchor performance. A moderate angle difference value (0.1° to 0.2°) can alleviate the transverse stress on the CFRP cable, but a too large value (more than 0.3°) will reduce the force transmission between the MCISW and barrel, resulting in premature cable pullout. Increasing the anchor length can reduce transverse stress and cable slip, but the reduction effect is not significant. After analysis, the anchor length of 90 mm can satisfy the anchoring requirement. According to the influence law of the above three factors, the parameter design scheme of the NISWAS was finally proposed.

Experimental investigation on the performance of Cable-Girder anchorage structure of hybrid Cable-Stayed suspension bridges

As the key component of the stay cable connecting the girder and tower in the hybrid cable-stayed suspension system, the cable anchorage structure needs to bear the powerful cable force transmission function. Compared with normal anchorages, the structural features of a new type of anchor box structure cable-girder anchorage (CGA) that has strong bearing capacity and more uniform stress distribution for a long-span hybrid cable-stayed suspension bridge with steel box girder was investigated by a 1:2 scale specimen test and a series of finite-element analysis. Through finite element analysis (FEA) and test results, the stress distribution and cable load transfer pathway of anchor box structure are obtained. The test results show that the CGA design is reasonable and reliable. The four welds connected to the anchor box support plates and the steel box girder webs bear 87% of the cable force load transfer, and the remaining 13% of the cable load is delivered from the anchor box bearing plate to webs. A large stress concentration in the six welds, but the maximum von Mises stress (VMS) of welds is 130–151 MPa. According to the parametric studies,the installation angle of the anchor box considerably affects the stress characteristics. Also, the thickness and length of the anchor box plate are changed, the transmission and distribution proportion of the cable force between the main welds of the anchor box increase alternately.

An enhanced absolute nodal coordinate formulation for efficient modeling and analysis of long torsion-free cable structures

Long cable structures can be accurately modeled in the absolute nodal coordinate formulation (ANCF), but often at the expense of using too many degrees of freedom (DOFs). This research refines the section of node coordinates and configuration description of the element and forms an enhanced ANCF that required modeling DOFs are greatly reduced. In this formulation, the cable is treated as an elastic line and discretized with two-node elements. The gradients of all nodes and the absolute positions of only head node are selected as generalized coordinates. The gradient field of the element is linearly interpolated in nodal gradients. Unlike the traditional ANCFs, the absolute position vector of an arbitrary point of the element is calculated by evaluating an integral of the element gradient over the element length plus the position vector of the starting node of the element, instead of cubic polynomial interpolation of nodal position and gradient vectors of the element. This leads to considerable DOFs saving. Governing motion equations of the cable are derived. Benchmark examples are used to show the performance of the enhanced formulation against with the classical ANCF cable element. Comparative studies show the validity and the efficiency of the enhanced formulation.

Manipulation Planning for Wiring Connector-Attached Cables Considering Linear Object’s Deformability

In this paper, we propose a method of manipulation planning for cable wiring. The method enables to take into account the deformation of cables while connector incorporation process. Using a physical simulation that predicts the shape of a cable based on the pose of both ends of the cable, we generate a connector moving path that avoids intereference between the cable and surrounding structures. We conducted experiments under several different environments and several different lengths of cables, and confirmed that actual cable manipulation can stably be achieved by using the proposed method.

Piecewise-Fitted Formula for Cable Force Identification Considering Bending Stiffness, Sag, and Inclination

The identification of cable forces plays an important role in the construction, vibration control, and health monitoring of cable structures. In practice, cable vibrations are mainly affected by the coupling of bending stiffness, sag, inclination, and boundary conditions, so it is difficult to establish an explicit functional relationship between frequency and cable force through the vibration method for facilitating application to engineering. To overcome this difficulty, the explicit expression of the frequency of the cable considering bending stiffness, sag, and inclination is derived for the first time and a novel cable force identification method for determining the piecewise-fitted formula (PFF) according to the cable parameters is proposed. The paper first reviews the cable force identification formulas based on cable frequencies. Then, the theoretical analysis model and differential equation of cable vibration considering the aforementioned factors are established. Based on these derivations, the explicit general formula of cable force identification based on fundamental frequency is derived. Next, according to the cable parameters, the value ranges of two nondimensional parameters characterizing the bending stiffness and sag of cables are divided to fit the corresponding coefficients of the PFF. Finally, numerical simulation and experimental data show that the PFF is more accurate and applicable than the existing formulas. This method can be conveniently applied to the field detection and online monitoring of cable forces.

Current sharing optimization of multilayer high temperature superconducting cable

Large-capacity high-temperature superconducting (HTS) cables generally adopt a multilayer structure to increase the current-carrying capacity. However, the multilayer structure of the HTS cables will increase the uneven current distribution, decreasing the critical current and heighten the AC loss. Therefore, the current sharing technology between each layer of the HTS cable is essential to improve transmission performance. This paper proposes two hybrid HTS current sharing optimization algorithms based on particle swarm optimization and artificial bee colonies. The current distribution of the HTS cable in each layer under pre- and post-optimization is estimated and the structure parameters are obtained. A 3D model is established to evaluate the characteristics of the optimized HTS cable. The results show that the proposed hybrid current sharing optimization schemes can well improve the inner current sharing of the HTS cable, and the feasibility and effectiveness are therefore demonstrated.

Monocyte adhesive hyaluronan matrix induced by hyperglycemia in diabetic lung injuries

Infiltrated pre-inflammatory monocytes and macrophages have important roles in the induction of diabetic lung injuries, but the mechanism mediating their infiltration is still unclear. Here, we showed that airway smooth muscle cells (SMCs) activated monocyte adhesion in response to hyperglycemic glucose (25.6mM) by significantly increasing hyaluronan (HA) in the cell matrix, with concurrent 2- to 4-fold increases in adhesion of U937 monocytic-leukemic cells. The HA-based structures were attributed directly to the high-glucose and not to increased extracellular osmolality, and they required growth stimulation of SMCs by serum. Treatment of SMCs with heparin in high-glucose induces synthesis of a much larger HA matrix, consistent with our observations in the glomerular SMCs. Further, we observed increases in tumor necrosis factor-stimulated gene-6 (TSG-6) expression in high-glucose and high-glucose plus heparin cultures, and the heavy chain (HC)-modified HA structures existed on the monocyte-adhesive cable structures in high-glucose and in high-glucose plus heparin-treated SMC cultures. Interestingly, these HC-modified HA structures were unevenly distributed along the HA cables. Further, the invitro assay with recombinant human TSG-6 and the HA14 oligo showed that heparin has no inhibitory activity on the TSG-6-induced HC-transfer to HA, consistent with the results from SMC cultures. These results support the hypothesis that hyperglycemia in airway smooth muscle induces the synthesis of a HA matrix that recruits inflammatory cells and establishes a chronic inflammatory process and fibrosis that lead to diabetic lung injuries.

Time series prediction based on LSTM neural network for top tension response of umbilical cables

The umbilical cable is an essential component of offshore oil and gas extraction systems. The severe marine environment poses a high challenge to the safety of the umbilical cable structure during operation. The analysis of an umbilical cable requires complex and resource-demanding finite element time-domain simulations to obtain their nonlinear dynamic response. Therefore, in order to solve the problem of structural safety monitoring and real-time assessment of remaining life of umbilical cables under extreme sea states, there is a great need to predict the dynamic response of umbilical cables quickly and accurately during operation, for ease of making fast decisions for system operation and maintenance before the arrival of extreme sea states. Given the strong nonlinear function-approximation ability of the neural network, this study proposes an efficient method for the prediction of the time series of umbilical cable top tension response based on LSTM (long short-term memory) neural network. We use LSTM neural network and ARIMA (autoregressive integrated moving average) model in a real engineering case for time series prediction of the top tension response of the umbilical cable, and the results of the two models are analyzed and compared, and the efficiency and accuracy of the LSTM neural network model are verified. Furthermore, the hyperparameter, dataset and generalization ability of LSTM model are discussed. The results indicate that feasibility of the tension response prediction of umbilical cables under dynamic load in complex marine environments.

Research on the Diffusion Model of Cable Corrosion Factors Based on Optimized BP Neural Network Algorithm

Corrosion factors enter the cable via diffusion and penetration from the defect position of the cable or the connection position between the anchoring system and the cable section, seriously affecting the cable’s durability. Exploring the transmission mechanism of corrosion factors in the cable structure is essential to reveal the durability and the long-term performance of the cable structure and to judge the corrosion damage of steel wires in the cable structure. Based on the machine learning (ML) method and the analytical solution of Fick’s second law, the laws between different temperatures, humidity, cable inclinations, cable defect areas, etc., and the diffusion coefficient of corrosion factors and the concentration of surface corrosion factors are obtained, also a spatial diffusion model of corrosion factors is established. According to the research, the optimum simulation result is achieved by employing the optimized back propagation (BP) neural network algorithm, which has a faster convergence speed and better robustness. Although ambient temperature, humidity, and corrosion time all impact the diffusion rate of corrosion factors, the tilt angle of the cable and the size of cable defects are the main factors influencing the diffusion coefficient of corrosion factors and the concentration of surface corrosion factors. The error between the concentration of corrosion factors calculated by the model in this article and the measured values at each spatial point of the cable is controlled within 15%, allowing for the spatial diffusion of corrosion factors to be effectively predicted and evaluated in practical engineering.

Tensile strengths of super high-strength steel strand wire ropes and wire rope open swaged socket connections at fire and post fire

PurposeThe main purpose of this study was to evaluate the tensile strengths of JIS G3549 super high-strength steel strand wire ropes (1,570 MPa-class high-carbon steels) and wire rope open swaged socket connections at fire and post fire.Design/methodology/approachSteady-state tests from ambient temperature (20 °C) to 800 °C, transient-state tests under the allowable design tensile force and tensile tests in an ambient temperature environment after heating (heating temperatures of 200–800 °C) were conducted.FindingsThe tensile strengths of the wire rope and end-connection specimens at both fire and post fire were obtained. The steel wire rope specimens possessed larger reduction factors than general hot-rolled mild steels (JIS SS400) and high-strength steel bolts (JIS F10T). The end-connection specimens with sufficient socket lengths exhibited ductile fracture of the wire rope part at both fire and post fire; however, those with short socket lengths experienced a pull-out fracture at the socket.Originality/valueThe fundamental and important tensile test results of the super high-strength steel strand wire ropes (1,570 MPa-class high-carbon steels) and wire rope open swaged socket connections were accumulated at fire and post fire, and the fracture modes were clarified. The obtained test results contribute to fire resistance performance-based design of cable steel structures at fire and fire-damage investigations to consider their reusability post fire.

Investigation of the Structural Dependence of the Cyclical Thermal Aging of Low-Voltage PVC-Insulated Cables

The increasing penetration of distributed generation sources in low-voltage distribution grids, electric vehicles, and new appliances from the consumer side can generate short repetitive overloads on the low-voltage cable network. This work investigates the change in the dielectric properties of low-voltage cable insulation caused by short-term overloads, examining how the cable structure affects the dielectric characteristics of the cable specimens in the case of cyclic short-term thermal aging. PVC-insulated low-voltage cable samples were exposed to an accelerated aging test in a temperature-controlled oven after changing their structures by removing different layers. Three aging cycles, each of six hours, were applied to the samples. After each cycle, the tan δ and capacitance were measured by an Omicron DIRANA Dielectric Response Analyzer in the laboratory at room temperature 24 ± 0.5 °C. Furthermore, the polarization and depolarization currents were also studied. The results show that changing the cable structure impacts the dielectric parameters; in particular, the effect of the belting layer is significant. From the point of view of aging, the PVC belting layer protects the diffusion of the plasticizers of the inner structure. The findings of the study show that an asymmetric aging phenomenon can be observed in different polymeric components of the cables, even though the cables were aged in an air-circulated oven ensuring a homogeneous temperature distribution in the samples.