Cable Network Structures Research Articles

Intelligent Health Monitoring of Cable Network Structures Based on Fusion of Twin Simulation and Sensory Data

The precise and effective prognosis of safety risks is vital to ensure structural safety. This study proposed an intelligent method for the health monitoring of cable network structures, based on the fusion of twin simulation and sensory data. Firstly, the authors have established a framework that integrate simulation data with sensory data. The authors have established a high-fidelity twin model using genetic algorithm. The mechanical parameters of the structures were obtained based on the twin model. The key components of the structure are captured by using Bayesian probability formula and multiple mechanical parameters. The fusion mechanism of twin simulation and random forest (RF) was established to capture the key influencing factors. The coupling relationship between structural safety state and key factors was obtained, and the safety maintenance mechanism was finally formed. In view of the risk prognosis of the structure, the establishment method for the database of influencing factors and maintenance measures was formed. The authors used the Speed Skating Gymnasium of 2022 Winter Olympic Games (symmetric structure) as the case study for validating the feasibility and effectiveness of the proposed method. The theoretical method formed in this study has been applied to the symmetric structure, which provides ideas for the safety maintenance of large symmetric structures. Meanwhile, this research method also provides a reference for the health monitoring of asymmetric structures.

Effect of Construction Errors in Cable Forces of Single-Story Orthogonal Cable Network Structures Based on GA-BPNN

The construction process of cable net structure is complicated, which leads to the strong randomness of construction errors. The safety state of the cable net structure is very sensitive to construction errors. Obtaining the coupling relationship between construction errors and cable force response efficiently and accurately is critical to developing the construction technique of cable structures. This paper proposed an analysis method based on a genetic algorithm optimized back propagation neural network (GA-BPNN) to judge the influence of construction error on the cable force of single-layer orthogonal cable network structures. Taking the speed skating stadium of the 2022 Winter Olympic Games as the research object, this paper analyzed the structure form of the venue. According to the characteristics of cable network structure and GA-BPNN calculation, the principle of construction error analysis was put forward. The influence of construction errors of load-bearing cables and stable cables on cable force response was analyzed. The influence degree of different component errors on structural cable forces was obtained, and the most unfavorable key components were obtained. For the key components, the influence trend of different construction errors on cable force was analyzed, and the fitting formula was given. Driven by GA-BPNN, it can realize the analysis of structural and mechanical responses under the action of multi-type, multi-component, and multi-combination construction errors. The results show that the research method efficiently and accurately obtains the performance law of structural cable force under the influence of construction error, effectively predicts the influencing factors of the structural safety risk, and effectively avoids structural safety accidents caused by construction error. The construction errors analysis method based on GA-BPNN proposed in this paper can provide a reference for similar structural analysis and application.

Optimal Shape Adjustment of Large High-Precision Cable Network Structures

Traditional shape adjustment methods for large high-precision cable network structures usually use many actuators and are only applicable to predictable shape distortions. To this end, a new method, namely, the minimum residual nodal displacement method, for optimal shape adjustment of large high-precision cable network structures is developed. The new shape adjustment method can significantly reduce shape distortion of a cable network structure by automatically placing a small number of actuators at optimal locations. This new method is applicable to cable network structures under both predictable and unpredictable shape distortions, and can determine the minimum number of actuators needed to satisfy prescribed design requirement for surface accuracy. In this method, a simple linear relationship between nodal displacements, external loads, and undeformed member lengths of a cable network structure is established, and residual nodal displacement of the structure is minimized. The effectiveness of this new method is proved in numerical simulation results, where a planar cable network structure and a reconfigurable deployable mesh reflector are investigated.

Form finding and design optimization of cable network structures with flexible frames

Cable network structures consist of the cable networks and supporting frames, and the whole structures form the equilibrium states under the interactions between them. The existing methods haven’t considered the flexibility of the supporting frames and thus fail to fully capture the interactive effect between cable networks and flexible frames in the design optimization. This leads to the deviations between the design results and the real equilibrium states. Here we propose a form finding and design optimization approach for cable network structures with flexible frames. By solving the non-compatibility problem between cable and beam elements (due to rotation DOF), the cable network and supporting frame can be coupled to accurately model the real equilibrium state in the optimization model. We also derive the linear form for the determination of the free node coordinates from systematic equilibrium equations, which greatly reduces the computing cost of the optimization design and makes the multi-variable optimization more achievable. The proposed approach is effective for the form finding and design optimization of flexible supported cable networks with high surface accuracy requirements and multiple design variables. It is applied to mesh reflector antennas, and case studies are provided to verify the effectiveness of the methodology.

Pretension design of cable-network antennas considering the deformation of the supporting truss: A double-loop iterative approach

Cable-network structures are usually adopted as an ideal form of satellite antennas. The performance of cable-network antennas crucially depends on the surface accuracy and the tension distribution. In some cases, conventional algorithms, such as the equal tension algorithm and the equal force density algorithm, may lead to the decrease of the effective region. Thus the equal length algorithm based on the force density method is proposed in this paper. In this algorithm, the free nodes are restricted as close as possible to their desired positions, which ensures the area of the effective region and the high surface accuracy. The cable tensions are restricted by the maximum tension ratios, which ensures the uniform tension distribution. Furthermore, the elastic deformation of the supporting truss seriously affects the antenna’s performance. Therefore, a double-loop iterative form-finding approach for the cable-network antenna with flexible supporting truss is proposed to find a pre-tensioned configuration that meets the requirements of the surface accuracy and the tension distribution. Firstly, an inner loop based on the equal length algorithm is established for the form-finding of the cable-network. Through this inner loop, the high surface accuracy and the uniform tension distribution can be achieved. Secondly, a compatible strategy between the cable-network and the flexible supporting truss is proposed. Through this strategy, a nonlinear finite element (FE) model of the cable-network antenna is established to capture the compatible deformation. Thirdly, an outer loop combining the equal length algorithm and the compatible strategy is established, in which the node coordinates and the cable tensions are iteratively fed to the force density model and the FE model in steps 1 and 2. Through this outer loop, the compatible deformation is fully considered. The whole loop will stop and converge to a reasonable solution of the surface accuracy and the tension distribution within given criterions. Numerical examples of an offset cable-network antenna are provided, and the results are compared with previous literature.

Method for Deployable Mesh Antenna Cable Network Structures’ Form-finding Design Based on Force Density

Method for Deployable Mesh Antenna Cable Network Structures’ Form-finding Design Based on Force Density

Mesh topological form design and geometrical configuration generation for cable-network antenna reflector structures

A well-designed mesh shape of the cable net is of essential significance to achieve high performance of cable-network antenna reflectors. This paper is concerned with the mesh design problem for such antenna reflector structure. Two new methods for creating the topological forms of the cable net are first presented. Among those, the cyclosymmetry method is useful to generate different polygon-faceted meshes, while the topological mapping method is suitable for acquiring triangle-faceted meshes with different mesh grid densities. Then, the desired spatial paraboloidal mesh geometrical configuration in the state of static equilibrium is formed by applying a simple mesh generation approach based on the force density method. The main contribution of this study is that a general technical guide for how to create the connectivities between the nodes and members in the cable net is provided from the topological point of view. With the new idea presented in this paper, multitudes of mesh configurations with different net patterns can be sought by a certain rule rather than by empiricism, which consequently gives a valuable technical reference for the mesh design of this type of cable-network structures in the engineering.

Initial Equilibrium Configuration Determination and Shape Adjustment of Cable Network Structures

This article presents a rigorous static analysis of cable network structures, which relates the nodal position, the unstressed cable length and the external load using the elastic catenary cable element in order to take into consideration the cable curve effect and the fact that cables can only be tensioned. The incremental relationship between nodal position and cable length is employed for solving the unstressed cable length in the initial equilibrium configuration determination problem and for accomplishing the shape adjustment operation with an iterative method. Detailed procedures of investigating the problems of the initial equilibrium configuration and shape adjustment of the cable network supporting structure for a large reflector are presented to demonstrate the validity and effectiveness of the method.

A Design Method for Cable Network Structures Considering the Flexibility of Supporting Structures

A Design Method for Cable Network Structures Considering the Flexibility of Supporting Structures

Numerical method for the undamped forced dynamics of steel cable network structures

Steel cable network structures are characterized by strong geometric nonlinearities and high flexibility, which are the main causes of their unexpected behavior, especially under dynamic loading conditions (Levy and Spillers 1995). Excluding cable-stayed and cable-suspended structural systems as well as low-tension cable nets, the majority of static and dynamic analysis techniques used are approximate and complex in nature, while their approaches differ significantly. There are five widely accepted methodologies dealing with the foregoing structural systems, with their salient features summarized in the work of Kwan (1998), while combinations, variations and extensions of these, taking into account numerous parameters, such as slackening, friction, pre-stress etc., have also been reported (Goslin and Korban 2001, Kanno et al. 2002, Kanno and Ohsaki 2005, Talvik 2001, Volokh et al. 2003, and others not cited herein). To this end, in the present study a numerical technique for the undamped dynamics of cable networks is proposed, in which pretension of cable elements, uniform time dependent temperature change as well as flexibility and temporal dependence of boundary conditions are accounted for. Applications of the method produce results in very good agreement with existing ones and important conclusions for structural design purposes are drawn.

Interactive microcomputer-aided analysis of tensile network structures

Cable network structures not only provide economical solutions for spanning large-span earth structures but are potentially useful for space applications for three reasons: light structural weight, speed of construction, and reusability. Analysis of cable network systems can be complex because of their geometrically nonlinear behavior. This paper presents interactive microcomputer-aided analysis of tensile network structures. A multi-window graphic-oriented system has been developed for interactive analysis of three different classes of network structures: freely suspended synclastic-surface (dish-shaped) nets, prestressed flat nets, and prestressed anticlastic-surface (saddle-shaped) nets. The program is written in the QuickBASIC programming language for the IBM PS/2 computers. An iterative Newton-Raphson method is employed for the solution of the nonlinear system of equations; incremental loading is used for highly nonlinear network structures. Extensive graphic displays aid the user during preprocessing and postprocessing.

Traversing Singularities in Nonlinear Analyses on Cable Network Structures.

Nonlinear analyses of cable network structures using Newton's iteration often encounter difficulties in solving for a singular stiffness matrix stemming from the tension-stabilizing nature and slackening of cables. This paper presents a solution method, called null space projection, to traverse such a singular linear system in Newton's iteration. In the method, the current unbalance of internal and external forces is projected on the null space of the stiffness matrix and the contributions of null space basis for the variable updating are derived such that the total potential energy is reduced. Numerical example shows that the method successfully traverses singular systems in Newton's iteration process and consequently gives the equilibrium state of the structure.

Imaging techniques for cable network structures

AbstractImaging techniques are presented for developing interactive computer display of cable network structures on a microcomputer such as the IBM PS/2®. These structures create surfaces formed by an orthogonal mesh of cables and are primarily loaded normal to the surface. A three‐dimensional perspective representation of network structures is developed for fast drawing of cable structures on microcomputers.