Cable Mesh Research Articles

Failure characteristics and control technology of surrounding rock during roadway passing collapse column

The collapse column may result in failure of the surrounding rock during roadway excavation. It is of considerable importance to elucidate the failure characteristics and develop the corresponding control technologies for the surrounding rock. A discrete fracture mesh (DFN) and a strain-softening constitutive model are employed to simulate the properties of a collapse column. The stress zoning model was developed to characterize the rock surrounding the collapse column. Additionally, the zoned support technology was proposed to stabilize the roadway surrounding the rock. From the center outward, the results indicate that the collapse column can be individually divided into four zones: an internal impact zone of the collapse column, a stress decreasing zone, a stress increasing zone, and an initial stress zone. Upon the visibility of the collapse column, the tensile failure occurs in the roof, leading to a decrease in stress in front of the roadway and an increase in stress on both sides of the collapse column. The collapse amplifies the range of plastic failure by inducing an overlap between the roof stress and the stress elevation zones. The impact zone of the collapse column was reinforced by means of an integrated support system consisting of “pre-grouting, bolt cable mesh, and steel shed”. The “bolt cable mesh” provides integrated support beyond the area affected by the collapse column. Following a 20d excavation period, the roof and the two sides were stabilized, with an effectively controlling for the surrounding rock.

Biomimetic Design of a New Semi-Rigid Spatial Mesh Antenna Reflector.

The reflective surface accuracy (RSA) of traditional space mesh antennas typically ranges from 0.2 to 6 mmRMS. To improve the RSA, an active control scheme can be employed, although it presents challenges in determining the installation position of the actuator. In this study, we propose a novel design for a semi-rigid cable mesh that combines rigid members and a flexible woven mesh, drawing inspiration from both rigid ribbed antennas and biomimicry. Initially, we investigate the planar mesh topology of spider webs and determine the bionic cable surface's mesh topology based on the existing hexagonal meshing method, with RSA serving as the evaluation criterion. Subsequently, through motion simulations and careful observation, we establish the offset angle as the key design parameter for the bionic mesh and complete the design of the bionic cable mesh accordingly. Finally, by analyzing the impact of the node quantity on RSA, we determine a layout scheme for the flexible woven mesh with a variable number of nodes, ultimately settling for 26 nodes. Our results demonstrate that the inclusion of numerous rigid components on the bionic cable mesh surface offers viable installation positions for the actuator of the space mesh antenna. The reflector accuracy achieved is 0.196 mmRMS, slightly surpassing the lower limit of reflector accuracy observed in most traditional space-space mesh antennas. This design presents a fresh research perspective on combining active control schemes with reflective surfaces, offering the potential to enhance the RSA of traditional rigid rib antennas to a certain extent.

Design and analysis of a hoop truss deployable antenna mechanism based on convex pentagon polyhedron unit

Hoop truss deployable mechanism is widely applied in large aperture space antennas. In this paper, an integrated assembling concept is proposed for large aperture hoop antennas. First, a new deployable unit with height difference between inner and outer layer is proposed to combine a novel hoop truss deployable mechanism, and the optimization calculation method of the components are conducted based on the reflective cable mesh profile. Second, the degree-of-freedom (DOF) of the deployable unit and the whole mechanism are calculated based on screw theory, the result showed that they all have only one DOF. Then, the kinematic model is established through Lie bracket operation and screw theory, and the actuation allocation of the mechanism is analyzed. Finally, a prototype of the proposed hoop truss deployable mechanism is constructed, and a deployment test is conducted, which demonstrated the mobility and deployment performance of the whole mechanism. The mechanism proposed in this paper provides a theoretical reference for the integrated assembling of the deployable mechanism and reflective cable mesh, which is potentially valuable in the application of large aperture deployable antennas.

The Pretension Design of Cable Mesh considering the Large Deformation of Ring Truss

The conventional pretension design of cable mesh usually takes the ring truss as a rigid body or assumes small deformation. This method needs to be more accurate in designing super large aperture antennas. A cable mesh design method considering the large deformation of the ring truss is proposed in this paper based on the flexible multibody dynamics (FMD) and the force density method (FDM). With this method, the significant range deviation of the boundary points’ position of the ring truss under the tension of the external area of the cable mesh after the completion of the pretension design can be predicted with high accuracy. After the ring truss and cable mesh surface are assembled stably, there is only a minimal deviation between the actual mesh surface and the theoretical mesh surface of the antenna, and there is only a minimal deviation between the genuine mesh pretension and the design pretension. The above calculation method is verified by numerical simulation, and the simulation results show that the technique can be applied to the mesh pretension design of a super large aperture ring deployable antenna.

Form-finding design optimization method of cable mesh reflectors based on a weighting surface accuracy with electromagnetic performance

Form-finding design optimization method of cable mesh reflectors based on a weighting surface accuracy with electromagnetic performance

Bolt-Cable-Mesh Integrated Support Technology for Water Drenching Roadway in Thick Coal Seam.

Aiming at the problems of large deformation and difficult control of the mining roadway water drenching in a thick coal seam, the principle of double-arch zoning cooperative surrounding rock control is studied by using the combined method of theoretical analysis, numerical simulation, and industrial experiment. The water-rock interaction of the surrounding rock of water-drenching roadway is proposed, taking into account the damage to the mechanical parameters of the surrounding rock caused by soaking water. The water-mechanical-damage coupling model for surrounding rock of a coal seam roadway is constructed, and is numerically solved by the code development using the FISH language. The principle of "high prestressed bolt-cable-mesh" zone coordinated control is revealed, and the existence of a compressive stress arch is verified by FLAC3D software. The three support schemes were compared and analyzed by numerical simulation software. We affirmed the bolt length of 2400 mm, spacing of 0.9 m, row spacing of 1 m, cable length of 7300 mm, and arrangement 3-2-3 as the optimal support scheme and applied this scheme in the Zhangcun Coal Mine. The results show that the maximum deformation of the roadway roof is 142 mm, and the ultimate convergence of the two sides is 83 mm. The surrounding rock has been effectively controlled.

Complexe Sportive de Meudon – Structural Design and Construction

AbstractThe “Complexe Sportive de Meudon” is a multisport venue in Trivaux – Paris, France, with a rectangular footprint of about 110 meters long by 70 meters wide. It includes an ice rink with 700No. seating places, a fitness centre, squash and padel courts, a climbing wall, and a full size 11‐aside football field, along with public and private parking space. The building's roof is entirely occupied by the football field, which is netted all around with a stainless‐steel cable mesh supported on discrete vertical steel elements, resembling “tuning forks”. A substantial part of the roof structure is supported off 12No. 45m long, varying depth plate girders, weighing 30tonnes each. This communication is focused on this part of the building's structure.

Influence Research for Softening and Swelling of Weakly Cemented Soft Rock on the Stability of Surrounding Rock in Roadway

In order to study the influence of the softening and swelling of weakly cemented soft rock on the stability of roadway surrounding rock, based on the background of the general return airway in the south wing of Yuwu coal mine, 4 different schemes are designed according to whether the softening or swelling effect of weak cemented soft rock is considered. Based on the numerical simulation program, FLAC3D was used to analyze the distribution characteristics of the shear stress, displacement, and plastic zone of the surrounding rock of the roadway under these 4 designs. On this basis, in view of the geological conditions of the roadway, a new type of “grouting + anchor cable mesh + bottom arch” combined support plan is proposed. The research results show that, under the conventional anchor-net-cable-spraying support scheme, the surrounding rock of the roadway can remain stable without considering the softening and expansion of the weakly cemented soft rock in contact with water and its maximum displacement and plastic zone depth are only 66.9 mm and 2.8 m. When considering the softening and swelling of weakly cemented soft rock roadways, due to the synergistic effect of the two, the maximum displacement of the surrounding rock of the roadway and the depth of the plastic zone will reach 517.4 mm and 6.7 m, respectively, which will continue to increase with excavating along the roadway and lead to ultimately destabilization and destruction. After adopting the combined support of “grouting + anchor cable mesh + bottom arch,” the maximum displacement of the surrounding rock of the roadway and the depth of the plastic zone will be reduced by 77.1% ∼ 92.0% and 18.7% ∼ 72.4%, respectively, and they will basically remain stable after excavation of 5 days.

Study on Zonal Cooperative Control Technology of Surrounding Rock of Super Large Section Soft Rock Chamber Group Connected by Deep Vertical Shaft

Aiming at solving the problem of asymmetric deformation, failure, and stability control of surrounding rock caused by the excavation of deep super large section soft rock chamber group passing through multilayer strata, taking super large section soft rock chamber group connected by deep vertical shaft in Wuyang Coal Mine as the engineering background, the deformation development mode of surrounding rock, the expansion situation of loosening range, and the plastic failure response characteristics in chamber group under the disturbance influence are monitored and numerically analyzed. On this basis, the super large section chamber group is divided into four maintenance control areas: area I (severe deformation area), area II (stable deformation area), area III (medium deformation area), and area IV (small deformation area), and the asymmetric deformation and failure mechanism of the surrounding rock of the chamber group is analyzed. The influence mechanism of specific support technologies on the deformation control effect of surrounding rock of chamber group is systematically studied, including high‐strength prestressed bolt (cable) mesh shotcreting coupling support technology, reinforced concrete wall subarea brickwork support technology, and hollow bolt (cable) grouting reinforcement technology of fragmented coal and rock mass. The basic control ideas and technical methods of surrounding rock of deep large section soft rock chamber group are formed. The subarea collaborative control technology of “high‐strength prestressed bolt (cable) mesh shotcreting coupling + reinforced concrete wall brickwork support technology + high‐strength bolt (cable) grouting of fragmented coal and rock mass” is proposed. The field application shows that this technology realizes effective control of surrounding rock of super large section chamber group.

Shear performance of 3D printed concrete reinforced with flexible or rigid materials based on direct shear test

Flexible and rigid materials, such as stainless steel cable (SSC), stainless steel cable with blades (SSCB), stainless steel cable mesh (SSCM), and carbon fibre reinforced polymer grid (CFG), were used to reinforce printed concrete. Based on the directed double-sided shear test, the shear responses of printed concrete, such as the failure mode, shear strength, and shear load–displacement curve, were obtained, and the enhancement efficiencies of different reinforcing methods were discussed by considering the variation in the ratio of reinforcement. Furthermore, the mechanical mechanism was proposed, and prediction models were established based on the different contributions of the flexible and rigid reinforcing materials to the shear behaviour of printed concrete. The results indicated that the stiffness of the reinforcing materials evidently affects the shear performance of printed concrete, and lateral reinforcement is beneficial for improving the shear strength and toughness of printed concrete.

High surface accuracy and pretension design for mesh antennas based on dynamic relaxation method

Cable truss structures are widely used in large satellite antennas with ultrahigh electromagnetic performance. The electromagnetic performance is directly determined by the mesh reflector's surface accuracy, which triggers research on the pretension design. In this paper, a novel pretension design method for both high surface accuracy and uniform tension distribution is proposed based on the dynamic relaxation (DR) method. In this approach, members of the cable network are regarded as string elements with 3 degrees of freedom to resist the axial tensile force, and members of the supporting truss are regarded as Euler-Bernoulli beams with 6 degrees of freedom to resist the axial and transverse forces and the bending and torsion moments. The DR method is adopted to find the static equilibrium of the whole mesh antenna, including both the cable mesh and the supporting truss. Thus, the deformation of the cables and rods and their interactive effects are fully captured. Then, to find an expected high-precision mesh surface with a uniform tension distribution, the inverse iteration algorithm (IIA) is adopted to adjust the original cable lengths of the cable network in each DR calculation cycle until the convergence criterion is met. Finally, this approach is effectively applied to the pretension design of symmetric and asymmetric mesh antennas, and the results indicate that the method is effective in obtaining both high surface accuracy and uniform tension distribution with high computational efficiency.

Cable-stayed coverings for large-span public buildings

Structural schemes of coverings using lightweight roof structure from modern composite materials are investigated in this paper. A comparison of two options for cable-stayed covering of a circus auditorium, one with an orthogonal mesh of cables (according to a standard design) and another one, with a mesh of cables formed by two groups of stabilizing cables are considered. The possibilities of reinforcement with composite material are analyzed. Calculation and preliminary selection of cable-stayed sections are also carried out and presented. The variations of the conditional volume with the relative sag arrows, for varying values of the coefficient qk have been investigated and shown on graphs. An optimization problem was solved and the optimal result with detailed calculations are proposed and presented in this research which enable the design of the cable-stayed coating with determination of its design characteristics. As a result, the optimum and most economical sections of the cable-stayed covering were obtained. The calculations also show the inexpediency of using a heavy roof structure for saddle cable-stayed coverings due to the exclusion of stabilizing cables from the operation with a large roof weight.

Investigation on design methods for cable mesh configuration of deployable space antenna reflector

Mesh reflectors are always a preferable option for large size deployable antenna reflector over solid surface reflectors due to their flexibility of adjustment in minimum possible space and ability to get deployed to full configuration in space. Maintaining surface properties and accuracy are two important requirements in the design of the mesh reflector for the performance of cable network antenna reflectors. The present work considers the various design approaches for cable mesh configuration of space deployable antenna reflectors. The equal force density shape forming criteria such is applied for obtaining the desired parabolic curvature of the mesh configuration. The ring structure for the deployable mechanism is considered as rigid linkages for designing mesh configuration. A generalized numbering scheme for nodes and cable mesh link is formulated for carrying forward various shapes forming criteria which help in making an algorithm. The algorithm for a better understanding of these methods is developed using MATLAB with nodal coordinates and its connection. Mesh configuration is developed with a different number of divisions. A study is also carried out for finding the required number of divisions for a highly accurate parabolic profile for a particular band frequency. A demonstration model is developed and a comparison of the coordinates of the prototype is made with those arrived at using the model.

Integrated structural-electromagnetic optimization of cable mesh reflectors considering pattern degradation for random structural errors

To alleviate the effects of random structural errors on the radiation performance and directly guide the structural design of cable mesh reflectors, an integrated structural-electromagnetic optimization procedure is proposed considering the radiation pattern degradation for random structural errors. Based on analytical expressions and the structural sensitivity concept, the radiation pattern is directly expressed as two matrix-form functions with respect to the random structural errors. By applying the pattern calculation into the multidisciplinary design and selecting the average boresight directivity as the objective function, an optimum result with better radiation performance compared with the traditional structural design is obtained. To reveal the fundamentals of the optimum result, the concept of sensitivity analysis of the average boresight directivity with respect to the random structural errors is introduced. The effectiveness and benefits of this study are demonstrated via an offset cable mesh reflector.

Optimization Design of Structural Surface Precision of Shape Memory Cable Mesh

Optimization Design of Structural Surface Precision of Shape Memory Cable Mesh

A Novel Space Large Deployable Paraboloid Structure with Power and Communication Integration

The combination of a solar array and a communication antenna can reduce the entire mass, physical size, and cost in space applications. Currently, related studies mainly focus on the combination of the two structures on the one flat plate structure (FPS). Compared with the FPS, a paraboloid structure has a lower surface density and higher conversion efficiency. Therefore, a novel space large deployable paraboloid structure with power and communication integration (SSPCI) is proposed and designed in detail, for spacecraft on a sun synchronous earth orbit; it consists of a cable mesh membrane reflector (CMMR), an energy conversion device (ECD), and a three-extensible-rod (TER) pointing mechanism. To achieve the goal of integrating power and communication, the TER pointing mechanism drives the CMMR/ECD to track the sun in the sunshine region or to turn to face the ground station/other target in the Earth’s shadow region. Then, through simulation analyses of the deploying process, static force at a limit orientation, and sun tracking process of the SSPCI, it is proved that the SSPCI is feasible and has satisfactory performance. Finally, deploying experiments of the folded hoop of the CMMR and sun tracking experiments of the TER pointing mechanism on the ground were carried out successfully, which proves that the folded hoop can be deployed successfully with fairly high deploying dependability, and the TER pointing mechanism is feasible for the SSPCI from the mechanism principle and the control mode in space applications indirectly. Moreover, the tracking accuracy of the TER pointing mechanism is estimated to be within ±0.4° although the machining precision of its components is not high.

Conceptual design of a new thermal‐electric conversion device in lightweight concentrating solar thermal power system

AbstractConcentrating solar thermal power (CSTP) technology has become a hot issue in the present research because of its high conversion efficiency. However, traditional schemes cannot be widely applied due to their complex structure, low power density, and high cost. In view of this, based on a new type of lightweight cable mesh reflector structure and the Rankine cycle, a new conceptual design of thermal‐electric conversion device in CSTP system is proposed. The process of thermal‐electric conversion is actualized through smart and lightweight structural design; the performance estimation of the device is carried out through focusing performance analysis and thermodynamic analysis; the cycling feasibility is verified through multifield coupling simulation analysis. Compared with the existing thermal‐electric conversion devices, the device proposed in this paper has higher power‐to‐weight ratio. And the power generation system that combines the proposed device with the flexible cable net reflector has the characteristics of lightweight, portability, and small land area, which has a great significance for the popularization and application of distributed layout CSTP system.

A novel ultralight dish system based on a three-extensible-rod solar tracker

The use of dish systems is among the most potential methods for solar power collection. However, the popularization of the application of traditional dish systems has been impeded because they are heavy, structurally complex, and costly. Accordingly, a novel ultralight dish system is proposed; it consists of a cable mesh reflector, an ultralight thermoelectric conversion device, and a three-extensible-rod (TER) solar tracker. Compared with previous reflectors consisting of rigid solid panels, the reflector of the proposed dish system (PDS) adopts an ultralight rigid–flexible combined structure based on a space cable mesh reflector antenna. The lightweight thermoelectric conversion device of the PDS is reasonably considered. Thereafter, a TER solar tracker (specifically, 3-RPS) is mainly selected and designed for the PDS. Through an inverse kinematic analysis of the tracker, a sun-tracking control strategy of height variation is employed to reduce the number of sections in each extensible rod from three to two and to decrease total energy consumption. Meanwhile, a compound joint consisting of hook and rotary joints is substituted for the spherical joint of the solar tracker to overcome its inadequate rotational range and facilitate fabrication. By setting the PDS to an extreme orientation and subjecting it to wind and gravitational loads, its structural parameters are further determined through analysis and optimization. Although the surface density of the PDS is only approximately 1 kg/m2, the system performs satisfactorily even when subjected to loads. The dynamic model of the PDS is established by the Newton–Euler formulation. The power requirement of the PDS is determined through the dynamic analysis; it is found that during winter solstice, its maximum power is only 0.024 W, and the daily energy consumption is only 210.05 J. Finally, sun-tracking experiments on the TER solar tracker are performed to verify the theoretical and simulation analysis results; the sun-tracking accuracy is estimated to be within ±0.7°, which satisfies the PDS requirement although the machining precision of its components is not high.

Form-Finding Design of Cable–Mesh Deployable Reflector Antennas Considering Wire Mesh Properties

The wire mesh is a key component of a cable–mesh deployable antenna; it is laid on the cable net to reflect electromagnetic waves. The knitting form, mesh size, and wire mesh ductility directly affect the accuracy of the reflector. In this paper, a form-finding design method that considers wire mesh properties is proposed for cable–mesh deployable reflector antennas. First, a three-dimensional geometric model of the wire mesh is established. Based on the augmented Lagrange multiplier method, the finite element method model of the wire mesh is derived, and its accuracy is verified by experimental data. Second, to simplify the computation for a large-scale flexible wire mesh structure, the mechanical model is made equivalent to an anisotropy membrane. Third, based on the nonlinear finite element method, the form-finding design method of the cable–membrane composite structure is proposed. The simulation and experimental results demonstrate the significant influence of the mechanical properties of wire mesh and the validity of the proposed design method.

A Case Study on Large Deformation Failure Mechanism and Control Techniques for Soft Rock Roadways in Tectonic Stress Areas

Large deformation and failure of soft rock are pressing problems in the mining practice. This paper provides a case study on failure mechanisms and support approaches for a water-rich soft rock roadway in tectonic stress areas of the Wangzhuang coal mine, China. Mechanic properties of rock mass related to the roadway are calibrated via a geological strength index method (GSI), based on which a corresponding numerical simulation model is established in the Universal Discrete Element Code (UDEC) software. The failure mechanism of the roadway under water-saturating and weathering conditions is revealed by field tests and numerical simulation. It is found that the stress evolution and crack development are affected by weathering and horizontal tectonic stresses. The roadway roof and floor suffer from high stress concentration and continuous cracking, and are consequently seen with rock failure, strength weakening, and pressure relief. Unfortunately, the current support system fails to restrain rock weathering and strength weakening, and the roadway is found with serious floor heave, roof subsidence, and large asymmetric deformation. Accordingly, a new combined support system of “bolt–cable–mesh–shotcrete + grouting” is proposed. Moreover, numerical simulation and field testing are conducted to validate the feasibility and effectiveness of the proposed approach, the results of which demonstrate the capacity of the proposed new support method to perfectly control the surrounding rock. Findings of this research can provide valuable references for support engineering in the soft rock roadway under analogous geological conditions.