Design Of Space Structures Research Articles

Study on the fracture propagation of ground fissures with syn-depositional structure in Fenwei Basin, China

In Fenwei Basin, most of the tectonic ground fissures show characteristics of growth faults on the section. They continue to destroy the engineering properties of soil at different depths. This has introduced significant security risks to the construction processes of deep underground spaces. However, there are few studies have been conducted on syn-depositional ground fissures. Therefore, in this study, a physical simulation test was used to study the fracture propagation of syn-depositional ground fissures. The characteristics of sections and surface fractures were analyzed. The engineering properties of model soil were divided into bad and poor areas. The syn-depositional ground fissure fracture propagation process was divided into five phases. The results show that soil profile exhibited a composite Y-shaped fracture morphology. Syn-deposition affects the fracture angle and healing state of fractures. The soil strain and surface displacement were positively correlated with the number of deposition layers. The conclusions of this study provide a theoretical geological basis and practical engineering significance for design of deep underground space structures.

A metaheuristic‐based method for analysis of tensegrity structures

SummaryTensegrity systems are construction system that offers solutions for lighter designs compared with a standard truss system consisting of tension and compression elements. Due to their structure, they are recommended in the design of space structures due to the use of lighter and easy‐to‐assemble structural elements such as cables, ropes, and similar to provide the desired durability. In this study, energy minimization was carried out to solve the structural element displacements. It is expected to reduce the total potential energy of the system with minimization. By minimizing the total potential energy of the tensegrity system models, the displacement of each building element is found for the equilibrium condition. Tensegrity models were analyzed by minimizing energy via the adaptive harmony search (AHS) algorithm. In this research, two distinct tensegrity structure specimens were employed. One comprised a cantilever beam, while the other adopted a cyclic model, forming eight equal octagons from eight nodes at both the base and the top. Additionally, an examination was conducted on a two‐layer iteration of the cyclic model. The method is robust for both space and planar tensegrity structures, allowing the determination of deformed shapes under various loads without design assumptions. The TPO/MA method demonstrates superiority in handling nonlinear and barely stable systems, as evidenced by examples illustrating its efficacy in maintaining structural form under increasing loads and challenging conditions.

Traveling wave modes of flexible structures with distributed gyros

With the development of space structures, flexible structures are widely studied. To achieve attitude and vibration control of flexible structures, flywheels or control moment gyros can be introduced. However, the critical challenge in studying gyro flexible structures is establishing a systematic framework to manage its physical properties and calculate the control moment precisely. This study aims to construct a theoretical framework for a two-dimensional flexible structure with distributed gyros using classical methods and explore the contribution of the gyro moment on the dynamic mode shapes. Both eigenvalue and traveling wave mode shape analysis are applied to investigate the dynamical behaviors of the system. It is found that dynamic modes with nodal lines showing whirling phenomena have arisen instead of the traditional modes featured with static nodal lines triggered by the gyro moment, and the dynamic mode shapes can be displayed by the direction and frequency of the mode nodal lines motion. The discovery and research of gyro flexible structure traveling wave modes can provide a solid base for the design of large space structures, improve their stability, and avoid harmful vibrations.

Design of deployable circular structures based on Miura origami pattern

A high deploy/fold ratio is essential for space deployable structures to maintain the storage efficiency of the spacecraft. This paper proposes a planar deployable circular structure (DCS) based on the Miura-ori pattern, as well as the design of system parameters and an optimization model for the deploy/fold ratio. In addition, another method for designing curved-surface DCS is proposed that is based on the parallel projection principle. To ensure the structure's foldability and surface accuracy, a mathematical model is established based on the projected vertices on the innermost circle of the target spherical surface. Moreover, suitable numerical design methods for obtaining the vertices of planar and curved-surface DCSs are summarized. Furthermore, the actuation methods for planar and curved-surface deployable structures are presented. The physical prototypes are fabricated, and deployment experiments are conducted to verify the feasibility of the proposed design approach. The novel design of planar and curved-surface DCSs presented in this paper provides a new inspiration for the practical design of deployable space structures.

Influences of space perturbations on robotic assembly process of ultra-large structures

The space assembly of two flexible beams by a dual-arm space robot is a typical assembly scenario to construct ultra-large space structure. Yet, previous studies mainly focused on the assembly of small structures, neglecting the influences of space perturbations. Two models are developed in this research to investigate the effects of space perturbations on the space assembly process of ultra-large space structures. Firstly, a theoretical modelling method is proposed based on quasi-static hypothesis and linear structural mechanics. The theoretical model can be utilized for analytically estimating the transverse and axial distributed forces of the flexible beams, structural vibrations, and the control moments of the space robot. An orbit–attitude–structure coupled simulation model is then established to validate the theoretical model and study the dynamic behaviours more accurately, using absolute nodal coordinate formulation and natural coordinate formulation. Finally, the effects of the attitude angle, orbital radius, and lengths of beams on the dynamic responses during assembly are investigated. Theoretical and simulation results show that the control moments and structural vibration amplitude increase dramatically with the length of the beams. The effects of Coriolis force and gravity gradient must be considered for ultra-large space structures during assembly, otherwise the control moments and structural vibrations would be substantially underestimated. The results are instructive to the assembly strategy design as well as modular component design of ultra-large space structures.

Design and analysis of parabolic membrane crease inspired by origami

Reducing the folding size of antennas, battery panels, and other structures is of great significance for the transportation of spacecraft. At present, the deployed–folded ratio of deployable structures do not satisfy the requirements of space engineering. By analysing the folding process of the flasher type, we established a mathematical model for multi-unit flat membrane folding. The deployed–folded ratio of this folding method can be higher than 70. The correctness of the mathematical model was proven through an origami example. Two folding methods for parabolic membranes were designed based on the folding of a flat membrane. We then established mathematical models of the two parabolic membrane folding methods. The accuracy of the model was verified. The errors of these mathematical models were also analysed and stated. The geometry and motion of the system of flat membrane folding and parabolic membrane folding were studied to reveal the actual folding incompatibility during motion. The models provide a reliable basis for the design of space structures.

Morphing composite cylindrical lattices with enhanced bending stiffness

A key aspect in the design of deployable space structures comprising slender elements such as booms is their deployed bending stiffness. In space, due to zero gravitational loading, a high level of bending stiffness is not required to support neighbouring structures, but instead is desirable to resist vibrations generated by the attitude control system. The morphing composite cylindrical lattice that is under development is a structure with significant potential for deployable applications in space, however, concepts developed so far may lack sufficient bending stiffness. Therefore, current work focuses on developing a method of increasing the lattice bending stiffness, while minimising any increase in both mass and stowed volume. These goals are achieved by using additional composite strips mounted adjacent and concentric to pre-existing strips. These strips are attached using pre-existing fasteners, thus, only increasing the weight of the structure by the mass of the composite strips. A finite element model of the new lattice configuration is developed and validated by comparison to experimental results. For this comparison, three different lattice configurations were manufactured, two lattices with a conventional strip configuration, an eight-strip lattice and a four-strip lattice, and a third using a new lattice configuration developed in this work. In comparison with the eight-strip lattice, the new lattice configuration is 32% less stiff, however it weights 33% less and stows to approximately half the stowed height. Compared to the four-strip lattice, the new configuration weighs 75% more, but it is 281% stiffer while stowing to the same volume. By increasing the deployed bending stiffness, this work makes the morphing cylindrical lattice a more viable candidate for deployable space structures.

Environmental Landscape Design Based on Artificial Intelligence and Digital Space Technology

In order to improve the effect of future environmental landscape design, this study combines artificial intelligence technology and digital space technology to construct an environmental landscape design system. Moreover, this study uses polygons to model external landscape plants instead of modeling the microelement structure of landscape plants and re-polygonize them, which simplifies the model structure of landscape plants and improves computational efficiency. In addition, this study conducts collision detection in the growth of landscape plants to make it more realistic and more efficient and studies and analyzes the digital construction of landscape plants. Finally, after constructing an intelligent system, the effect of the system in this study is verified. Through data analysis, it can be seen that the environmental landscape design system based on artificial intelligence and digital space technology proposed in this study has good digital space structure expression effect and design effect.

Optimum design of space structures using hybrid particle swarm optimization and genetic algorithm

Purpose This paper aims to present a new hybrid algorithm of Particle Swarm Optimization and the Genetic Algorithm (PSOGA) to optimize the space trusses with continuous design variables. The PSOGA is an efficient hybridized algorithm to solve optimization problems. Design/methodology/approach These algorithms have shown outstanding performance in solving optimization problems with continuous variables. The PSO conceptually models the social behavior of birds, in which individual birds exchange information about their position, velocity and fitness. The behavior of a flock is influencing the probability of migration to other regions with high fitness. The GAs procedure is based on the mechanism of natural selection. The present study uses mutation, random selection and reproduction to reach the best genetic algorithm by the operators of natural genetics. Thus, only identical chromosomes or particles can be converged. Findings In this research, using the idea of hybridization PSO and GA algorithms are hybridized and a new meta-heuristic algorithm is developed to minimize the space trusses with continuous design variables. To showing the efficiency and robustness of the new algorithm, several benchmark problems are solved and compared with other researchers. Originality/value The results indicate that the hybrid PSO algorithm improved in both exploration and exploitation. The PSO algorithm can be used to minimize the weight of structural problems under stress and displacement constraints.

Optimization of weight and collapse energy of space structures using the multi-objective modified crow search algorithm

Due to the use of space structures in monumental and significant buildings, providing adequate safety and proper structural performance must always be taken into account. In this study, the geometric and material nonlinear behaviors are directly considered in the design of space structures so that the resulting designs are economical while having appropriate collapse behavior. Weight and collapse energy are considered the objective functions, and the problem is considered as a multi-objective optimization problem. This is the first attempt to combine the weight and collapse energy simultaneously for the optimal design of structures. To solve such problems, two new multi-objective algorithms based on the recently introduced crow search algorithm (CSA) have been proposed. These algorithms are called multi-objective crow search algorithm (MOCSA) and multi-objective modified crow search algorithm (MOMCSA). MOCSA and MOMCSA have similar structures and details, except that the MOCSA generates the new solution as the CSA approach does while generating the new solution in the MOMCSA is modified. The modification of the search vector and the search range is employed as two simple and effective changes in MOMCSA to enhance the exploration and exploitation. To evaluate the proposed algorithms, three space structures were optimized using the proposed algorithms and two well-known algorithms, MOPSO and NSGA-II. The results indicate superiority of MOMCSA to the other algorithms.

An enhanced shuffled Shepherd Optimization Algorithm for optimal design of large-scale space structures

Shuffled Shepherd Optimization Algorithm (SSAO) is a swarm intelligence-based optimizer inspired by the herding behavior of shepherds in nature. SSOA may suffer from some shortcomings, including being trapped in a local optimum and starting from a random population without prior knowledge. This study aims to enhance the performance of the SSOA by incorporating two efficient devices. The first device is utilized from the Opposition-Based Learning (OBL) approach to improve the initialization phase of the algorithm. The second device is incorporated a solution generator in the cyclic body of the SSOA based on the statistical results of the solutions. This feature is the so-called statistically regenerated stepsize. The proposed devices provide a good balance between exploration and exploitation capability of the algorithm and reduce the probability of getting tapped in a local optimum. The viability of the proposed Enhanced Shuffled Shepherd Optimization Algorithm (ESSOA) is demonstrated through three large-scale design examples. ESSOA is compared to the standard SSOA and some other existing metaheuristic algorithms. The optimization results reveal the competence and robustness of the ESSOA for optimal design of the large-scale space structures.

Thermoelastic and vibration response analysis of shape memory alloy reinforced active bimorph composites

In this paper, thermoelastic and free vibration responses of hybrid Shape Memory Alloy (SMA) and E-glass fiber-reinforced composites are investigated using finite element analysis. We consider four composites for analysis and comparison of performances, (1) single layer SMA fiber-reinforced hybrid composite (unimorph SMAHC), (2) a two-layer (cross-ply) SMA fiber-reinforced hybrid composite (bimorph SMAHC), (3) single layer SMA fiber-reinforced with a honeycomb core, and (4) single layer SMA fiber-reinforced with reentrant-honeycomb or auxetic core. We analyze the bending response of all the aforementioned composite structures, focusing on the bimorph anticlastic and synclastic bending with negative and positive Gaussian curvatures, respectively. The uniqueness of this work is utilizing the shape memory effect of the SMA fibers to achieve active shape control of low-stiffness and lightweight auxetic composite structures. We investigated the free vibration response and analyzed the effect of the fiber volume fraction and the fiber orientation angle on the natural frequency of the system. Further, the role of the reentrant angle and stiffness of honeycomb struts on the overall effective mechanical properties of the ply is also studied. Results confirm the non-linearity of the parametric combination and the importance of optimization of these parameters for improved Gaussian curvature. The findings are envisaged to be useful for the design of lightweight rigidizable space structures and tensairity structures.

Computational design and fabrication of highly customizable architectural space frames: Making a flat-cut Weaire-Phelan structure

This paper documents a computational approach to the design, fabrication, and assembly of customizable space structures built entirely out of flat-cut interlocking elements without the need of nodes, fasteners, cement, or glue. Following a Research by Design (RbD) methodology, we establish a framework comprising geometric and parametric modeling, structural analysis, and digital fabrication stages to examine the following research question: how might the modularity of a construction kit be combined with the plasticity of parametric descriptions to facilitate the design and fabrication of flat-cut space structures? We find that an adaptive joint design that resolves local deformations at the node and element levels can facilitate the construction of flat-cut space structures by making modular components responsive to local geometric, material, and mechanical demands. The research centers on the design and construction of an architecture-scale installation based on the Weaire-Phelan structure—an aperiodic space-filling geometric structure that approximates the geometry of foam—entirely out of flat-cut interlocking elements. Documenting the process in technical detail, as well as some limitations, the paper contributes to recent efforts to develop digital materials suitable for architectural applications. In addition, it contributes to extend the formal and architectural possibilities of flat-cut space structure design by facilitating “bottom-up” design explorations in concert with the structure’s tectonic resolution.

Wide Area Reversible Adhesive for In‐Space Assembly

AbstractThe design of future space structures may anticipate a greater need for in‐space assembly due to larger planned space structures and changes in mission profiles over their operational lifetimes. A rapid and reversible adhesive coating over the structure’s surface would allow additional components to be bonded at any arbitrary time in the future. A scalable wide‐area reversible adhesive utilizing a high glass transition thermoset polymer possessing thermally exchangeable bonds can serve as an enabling technology for in‐space assembly. Coatings of aromatic thermosetting copolyesters can be deposited on aluminum and titanium coupons, which bond when heated to 400 °C with the counterpart surfaces under pressure. Reversibility over multiple cycles is shown within a dynamic mechanical analyzer with the limiting constraint being the necessity of nondelaminatory (cohesive) debonding of the bonded coupons. Bonded coupons can sustain a thermal cycle spanning the representative temperatures in low earth orbit under tension with no failure. A localized rapid heating method amenable for in‐space assembly can be used to bond titanium coupons using induction heating with a bonding time of 40 s.

К расчету напряженно-деформированного состояния трансформируемой крупногабаритной космической конструкции

Design and development of transformable large-scale space structures requires thoroughly analysing their operating conditions and existing internal and external forces, as well as determining the stress-strain state of load-bearing frameworks. As a rule, complete fullscale tests of orbital operation of transformable structures is impossible on Earth. This fact means that the problem of developing mathematical models that properly simulate mechanical properties of such structures becomes crucial for their design. These models should allow design computations to be carried out efficiently and various layouts to be analysed. We present our procedure of computing the stress-strain state for load-bearing framework elements using deployment of a 20 m diameter annular antenna as an example. The stress-strain state of the load-bearing frame elements is determined by impact loads generated during deployment when adjacent links are mounted on locking plates. In order to determine these impact loads, we computed framework deployment parameters, calculating the velocities of framework elements at the moments when they come into contact with the locking plates. We then assume the velocities obtained for the transformable load-bearing framework links to be the initial conditions for a finite element model of the structure used to compute its stress-strain state. As a result, the calculations yielded equivalent stresses generated in the load-bearing framework components during deployment.

Construction Process Simulation and In Situ Monitoring of Dendritic Structure on Nanjing Niushou Mountain

For complex structures, where there are great differences between the structural form in the construction process and the design forming state, mechanical analysis of the construction process is required. The dendritic structure on Nanjing Niushou Mountain is taken as an engineering case study, with a narrow construction space, weak construction platform, and difficulty in setting the equipment in the site. A new construction method, self‐balancing elevating scheme, is introduced according to the special condition of the construction field. The lifting frame and the connection joint between the trunk and the branch employed in the self‐balancing elevating scheme are optimized according to the structure’s behavior. A construction monitoring scheme was adopted in this project to ensure construction safety. The maximum cable force and deformation occurred at the beginning of the lifting. The construction process simulation was conducted by space structure design software 3D3S. The analysis results were well consistent with the in situ construction monitoring results. The analysis results show that the self‐balancing elevating scheme could satisfy the construction requirement on the special construction condition and provide reference on future practical application.

Design analysis and experimental verification of vibration reduction of spatial composite damping truss structure

In order to solve the problem that the photoelectric instrument may fail when the vibration response of the truss composite structure is too large, the method of applying the viscoelastic-constrained damping layer on the truss wall and the box panel is used to reduce the vibration of the whole structure. In this article, a broken long tube with viscoelastic-constrained damping layer is introduced. The long tube of the original structure is broken into two identical short tubes, and a tube with free damping layer is added to the junction of the two short pipes, which is connected by adhesive and broken long pipe. By analyzing the frequency response of the traditional space truss and spaceflight load structure, and a broken long tube structure, the acceleration response cloud diagram and the acceleration response curve of the fixed measuring node are obtained. Experiments were carried out to verify the feasibility of the structure. The test results show that the method of broken long pipe with viscoelastic-constrained damping layer can achieve better damping effect than the traditional truss structure, and it can effectively reduce the vibration level of the space load at the end of the truss, and has important reference significant for the vibration reduction design of other space structures.

Dynamic coupling on the design of space structures

For the design of space structures, the dynamic coupling between equipment and the satellite (or between a satellite and the launcher) is usually avoided due to negative effects like high stresses produced by structural resonance. The usual procedure to assure the dynamic decoupling is by limiting the minimum value of natural frequency of the secondary structure to a value high enough above the main natural frequencies of the main structure. However, in some spacecraft configurations, it is unavoidable that some parts or equipment present natural frequencies close to the main natural frequencies of the spacecraft because these parts may be massive or may have a special interface design with low stiffness. This dynamic coupling provokes modifications on the modal behavior of the satellite, which can lead to a significant decrease in the first natural frequency of the entire satellite. To analyze this phenomenon, a representative but simple mathematical model is studied to evaluate the influence of the design parameters of space structures. Analytical expressions are obtained that can help to highlight the influence of the parameters. The results are demonstrated with the example of the UPMSat-2 satellite design.

Comparison study of two criteria for identification of structural dynamic stability

Dynamic stability analyses of structures are becoming increasing prevalent in applications for tall buildings and space structure designs. This paper presents an effective energy criterion for identifying the dynamic stability of generalized structures through the modification of an earlier developed energy criterion for hardening structures. Two time-varying effective energy indices are introduced to account for the dynamic stability of both the hardening and deteriorating structures; one for the description of structural properties, i.e., the structural effective intrinsic energy, and the other for the measurement of the input energy, i.e., the valid external work. It is shown that a structure’s stability can survive provided the effective intrinsic energy is always less than the valid external work during a dynamic excitation. The first passage of the effective intrinsic energy over the valid external work indicates the dynamic instability of the structure. A comparison study is carried out regarding the validity and applicability between the energy and effective energy criteria as applied to the dynamic stability analysis of three different structures.

Study on Seismic Response of Single-layer Cylindrical Reticulated Shell Due to Horizontal One-dimensional Earthquake

A single-layer cylindrical reticulated shell structure model was established by selecting real seismic waves and using ANSYS structural analysis module, and the structural model was subjected to multi-point earthquake input and consistent input time history response calculations. The result shows that in the seismic design of large-span space structures, the traveling wave effect must be considered. When the traveling wave effect is studied, if we only pay attention to the maximum axial force of the structural member, horizontal one-dimensional input can be performed.