The Imperfection Sensitivity of Sheet Space Structure Based on the Contact Interactive

2012 ◽  
Vol 204-208 ◽  
pp. 1260-1266
Author(s):  
Tian Jiao Jin ◽  
Xiao Ming Guo ◽  
Wei Sun
Keyword(s):  
Critical Load ◽  
Space Structure ◽  
Space Structures ◽  
Imperfection Sensitivity ◽  
Distribution Law ◽  
Sample Number ◽  
Key Issues ◽  
Initial Geometric Imperfections ◽  
The Stability ◽  
Quantitative Indicators

The initial geometric imperfections and the contact problem between sheets and skeletons are two key issues of the stability analysis of sheet space structures. In this paper ,the distribution law of the critical load is found out, the appropriate sample number and the critical load value formula are chosen for stochastic imperfection method, while the value of probability reliability is ensured. The results of contact model and fully coordinated model are compared to indicate that the effect of contact must be considered in the imperfection sensitive analysis of the structure after stochastic imperfection sensitivity analysis of sheet space structures. The paper also raises the quantitative indicators to characterize the imperfection sensitivity of sheet space structure, and it is the necessary preparation to quantify the sensitivity of structures.

The Stochastic Imperfection Method of Sheet Space Structure Based on Truncated Univariate Normal Distributions

2014 ◽  
Vol 937 ◽  
pp. 707-711
Author(s):  
Tian Jiao Jin ◽  
Xiao Ming Guo
Keyword(s):  
Space Structure ◽  
Acceptance Rate ◽  
Space Structures ◽  
Design Code ◽  
Geometric Imperfections ◽  
Spherical Coordinate ◽  
Normal Distributions ◽  
Truncated Normal ◽  
Initial Geometric Imperfections ◽  
The Stability

The initial geometric imperfections is a key issue of the stability analysis of sheet space structures. A new described method of the initial geometric imperfections which is located in local spherical coordinate system is given, and the random imperfection variable is assumed to follow a truncated univariate normal distribution (TUVN). A well working envelope function for TUVN is chosen, and the acceptance rate is high for constrained region of the design code. The method provided in the paper is called spherical truncated normal stochastic imperfection method (STNS). The results of consistent mode imperfections method, traditional stochastic imperfection method and STNS method are compared, by which some conclusions that are useful for the design and the study of sheet space structures are obtained.

Empirical Formula Considering the Smoke Ventilation for Air Temperature in Large Space Structure under Fire

2011 ◽  
Vol 94-96 ◽  
pp. 587-593 ◽  
Author(s):  
Jin Liang ◽  
Su Duo Xue ◽  
Xiong Yan Li
Keyword(s):  
Air Temperature ◽  
Empirical Formula ◽  
Steel Structures ◽  
Space Structure ◽  
Space Structures ◽  
Large Space ◽  
Fire Temperature ◽  
Large Space Structure ◽  
Fire Smoke ◽  
Resistance Performance

Abstract.The fire smoke is one of the most important factors for the fire temperature field. Once the fire smoke has been exhausted effectively, the fire temperature will be reduced and the fire-resistance performance of steel structures may be improved as well. However, the research on the fire temperature in the space structures is almost bold, which could lead to the theoretical analysis result on fire temperature is quite different from the real condition. Accordingly, the air temperature condition on fire for large-space structures has been analyzed. Taken into account smoke ventilation, the empirical formula for air temperature in large space structure under fire has been modified.

scholarly journals ASSESSING THE SAFETY OF EXISTING STRUCTURES: RELIABILITY BASED ASSESSMENT FRAMEWORK, EXAMPLES AND APPLICATION

2004 ◽  
Vol 10 (2) ◽  
pp. 131-141
Author(s):  
Luc Schueremans ◽  
Dionys Van Gemert
Keyword(s):  
Assessment Framework ◽  
City Wall ◽  
Existing Structures ◽  
Surface Splines ◽  
Model Response ◽  
Low Degree ◽  
Key Issues ◽  
Reliability Methods ◽  
Reliability Algorithms ◽  
The Stability

Safety, reliability and risk are key issues in the preservation of our built, cultural heritage. Several structural collapses make us aware of the vulnerability of our technical and natural environment and demand an adequate engineering response. In the analysis phase, an objective way to assess the safety of the structure is essential. The present raises the need for a reliability based assessment framework for existing masonry structures. Although this field of research is relatively young, different techniques have been proposed and optimised. These permit to calculate the global probability of failure of complex structures, relying on deterministic techniques able to calculate the stability state for a prescribed set of parameters. This paper illustrates how these techniques can be a valid tool to evaluate the bearing capacity of existing structures. Focus is on reliability methods based on simulation procedures (Monte Carlo, Directional Sampling), combined with an adaptive meta‐model (Response Surface, Splines, Neural Networks). Several benchmark examples demonstrate the applicability of the methodology. The mutual efficiency of the different reliability algorithms is discussed. The application focuses on the assessment of an existing masonry structure. The overall stability of a Romanesque city wall of Leuven (B) is studied in detail. The analysis treats the present safety of the city wall, regarding the uncertainties in load, geometry and resistance. Because of the low degree of safety of several parts of the wall, consolidation measures and strengthening techniques are proposed.

scholarly journals Mathematical modeling of transformable space structure dynamics

2019 ◽  
Vol 221 ◽  
pp. 01018 ◽  
Author(s):  
Vladimir Zimin ◽  
Alexey Krylov ◽  
Sergey Churilin ◽  
Zikun Zhang
Keyword(s):  
Strain State ◽  
Element Model ◽  
Space Structure ◽  
Space Structures ◽  
Elastic Rod ◽  
Stress Strain ◽  
Large Space ◽  
Structure Dynamics ◽  
Stress Strain State ◽  
Large Space Structure

Today large space structures are in focus of attention of engineers and designers of rocket and space equipment. In ground-based experiments, it is not always possible to carry out complex tests of large space structure functionality. Therefore, the development of mathematical models describing properly the transformable structure dynamics when they opened from the densely packed transport state to the operating position in the orbit becomes very important. To determine the stress-strain state of the frame elements when it is unfolding the shape of the framework is taken at the moments when relative velocities of the adjacent sections are maximal. Supposed, that at these moments the frame elements are getting on the stops limiting their relative angular displacements, and the structure behaves as an elastic rod with specified characteristics. Numerical analysis of the stress-strain state in the framework is carried out by means of a finite element model. Therefore, the represented mathematical model can be effectively used to predict the functional suitability of such transformable space structures already on the early stages of their development.

scholarly journals The convergence-theoretic approach to weakly first countable spaces and symmetrizable spaces

2019 ◽  
Vol 69 (1) ◽  
pp. 185-198
Author(s):  
Fadoua Chigr ◽  
Frédéric Mynard
Keyword(s):  
Space Structures ◽  
Theoretic Approach ◽  
Hausdorff Spaces ◽  
Sequential Space ◽  
Countable Space ◽  
The Stability ◽  
First Countable Space ◽  
Algebraic Proofs ◽  
Non Hausdorff Spaces

AbstractThis article fits in the context of the approach to topological problems in terms of the underlying convergence space structures, and serves as yet another illustration of the power of the method. More specifically, we spell out convergence-theoretic characterizations of the notions of weak base, weakly first-countable space, semi-metrizable space, and symmetrizable spaces. With the help of the already established similar characterizations of the notions of Frchet-Ursyohn, sequential, and accessibility spaces, we give a simple algebraic proof of a classical result regarding when a symmetrizable (respectively, weakly first-countable, respectively sequential) space is semi-metrizable (respectively first-countable, respectively Fréchet) that clarifies the situation for non-Hausdorff spaces. Using additionally known results on the commutation of the topologizer with product, we obtain simple algebraic proofs of various results of Y. Tanaka on the stability under product of symmetrizability and weak first-countability, and we obtain the same way a new characterization of spaces whose product with every metrizable topology is weakly first-countable, respectively symmetrizable.

scholarly journals Study of the inhibitory ability of inorganic di- and polyphosphate compositions

2020 ◽  
Vol 315 ◽  
pp. 04002
Author(s):  
Aktoty Niyazbekova ◽  
Timur Shakirov ◽  
Mayra Almagambetova
Keyword(s):  
Experimental Data ◽  
Kinetic Data ◽  
Research Work ◽  
Corrosion Process ◽  
Degree Of Protection ◽  
Inhibitory Ability ◽  
Depth Index ◽  
Corrosion Deposits ◽  
The Stability ◽  
Quantitative Indicators

The article considers the anticorrosive properties of inorganic di-and polyphosphate compositions in relation to St-3 steel, depending on the pH of the medium, the nature and concentration of phosphate, and the nature of the modifier ion. The research was conducted using GOST-based methods: gravimetry, potentiometry, photocolorimetry, infrared spectroscopy and scanning electron microscopy. On the basis of experimental data, quantitative indicators of corrosion process were determined: the rate of corrosion process, the degree of protection, the depth index, the coefficient of inhibition and the assessment of the stability of the formed film on the ball scale of corrosion resistance against steel. The analysis of experimental data allows to establish the influence of the above factors on the corrosion processes in the systems under study. The experimental data are supplemented by thermodynamic calculations of the corrosion process parameters, the results of which correlate well with the kinetic data of the process under study. In the course of the research work, the analysis of corrosion deposits was also carried out. The regularities established during the work contribute to the creation of effective di-and polyphosphate inhibitors with the highest degrees of protection.

Quantum Chemical Simulation of Relaxation and Thermally Stimulated Processes: a Vibration Excitation-relaxation Stochastic Optimization

2005 ◽  
Vol 60 (11-12) ◽  
pp. 797-804 ◽  
Author(s):  
Volodymyr D. Khavryuchenko ◽  
Oleksiy V. Khavryuchenko ◽  
Vladyslav V. Lisnyak
Keyword(s):  
Stochastic Optimization ◽  
Inelastic Neutron Scattering ◽  
Optimization Method ◽  
Inelastic Neutron ◽  
Space Structure ◽  
Space Structures ◽  
Vibration Excitation ◽  
Scattering Spectra ◽  
Chemical Simulation ◽  
Probable Space

A new method for theoretical examination of thermal inter-conversions via the space structure vibration excitation-relaxation stochastic optimization method has been proposed. The software to perform implementation of the methodology has been developed and tested on a silica 27SiO2 cluster. A set of thermodynamically probable space structures of amorphous silica particles and temperatures of their inter-conversions has been simulated. The simulated space structures have been verified by comparison of calculated inelastic neutron scattering spectra of different highly dispersed silicas with experimental ones.

Semi-Rigid Connection in Timber Structure: Stiffness Reduction and Instability Interaction

2020 ◽  
Vol 20 (07) ◽  
pp. 2050072 ◽  
Author(s):  
A. Manuello
Keyword(s):  
Joint Stiffness ◽  
Structural Response ◽  
Actual Condition ◽  
Space Structures ◽  
Beam Elements ◽  
Stiffness Reduction ◽  
Rigid Connection ◽  
Geometrical Imperfections ◽  
The Stability ◽  
Rigid Joints

Latticed shells and domes usually consist of hundreds, sometimes thousands, beam elements connected by rigid or semi-rigid joints. These connecting elements result, generally, very sophisticated, made with different materials and constituted by disparate connection systems. Recently, the stiffness connections were studied, numerically and experimentally, as one of the most important factors influencing significantly the structural response of space structures and domes. Very often, in the design process, the joints are assumed to be hinged or clamped. This assumption may result significantly far from the actual condition of in-service structure and components, leading to not understanding or not being able to prevent sudden catastrophic collapses (buckling, snap-through). Thus, the inclusion of joint stiffness reduction in the numerical model is necessary, more and more also due to the types of external loads, such as overloads that occur during the life of the structure or, especially, seismic solicitations. In this paper, the stability of an existent timber dome has been studied increasing the yieldingness of the connecting nodes according to an original approach. In addition, sensitivity of this kind of structure to the amplitude and the geometrical imperfections shape have been also considered. Numerical analyses have been conducted with local displacement controls, to take into account the geometric nonlinearity effects. Results evidenced that the dome is affected by instability interaction for particular slenderness and stiffness reduction of the connections.

Research on novel spatial structure of power generation of spherical robot

2020 ◽  
Vol 234 (6) ◽  
pp. 600-612
Author(s):  
Yuyi Zhai ◽  
Zihang Ding ◽  
Yunjia Liu ◽  
Shaohua Jin ◽  
Liang Kang
Keyword(s):  
Power Generation ◽  
Space Structure ◽  
Induced Voltage ◽  
Spherical Robot ◽  
Energy Harvesters ◽  
Long Time ◽  
The Stability ◽  
The One ◽  
Spherical Mobile Robot ◽  
Pipeline Model

Continuous energy supply is essential to spherical mobile robot in the Antarctic investigation. This paper puts forward energy harvesters that can generate electricity from the wind to achieve the long time and the long range exploration. The major contribution is to present the preliminary models of the energy harvester which uses the law of electromagnetic induction, and meanwhile the spatial structures about generating electricity are analyzed, and the influence of different structures on the power generation and efficiency will be obtained. In order to get the characteristics of power generation efficiency, this paper designs one element pipeline model and two element pipeline model, and then the motion of magnet in harvester will be simulated in different installed structures and wind speed. The varying rules of induced voltage are concluded at last. Finally, experiments are implemented based on the simulated model. The experimental results verify the dependability of different structural schemes of the robot and the validity of induced voltages’ varying rules. The results show that the induced electromotive force value obtained by the one element pipeline structure model is larger than the two element pipeline model, but the stability of the latter is better. Through the research in this paper, it can provide a basis for selecting a suitable spherical robot space structure according to the environmental conditions to improve the endurance.

VIBRATION CHARACTERISTICS SIMULATION OF WRINKLED CIRCULAR ANNULUS-SHAPED GOSSAMER SPACE STRUCTURE

2008 ◽  
Vol 05 (01) ◽  
pp. 189-198 ◽  
Author(s):  
CHANGGUO WANG ◽  
XINGWEN DU ◽  
XIAODONG HE ◽  
GUOZHI SONG
Keyword(s):  
Structural Design ◽  
Membrane Structure ◽  
Space Structure ◽  
Vibration Characteristics ◽  
Structural Vibration ◽  
Space Structures ◽  
Deformation State ◽  
Wrinkling Analysis ◽  
Wrinkled Membrane ◽  
And Control

Ultra-lightweight Gossamer space structures have received the wide attention due to their small packaging volume and low launching cost. Since wrinkles are a common deformation state and the main failure mode of such structures and vibration behaviors are the major factor of the structural design and control, a better understanding of the wrinkling characteristics and the vibration behaviors of the wrinkled membrane structure is thus very essential and desirable. In this paper, a modal analysis method incorporating the wrinkling analysis is presented to simulate the vibration characteristics of a wrinkled membrane structure. The effects of the wrinkles on the structural vibration behaviors are also summarized in detail in the end.

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