Kinematic Synthesis of Deployable-Foldable Truss Structures Using Graph Theory, Part 2: Generation of Deployable Truss Module Design Concepts

1995 ◽  
Vol 117 (1) ◽  
pp. 117-122 ◽  
Author(s):  
D. B. Warnaar ◽  
M. Chew
Keyword(s):  
Graph Theory ◽  
Truss Structures ◽  
Kinematic Synthesis ◽  
Design Concepts ◽  
Module Design

A special type of truss structures, called truss modules, is presented. Graphs of this class of structures form a subset of the graphs that are generated using the approach presented in Part 1. Two procedures are presented that are applied to recognize these graphs among graphs of truss structures. The procedures also generate information on the relative lengths of the links in a truss module by examining the graph it represents. This enables the generation of numerous novel (deployable) truss modules as well as those that have been reported in the literature. Promising alternatives to existing designs are identified.

Kinematic Synthesis of Deployable-Foldable Truss Structures Using Graph Theory, Part 1: Graph Generation

1995 ◽  
Vol 117 (1) ◽  
pp. 112-116 ◽  
Author(s):  
D. B. Warnaar ◽  
M. Chew
Keyword(s):  
Graph Theory ◽  
Conceptual Design ◽  
Design Process ◽  
Degrees Of Freedom ◽  
Truss Structure ◽  
Truss Structures ◽  
Structural Synthesis ◽  
Deployable Structures ◽  
Kinematic Synthesis ◽  
Graph Generation

Kinematic structural synthesis has been relatively successful when applied to the conceptual design of mechanisms. The approach presented in this paper, however, views the design process from an initial standpoint of a truss structure. First, graphs are generated that represent truss structures with a given number of nodes and links. Each graph is then modified by designating certain edges in the graph to represent links in the structure that incorporate additional degrees of freedom. In so doing, the graph of a structure is transformed into one representing a mechanism. A procedure is presented that enables the exhaustive generation of these graphs for deployable structures of any given number of nodes and links. From these graphs, it is then possible to obtain enumerable novel deployable truss structures as well as those that have been reported in the literature.

A Plug-and-Contract Mechanism for a Robust Assessment of Design Concepts

2005 ◽  
Author(s):  
Bernard Yannou ◽  
Roy Awedikian
Keyword(s):  
Design Space ◽  
Truss Structures ◽  
Space Representation ◽  
Design Decision ◽  
Functional Requirements ◽  
Design Concepts ◽  
Design Variables ◽  
Variable Domains ◽  
Parameterized Model ◽  
Relative Potential

Starting from a need and a set of functional requirements (FRs), a designer is often perplexed to assess the potential of a given concept to fit these requirements. He is even more perplexed when several concepts are candidates. This paper proposes a definition of a concept in a practical way as a parameterized model linking a set of design variables (DVs) to a set of performance variables (PVs). This set of PVs is supposed to be the same for any concept candidate to fulfill a need. This is why our model propose to “plug” a card of FRs into candidate concepts in order to lead concurrent reasonings on competing concepts until one or several of them appear to be of poor interest. The plugging mechanism is implemented by constraint programming techniques (evolved interval arithmetics) that immediately contract the performance and design variable domains to provide an outer approximation of the solution (or design) space. Two sets of comparison operators between solution spaces are proposed: operators for comparing the relative potential of two concepts submitted to the same FRs, and operators for comparing two successive stages of solution spaces of a given concept. These last operators provide the way to tackle the robustness of design decision making under uncertainty. All the mentioned features: plugging mechanism, contraction of domains and design space representation, comparison operators and robustness considerations have been experimented on an example of a pair of candidate concepts of truss structures.

Conceptual Configuration Synthesis of Line-Foldable Deployable Space Truss Structures Utilizing Graph Theory and Entropy

2021 ◽  
Author(s):  
Shoufei Wang ◽  
Yong Zhao
Keyword(s):  
Graph Theory ◽  
Graph Model ◽  
Geometric Dimension ◽  
Maximum Clique ◽  
Entropy Change ◽  
Truss Structures ◽  
Space Truss ◽  
Linear Configuration ◽  
Configuration Synthesis ◽  
Necessary And Sufficient

Abstract From the perspective of the truss as a whole, this research presents an approach to synthesizing conceptual configurations for deployable space truss structures that are line-foldable with the help of graph theory and entropy. First, according to graph theory, the bijection between a truss and its graph model is established by defining a bijective mapping between set elements. Therefore, operations can be performed based on graph models. Second, the principle of configuration evolution is interpreted by employing Maxwell’s rule, it also discusses the necessary and sufficient condition of configuration evolution. Configurations of evolution belong to three phases: space configuration, transformation configuration, and linear configuration. And it finds that the reasonable transformation configuration plays a key role. Further, maximum clique detection depending on backtracking is used to screen out unreasonable transformation configurations. Third, it introduces entropy, and the phenomenon of entropy change in configuration evolution is revealed and induction weights of rigid links are defined. It calculates the weight value of a transformation configuration by adding up induction weights of rigid links removed, also, weight values are used to classify transformation configurations. Finally, based on the previous analysis, a procedure to synthesize transformation configurations is formed and it is verified by a truss model with 7 nodes. This research lays the foundation for geometric dimension design and engineering applications.

scholarly journals CALCULATION OF RESIDUAL LIFE OF A BUILDING USING PROBABILISTIC METHODS AND GRAPH THEORY

2020 ◽  
Vol 2 (5) ◽  
pp. 5-12
Author(s):  
M. Shutova ◽  
S. Evtushenko
Keyword(s):  
Graph Theory ◽  
Residual Life ◽  
Technical Condition ◽  
Probabilistic Methods ◽  
Truss Structures ◽  
Complex Method ◽  
Destructive Testing ◽  
Roof Structure ◽  
The City ◽  
Non Destructive

methods and approaches to determining the residual resource of construction objects are considered, methods are analyzed to select the optimal one. To calculate the residual life of structures of the industrial workshop in the city of Saratov, a complex method was applied based on probabilistic methods (for structures whose strength characteristics were determined by non-destructive testing) and using graph theory (for other structures, the technical condition of which was established by external signs ) The established value of the residual resource (time before the onset of an inoperative state) before the reconstruction was 3.8 years, taking into account the operation of structures in the industrial enterprise mode. The residual resource of the building in the mode of the shopping center was 18.1 years, taking into account the reduction in operational loads (there are no crane loads, the roof structure was changed), this resource is insufficient for the object put into operation. In the process of reconstruction, communications, external and internal decoration, improvement of the adjacent territory were restored, truss structures were strengthened, the structures of the coating and external walls were partially replaced. The technical condition of the building was improved, which is reflected in the residual life - 64.7 years, which is more than the design life for buildings of this type. Therefore, a comprehensive calculation of the residual resource is an effective method for determining the scope and types of work on reconstruction and restoration of buildings.

Conceptual configuration design of line-foldable deployable space truss structures employing graph theory

2022 ◽  
pp. 095440622110621
Author(s):  
Shoufei Wang ◽  
Yong Zhao
Keyword(s):  
Graph Theory ◽  
Graph Model ◽  
Geometric Dimension ◽  
Maximum Clique ◽  
Truss Structures ◽  
Configuration Design ◽  
Topological Graph ◽  
Space Truss ◽  
Configuration Synthesis ◽  
Chordless Cycle

From the perspective of the truss as a whole, this research investigates the conceptual configuration design for deployable space truss structures that are line-foldable with the help of graph theory. First, the bijection between a truss and its graph model is established. Therefore, operations can be performed based on graph models. Second, by introducing Maxwell’s rule, maximum clique, and chordless cycle, the principle of conceptual configuration synthesis is analyzed. A corresponding procedure is formed and it is verified by a truss with seven nodes. Third, assisted by some theorems of graph theory, the simplified double-color topological graph of deployable space truss structures is acquired and it also displays the procedure with a case. Finally, based on the above analysis, it obtains the optimal conceptual configurations. This novel research lays the foundation for kinematic synthesis and geometric dimension designs.

Prospects for Application of Ship’s Multi-Module Gas Turbine Engines on the Basis of Ceramic Tunnel Turbomachines

2011 ◽  
Author(s):  
A. V. Sudarev ◽  
A. A. Suryaninov ◽  
V. G. Konakov
Keyword(s):  
Wide Spectrum ◽  
Turbine Engines ◽  
Thermal Engineering ◽  
Gas Turbine Engines ◽  
Design Concepts ◽  
Module Design ◽  
Engine Efficiency ◽  
Innovative Materials ◽  
Notable Increase ◽  
Engineering Parameters

Analysis of thermodynamic and thermal-engineering parameters of GTE for mercantile and naval marines was conducted. A conclusion was made that GTEs designed specially for application under sea conditions have the highest efficiency. This is the 36–37% efficiency for simple cycle GTEs. With application of the complex cycle, a notable increase in the engine efficiency could be attained, particularly, by use of structural ceramics (SCMs) on the basis of innovative materials and some novel technological and design concepts. It permits to raise the engine efficiency up to 50% even with the net power of 300–500 kW. Results of numerical calculations for single unit and thirty two module GTEs demonstrated as follows. With the same baseline conditions, a multi-module unit has the volume which is more than twice less and the mass more than five times lower. Though when the number of GTE modules still further increases, decreasing of the turbomachine efficiency becomes a negative factor. To compensate it, it is required to increase the air heater regeneration ratio, to apply helical-channel turbomachines made of heat resistant SCMs, etc. Advantages of multi-module GTEs are evident. Thus, the mean efficiency of a machine during its lifetime increases. The handling independency increases, too. A need in outages to repair machines is eliminated. The control, governing and protection systems become simpler. The fire- and explosion safety increases. In fact, all the designing procedure now reduces to identification of the module number under conditions specified and within a space targeted. As opposed to a conventional ship’s GTE design with the engine having only a single electric net power generator, the multi-module design allows a fast implementation of the entire wide spectrum of operation duties required.

High resolution at low voltage: A new approach

1989 ◽  
Vol 47 ◽  
pp. 76-77
Author(s):  
Arthur V. Jones
Keyword(s):  
Low Voltage ◽  
Emission Sources ◽  
New Approach ◽  
Design Concepts ◽  
Probe Diameter ◽  
Low Voltage Operation ◽  
Sufficient Intensity ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Immersion Type

With the introduction of field-emission sources and “immersion-type” objective lenses, the resolution obtainable with modern scanning electron microscopes is approaching that obtainable in STEM and TEM-but only with specific types of specimens. Bulk specimens still suffer from the restrictions imposed by internal scattering and the need to be conducting. Advances in coating techniques have largely overcome these problems but for a sizeable body of specimens, the restrictions imposed by coating are unacceptable.For such specimens, low voltage operation, with its low beam penetration and freedom from charging artifacts, is the method of choice.Unfortunately the technical dificulties in producing an electron beam sufficiently small and of sufficient intensity are considerably greater at low beam energies — so much so that a radical reevaluation of convential design concepts is needed.The probe diameter is usually given by

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