Decomposition-Based Assembly Synthesis of Space Frame Structures Using Joint Library

2004 ◽  
Vol 128 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Naesung Lyu ◽  
Kazuhiro Saitou
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Structural Characteristics ◽  
Finite Element Analyses ◽  
Space Frame ◽  
Passenger Vehicles ◽  
Joint Location ◽  
The Cross

This paper presents a method for identifying the optimal designs of components and joints in the space frame body structures of passenger vehicles considering structural characteristics, manufacturability, and assembleability. Dissimilar to our previous work based on graph decomposition, the problem is posed as a simultaneous determination of the locations and types of joints in a structure and the cross sections of the joined structural frames, selected from a predefined joint library. The joint library is a set of joint designs containing the geometry of the feasible joints at each potential joint location and the cross sections of the joined frames, associated with their structural characteristics as equivalent torsional springs obtained from the finite element analyses of the detailed joint geometry. Structural characteristics of the entire structure are evaluated by finite element analyses of a beam-spring model constructed from the selected joints and joined frames. Manufacturability and assembleability are evaluated as the manufacturing and assembly costs estimated from the geometry of the components and joints, respectively. The optimization problem is solved by a multiobjective genetic algorithm using a direct crossover. A case study on an aluminum space frame of a midsize passenger vehicle is discussed.

Decomposition-Based Assembly Synthesis of Space Frame Structures Using Joint Library

2004 ◽  
Author(s):  
Naesung Lyu ◽  
Kazuhiro Saitou
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Structural Characteristics ◽  
Finite Element Analyses ◽  
Space Frame ◽  
Multi Objective Genetic Algorithm ◽  
Joint Location ◽  
The Cross

This paper presents a method for identifying the optimal designs of components and joints in the space frame body structures of passenger vehicles considering structural characteristics, manufacturability and assembleability. Dissimilar to our previous work based on graph decomposition, the problem is posed as a simultaneous determination of the locations and types of joints in a structure and the cross sections of the joined structural frames, selected from a predefined joint library. The joint library is a set of joint designs containing the geometry of the feasible joints at each potential joint location and the cross sections of the joined frames, associated with their structural characteristics as equivalent torsional springs obtained from the finite element analyses of the detailed joint geometry. Structural characteristics of the entire structure are evaluated by finite element analyses of a beam-spring model constructed from the selected joints and joined frames. Manufacturability and assembleability are evaluated as the manufacturing and assembly costs estimated from the geometry of the components and joints, respectively. The optimization problem is solved by a multi-objective genetic algorithm using a direct crossover. A case study on an aluminum space frame (ASF) of a middle size passenger vehicle is discussed.

Use of DNVGL-RP-C203 for Determining the Fatigue Capacity of Connectors

2021 ◽  
Author(s):  
Anthony Muff ◽  
Anders Wormsen ◽  
Torfinn Hørte ◽  
Arne Fjeldstad ◽  
Per Osen ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Testing ◽  
Experimental Testing ◽  
High Strength ◽  
Element Model ◽  
Fatigue Analysis ◽  
Full Scale ◽  
The Finite Element Model

Abstract Guidance for determining a S-N based fatigue capacity (safe life design) for preloaded connectors is included in Section 5.4 of the 2019 edition of DNVGL-RP-C203 (C203-2019). This section includes guidance on the finite element model representation, finite element based fatigue analysis and determination of the connector design fatigue capacity by use of one of the following methods: Method 1 by FEA based fatigue analysis, Method 2 by FEA based fatigue analysis and experimental testing and Method 3 by full-scale connector fatigue testing. The FEA based fatigue analysis makes use of Appendix D.2 in C203-2019 (“S-N curves for high strength steel applications for subsea”). Practical use of Section 5.4 is illustrated with a case study of a fatigue tested wellhead profile connector segment test. Further developments of Section 5.4 of C203-2019 are proposed. This included acceptance criteria for use of a segment test to validate the FEA based fatigue analysis of a full-scale preloaded connector.

The determination of the cross sections for the reactions 27 Al( n , α ) and 56 Fe( n , p ) for 14 MeV neutrons by an absolute method

1966 ◽  
Vol 292 (1429) ◽  
pp. 180-192 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Standard Error ◽  
Particle Method ◽  
Systematic Errors ◽  
Aluminium Foil ◽  
The Mean ◽  
The Cross ◽  
Experimental Values

Measurements of the cross sections for the reactions 27 Al( n , α ) 24 Na and 56 Fe( n, p ) 56 Mn for neutrons of energy 13.5 ± 0.1 MeV have been made by a radioactivation method. The neutron flux was determined by a variant of the 'associated particle’ method, in which the α -particles produced concurrently with the neutrons from the D + T reaction were estimated in terms of the volume of helium which accumulated when they were brought to rest in an aluminium foil. Cross section values obtained at 13.5 MeV were: for 27 Al( n , α ): 118.1 ± 6.0 mb : for 56 Fe( n, p ): 106.7 ± 4.7 mb. The errors quoted include both the standard error on the mean of the experimental values and an estimate of possible residual systematic errors. The excitation functions for both reactions in the energy region 13.5 to 14.8 MeV have also been investigated, in order to provide secondary cross section values over this range of energies. At 14.8 MeV the values found were: 27 Al( n , α )103.6 ± 5.5 mb; 56 Fe( n, p )96.7 ± 4.5 mb.

scholarly journals Determination of the cross sections for the production of fragments from relativistic nucleus-nucleus interactions. II. Parametric fits

1990 ◽  
Vol 42 (6) ◽  
pp. 2530-2545 ◽  
Author(s):  
J. R. Cummings ◽  
W. R. Binns ◽  
T. L. Garrard ◽  
M. H. Israel ◽  
J. Klarmann ◽  
...  
Keyword(s):  
Cross Sections ◽  
Relativistic Nucleus ◽  
The Cross

Constraint Solutions for Cracked Plates and Cylinders

2016 ◽  
Author(s):  
Caroline Meek ◽  
Marius Gintalas ◽  
Andrew H. Sherry ◽  
Robert A. Ainsworth
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Biaxial Loading ◽  
Analytical Determination ◽  
Plastic Collapse ◽  
Finite Element Analyses ◽  
Elastic Plastic ◽  
Cracked Plates ◽  
Computing Effort

There is little advice in fitness for service procedures for assessing constraint parameters T (elastic) and Q (elastic plastic) for biaxially loaded plates and cylinders. This paper presents the analytical determination of T stresses for biaxially loaded plates and the determination of Q for plates and cylinders using finite element analyses. It demonstrates the extent to which T can be used to conservatively predict Q and how, near collapse, Q can be estimated from the stress field corresponding to plastic collapse, enabling a significant reduction in computing effort. The effect of biaxial loading of plates and cylinders on these parameters is discussed as well as the differences found when comparing the values for plates and cylinders.

Industrial Application of the Method “Early Determination of Product Properties”

1998 ◽  
Author(s):  
Udo Lindemann ◽  
Ralf Stetter
Keyword(s):  
Finite Element ◽  
Product Development ◽  
Development Process ◽  
Product Development Process ◽  
Complex Method ◽  
Finite Element Analyses ◽  
Negative Effects ◽  
Influencing Parameters ◽  
Industrial Company

Abstract Nothing is more critical for the success of a project than a design flaw that remains undetected until the product is in production or even handed over to the customer. In order to prevent the negative effects of undetected flaws, the method “early determination of product properties” has been developed at the Chair of Design at the Technische Universität München. In this paper the introduction of the method in a mid-size industrial company and the first resulting tool, the Parameter Checklist, are described. The presented research started with a detailed analysis of the product development process in the industrial company. In order to introduce a complex method in an industrial company, many aspects of the situation of the designers, from existing tools and procedures to the designers’ capabilities have to be considered. Because of this, the method was divided into distinct ideas, stages and tools, and compared individually to the situation given. On this basis a first methodical tool was developed, intended to support designers while using the method. The tool called Parameter Checklist supports designers in planning analyses (e.g. tests with physical prototypes, finite element analyses) and in interpreting the results of these analyses. Furthermore, by using the tool, a database is filled that provides enough information to reconstruct the described analyses. In contrast with conventional testing instructions, the Parameter Checklist contains an explicit description of the model, in some respects found to be important, and a list of the influencing parameters. This is the basis for both a simple but conscious form of analysis planning and a more thorough interpretation of the analysis results.

Optimal Subassembly Partitioning of Space Frame Structures for In-Process Dimensional Adjustability and Stiffness

2005 ◽  
Vol 128 (3) ◽  
pp. 527-535 ◽  
Author(s):  
Naesung Lyu ◽  
Byungwoo Lee ◽  
Kazuhiro Saitou
Keyword(s):  
Cross Sections ◽  
Optimization Problem ◽  
Vehicle Body ◽  
Structural Stiffness ◽  
Unified Framework ◽  
Space Frame ◽  
Critical Dimensions ◽  
Optimization Routine ◽  
The Given

A method for optimally synthesizing multicomponent structural assemblies of an aluminum space frame (ASF) vehicle body is presented, which simultaneously considers structural stiffness, manufacturing and assembly costs and dimensional integrity under a unified framework based on joint libraries. The optimization problem is posed as a simultaneous determination of the location and feasible types of joints in a structure selected from the predefined joint libraries, combined with the size optimization for the cross sections of the joined structural frames. The structural stiffness is evaluated by finite element analyses of a beam-spring model modeling the joints and joined frames. Manufacturing and assembly costs are estimated based on the geometries of the components and joints. Dissimilar to the enumerative approach in our previous work, dimensional integrity of a candidate assembly is evaluated as the adjustability of the given critical dimensions, using an internal optimization routine that finds the optimal subassembly partitioning of an assembly for in-process adjustability. The optimization problem is solved by a multiobjective genetic algorithm. An example on an ASF of the midsize passenger vehicle is presented, where the representative designs in the Pareto set are examined with respect to the three design objectives.

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