scholarly journals A highly efficient user-defined finite element for load distribution analysis of large-scale bolted composite structures

2011 ◽  
Author(s):  
P.J. Gray ◽  
C.T. McCarthy
Keyword(s):  
Finite Element ◽  
Load Distribution ◽  
Composite Structures ◽  
Large Scale ◽  
Distribution Analysis ◽  
Highly Efficient

Temperature Distribution Analysis in Plates Joined by Friction Stir Welding

2009 ◽  
Author(s):  
Mauricio Rangel Pacheco ◽  
Jean Paul Kabche ◽  
Ivan Thesi ◽  
Fabiano Nunes Diesel
Keyword(s):  
Finite Element ◽  
Friction Stir Welding ◽  
Temperature Distribution ◽  
Large Scale ◽  
Heat Dissipation ◽  
Welding Process ◽  
Experimental Investigations ◽  
Welding Parameters ◽  
Distribution Analysis ◽  
Friction Stir

Friction Stir Welding (FSW) is a solid-state welding process which generates heat through mechanical friction between a moving workpiece and a fixed component, in order to plastically combine materials. This process has been gaining considerable attention due to several key advantages, which include: good mechanical properties of the combined materials after welding, absence of toxic fumes and molten material spatter, low environmental impact, and low concentration of defects while allowing a large variation of parameters and materials. Although a reasonable number of experimental investigations on FSW are available in the literature, numerical modeling of this process has not been performed on a large scale. In that light, this paper presents a numerical investigation of the temperature distribution in plates welded by FSW, using finite element analysis. The finite element model developed includes friction between the workpiece and the fixed component, as well as the corresponding heat dissipation that results from plastic deformation of the material. The model was found appropriate for estimating important welding characteristics, such as the heat-affected zone (HAZ), and their sensitivity to various welding parameters.

scholarly journals Research Progress on High-Intermediate Frequency Extension Methods of SEA

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Jintao Su ◽  
Ling Zheng ◽  
Zhaoxiang Deng ◽  
Yuhan Jiang
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Energy Analysis ◽  
Intermediate Frequency ◽  
Basic Theory ◽  
Research Progress ◽  
Distribution Analysis ◽  
Statistical Energy Analysis ◽  
Variable Response ◽  
Interval Variable

Statistical energy analysis (SEA) can accurately describe the average vibration characteristics through system energy flow and transmission feedback. It is a powerful tool to solve the problem of high-frequency acoustics-vibration. SEA is widely used in vehicles, ships, aviation, and other transportation engineering fields. However, the expansion of SEA, based on the assumption of modal equipartition and weak coupling, is limited to the intermediate frequency. Although the SEA basic theory can be extended by relaxing the hypothesis conditions or the analysis of the medium-frequency acoustics-vibration can be carried out using the finite element method (FEM) and SEA mixing method, there are still many challenges associated with these options. To improve the basic theory of SEA and knowledge of intermediate frequency extension methods, as well as attract the attention of domestic scholars, this paper describes classical SEA and intermediate frequency extension methods. First, coupling loss factor (CLF) error propagation and parameter acquisition in classical SEA are introduced, and the three relative error calculation methods of CLF are compared. Then, the method of obtaining parameters is described from three aspects of energy transfer, input load, and modal density. Second, SEA intermediate frequency extension technology (experimental statistical energy analysis (ESEA), finite element statistical energy analysis (FE-SEA), statistical modal energy distribution analysis (SMEDA), and waveguide analysis (WGA)) are introduced. Neutron structure assembly and modeling, interval and mixed interval analysis, interval variable and mixed interval variable response are also described, so as to justify the development of a hybrid, large-scale interval algorithm. Finally, the engineering application of the above method is introduced, the limitations and shortcomings of SEA and intermediate frequency extension methods are reviewed, and unsolved problems are further discussed.

Design of Lightweight Composite Structures: A Parameter Free Structural Optimization Approach

2012 ◽  
Vol 504-506 ◽  
pp. 1391-1396
Author(s):  
Michael Fischer ◽  
Helmut Masching ◽  
Matthias Firl ◽  
Kai Uwe Bletzinger
Keyword(s):  
Finite Element ◽  
Structural Optimization ◽  
Industrial Application ◽  
Composite Structures ◽  
Large Scale ◽  
Finite Element Models ◽  
Optimization Approach ◽  
Geometrically Nonlinear ◽  
Gradient Based ◽  
Algorithmic Techniques

This contribution presents computational concepts and algorithmic techniques for simulation and gradient-based optimization of geometrically nonlinear and large-scale finite element models of composite structures. Several industrial application examples illustrate the methods, show the applicability to large problems, and prove the high parallel efficiency.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

Behaviour of Axially Loaded Composite Wall Panel by Using Finite Element Analysis

2015 ◽  
Vol 815 ◽  
pp. 49-53
Author(s):  
Nur Fitriah Isa ◽  
Mohd Zulham Affandi Mohd Zahid ◽  
Liyana Ahmad Sofri ◽  
Norrazman Zaiha Zainol ◽  
Muhammad Azizi Azizan ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Composite Structures ◽  
Element Analysis ◽  
Steel Sheets ◽  
Linear Behavior ◽  
Non Linear ◽  
Composite Wall ◽  
Experimental Values ◽  
Civil Engineering Infrastructure

In order to promote the efficient use of composite materials in civil engineering infrastructure, effort is being directed at the development of design criteria for composite structures. Insofar as design with regard to behavior is concerned, it is well known that a key step is to investigate the influence of geometric differences on the non-linear behavior of the panels. One possible approach is to use the validated numerical model based on the non-linear finite element analysis (FEA). The validation of the composite panel’s element using Trim-deck and Span-deck steel sheets under axial load shows that the present results have very good agreement with experimental references. The developed finite element (FE) models are found to reasonably simulate load-displacement response, stress condition, giving percentage of differences below than 15% compared to the experimental values. Trim-deck design provides better axial resistance than Span-deck. More concrete in between due to larger area of contact is the factor that contributes to its resistance.

scholarly journals Stator Non-Uniform Radial Ventilation Design Methodology for a 15 MW Turbo-Synchronous Generator Based on Single Ventilation Duct Subsystem

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2760
Author(s):  
Ruiye Li ◽  
Peng Cheng ◽  
Hai Lan ◽  
Weili Li ◽  
David Gerada ◽  
...  
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Design Methodology ◽  
Large Scale ◽  
Synchronous Generator ◽  
Axial Direction ◽  
Scale Model ◽  
Element Analysis ◽  
Axial Temperature ◽  
Ventilation Duct

Within large turboalternators, the excessive local temperatures and spatially distributed temperature differences can accelerate the deterioration of electrical insulation as well as lead to deformation of components, which may cause major machine malfunctions. In order to homogenise the stator axial temperature distribution whilst reducing the maximum stator temperature, this paper presents a novel non-uniform radial ventilation ducts design methodology. To reduce the huge computational costs resulting from the large-scale model, the stator is decomposed into several single ventilation duct subsystems (SVDSs) along the axial direction, with each SVDS connected in series with the medium of the air gap flow rate. The calculation of electromagnetic and thermal performances within SVDS are completed by finite element method (FEM) and computational fluid dynamics (CFD), respectively. To improve the optimization efficiency, the radial basis function neural network (RBFNN) model is employed to approximate the finite element analysis, while the novel isometric sampling method (ISM) is designed to trade off the cost and accuracy of the process. It is found that the proposed methodology can provide optimal design schemes of SVDS with uniform axial temperature distribution, and the needed computation cost is markedly reduced. Finally, results based on a 15 MW turboalternator show that the peak temperature can be reduced by 7.3 ∘C (6.4%). The proposed methodology can be applied for the design and optimisation of electromagnetic-thermal coupling of other electrical machines with long axial dimensions.

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