scholarly journals Model refinements of transformers via a subproblem finite element method

2017 ◽  
Vol 36 (1) ◽  
pp. 309-319 ◽  
Author(s):  
Patrick Dular ◽  
Patrick Kuo-Peng ◽  
Mauricio Valencia Ferreira da Luz ◽  
Laurent Krahenbuhl
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Local Fields ◽  
Fe Method ◽  
Content Type ◽  
Flux Tubes ◽  
Magnetic Cores ◽  
Complex Models ◽  
Three Dimensional Models ◽  
Correction Step

Purpose This paper aims to develop a methodology for progressive finite element (FE) modeling of transformers, from simple to complex models of both magnetic cores and windings. Design/methodology/approach The progressive modeling of transformers is performed via a subproblem (SP) FE method. A complete problem is split into SPs with different adapted overlapping meshes. Model refinements are performed from ideal to real flux tubes, one-dimensional to two-dimensional to three-dimensional models, linear to nonlinear materials, perfect to real materials, single wire to volume conductor windings and homogenized to fine models of cores and coils, with any coupling of these changes. Findings The proposed unified procedure efficiently feeds each SP via interface conditions (ICs), which lightens mesh-to-mesh sources transfers and quantifies the gain given by each refinement on both local fields and global quantities, with a clear view on its significance to justify its usefulness, if any. It can also help in education with a progressive understanding of the various aspects of transformer designs. Originality/value Models of different accuracy levels are sequenced with successive additive corrections supported by different adapted meshes. The way the sources act at each correction step, up to the full models with their actual geometries, is given a particular care and generalized, allowing the proposed unified procedure. For all the considered corrections, the sources are always of IC type, thus only needed in layers of FE along boundaries, which lightens the required mesh-to-mesh projections between subproblems.

A MSFEM to simulate the eddy current problem in laminated iron cores in 3D

2019 ◽  
Vol 38 (5) ◽  
pp. 1667-1682 ◽  
Author(s):  
Karl Hollaus
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Eddy Current ◽  
Eddy Currents ◽  
Three Dimensional ◽  
Harmonic Balance Method ◽  
Three Dimensions ◽  
Magnetic Vector Potential ◽  
Content Type ◽  
Element Method

Purpose The simulation of eddy currents in laminated iron cores by the finite element method (FEM) is of great interest in the design of electrical devices. Modeling each laminate by finite elements leads to extremely large nonlinear systems of equations impossible to solve with present computer resources reasonably. The purpose of this study is to show that the multiscale finite element method (MSFEM) overcomes this difficulty. Design/methodology/approach A new MSFEM approach for eddy currents of laminated nonlinear iron cores in three dimensions based on the magnetic vector potential is presented. How to construct the MSFEM approach in principal is shown. The MSFEM with the Biot–Savart field in the frequency domain, a higher-order approach, the time stepping method and with the harmonic balance method are introduced and studied. Findings Various simulations demonstrate the feasibility, efficiency and versatility of the new MSFEM. Originality/value The novel MSFEM solves true three-dimensional eddy current problems in laminated iron cores taking into account of the edge effect.

Fast Three-Dimensional Finite Element Analysis of Weld Overlay Application on a Formed Feeder Elbow

2011 ◽  
Author(s):  
Francis H. Ku ◽  
Pete C. Riccardella
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Residual Stresses ◽  
Nuclear Reactor ◽  
Three Dimensional ◽  
Fe Method ◽  
Element Analysis ◽  
Weld Overlay ◽  
Welding Processes

This paper presents a fast finite element analysis (FEA) model to efficiently predict the residual stresses in a feeder elbow in a CANDU nuclear reactor coolant system throughout the various stages of the manufacturing and welding processes, including elbow forming, Grayloc hub weld, and weld overlay application. The finite element (FE) method employs optimized FEA procedure along with three-dimensional (3-D) elastic-plastic technology and large deformation capability to predict the residual stresses due to the feeder forming and various welding processes. The results demonstrate that the fast FEA method captures the residual stress trends with acceptable accuracy and, hence, provides an efficient and practical tool for performing complicated parametric 3-D weld residual stress studies.

scholarly journals 3D harmonic modeling of eddy currents in segmented conducting structures

2019 ◽  
Vol 38 (1) ◽  
pp. 2-23 ◽  
Author(s):  
C.H.H.M. Custers ◽  
J.W. Jansen ◽  
M.C. van Beurden ◽  
E.A. Lomonova
Keyword(s):  
Finite Element ◽  
Eddy Current ◽  
Eddy Currents ◽  
Three Dimensional ◽  
Spatial Period ◽  
Content Type ◽  
Current Distributions ◽  
Wide Range ◽  
Conductivity Function ◽  
Electromagnetic Quantities

PurposeThe purpose of this paper is to describe a semi-analytical modeling technique to predict eddy currents in three-dimensional (3D) conducting structures with finite dimensions. Using the developed method, power losses and parasitic forces that result from eddy current distributions can be computed.Design/methodology/approachIn conducting regions, the Fourier-based solutions are developed to include a spatially dependent conductivity in the expressions of electromagnetic quantities. To validate the method, it is applied to an electromagnetic configuration and the results are compared to finite element results.FindingsThe method shows good agreement with the finite element method for a large range of frequencies. The convergence of the presented model is analyzed.Research limitations/implicationsBecause of the Fourier series basis of the solution, the results depend on the considered number of harmonics. When conducting structures are small with respect to the spatial period, the number of harmonics has to be relatively large.Practical implicationsBecause of the general form of the solutions, the technique can be applied to a wide range of electromagnetic configurations to predict, e.g. eddy current losses in magnets or wireless energy transfer systems. By adaptation of the conductivity function in conducting regions, eddy current distributions in structures containing holes or slit patterns can be obtained.Originality/valueWith the presented technique, eddy currents in conducting structures of finite dimensions can be modeled. The semi-analytical model is for a relatively low number of harmonics computationally faster than 3D finite element methods. The method has been validated and shown to be computationally accurate.

Study on the structural stability evaluation of umbilical winch for ROV LARS

2018 ◽  
Vol 35 (1) ◽  
pp. 202-210
Author(s):  
Namsub Woo ◽  
Sangmok Han ◽  
Youngju Kim ◽  
Sunchul Huh ◽  
Hyunji Kim
Keyword(s):  
Structural Analysis ◽  
Dynamic Simulation ◽  
Structural Stability ◽  
Three Dimensional ◽  
High Technology ◽  
Design Methods ◽  
Stability Evaluation ◽  
Content Type ◽  
Dimensional Models ◽  
Three Dimensional Models

Purpose The purpose of this study is structural stability evaluation of umbilical winch. In accordance with the recent trend for developing natural resources, high-technology equipment on exploration ships is becoming more technologically advanced. One such piece of high-technology equipment is the umbilical winch. In this study, the umbilical winch is divided into two parts (drum and winch), where each is respectively designed with three dimensional models using CATIA, and dynamic simulation and structural analysis are performed using ANSYS. Design/methodology/approach In this paper, the winch is divided into two parts for finite element analysis, the drum and whole winch model, and the parts are designed as three-dimensional models except for some small parts, such as bolt holes. Dynamic simulation and structural analysis are then performed using ANSYS. The analysis results ensure the reliability of the design methods and will be used in the domestic localization of remote operated vehicle (ROV) launch and recovery systems (LARS). Findings The strain is identified from the results, but it is very small. Some stress is concentrated at the lower corner of the drum, but the maximum stress value is lower than the allowable stress; therefore, the structure has no impact on the strain and stress. Thus, it is determined that the designed structure is safe. The results ensure the reliability of the design methods and will be used in the domestic localization of ROV LARS. Originality/value Previous studies focus on the static and mechanic problems of the winch by considering winch and drum breakage in the umbilical winch system. However, ships have a nonlinear motion characteristic with six degrees of freedom according to the constant influence of the external environment. In addition, from a design perspective, the dynamic characteristics (e.g. the ship’s motions) are more important than the static characteristics. Thus, the authors focus on winch stability securement with variable loads, such as ships moving, wave disturbance and other such important environment conditions.

scholarly journals Theoretical and Finite Element Modeling of Fine Kirschner Wires in Ilizarov External Fixator

2010 ◽  
Vol 4 (3) ◽  
Author(s):  
A. R. Zamani ◽  
S. O. Oyadiji
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Kirschner Wires ◽  
Fe Method ◽  
Mathematical Solution ◽  
New Exact Solutions ◽  
Ilizarov Apparatus ◽  
Dimensional Finite Element ◽  
Experimental Findings ◽  
Three Dimensional Finite Element

The mechanical behavior of the transosseous elements is a defining factor in the overall stiffness, stability, and reliability of an external fixation system. Mechanics involving the application of thin Kirschner wires in Ilizarov apparatus is yet to be fully explained. To address this problem, load-deflection behavior of the pretensioned thin wires laterally loaded by the bone is necessary to be studied. In this paper, the lateral deflections of thin Kirschner wires are studied both theoretically and computationally. Fully three dimensional finite element (FE) modeling and analyses were performed in which the bone was modeled as a hollow cylinder, and the wire-bone interaction was assumed to be frictionless. The mathematical solution resulted in new exact solutions for the deflection as well as final tension in the wires subjected to the lateral loading under a cylinder representing the bone. Results from the FE analyses turned out to be very close to those from the mathematical solution. The results obtained from theory and FE method are comparable to published experimental findings. Some aspects of the pretensioned thin wire behavior in ring fixation systems, e.g., stiffness-tension proportionality, were revealed in the results. The current study adds to the existing knowledge on the general behavior of tensile elements.

Design of Above-Knee Prosthesis: A Finite Element Stress Analysis

2015 ◽  
Vol 1125 ◽  
pp. 432-436 ◽  
Author(s):  
Sandro Mihradi ◽  
Calvindoro Zeus Abdiwijaya ◽  
Tatacipta Dirgantara ◽  
Andi Isra Mahyuddin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Knee Prosthesis ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Strength Criteria ◽  
Finite Element Stress Analysis ◽  
Three Dimensional Models ◽  
Four Bar Linkage

In the present research, three-dimensional models of above-knee prosthesis, consist of socket, four-bar linkage knee, pylon and foot, are developed. These models have to fulfill criteria such as stability, ability to withstand up to 90 kg of bodyweight, ability to flex up to 130 degree, easy for maintenance, simple manufacturing process, affordable and yet reliable. As the first step of development, these models were evaluated using finite element method software to determine whether or not the design has fulfilled strength criteria. The results show that the last iteration of the three dimensional model of the knee prosthesis has satisfied the criteria.

Process modeling, joint-property characterization and construction of joint connectors for mechanical fastening by self-piercing riveting

2014 ◽  
Vol 10 (4) ◽  
pp. 631-658 ◽  
Author(s):  
Mica Grujicic ◽  
Jennifer Snipes ◽  
S. Ramaswami ◽  
Fadi Abu-Farha
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Large Scale ◽  
Constitutive Relations ◽  
Computational Cost ◽  
Three Dimensional ◽  
Modeling And Simulations ◽  
Content Type ◽  
Material Parameters ◽  
Computational Analyses

Purpose – The purpose of this paper is to propose a computational approach in order to help establish the effect of various self-piercing rivet (SPR) process and material parameters on the quality and the mechanical performance of the resulting SPR joints. Design/methodology/approach – Toward that end, a sequence of three distinct computational analyses is developed. These analyses include: (a) finite-element modeling and simulations of the SPR process; (b) determination of the mechanical properties of the resulting SPR joints through the use of three-dimensional, continuum finite-element-based numerical simulations of various mechanical tests performed on the SPR joints; and (c) determination, parameterization and validation of the constitutive relations for the simplified SPR connectors, using the results obtained in (b) and the available experimental results. The availability of such connectors is mandatory in large-scale computational analyses of whole-vehicle crash or even in simulations of vehicle component manufacturing, e.g. car-body electro-coat paint-baking process. In such simulations, explicit three-dimensional representation of all SPR joints is associated with a prohibitive computational cost. Findings – It is found that the approach developed in the present work can be used, within an engineering optimization procedure, to adjust the SPR process and material parameters (design variables) in order to obtain a desired combination of the SPR-joint mechanical properties (objective function). Originality/value – To the authors’ knowledge, the present work is the first public-domain report of the comprehensive modeling and simulations including: self-piercing process; virtual mechanical testing of the SPR joints; and derivation of the constitutive relations for the SPR connector elements.

scholarly journals Parallel computations in nonlinear solid mechanics using adaptive finite element and meshless methods

2016 ◽  
Vol 33 (4) ◽  
pp. 1161-1191 ◽  
Author(s):  
Zahur Ullah ◽  
Will Coombs ◽  
C Augarde
Keyword(s):  
Finite Element ◽  
Parallel Algorithms ◽  
Meshless Method ◽  
Three Dimensional ◽  
Meshless Methods ◽  
Basis Functions ◽  
Two Dimensional ◽  
Content Type ◽  
Linear Elastic ◽  
Geometrical Nonlinearities

Purpose – A variety of meshless methods have been developed in the last 20 years with an intention to solve practical engineering problems, but are limited to small academic problems due to associated high computational cost as compared to the standard finite element methods (FEM). The purpose of this paper is to develop an efficient and accurate algorithms based on meshless methods for the solution of problems involving both material and geometrical nonlinearities. Design/methodology/approach – A parallel two-dimensional linear elastic computer code is presented for a maximum entropy basis functions based meshless method. The two-dimensional algorithm is subsequently extended to three-dimensional adaptive nonlinear and three-dimensional parallel nonlinear adaptively coupled finite element, meshless method cases. The Prandtl-Reuss constitutive model is used to model elasto-plasticity and total Lagrangian formulations are used to model finite deformation. Furthermore, Zienkiewicz and Zhu and Chung and Belytschko error estimation procedure are used in the FE and meshless regions of the problem domain, respectively. The message passing interface library and open-source software packages, METIS and MUltifrontal Massively Parallel Solver are used for the high performance computation. Findings – Numerical examples are given to demonstrate the correct implementation and performance of the parallel algorithms. The agreement between the numerical and analytical results in the case of linear elastic example is excellent. For the nonlinear problems load-displacement curve are compared with the reference FEM and found in a very good agreement. As compared to the FEM, no volumetric locking was observed in the case of meshless method. Furthermore, it is shown that increasing the number of processors up to a given number improve the performance of parallel algorithms in term of simulation time, speedup and efficiency. Originality/value – Problems involving both material and geometrical nonlinearities are of practical importance in many engineering applications, e.g. geomechanics, metal forming and biomechanics. A family of parallel algorithms has been developed in this paper for these problems using adaptively coupled finite element, meshless method (based on maximum entropy basis functions) for distributed memory computer architectures.

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