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Article
Publication date: 9 July 2020

Dominique Giraud, Baptiste Ristagno, Denis Netter, Julien Fontchastagner, Nicolas Labbe and Vincent Lanfranchi

This paper aims to propose a method to evaluate the information obtained on harmonics calculations and to estimate the precision of results using finite element method for…

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Abstract

Purpose

This paper aims to propose a method to evaluate the information obtained on harmonics calculations and to estimate the precision of results using finite element method for an innovative motor topology in which some well-known meshing rules are difficult to apply.

Design/methodology/approach

The same magnetostatic problem is solved with several mesh sizes using both scalar and vector potentials magnetics formulations on a complex topology, an axial claw pole motor (ACPM). The proposed method lies in a comparison between the two weak formulations to determine what information is obtained on harmonics calculations and to estimate its precision. Moreover, an original mesh method is applied in the air gap to improve the numerical results.

Findings

The precision on harmonics calculations using finite element method on an ACPM is estimated. For the proposed motor and mesh, only the mean value (even with large mesh) and the first harmonic (with fine mesh) of torque are calculated with a good accuracy. This results confirm that the non-respect of the meshing rules have a strong impact on the results and that scalar and vector potentials magnetics formulations do not give exactly the same results. Before using torque harmonics values in vibration calculations, a finite element model has to be validated by using both fomulations.

Research limitations/implications

This method is time-consuming and only applied on an ACPM in this work.

Originality/value

The axial claw pole motor, for which the classic meshing rules cannot be applied, is a complex topology very under-studied. To improve the calculation of space harmonics, the authors proposed to split the airgap into four parts. Then in the two central parts, the meshing step of the structured mesh is equal to the rotating step.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 39 no. 5
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 4 May 2020

Guangzhou Zhu and Wenfang Song

The paper presents a method for the patterns simulation in the 3D virtual stitching and try-on system.

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143

Abstract

Purpose

The paper presents a method for the patterns simulation in the 3D virtual stitching and try-on system.

Design/methodology/approach

First, the patterns are designed using the garment CAD software and stored in the DXF format. Second, the regular grid method is employed to mesh the patterns to be quadrangular, and the patterns triangular meshing can be obtained by connecting the diagonal of the quadrangular. Then a mass-spring model is established, and the forces analysis and the explicit Euler integration method are employed to accomplish the patterns simulation. The paper demonstrates the robustness of our simulation through two sets of experiments, including a lady’s dress patterns meshing experiments and the experiments of the virtual stitching of the lady’s dress.

Findings

The patterns meshing algorithm can meet the requirements of the internal meshing and the boundary meshing, and it is very important to select an appropriate meshing density. The implementation of the virtual stitching of the lady’s dress proves the effectiveness and usability of the simulation methods.

Research limitations/implications

The lady’s dress used in the experiments is a relatively simple fashion style, with only the front and back pattern. It is very worthy of further research on the effectiveness of the complex structure of clothing.

Practical implications

The paper includes practical implications of the methods of the patterns meshing and the virtual stitching of the simple fashion styles.

Originality/value

The simulation system is developed using VC++ 2015 with the help of the OpenGL functions library, which is proved as a simple, lower computation and robustness for the patterns simulation of the simple garments.

Details

International Journal of Clothing Science and Technology, vol. 32 no. 6
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 1 April 1993

E. OÑATE and G. BUGEDA

The concepts of solution error and optimal mesh in adaptive finite element analysis are revisited. It is shown that the correct evaluation of the convergence rate of the…

Abstract

The concepts of solution error and optimal mesh in adaptive finite element analysis are revisited. It is shown that the correct evaluation of the convergence rate of the error norms involved in the error measure and the optimal mesh criteria chosen are essential to avoid oscillations in the refinement process. Two mesh optimality criteria based on: (a) the equal distribution of global error, and (b) the specific error over the elements are studied and compared in detail through some examples of application.

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Engineering Computations, vol. 10 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 March 1990

Y.C. Liu, H.A. ElMaraghy and K.F. Zhang

A knowledge‐based system for forming quadrilateral finite elements, XFORMQ, was developed at the Centre of Flexible Manufacturing Research and Development of McMaster…

Abstract

A knowledge‐based system for forming quadrilateral finite elements, XFORMQ, was developed at the Centre of Flexible Manufacturing Research and Development of McMaster University, Canada. It automatically forms quadrilateral elements of good quality in conjunction with existing triangular mesh generators. XFORMQ can model geometries as complicated as those handled by triangular mesh generators. It allows for pre‐specified element sizes and rapid transition of element density. The concepts of ‘layer’ and ‘polygon patterns’, which considerably simplify the mesh generation rules and ensure the quality of formed elements, are introduced. Several test cases with different degrees of difficulties were used to evaluate XFORMQ's capabilities with satisfactory results. XFORMQ has the potential of generating meshes arising from the adaptive finite element analysis with quadrilateral elements.

Details

Engineering Computations, vol. 7 no. 3
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 January 1983

B. WÖrdenweber

This article describes a method for mesh generation, suitable for applications of the finite‐element method, which proceeds fully automatically from a geometric model of…

Abstract

This article describes a method for mesh generation, suitable for applications of the finite‐element method, which proceeds fully automatically from a geometric model of the object provided by a CAD‐system. It first generates a coarse mesh which is then adapted to fit the finite‐element problem. A resulting system of equations can be solved by a Gaussian‐type matrix method with as few computations as are necessary for a well‐banded matrix, but without the need for node or element numbering.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 2 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 22 May 2007

Viktor Šajn, Dejan Nožak, Tadej Kosel and Franc Kosel

This paper aims to present an algorithm for local mesh refinement of finite elements in a two‐dimensional compressible fluid flow.

Abstract

Purpose

This paper aims to present an algorithm for local mesh refinement of finite elements in a two‐dimensional compressible fluid flow.

Design/methodology/approach

The algorithm works on a principle of maximum gradient of fluid variables, e.g. pressure, velocity and density. The simulation of two‐dimensional, transient, viscous, compressible, adiabatic flow of turbulent fluid through a De Laval nozzle was performed by the finite element method. The pressure gradient was used as a condition for mesh refinement.

Findings

With the gradient method faster numerical calculations can be obtained. Boundary layer separation and locations of normal shock waves can be described on locally refined mesh.

Research limitations/implications

Further development of the algorithm is required, especially the determination of the gradient criterion.

Originality/value

The paper provides a new approach to mesh refinement. The mesh is refined automatically. Calculation time and required computer memory are decreased.

Details

Aircraft Engineering and Aerospace Technology, vol. 79 no. 3
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 August 1998

S.B. Petersen, B.P.P.A. Gouveia, J.M.C. Rodrigues and P.A.F. Martins

This paper presents an algorithm for automatic generation of graded initial quadrilateral meshes targeted for the finite element analysis of metal‐forming processes…

Abstract

This paper presents an algorithm for automatic generation of graded initial quadrilateral meshes targeted for the finite element analysis of metal‐forming processes. Meshing the domain geometry deals with a universe of shapes, and the procedure therefore takes into account the initial geometry of the billet. A grid‐based approach is utilised for generating an initial coarse mesh with well‐shaped (internal) elements, and in cases where non‐rectangular shapes are to be discretized, linking with the boundary is performed on the basis of constrained Delaunay triangulation. By analysing the contact situation between dies and mesh, an attempt is made to identify regions where plastic deformation is likely to be concentrated during the early stages of processing, and accordingly refinement of the mesh is performed locally by elemental subdivision. Simulation examples for closed‐die forging, forward rod and backward can extrusion substantiate the feasibility of this approach in terms of lowering the overall calculation error and limiting the interference between mesh and die.

Details

Engineering Computations, vol. 15 no. 5
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 September 1997

Longwu Wu

FEM analysis has been increasingly employed to simulate sheetmetal forming processes for industrial application purposes. From the simulation results, finite element…

Abstract

FEM analysis has been increasingly employed to simulate sheetmetal forming processes for industrial application purposes. From the simulation results, finite element analysts are able to predict the occurrences of splits and wrinkles therefore they can make recommendations of changes to the die design and/or to the part design to avoid possible stamping failures. The number of real die tryouts can be reduced, thus, the design cycle is shortened and manufacturing costs lowered. In the early times, application analysts were mostly concentrated on simulation of the stamping process itself starting from simple models, later running full size 3D models with large number of elements.

Details

Engineering Computations, vol. 14 no. 6
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 13 December 2021

Yongliang Wang and Jianhui Wang

This study presents a novel hp-version adaptive finite element method (FEM) to investigate the high-precision eigensolutions of the free vibration of moderately thick…

Abstract

Purpose

This study presents a novel hp-version adaptive finite element method (FEM) to investigate the high-precision eigensolutions of the free vibration of moderately thick circular cylindrical shells, involving the issues of variable geometrical factors, such as the thickness, circumferential wave number, radius and length.

Design/methodology/approach

An hp-version adaptive finite element (FE) algorithm is proposed for determining the eigensolutions of the free vibration of moderately thick circular cylindrical shells via error homogenisation and higher-order interpolation. This algorithm first develops the established h-version mesh refinement method for detecting the non-uniform distributed optimised meshes, where the error estimation and element subdivision approaches based on the superconvergent patch recovery displacement method are introduced to obtain high-precision solutions. The errors in the vibration mode solutions in the global space domain are homogenised and approximately the same. Subsequently, on the refined meshes, the algorithm uses higher-order shape functions for the interpolation of trial displacement functions to reduce the errors quickly, until the solution meets a pre-specified error tolerance condition. In this algorithm, the non-uniform mesh generation and higher-order interpolation of shape functions are suitable for addressing the problem of complex frequencies and modes caused by variable structural geometries.

Findings

Numerical results are presented for moderately thick circular cylindrical shells with different geometrical factors (circumferential wave number, thickness-to-radius ratio, thickness-to-length ratio) to demonstrate the effectiveness, accuracy and reliability of the proposed method. The hp-version refinement uses fewer optimised meshes than h-version mesh refinement, and only one-step interpolation of the higher-order shape function yields the eigensolutions satisfying the accuracy requirement.

Originality/value

The proposed combination of methodologies provides a complete hp-version adaptive FEM for analysing the free vibration of moderately thick circular cylindrical shells. This algorithm can be extended to general eigenproblems and geometric forms of structures to solve for the frequency and mode quickly and efficiently.

Details

Engineering Computations, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 28 December 2021

Niels Koester, Oliver Koenig, Alexander Thaler and Oszkár Bíró

The Cauer ladder network (CLN) model order reduction (MOR) method is applied to an industrial inductor. This paper aims to to anaylse the influence of different meshes on…

Abstract

Purpose

The Cauer ladder network (CLN) model order reduction (MOR) method is applied to an industrial inductor. This paper aims to to anaylse the influence of different meshes on the CLN method and their parameters.

Design/methodology/approach

The industrial inductor is simulated with the CLN method for different meshes. Meshes considering skin effect are compared with equidistant meshes. The inductor is also simulated with the eddy current finite element method (ECFEM) for frequencies 1 kHz to 1 MHz. The solution of the CLN method is compared with the ECFEM solutions for the current density in the conductor and the total impedance.

Findings

The increase of resistance resulting from the skin effect can be modelled with the CLN method, using a uniform mesh with elements much larger than the skin depth. Meshes taking account of the skin depth are only needed if the electromagnetic fields have to be reconstructed. Additionally, the convergence of the impedance is used to define a stopping criterion without the need for a benchmark solution.

Originality/value

The work shows that the CLN method can generate a network, which is capable of mimicking the increase of resistance usually accompanied by the skin effect without using a mesh that takes the skin depth into account. In addition, the proposed stopping criterion makes it possible to use the CLN method as an a priori MOR technique.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0332-1649

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