Geometry (with Sketcher) and mesh tutorial · · 2014-09-12CD packae or electromanetic and thermal analysis usin nite elements Flux by CEDRAT Geometry (with Sketcher) and mesh tutorial

CAD package for electromagnetic and thermal analysis using finite elements

Fluxby CEDRAT

Geometry (with Sketcher) and mesh tutorial2D basic example

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Flux software: COPYRIGHT CEDRAT/INPG/CNRS/EDF Flux tutorials : COPYRIGHT CEDRAT

This tutorial was edited on 11 November 2013

Ref.: KF 2 05 - F - 112 - EN -11/13

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Foreword

*(Please read before starting this document)

Description of the example

The goal of this basic example is to familiarize the user with the Flux 2D Sketcher context and mesh description process using a simple device. The user who wants to learn the geometry context of Flux will consult the Geometry and mesh tutorial. The user who wants to learn the physics, solving and post-processing description process will consult one of the three basics examples.

Organization information

The organization of the chapters is the following. all topics beginning with a verb (create, add, assign, …) contain

information about actions you must complete all topics beginning with the word “about” contain definitions or

general information about specific features. Required knowledge

If you are a beginner with Flux, it is recommended that you read and work through the complete text of the chapters. If you are an experienced user of Flux, you may be able to enter the problem information quickly without having to read the “about” paragraphs.

Support files included...

You can refer to the supplied files in case of difficulties completing this tutorial, or directly adapt this tutorial to your needs, without going through all the steps to construct the model. If you install Flux with the documentation and the examples, files are placed in the folder: C:\CEDRAT (or your installation folder) \FluxDocExamples_11.1\Examples2D \ GeometryWithSketcherMesh. Supplied files are command files written in PyFlux language. The user can launch them in order to automatically recover the Flux projects for each case.

**(.py files are launched by accessing Project/Command file from the Flux drop down menu.)

Supplied files Contents Flux file obtained after launching the .py file

Geometry of the the device with the Sketcher

BuildGeomesh.py

Meshing of the device geomeshbuilt.FLU

The main.py enables the launch of these command files

Flux TABLE OF CONTENTS

TABLE OF CONTENTS 1. General information .................................................................................................................1

1.1. Overview .......................................................................................................................................3 1.1.1. Introduction .....................................................................................................................4 1.1.2. The studied device: a variable reluctance speed sensor ...............................................5 1.1.3. The studied device modelled with Flux Sketcher ...........................................................6

1.2. Get started with Flux .....................................................................................................................7 1.2.1. Start the Flux Supervisor ................................................................................................9 1.2.2. About the Flux Supervisor ............................................................................................10 1.2.3. Open Flux2D.................................................................................................................12

2. Geometric description of the device using sketcher context..................................................15 2.1. Project creation and Flux environment .......................................................................................17

2.1.1. Create a project for the device .....................................................................................18 2.1.2. About the sketcher context ...........................................................................................19 2.1.3. About the Help menu / User guide ...............................................................................21 2.1.4. Name the project ..........................................................................................................23 2.1.5. About the Flux2D window.............................................................................................24

2.2. Strategy and tools for geometry description of the device..........................................................25 2.2.1. Available geometric tools and analysis before geometry description of the

device............................................................................................................................26 Main stages for the device geometric description.......................................................................28

2.3. Creation of geometric tools .........................................................................................................31 2.3.1. About geometric parameters ........................................................................................32 2.3.2. Create the geometric parameters.................................................................................33 2.3.3. About coordinate systems ............................................................................................36 2.3.4. Create the coordinate system.......................................................................................38

2.4. Theoretical aspects: data management and preferences...........................................................41 2.4.1. About the undo command.............................................................................................42 2.4.2. About edition functionalities..........................................................................................43 2.4.3. About graphic functionnalities.......................................................................................45 2.4.4. About global correction tools ........................................................................................47

2.5. Creation of the cogged wheel .....................................................................................................49 2.5.1. About creation tools ......................................................................................................50 2.5.2. About circles .................................................................................................................51 2.5.3. Create the inner circle of the cogged wheel .................................................................52 2.5.4. Create the outer circle and adjust the radius of the two circles....................................57 2.5.5. About rectangles...........................................................................................................60 2.5.6. About arcs.....................................................................................................................61 2.5.7. Create the first teeth of the cogged wheel....................................................................62 2.5.8. About circular repetition................................................................................................67 2.5.9. Create the second and the third teeth by circular repetition.........................................68 2.5.10. Correct global defects...................................................................................................70

2.6. Creation of the probes.................................................................................................................71 2.6.1. Create two rectangles for the half of the probe ............................................................72 2.6.2. About symmetry............................................................................................................74 2.6.3. Create the second half of the probe by symmetry........................................................75 2.6.4. Create the second probe by circular repetition.............................................................78 2.6.5. Rotation of the cogged wheel .......................................................................................80

2.7. Close the sketcher context..........................................................................................................81 2.8. Completing the domain ...............................................................................................................83

2.8.1. About an infinite box .....................................................................................................84 2.8.2. Add an infinite box ........................................................................................................85

3. Mesh generation of the sensor ..............................................................................................87 3.1. Strategy and tools for mesh generation of the sensor ................................................................89

3.1.1. Available meshing tools and analysis before mesh generation ...................................90 3.1.2. Main stages for mesh description.................................................................................91

3.2. Meshing the sensor with aided mesh..........................................................................................93

Geometry (with Sketcher) and mesh tutorial PAGE A

TABLE OF CONTENTS Flux

PAGE B Geometry (with Sketcher) and mesh tutorial

3.2.1. Change to the mesh context.........................................................................................94 3.2.2. About the mesh context ................................................................................................95 3.2.3. About Aided mesh.........................................................................................................96 3.2.4. Synchronize Aided mesh value and mesh lines and faces ..........................................97

3.3. Optimize the mesh ................................................................................................................... 101 3.3.1. About mesh tools ....................................................................................................... 103 3.3.2. Modify the Aided relaxation on lines and faces ......................................................... 106 3.3.3. Modify the mesh points.............................................................................................. 107 3.3.4. Assign mesh points to points ..................................................................................... 108 3.3.5. Create a mesh point................................................................................................... 110 3.3.6. Assign the mesh point to points................................................................................. 111 3.3.7. Create a mesh line..................................................................................................... 113 3.3.8. Assign meshline to lines ............................................................................................ 115 3.3.9. Mesh lines and faces ................................................................................................. 117 3.3.10. Save the project and close the Flux2D window......................................................... 119

4. Annex ..................................................................................................................................121 4.1. Use of command files............................................................................................................... 123

4.1.1. About command files and the Python language ........................................................ 124 4.1.2. Execute command file................................................................................................ 125

Flux Geometry (with Sketcher) and mesh tutorial

1. General information

Introduction This part A contains the presentation of the studied device and some

information about the Flux software.

Contents This part contains the following topics:

Topic See Page Overview 3 Get started with Flux 7

Geometry (with Sketcher) and mesh tutorial PAGE 1

Geometry (with Sketcher) and mesh tutorial Flux

PAGE 2 Geometry (with Sketcher) and mesh tutorial


1.1. Overview

Introduction This chapter presents the studied device (a variable reluctance speed sensor)

and the strategy of the device description in Flux.

Contents This chapter contains the following topics:

Topic See Page Introduction 4 The studied device: a variable reluctance speed sensor 5 The studied device modelled with Flux Sketcher 6



1.1.1. Introduction

Introduction Flux is a finite elements software for electromagnetic simulation. Flux

handles the design and analysis of any electromagnetic device.

To perform a study with Flux, you build a finite elements project. This process is broken into 5 phases: geometry description* mesh generation description of the physical properties solving process analysis of the results

Only the first two phases are presented in this document.

* In this document the geometry description is carried out using the Sketcher context. I is also possible to create, modify or delete geometric entities in the Flux geometry context.

Objective The objective of this document is the discovery and mastering of various

functionalities in the software through the example of a simple device.

The device is a variable reluctance speed sensor described in the following paragraphs.

The studied functionalities* of the software are those, related to the phases of construction of the geometry using the Sketcher context and generation of the mesh.

The user will also find in this document useful information concerning the software: description of the environment, data management, graphic representation, etc.

* The functionalities of the software related to the following phases - description of the physical properties, resolution, and analysis of the results - are not detailed in this document.



1.1.2. The studied device: a variable reluctance speed sensor

Introduction The device to be analyzed is a speed sensor.

Structure The variable reluctance speed sensor consists of a cogged wheel, a magnet

and a coil connected to a measuring resistance.

Operation The rotation of the cogged wheel near the tip of the sensor changes the

magnetic Flux, creating an analog voltage signal that can be recovered in probes.

Typical applications

Typical applications are: ignition system engine speed and position speed sensing for electronically controlled transmissions vehicle speed sensing wheel speed sensing for ABS and traction control systems




1.1.3. The studied device modelled with Flux Sketcher

Geometric structure

The device consists of: one cogged wheel with three teeth two probes with a magnet and a coil around The device will be modelled as below in the 2D Sketcher:

PROBE 1

COIL 1-

COIL 1+

MAGNET 2

COIL 2-

COIL 2+

WHEEL

MAGNET 1

PROBE 2


1.2. Get started with Flux

Introduction This chapter shows how to start working with Flux and includes a

presentation of the Flux Supervisor.

It also shows how to start the preprocessor for Flux2D.

More detailed information about Flux2D menus and commands is presented in Part B.


Topic See Page Start the Flux Supervisor 9 About the Flux Supervisor 10 Open Flux2D 12





1.2.1. Start the Flux Supervisor

Goal Starting Flux involves opening the Flux Supervisor.

Action To start Flux from the Windows taskbar:

Start All programs Cedrat Flux

Result The Flux Supervisor window opens.



1.2.2. About the Flux Supervisor

The Flux Supervisor window

The Flux Supervisor window is divided into several zones. The different zones are identified in the figure below and then detailed in following blocks.

Zones of the Supervisor

The different zones of the Flux Supervisor and their functions are presented in the table below.

Zone Function

Dimensions The user selects the dimension in which he wishes to model his project: 2D or 3D, Skew

Contexts

The user have the choice between several use contexts of supervisor: New project Open un project Open example Python for Flux Batch solve



Working directory Directory selector

The user chooses a working directory. The path of this directory is displayed. It is possible to manage folders and files by clicking on button :

Customized zone

The content of this zone is adapted according to the context of use chosen.

The action button is also customized.

How to proceed ? The process of use of each context is in this zone. It is possible to hide/display this zone by clicking on

Cross functions

The user also has access by the supervisor at cross-functions: Specific functions to Flux (Options, License,

Materials, Units) Functions of coupling with external softwares

(Got-It, Portunus, Simulink ...)

This icon allows to access to : Help (HTML documentation) PDF documents (user guide, tutorials, new

features document…) User portal (sharing plateform) …



1.2.3. Open Flux2D

The preprocessor Flux2D will be opened directly on the sketcher context to manage the geometry building of the device and mesh generation.

Goal

Some checks before you begin

From the Flux Supervisor you should: Select the Flux 2D tab in order to access the specific Flux 2D programs. Access your working directory by selecting it in the supervisor’s directory

manager window. Verify that the title of the Program manager area is the standard version

(Flux2D: Standard). If not, in the menu bar, select Versions and check Standard.

To open Flux2D from the Flux Supervisor, follow the procedure on How to proceed block. Select 2D, choose the Working directory and click on Start a new project.

Action

Continued on next page



Result The PreFlux window for Flux 2D applications is opened directly in the

Sketcher context

* A new project must be created to see the complete set of PreFlux commands.





2. Geometric description of the device using sketcher context

Introduction This chapter presents the general steps of the geometry construction and the

data required to describe the geometry.

The device is presented in the figure below.


Topic See Page Project creation and Flux environment 17 Strategy and tools for geometry description of the 25 Creation of geometric tools 31 Theoretical aspects: data management and preferences 41 Creation of the cogged wheel 49 Creation of the probes 71 Close the sketcher context 81 Completing the domain 83





2.1. Project creation and Flux environment

Introduction Each time that a Flux program is started, it is possible to open an existing

project or create a new project.

Contents This section contains the following topics:

Topic See Page Create a project for the device 18 About the sketcher context 19 About the Help menu / User guide 21 Name the project 23 About the Flux2D window 24



2.1.1. Create a project for the device

Goal At the beginning of the geometry description a new project will be created.

Action To create a new project from the …

Project menu: 1. Click on New

OR

Project toolbar: 1. Click on the icon

Result Flux retrieves a great deal of information from the database model in order to

build the proper database of the new project. This project is temporarily named ANONYMOUS. Since Flux 11.2, the Flux2D window for 2D applications is opened directly in the Sketcher context as below. It is however possible to close the Sketcher context in order to describe the geometry in Flux, as in the previous versions.



2.1.2. About the sketcher context

Definition The 2D sketcher is an environment for the creation of « high level »

geometric objects, automating the definition of points and lines. Integrated into Flux, it gives an alternative to the creation of points by coordinates and of lines by selection of points. It is a tool that permits the user to rapidly « draw » a CAD application having as main objectives to: Facilitate and improve the description of the geometry by the graphic

drawing functions Create by « freehand » drawing of the lines (points automatically

associated)

Sketcher 2D integrated in Flux

The 2D sketcher integrated in Flux is a dedicated context accessible starting from a Flux 2D or a Skew project. The 2D sketcher context is directly opened upon the opening of a new project (nevertheless this is an option that is modifiable starting from the supervisor options).

The standard Flux geometric description remains usable in duplicate outside the sketcher context.

Environment The environment of the sketcher context is similar to the Flux environment

with the data tree, a graphic window, the command window and the history of the commands. The graphic window is personalized as compared to that of Flux (nevertheless this is an option that is modifiable starting from the supervisor options).

PyFlux All the operations carried out in the sketcher are recorded in the command

PyFlux as for Flux operation. Command files can also be executed starting from the sketcher by the Project menu.

Parametric study

It is possible to carry out parametric studies by means of a project described in the sketcher. The operation is identical as the one in the standard Flux context, representing the way to describe the geometric parameters that are used in the formulas defining the coordinates of certain points.

Information: mesh, region …

The sketcher can be opened by means of geometric entities that contain other data except those in the geometric description, namely the data on mesh, region and appearance. These data are stored after the sketcher has been opened, the modifications made and the sketcher closed.



Tools of the Sketcher con

After having activated the sketcher context, toolbars dedicated to the geometry description appear in the Flux2D window.

The different toolbars and their principal roles are briefly described below.

Geometry context toolbars Function 1 Hide/display tools

2 Edition tools

3 Creation tools

4

Construction tools

5

Correction tools

6 Other tools

Color code Geometric entities (points and lines) are graphically identified with a color

code. The user can distinguish 3 colors: Red: entities that are parameterized (the user cannot displaced such entities graphically. Black: standard entities (the user can displace graphically such entities and modify their coordinates or properties). Greyed: propagated entities (these entities are linked ti standard entities and they cannot be displaced graphically)



2.1.3. About the Help menu / User guide

Introduction There are several ways to access the user guide information:

the complete user guide the on-line help on an option

Method 1 From the Flux supervisor:

Click on icon and on Help

To open the complete user’s guide in Flux2D from the Help menu: Method 2

1. Click on Help

Method 3 To open the on-line help about an entity from its dialog box:

1. Click on the button




User guide The on-line version of the Flux user guide is presented in the figure below.

The corresponding sections of the Flux user’s guide can be opened by clicking on the hyperlinks.



2.1.4. Name the project

The new project, temporarily named ANONYMOUS, will be renamed and saved.

Goal

Action To rename the project from the …

Project menu:

1. Click on Save orSave as…

OR

Project toolbar: 1. Click on the icon

2. Type geomeshbuilt.FLU as project name

Note: The user can choose another name for the project and change the current project directory (working directory), displayed in the Save In field at the top. A periodic data backup is recommended.



2.1.5. About the Flux2D window

Flux2D window The Flux2D project window opens in the Sketcher context. The sketcher

context has the complete set of the tools to build the geometry of the device, and to visualize the device during different steps of the construction.

Areas The Flux2D project window is divided into four main areas. The different

areas can be resized or hidden.

Graphic

Data tree

Output

PyFlux Command

Area Function Data tree displays all the problem data in a tree structure that is

expanded using the key Graphic displays the graphic entities Outpu prints Python command instructions PyFlux Command

Manipulation of python commands: runs python commandes (left area) runs python files (center area) create python files (center area) edit (open and modify) python files (center area) saves all operations in a log.py files (right area)



2.2. Strategy and tools for geometry description of the device

Introduction This section shows:

the available tools for geometry building the analysis carried out for construction of the wheel geometry and the

selected strategy


Topic See Page

Available geometric tools and analysis before geometry description of the device

26

Main stages for the device geometric description 28



2.2.1. Available geometric tools and analysis before geometry description of the device

Available tools The tools available for geometric construction are: geometric parameters,

coordinate systems and transformations.

Device analysis and choice of const ruction tools

An analysis of the device is necessary to determine the strategy of construction and the choice of construction tools.

The analysis of the device and the construction tools chosen within the framework of this tutorial are summarized in the table below.

To carry out the operation to …

it is planned … … as in the figure below.

create the WHEEL_CS coordinate system

To creat the ALPHA parameter

position the wheel to create an WHEEL_CS coordinate system

WHEEL_CS

change dimensions of the wheel

to create 4 parameters to set dimensions of the wheel elementary pattern

BETA

TOOTH_IR

TOOTH_OR

WHEEL_R

create the other teeth of the cogged wheel

TOOTH_N

to create 1 parameter




position the probe

create a PROBE_CS Cartesian coordinate system specific to the probe

PROBE_CS

change dimensions of the magnet and the coil

create 5 parameters for setting the magnet and the coil dimensions

MAG_H

COIL_H MAG_R

COIL_IR

COIL_OR

create the second probe by circular repetition

ANGLE

create the ANGLE parameter



2.2.2. Main stages for the device geometric description

An outline of the geometry description process to build the device geometry is presented in the table below.

Outline

Stage Description

1 Creation of 12 geometric parameters

Angle for the wheel: ALPHA = 0 Wheel radius: WHEEL_R = 10 mm Tooth inner radius: TOOTH_IR = 12.5 mm Tooth outer radius: TOOTH_OR = 21.5 mm Number of teeth: TOOTH_N = 3 Tooth angle: BETA =15° Coil inner radius: COIL_IR = 2,8 mm Coil outer radius: COIL_OR = 3,5 mm Coil height: COIL_H = 16 mm Angle to position the second probe: ANGLE = 30° Radius of the magnet: MAG_R = 2,5mm Height of the magnet: MAG_H = 20 mm

2 Creation of 2 coordinate system

Cylindrical coordinate system: WHEEL_CS (global coordinate system for the wheel description)

Cylindrical coordinate system: PROBE_CS (local coordinate system for the probe description)

3 Creation of the inner circle

Freehand drawing of the inner circle

Graphic adjustment

4 Creation of the outer circle

Freehand drawing of the outer circle

adjustment with geometric parameter

5 Creation of the first teeth

Freehand drawing of the rectangle

Adjustment with geometric parameter

Deletion of the vertical lines

Simplication of the lines Creation of an arc



6 Creation of the other teeth

Creation of a line to permit a repeated mesh

Propagation of the tooth by circular repetition

Simplification of the lines

7 Creation of the first probe

Creation of a rectangle for the first half of the magnet

Creation of a rectangle for the first half of the coil

Propagation by symmetry to build the probe

8 Creation of the second probe

Circular repetition of the probe

9

Building of the faces in the Flux geometry context

Close the sketcher context

Build faces in the Flux geometry context

10 Close the study domain

Create a circular infinite box in order to close the study domain





2.3. Creation of geometric tools

Introduction The geometry building begins by the creation of geometric tools: geometric

parameters and a coordinate system.


Topic See Page About geometric parameters 32 Create the geometric parameters 33 About coordinate systems 36 Create the coordinate system 38



2.3.1. About geometric parameters

Principle of use Geometric parameters are entities that can be used for the geometry building

of the device, i.e. for the definition of points, coordinate systems, geometric transformations, infinite box dimensions and other geometric entities.

Defining parameters simplifies the construction of the geometry and enables modifications to be made more easily later. Many changes can be made by modifying only the definition of the parameters instead of modifying all the individual points, lines or nodes that might be built using the parameters. Parameters also can modify the scale of the geometry through their relationship with coordinate systems.

Definition of parameters

The geometric parameters are defined by the name and the algebraic expressions.

The algebraic expressions may contain: constants arithmetic operators (+, -, *, /, **) arithmetic functions allowed in FORTRAN (SQRT, LOG, SIN, etc.)* other parameters combinations of any of these

* Caution: ATAN2D is preferred over ATAN in order to have a better accuracy.

Parameters and measurement units

Please note that parameters are independent of any unit of measurement. In other words, the numerical value entered for a parameter is not changed when the unit of measurement is changed. Any measurement unit associated with a parameter derives from the coordinate system in which the parameter is used. For example, a parameter's value may be 10 in a coordinate system with millimeters as units. This parameter's value is still 10 whether the coordinate system's units are changed to inches or meters or kilometers or any other available unit. Thus, when you use parameters, you can also modify the scale of a geometric feature without reentering each point or item.



2.3.2. Create the geometric parameters

Goal Twelve parameters are required for the geometry description of the device.

The parameters, required to build the device, are presented in the next figure.

Parameters for the description of the wheel and the teeth:

BETA

TOOTH_IR

TOOTH_OR

WHEEL_R

TOOTH_N

ALPHA

Parameters for the description of the probe:

MAG_H

COIL_H MAG_R

COIL_IR

COIL_ORANGLE

MAGNET base

COIL base




Data The table below contains the values of the geometric parameters.

Geometric parameters

Name Comment Expression ALPHA Angle for the Wheel_CS 0 WHEEL_R Radius of the wheel 10 TOOTH_IR Inner radius of the tooth 12.5 TOOTH_OR Outer radius of the tooth 21.5 TOOTH_N Number of teeth 3 BETA Tooth angle 15 COIL_IR Inner radius of the coil 2.8 COIL_OR Outer radius of the coil 3.5 COIL_H Height of the coil 16 ANGLE Angle of the probe position 0 MAG_R Radius of the magnet 2.5 MAG_H Height of the magnet 20



Action To create the geometric parameters from the …

Data tree:

1. Double-click on Geometric parameter

OR

Menu:

1. Select Geometric parameter and click on New

2. Type ALPHA as name 3. Type Wheel angle as comment 4. Type 0 as algebraic expression

for the parameter 5. Click on OK

6. Repeat steps 2 to 5 in the new dialog, entering data for the remaining entities. (see the table on the previous page)

…

7. Click on Cancel to quit the sequence

Result The geometric parameters are listed in the data tree:



2.3.3. About coordinate systems

Introduction All geometric features are defined within a specific coordinate system.

Defining our own coordinate systems enables us to describe and modify the geometry much more easily. The Flux sketcher uses coordinates systems in the same way as Flux. The creation of a coordinate can be done in the sketcher context or in the geometry context.

Types of coordinate systems

The different types of coordinate systems for 2D domain and associated coordinates are presented below.

Cartesian coordinate system Coordinates (x, y)

Cylindrical coordinate system Coordinates (r, )

r

p

y

x

p

Reference coordinate systems

It is possible to distinguish the following coordinate systems: The global coordinate system is the coordinate system where all

computations are performed. It is inaccessible to the user. The global coordinate system is a universal Cartesian coordinate system using meters as the length unit and degrees as the angle unit.

The working coordinate systems are coordinate systems created by the user to cover the study needs. The working coordinate systems are defined: - with respect to the Global coordinate system, when they refer to the

global coordinate system - with respect to a Local coordinate system, when they refer to other

coordinate systems. All entities are defined in the working coordinate systems (user coordinate systems) and are evaluated in the global coordinate system for calculations.

Coordinate system units

The user can define the length and angle units for a coordinate system defined with respect to the global coordinate system (millimeter and degree by default).

A coordinate system defined with respect to the local coordinate system inherits the units of the reference coordinate system (parent coordinate system).




Predefined coordinate system

To assist the user, Flux provides a default coordinate system XY1. It is created for every new project. It is possible to rename it, to modify it or to delete it.

XY1 is the coordinate system of Cartesian type and defined with respect to the global coordinate system.

Coordinate system XY1 Characteristics Y

X

y

Origin of coordinate system: first component: 0 second component: 0 Rotation angle: about Z axis: 0

x

Activate coordinate system

In the sketcher, all the description is done automatically. The coordinate system taken into consideration during a creation is the activated coordinate system. The choice of the active coordinate system is done by means of a group listing the available coordinate systems.



2.3.4. Create the coordinate system

Goal Two coordinate systems are required to describe the geometry of the device,

as presented in the figure below.

WHEEL_CS PROBE_CS

32 mm

Data The table below describes the coordinate system:

Cylindrical coordinate system type defined with respect to the Global system

Origin coord. Rotation

angle Name Comment Units X Y About Z

WHEEL_CS Wheel coordinate system

millimeter/ degree

0 0 ALPHA

Cartesian coordinate system type defined with respect to the Local system

Origin coord.

Rotation angle Name Comment

Parent coord. system X Y About Z

PROBE_CS Probe coordinate system

MAIN_CS 32 0 0




Action To create the coordinate system from the …

Data tree: 1. Double-click

on Coordinate system

OR

Menu: 1. Select Coordinate system

and click on New

2. Type WHEEL_CS as name of coordinate system

3. Type Wheel coordinate system as associated comment

4. Select Cylindrical as type of coordinate system

5. Select Global as definition of coordinate system

6. Select MILLIMETER as length unit

7. Select DEGREE 8. Type 0 as first coordinate 9. Type 0 as second coordinate 10. Type ALPHA as rotation

angle about Z axis 11. Click on OK

12. Repeat steps 2 to 11 in the new dialog, entering data for the PROBE_CS coordinate system. (see the table on the previous page)

…





Result The coordinate system is listed in the data tree:

The list of coordinate system is placed bottom left under the graphic window.



2.4. Theoretical aspects: data management and preferences

Introduction Some theoretical aspects are presented in this section


Topic See Page About the undo command 41 About edition functionalities 43 About graphic functionnalities 45



2.4.1. About the undo command

Undo command There is a Flux command to undo operations. The user can use this command

if an error was made.

There are two possibilities described in the table below.

Method Function 1 to undo the previous operation to undo the last action 2 to undo several operations to undo all actions up to the indicated

action

To undo the previous operation from the Tools toolbar: Method 1

1. Click on the icon

Method 2 To undo several operations from the …

Tools menu:

1. Click on Undo

OR

Tools toolbar: 1. Click on the icon

2. Click on the last operation to undo



2.4.2. About edition functionalities

Selection of entities

The selection of the entities can be made : Starting from the data tree: one type only of entity can be selected in multi-

selection (key Ctrl) or Directly on the graph: no restriction to one type only of entity.

It is possible to select: - an entity « Point » or « Line » individually by clicking on the entity - several entities by clicking on each using the key CTRL (shortcut can be

equally used to deselect the entities). - several entities by framing them using the selection rectangle.

Once the selection is made, the entities will appear highlighted. To clear the selection, click on the graph to do-nothing or to pass to another selection. It is also possible to select all the entities of the geometry by using the shortcut CTRL+A or the command Select all available in the menu Edition

Rectangle selection

The selection rectangle operates by framing the entities to be selected. It is not a command to be activated; it is available in any activated mode. To use the selection rectangle simply frame the desired entities. Useful shortcuts : It is possible to make the multiple selection rectangle by using the key

CTRL after you have made a first selection rectangle in order to make a second one

It is also possible to include the selection rectangle entities, which are partially in the frame of selection, by using the key SHIFT during the selection. This permits the user, for example, to select an assembly of lines without having to frame them entirely.

Copy/Cut/Past After having operated a selection, it is possible to:

Copy and paste: permitting it to duplicate a selection of an entity by choosing its location with a click on the graph

Cut and paste: permitting the selection of an entity and to replace it by choosing its location with a click on the graph

The standard keyboard shortcuts are implemented: Copy : CTRL+C Cut : CTRL+X Paste : CTRL+V




Copy/Cut/Past: some rules

Some rules for using the operations Copy/Cut/Paste : The parameterized entities selected to Copy/Cut or Cut/Paste will no longer

be parameterized after the operation Paste because the location is no longer in conformity with the formulas defining the coordinates of the parameterized points.

The propagated entities Copy/Paste or Cut/Paste will no longer be linked by propagation to their entities of origin. They become independent entities.

Delete The function Delete is available with the sketcher and is different from the

commands Delete and Delete in force available in the standard Flux context. It permits the user to suppress : Any links with other entities once the selection of entities is chosen entities of different types (Point and Line)



2.4.3. About graphic functionnalities

Introduction The graphic functions are implemented to improve the ergonomics and use of

the 2D sketcher: the zoom selection the selection to move the graphic window the displaying filters the magnetization grid the direction lines

Zoom The zoom selection is standard and available in the menu Display/View or via

their corresponding icon: Framing : permits the user to adapt the zoom so as to visualize all the

geometry Reducing / Augmenting : equivalent to the role of the adjusting mouse

wheel Augmenting a zone: zoom over one zone by framing it.

Move the graphic window

The displacement of the window of visualization of the graph can be done:

By click right maintained + displacement of the mouse By positioning the cursor of the mouse on one of the sides of the graphic

window for several seconds: the window moves automatically. This automatic motion is also usable during the creation or the displacement of a selection of entity.

Display filters It is possible to adjust the displaying filters, via the menu Display/View or via

their corresponding icon, to display or not graphic elements: Axes of the global coordinate system the points the coordinate systems the entities of reference (point and line) the grid




The grid The grid is a graphic aid for all the operations of creation and displacement of

the entities. It permits the user to magnetize the cursor on the coupling points defined by three levels: Length of a cell of the grid (10 by default) Number of subdivision by cell (10 by default) Number of points of magnetization by subdivision (10 by default) The parameters of the grid are accessible by the menu Options → Edit.

The parameter of the grid can be configured before the opening of a project in the supervisor options.



2.4.4. About global correction tools

Global correction

The global correction tools permit to accurately render automatically according to the whole geometry on which there are potential faults. Several tools are available : Heal all intersections Heal all superimpositions Simplify all lines Heal and simplify all geometry

Access The different accesses for this mode of correction are presented in the

following table:

Access

icon Heal all intersections menu Tools Heal all intersections

icon Heal all super-impositions menu Tools Heal all superimpositions

icon Simplify all lines menu Tools Simplify all lines

icon Heal and simplify all geometry menu Tools Heal and simplify all geometry

Heal all intersections

The correction tool « Heal all intersections » permits to correct automatically all the intersections detected on the assembly of the geometry. On each intersection a fragmenting is made.

Heal all superim-positions

The correction tool « Heal all superimpositions » permits to correct automatically all the superimpositions of the lines detected on the assembly of the geometry. On each superposition, a merge is made so as to create a single line on the common sections.




Simplify all lines

The correction tool « Simplify all lines » permits to simplify automatically all the configurations of two adjacent lines, collinear and not superimposed on the assembly of the geometry in a single line.

Heal and simplify all geometry

The correction tool « Heal and simplify all geometry » permits to carry out together global corrections in one action, namely: correct all the intersections, all the superimpositions and simplify all the lines of the geometry.



2.5. Creation of the cogged wheel

Introduction The next step is the creation of the cogged wheel.

The next figure describes the geometry of the modelled object.


Topic See Page About creation tools 50 About circles 51 Create the inner circle of the cogged wheel 52 Create the outer circle and adjust the radius of the two circles 57 About rectangles 60 About arcs 61 Create the first teeth of the cogged wheel 62 About circular repetition 67 Create the second and the third teeth 68 About global correction tools 47 Simplifiy the geometry 70



2.5.1. About creation tools

Introduction This part provides information common to all the creation tools contained in

Flux sketcher: Polyline, Rectangle, Arc, Circle and Reference.

Where to find them?

The creation tools are available : via the Construction menu via the corresponding icon (tool bar)

Equivalence to Flux

After using the creation tools in the sketcher, the result obtained is translated into the Flux standard entities « Point » and « Line ».

Possibilities of creation

It is possible to create starting from/finishing: An « empty » location on the graph An existing point (a standard point or a reference point) An existing line (a segment or an arc or a reference line) fragmentation of the line done automatically (except for a reference line)

Magnetization Certain operations of correction are done automatically during the creation in

order to facilitate the geometric description. The “smart” correction operations are : superposition line – line superposition point – line fragmentation of a line if the creation starts on that line or if the creation is

over on that line

The « smart » correction is an option (by default activated) that can be deactivated in the menu Options Edit in the tab Smart correction.



2.5.2. About circles

Circle There are several modes of creation of a « Circle »*:

Circle center + radius defined by its center point and by its radius. The point center is a reference point, symbolized by a cross

Circle diameter defined by the two points of a circle diameter

*The circle created is not a full part entity but merely some points and lines « arc » : Circle centre + radius : three points and two arcs of the type « two points

with centre point » Circle diameter : two points and two arcs of the type «two points without

centre point »

Access / Cursor The different accesses and the personalized cursor for this mode of creation

are presented in the following table:

Access Cursor

icon Circle center + radius

menu Construction Circle Cercle center + radius

icon Circle diameter

menu Construction Circle Circle diameter



2.5.3. Create the inner circle of the cogged wheel

Goal A first circle is required to inner cicle the wheel base, as presented in the

figure below.

r = 10

Inner circle




Action (1) To create the circle:

1. First select the coordinate system in which you want to create the geometry (WHEEL_CS)

Then from the …

Menu:

2. Select Circle center + radius

OR

Creation toolbar:


3. Set the center point of the circle with a first left click

4. Moove the mouse (gives the value of the radius while the mouse moves)

5. Second left click in order to: Set the radius Validate the circle defined by two

arcs of 180° and a centre point Create the corresponding entities

(points and lines)




Result (1) The inner circle of the cogged wheel is created. The corresponding geometric

entities appear in the data tree as below:

Point1 Point 2 Point 3

Line 1

Line 2

Action (2) Select point 3 and displace it in order to obtain the correct radius for the inner

circle (r = 10) as below:

Point 3




Check Edit points and lines describing the inner circle to check if the coordinates and date are correct (See § 2.4.2 About edition). It is possible for instance to select of group of entities of the same time by selecting in the graphic with the Ctrl key maintained pressed and choosing Edit array command in the context menu.



Result The cylindrical coordinates (radius and angle) of the points describing the

inner circle are presented below:

The data of the lines describing the inner circle are presented below:



2.5.4. Create the outer circle and adjust the radius of the two circles

Goal A second circle is required to create the outer cicle ofthe wheel base, as

presented in the figure below.

r1 = TOOTH_IR

r1 r2

r2 = WHEEL_R

Outer circle




Action (1) To create the circle:


Then from the …

Menu:

2. Select Circle center + radius

OR

Creation toolbar:


3. Set the center point of the circle with a first left click

4. Moove the mouse (gives the value of the radius while the mouse moves)

5. Second left click in order to: Set the radius Validate the circle defined by two

arcs of 180° and a centre point Create the corresponding entities

(points and lines)




Result (1) The outer circle of the cogged wheel is created. The corresponding geometric

entities appear in the data tree as below:

Point 4 Point 5

Line 4

Line 3

Action (2) Adjust the radius of the inner and outer circle by editing the four lines as in

the figure below:

Apply WHEEL_R parameter to line 1 and 2 and apply TOOTH_IR parameter to line 3 and 4 as in the figure below:



2.5.5. About rectangles

Rectangles There are several modes of creation of a « Rectangle »*:

Rectangle diagonal described two points representing its diagonal Rectangle center defined by the center point and an extremity point

*The rectangle created is not a full part entity but merely four points and four lines



Access Cursor

icon Rectangle diagonal

menu Construction Rectangle Rectangle diagonal

icon Rectangle center

menu Construction Rectangle Rectangle center



2.5.6. About arcs

Arcs There are several creation modes for the « Arc » :

Arc 2 points, with a center defined by a center point and the two points of the arc extremities (the point center is a reference point symbolized by a cross)

Arc 2 points, without a center, defined by two points extremities Arc 3 points, defined by two points extremities and an intermediate point



Access Cursor

icon Arc 2 points with center menu Construction Line Arc 2 points

with center

icon Circle

diameter menu Construction Line Arc 2 points without center

Arc 2 points without center icon

Arc 3 points menu Construction Line Arc 3 points



2.5.7. Create the first teeth of the cogged wheel

Goal The fisrt teeth is created in 3 steps:

Action (1): a rectangle is drawn in the sketcher context. Action (2): The coordinates of the points of the rectangle are modified Action (3): the 2 vertical lines are deleted in order to create two arcs The first teeth will be built after these three action as below:

Action (1) To create the rectangle :


Then from the …

Menu:

2. Select Rectangle diagonal

OR

Creation toolbar:





3. Set the first point of the diagonal with a first left click

4. Moove the mouse in order to give the view of the future rectangle as well as the data of creation (coordinates of the future diagonal point, width and length of the rectangle)

5. Second left click in order to: set the second point of the diagonal of

the rectangle

validate the creation of the rectangle create the corresponding entities

« Point » and « Line »

Result (1) The rectangle for the first teeth of the cogged wheel is created. The

corresponding geometric entities appear in the data tree as below:

Point1

Line 1

L 8

L 6

L 5 L 7

P 9

P 7 P 8

P 6

Action (2) Set the coordinates of the four points by editing them as in the figure below:




Apply the parameters to the four points as in the figure below:

Result (2) The tooth appear as below:

Action (3) To create the two arcs of the first teeth:

1. Delete line 5 and 7 by graphically selecting them and chosing Delete in the context menu, as in the figure.





2. Detect geometry defects (check the geometry)

3. Correct the intersections between point 6 and line 4 and between point 8 and line 3 by selecting the command Heal all intersections in the Tools menu. Four lines are created as a result

L 3

L 4 L 7

L 4

L 5

L 3

4. Merge the two arcs into a single one by activating the command Simplify lines in the Tools menu and selecting lines 4 and 5. The first arc is created line 9.

5. Create the second arc of the teeth by activating the command arc two points with center in the menu Construction/Lines and selecting point 1, point 7 and point 9 respectively

P1 P9

P7

Result (3) The firs teeth is created as in the figure below:



Additional action

In order to carry out a repeated mesh (this action will be processed in the mesh description chapter in it necessary to create a segment as below:

Line 5



2.5.8. About circular repetition

Circular repetition

The sketcher mode « Circular repetition » permits the user to repeat graphically an assembly of entities once or several times « Point » and « Line » in relation with a pivot point.

Circular repetition

The sketcher mode « Circular repetition » permits the user to repeat graphically an assembly of entities once or several times « Point » and « Line » in relation with a pivot point.

Access Cursor

icon

menu Tools Circular repetition



2.5.9. Create the second and the third teeth by circular repetition

One circular repetition is required to create the second and the third tooth, as shown in the following figure.

Goal

360/TOOTH_N

Point 1

To create the Circular repetition from the menu Action

1. Select Tools and click on

Circular repetition




2. Graphically select the lines to be repeated

3. Graphically select pivot point

4. Type 360/TOOTH_N for the angle between repetition

5. Type 2 for the number of repetition

6. Select connected to origin 7. Click on OK

Result The CIRCULAR transformation is listed in the data tree and the two other

teeth are created as below:



2.5.10. Simplifiy the geometry

Goal The objective is to simplify the geometry to eliminate the useless points.

Simplify the geometry by selecting the command Simplify all lines in the Tools menu.

Action (1)

Result (1) The will for instance convert line 22 and line 3 into line 24 as well as line 23

and 1 into line 1.

L 22

L 3

L 23

L 1

Line 1

Line 24



2.6. Creation of the probes

Introduction The next step of the geometry description the probes as in the figure below:


Topic See Page Create two rectangles for the half of the probe 72 About symmetry 74 Create the second half of the probe by symmetry 75 Create the second probe by circular repetition 78



2.6.1. Create two rectangles for the half of the probe

Goal The goal is to create two rectangles in order to create the first half of the probe (half of the magnet part + half of the coil part).

Action To create the first rectangle representing the first half of the magnet:


Then from the …

Menu:

2. Select Rectangle diagonal

OR

Creation toolbar:





3. Set the first point of the diagonal with a

first left click 4. Moove the mouse in order to give the

view of the future rectangle as well as the data of creation (coordinates of the future diagonal point, width and length of the rectangle)

4. Second left click in order to: set the second point of the diagonal of

the rectangle validate the creation of the rectangle create the corresponding entities

« Point » and « Line »

5. Repeat steps 1 to 4 in order to create the second rectangle representing the first half of the coil



2.6.2. About symmetry

Symmetry The mode of construction « Symmetry*» permits the graphic description of

the symmetry of an assembly of entities « Point » and « Line » in relation to: a standard line or a reference line a standard point or a reference point

* Do not mistake it with the « symmetry of the domain » (available in the menu Domain , which permits to define physically the study domain and geometrically the infinite box closing the study domain



Access Cursor

icon

menu Tools Symmetry




2.6.3. Create the second half of the probe by symmetry

Goal One Symmetry is required to create the second half of the probe, as shown in

the following figure.

Action (1) To create the Symmetry:


Then from the …

Menu 2. Select Tools and click on

Symmetry OR

Tool bar: 2. Click on the icon

3. Graphically select the lines to be reproduced by symmetry

4. Graphically select the

symmetry axis 5. Select connected to

origin 6. Click on OK




Result (1) The SYMMETRY transformation is listed in the data tree and the second half

of the probe is created as below

Action (2) Set the coordinates of the points of the probe by editing them as in the figure

below:

1. Select Point and chose Edit Array in the context menu.

2. Graphically select all the points of the first half of probe.




odify the points coordinates with the geometric parameters as in the 3. Then m

figure below:

Result (2) t probe with the correct coordinates appear as below: The firs



2.6.4. Create the second probe by circular repetition

Goal One circular repetition is required to create the second probe, as shown in

the following figure.

Action o create the Circular repetition from the menu T

1. Select Tools and click on

Circular repetition




2. Graphically select the lines to be repeated

3. Type 1 as pivot point 4. Type ANGLE for the angle

between repetitions 5. Type 1 for the number of

repetition 6. Select No connected to

origin 7. Click on OK

Result The CIRCULAR1 transformation is listed in the data tree and the second

probe created as below:



2.6.5. Rotation of the cogged wheel

Goal The goal is to rotate the cogged wheel in order to obtain the desired position

(30°).

Action (1) Modify ALPHA parameter and enter 30 as algebraic expression.

Result The cogged wheel rotates of 30° and one tooth is in front of the first probe as

in the figure below:

Action (2) er context, run the Check geometry command.

Before closing the sketch



2.7. Close the sketcher context

Introduction

r context in order to start the mesh generation process. The geometry description is now finalized. It is necessary to close the sketche

Action Close the Sketcher context by clicking on the red cross as in the figure below:

Result t closes and the project opens in Flux standard geometry

conext. Face entities are created as well.

The Sketcher contex





2.8. Completing the domain

Introduction The last stage of geometry building is adding an infinite box to close the

study domain.


Topic See Page

About an infinite box 84 Add an infinite box 85



2.8.1. About an infinite box

Infinite box technique

inite the infinite box technique.

The exterior domain (infinite) is linked to an image domain (called the

In the Flux software, using a mathematical transformation to model an infdomain is called

infinite box) through a space transformation.

Principle of use The use of the infinite box im assumes a null field at infining boundaries of the infinite box

in the physical module.

plicitly ty. The boundary conditions on the correspondiare set automatically

Type of infinite box

The infinite box available for 2D study domain and their characteristics are presented in the table below.

Infinite box Characteristics

disc: centered in (0,0) in the global coordinate

system comprises 8 points, 4 lines dimensions set by the user

Length and angle units

Length and angle units are those associated with the domain.

How to choose the dimensions?

The dimensions of the infinite box are defined by the user. This requires a certain experience because there is no general rule.

We can, however, give some advice: the distance between the device and the interior surface of the infinite box is

at least equal to the dimension of the device in this direction the dimensions of the infinite box are related to the mesh. In Flux 3D, the

number of elements on the thickness of the box must be roughly equal (at least) to two (second-order elements) or to three (first-order elements).

The mesh and the size of the infinite box must take into account the studied phenomena. The computations should be performed as follows: for computing of a global or a local quantity inside the device, it is

unnecessary to refine the mesh of the infinite box; for computing of the field created outside the device, it is necessary to

define the box of more significant size and to refine the mesh inside.

It is recommended to parameterize the dimensions of the infinite box to adjust its size during the meshing.



2.8.2. Add an infinite box

Goal An infinite box will be added to close the study domain.

Data able.

The main characteristics of the infinite box are shown in the following t

Infinite box of Disc type

Internal radius External radius 60 70

Action e infinite box from the … To create th

Data tree: 1. Double-click

on Infinite box

OR

Geometry toolbar: 1. Click on the icon

2. Select Disc as type of the infinite box 3. Type 60 as internal radius 4. Type 70 as external radius

5. Click on OK

Result The infinite box is displayed in the graphic scene:





3. Mesh generation of the sensor

Introduction This chapter presents the general steps of mesh generation of the computation

domain and the data required to describe the sensor meshing.

The meshed sensor is presented in the figure below.


Topic See Page Strategy and tools for mesh generation of the sensor 89 Meshing the sensor with aided mesh 93 Optimize the mesh 101





3.1. Strategy and tools for mesh generation of the sensor

Introduction This section shows the available meshing tools and the main stages for mesh

generation of the sensor.


Topic See Page Available meshing tools and analysis before mesh generation 90 Main stages for mesh description 91



3.1.1. Available meshing tools and analysis before mesh generation

Local / global mesh adjustments

d / or the local adjustment (manual).

The global adjustment permits to adjust the automatic mesh (triangles count certain geometry

thin, or close to each other but that are not part of the same geometry). It is done automatically thanks to the Aided Mesh tool box.

entity nt, y the user (creation and assignment of

esh tools).

Two solutions are offered to users for the mesh adjustment: the global adjustment (automatic) an

elements) of the whole domain taking into acconstraints (faces or lines that are distorted,

The local adjustment permits to locline) or a group of entities defined b

ally adjust the mesh near an (poi

m

Use Usually, it is advised to first mesh the device with the Aided mesh preset default values. Then if the user is not completely satisfied of the mesh quality, it is possible to adjust the default values of the aided mesh and /or to add some local mesh information where needed.

Device analysis and choice of mesh tools

An analysis of the device is necessary to determine the strategy of meshing, and the choice of mesh tools.

The analysis of the device and the mesh tools chosen within the framework of this tutorial are summarized in the table below.

The operations … it is planned …

to control the node density of the infinite box

to modify 2 predefined mesh

points LARGE and MEDIUM

MEDIUM

LARGE



3.1.2. Main stages for mesh description

Outline

An outline of the mesh generating process is presented in the table below

Stage Description

.

1 Synchronize with aided mesh preset values 2 Mesh the device

3 Modification of 2 predefined m

Outer size infinite box mesh point: LARGE = 8 mm

esh points Inner size infinite box mesh point: MEDIUM = 4 mm

Assignment of the MEDIUM mesh point to points

MEDIUM

4

and assignment of the LARGE mesh point to points

LARGE

5 Creation of a mesh point MAG_MP = 0.5 mm

6

Assignment of the MAG_MP mesh point to the points of the two magnets

MAG_MP



7 line to the external arcs of each tooth

Assignment of the MESHLINE_1 mesh

MESHLINE_1MESHLINE_1

8 Meshing: meshing lines meshing faces



3.2. Meshing the sensor with aided mesh

Introduction e first s the sensor is meshing lines and faces with

ed mes

Thaid

tep of mesh generation of h preset values.


Topic See Page Change to the mesh context 94 About the mesh context 95 About Aided mesh 96 Synchronize Aided mesh value and mesh lines and faces 97



3.2.1. Change to the mesh context

Goal The Geometry context of Flux2D should be changed to the Mesh context.

Action To activate the Mesh context (display the Mesh toolbar) from the Context

toolbar:

1. Select the Mesh Context using the arrows



3.2.2. About the mesh context

Tools of the mesh context description appear in the Flux2D window.

After having activated the Mesh context, toolbars dedicated to the mesh

The different toolbars and their principal roles are briefly described below. 1 2 3 4 5 6

7

Mesh context toolbars Function 1

To edit Aided mesh box

2

to create mesh entities

3 to assign mesh entities to geometric entitiesto clear all mesh information

4

to orient the mesh to structure the mesh

5

to mesh domain, lines and faces

6

to delete the mesh to check the mesh

7

to display mesh points, mesh lines, nodes, surface elements, mesh defects



3.2.3. About Aided mesh

Introduction

ccount certain geometry

he Aided Mesh tool box.

The global adjustment permits to adjust the automatic mesh (triangles elements) of the whole domain taking into aconstraints (faces or lines that are distorted, thin, or close to each other but that are not part of the same geometry). It is done automatically thanks to t

Aided mesh The Aided Mesh box groups a list of tools preset with default values that are available to adjust the mesh globally: Aided mesh point (on free points) Deviation (on free lines/faces) Relaxation (on free line/ faces) The aided mesh is activated by default.

Use advised to first mes

the user is not completelyt the default values of the e local mesh

ation where needed.

e! If there is glo l and local ad l adjustment has the priority on global adjustment. In this case, the global adjustment

ation wil be assign on entitie l mesh information (free points, free lines and free faces.

Usually, it isThen if

h the device with the preset default values. satisfied of the mesh quality, it is possible

r to add somto adjusinform

aided mesh and /o

Not ba justment on the same project, the loca

inform l s that are free of loca



3.2.4. Synchronize Aided mesh value and mesh lines and faces

Goal The computation domain will be meshed in the following way: meshing

and meshing faces.

lines

Action …

Mesh menu:

To mesh lines from the

1. Point on Mesh and click on Mesh lines

OR

Mesh toolbar: 1. Click on the icon

Result

The next figure is displayed in the graphic scene.




Action 3 To mesh faces from the …

Mesh menu: 1. Point on Mesh and click on Mesh faces

OR


Result The results appear as below.

The output is displayed in the History zone: Total number of nodes --> 7481

Surface elements : Number of elements not evaluated : 0 % Number of excellent quality elements : 98.55 % Number of good quality elements : 1.29 % Number of average quality elements : 0.1 % Number of poor quality elements : 0 % meshFaces executed


6



Comments To optimize th vised to have at least a two

Infinite box and to dense and regularize the mesh in the probes and between the probe and cogged wheel (in order to take into account the physics).

e mesh, it is ad elements large





3.3. Optimize the mesh

Introduction After a first mesh, it is necessary to optimize the mesh result by setting aided

values and adding some ‘local” mesh information


Topic See Page About mesh tools 102 Modify the Aided relaxation on lines and faces 106 Assign mesh points to points 108 Create a mesh point 110 Assign the mesh point to points 111 Create a mesh line 113 Assign meshline to lines 115 Mesh lines and faces 117 Save the project and close the Flux2D window 119





3.3.1. About mesh tools

Mesh To mesh the device is to subdivide the computation domain into finite

elements: nodes line elements face elements volume elements

Meshing tools The meshing tools accessible in the Mesh context are the following:

Tool Function Mesh point to control the size of mesh elements through

the geometric points Mesh line to control the size of mesh elements through

the geometric lines Mesh generator (or algorithms for meshing)

to perform the subdivision into finite elements on faces or volumes

Relaxation to control the repartition of the mesh density through lines, faces and volumes

Shadow To control the mesh in the area where two object are close (only in 3D)

Mesh point The Mesh point distributes nodes on the lines based on weights assigned to

points. The node spacing on a line between two end points with different mesh points is determined by interpolation, taking into consideration the different values at the two ends of the line.

Default mesh points

There are three predefined mesh points: SMALL MEDIUM LARGE

Their values are computed by Flux according to dimensions of the geometry of the device.

The default mesh point values proposed to the user are expressed in millimeters.




Mesh line The Mesh line diline length.

stributes nodes on the lines based on a subdivision of the

distribution of nodes on lines:

tributed in a geometrical progression (non-uniform distribution of

to take into account the node distribution on curved lines f the deviation type (repartition of nodes in function of a

We can distinguish two modes of uniformly distributed nodes: line elements of the same length (uniform

distribution of nodes) dis nodes

nodes) It is also possiblewith the Mesh line odeviation criteria)

Mesh generators generic me

- none (no mesh) h generators (assoc

- linked

r lux2D.

Mesh generator

The different mesh generators are the following: sh generators:

ic - automat- mapped

users mes iated with a transformation):

- extrusion The automatic mesh generato is used by default in F

Function automatic to create t

tetrahedra(option to apply deviation on faces in 3D)

riangular elements on the surfaces and l elements on the volumes

mapped to create quadrangular elements on surfaces and the hexahedral elements on the volumes

none (no mesh) to impose non meshed zones linked to impose the same mesh on faces linked by a geometric

transformation extrusion to reproduce the same mesh in layers on domains

obtained by extrusion (the volume elements are prisms or hexahedrons, depending on the mesh of the base faces)




Relaxation uality

e

Medium relaxation on lines

High relaxation on lines

Relaxation enables the creation of triangular or tetrahedral good qelements as big as possible depending of the size of geometrical entity. Thmesh is denser on small entities and more relaxed on bigger entities, depending on the relaxation coefficient. The example below show relaxation on lines:

Low relaxation on lines

Shadow (3D) Shadow can be applied on faces closed to each other in 3D only. Shadow

jects.

enables to take into account the proximity of disconnected ob



3.3.2. Modify the Aided relaxation on lines and faces

Action as

Edit the Aided mesh box and modify the relaxation on lines and facesbelow.

1. Edit the Aided mesh box 2. Select Relaxation as parameters of aided

mesh 3. Select Low (r=0.25) as setting of

s relaxation

for lin 4. Select Low (r=0.25) as setting of relaxation

5. Click on OK

e

for faces



3.3.3. Modify the mesh points

Goal The LARGE mesh point, applied to the points on the outer lines of the

infinite box, and the MEDIUM mesh point, applied to the points on the inner lines of the infinite box, will be modified.

Data The table below describes the new values for the LARGE and MEDIUM

mesh points.

Mesh points

Name Comment Value Color LARGE Large mesh size 8 Red MEDIUM Medium mesh size 4 Yellow

Action To modify the mesh points from the Data tree:

1. Click on LARGE and MEDIUM, keeping the Ctrl key pressed

2. Right click to open the contextual menu

and click on Edit array

3. Type 8 as

value for the LARGE mesh point

4. Type 4 as value for the MEDIUM mesh point

5. Click on OK



3.3.4. Assign mesh points to points

Goal The mesh points will be assigned to the points on the infinite box as foll

the MEDIUM mesh point will be assigned to the points on the inner lines

ows:

MEDIUM

the LARGE mesh point will be assigned to the points on the outer lines

LARGE




Action To assign mesh point to points from the …

Mesh menu: 1. Point on Assign mesh information

and click on Assign mesh point to points

OR


2. Select the points in the graphic scene:

click on the points, keeping the Ctrl key pressed

=> its reference number enters 3. Select MEDIUM as mesh point 4. Click on OK

5. Repeat steps 2 to 4 in the nassign the LARGE mesh point to points(see the figure on the previous page)

ew dialog to …




3.3.5. Create a mesh point

Data The table below describes the characteristics of the mesh points for the probe.

Mesh point

Name Comment Unit Value Color MAG_MP Magnet mesh point millimeter 0.5 White

Action To create the mesh points from the …

Data tree: 1. Double-click on Mesh point

OR


2. Type MAG_MP as name 3. Type Magnet mesh point as comment 4. In the Definition tab select MILLIMETER

as associated length unit 5. Type 0.5 as value of the mesh point 6. Click on the Appearance tab 7. Select White as color

8. Click on OK


Result The new mesh point is listed in the data tree:



3.3.6. Assign the mesh point to points

Goal The mesh points will be assigned to the points belonging to two magnets, as

shown in the figure below.

MAG_MP

Action To assign a mesh point to points from the …

Mesh menu:

1 Point on Assign mesh information and click on Assign mesh point to point

OR Mesh toolbar: 1. Click on the icon




2. Click on 3. Click on Selection by

face

4. Select the face in the graphicscene:click on the four faces constituting the magnets

5. Click on Union

4. Select the face in the graphicscene:click on the four faces constituting the magnets

5. Click on Union

=> point reference

6. Select MAG_MP as mesh point7. Click on OK

numbers enter=> poi rence

6. Select MAG_MP as mesh point7. Click on OK

nt refe numbers enter


Result The points to which the mesh point were assigned appear in white for the

magnets



3.3.7. Create a mesh line

Data The table below describes the characteristics of the mesh line for teeth

extremities.

Mesh Line

Name Type Value Color MESHLINE_1 Relative deviation 1.0 White

Action To create the mesh line from the …

Data tree: 1. Double-click on Mesh point

OR

Mesh toolbar:


2. Type Meshline_1 as name 3. In the Definition tab select

Relative deviation 4. Type 1.0 as value of the mesh

point 5. Click on the Appearance tab 6. Select White as color

7. Click on OK

8.




Result The new mesh line is listed in the data tree:



3.3.8. Assign meshline to lines

Goal The meshline will be assigned to the lines constituting the extremity of the

cogged wheel. The goal is to increase the mesh density in the air gap between the teeth and the magnets when they are in front of each other.

Meshline_1

Action To assign a mesh line to lines from the …

Mesh menu:

2 Point on Assign mesh information and click on Assign meshline to lines

OR Mesh toolbar: 1. Click on the icon




2. Select the lines in graphic viewmaintaining Ctrl key pressed

3. Select meshline_1

4. Click OK

2. Select the lines in graphic viewmaintaining Ctrl

4. Click OK

key pressed

3. Select meshline_1




3.3.9. Mesh lines and faces

Goal The computation domain will be meshed in the following way: meshing lines

and meshing faces.

Action 1 To mesh lines from the …

Mesh menu: 1. Point on Mesh and click on Mesh lines

OR


Result 1 The next figure is displayed in the graphic scene.




Action 2 esh faces from the … To m

Mesh menu: 1. Point on Mesh and click on Mesh faces

OR


Result 2 The next figure is displayed in the graphic scene.

The output is displayed in the History zone: Total number of nodes --> 15463

Surface elements : Number of elements not evaluated : 0 % Number of excellent quality elements : 99.4 % Number of good quality elements : 0.58 % Number of average quality elements : 0.01 % Number of poor quality elements : 0 % meshFaces executed



3.3.10. Save the project and close the Flux2D window

Goal The current project wi Flux2D window will be closed to

return to the Flux Supervisor 11.1.

ll be saved and the

Action 1 To save the geomeshbuilt.FLU project from the …

Project menu: 1. click on Save

OR

Project toolbar: 1. click on the icone

Action 2 To close the Flux2D window from the …

Project menu: 1. click on Exit

OR

Project toolbar: 1. click on the icone





4. Annex

Introduction This chapter describes the utilization of command files.


Topic See Page About command files and the Python language 123 Execute command file 125





4.1. Use of command files

Introduction This section describes the use of command files.


Topic See Page About command files and the Python language 124 Execute command file 125



4.1.1. About command files and the Python language

Introduction Instead of manually executing a series of repetitive actions in Flux, you can

save time by building and executing a command file that performs the task in our place automatically (like a WORD or EXCEL macro).

y

Command file: definition

A command file is a series of Flux commands and instructions wrimatically.

tten in the Python language intended to execute a series auto

Interest and file is useful for: accelerating the most frequent operations combining several commands performing a complex series of tasks

A comm



4.1.2. Execute command file

Goal After making a copy of the py file (Flux2D_log.py) of the current project in a

new directory (Tutorial), we will restart the Flux2D window by executing this py file.

Action

To execute the py file from the Project menu:

1. Point on Execute command file… and click on Execute command file…

2. Select Preflu2D_log.py

3. Click on Open

vérifier le nom du fichier python…

Result The new files with .FLU extension are recreated in the new directory:

PROBE_2D.FLU WHEEL_BASE_2D.FLU SENSOR_2D.FLU

Documents

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