geometry and mesh tutorial / first steps in using flux

CAD package for electromagnetic and thermal analysis using finite elements

Fluxby CEDRAT

Geometry and mesh tutorial / First steps in using Flux2D basic example

Flux is a registered trademark.

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

This tutorial was edited on 3 juillet 2012

Ref.: KF 2 05 -G- 111 - EN -07/12

CEDRAT 15 Chemin de Malacher - Inovallée

38246 Meylan Cedex FRANCE

Phone: +33 (0)4 76 90 50 45 Fax: +33 (0)4 56 38 08 30

E-mail: [email protected] Web: http://www.cedrat.com

http://www.cedrat.com/�

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 geometry and mesh description process using a simple device. 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 \ GeometryMesh. 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 two probes PROBE_2D.FLU Geometry of the wheel base object WHEEL_BASE_2D.FLU

buildGeom.py Geometry of the sensor (complete device)

SENSOR_2D.FLU

buildMesh.py Meshed complete device SENSOR_2D.FLU*

The main.py enables the launch of these command files *SENSOR_2D.FLU is re-used as a base in the Magneto statics application tutorial

Flux TABLE OF CONTENTS

Geometry and mesh tutorial PAGE A

TABLE OF CONTENTS

Part A: General information 1

1. Overview..................................................................................................................................3 1.1. Introduction ...................................................................................................................................4 1.2. The studied device: a variable reluctance speed sensor..............................................................5 1.3. The device description in Flux: which strategy? ...........................................................................6 1.4. Main stages for geometry description ...........................................................................................7

2. Get started with Flux................................................................................................................9 2.1. Start the Flux Supervisor.............................................................................................................11 2.2. About the Flux Supervisor...........................................................................................................12 2.3. Open Flux2D ...............................................................................................................................13

Part B: Geometry and mesh description of the studied device 15

1. Geometric description of the probe object .............................................................................17 1.1. Create a Flux project for the probe .............................................................................................19

1.1.1. Create a new project for the probe ...............................................................................20 1.1.2. About the Flux2D window.............................................................................................21 1.1.3. About the Help menu / User guide ...............................................................................22 1.1.4. About the geometry context..........................................................................................24 1.1.5. Name the project ..........................................................................................................25

1.2. Strategy and tools for geometry description of the probe ...........................................................27 1.2.1. Available geometric tools and analysis before geometry description...........................28 1.2.2. Main stages for the probe geometry description ..........................................................30

1.3. Creation of geometric tools .........................................................................................................31 1.3.1. Deactivate Aided mesh.................................................................................................32 1.3.2. About creation of an entity ............................................................................................33 1.3.3. About geometric parameters ........................................................................................35 1.3.4. Create the geometric parameters.................................................................................36 1.3.5. About the undo command.............................................................................................38 1.3.6. About selection of graphic entities................................................................................39 1.3.7. About modification and deletion of an entity.................................................................41 1.3.8. About graphic view .......................................................................................................44 1.3.9. Change the background color ......................................................................................46 1.3.10. About coordinate systems ............................................................................................47 1.3.11. Create the coordinate systems.....................................................................................49

1.4. Creation of points and lines for the probe base ..........................................................................52 1.4.1. About points..................................................................................................................53 1.4.2. Create points for the probe base ..................................................................................54 1.4.3. About display of entities in the graphic scene ..............................................................56 1.4.4. About lines ....................................................................................................................57 1.4.5. Create lines for the probe base ....................................................................................58

1.5. Building faces for the probe ........................................................................................................61 1.5.1. About automatic construction .......................................................................................62 1.5.2. Build faces of the probe base .......................................................................................63 1.5.3. About transformations...................................................................................................64 1.5.4. Create the geometric transformation ............................................................................66 1.5.5. About propagation and extrusion..................................................................................68 1.5.6. About selection by criterion ..........................................................................................69 1.5.7. Propagate faces............................................................................................................70 1.5.8. Save and close the project ...........................................................................................73

2. Geometric description of the wheel base object ....................................................................75 2.1. Create a Flux project for the wheel base ....................................................................................77

2.1.1. Create and name a new project for the wheel base.....................................................78 2.2. Strategy and tools for geometry description of the wheel base object .......................................79

2.2.1. Available geometric tools and analysis before geometry description...........................80

TABLE OF CONTENTS Flux

PAGE B Geometry and mesh tutorial

2.2.2. Main stages for the wheel base geometric description.................................................82 2.3. Creation of geometric tools .........................................................................................................83

2.3.1. Deactivate aided mesh .................................................................................................84 2.3.2. Create the geometric parameters .................................................................................85 2.3.3. Create the coordinate system.......................................................................................87

2.4. Creation of points and lines for the wheel base ..........................................................................89 2.4.1. Create the points for the wheel base............................................................................90 2.4.2. Create the lines for the wheel base ..............................................................................92

2.5. Building the face for the wheel base ...........................................................................................95 2.5.1. Build the face ................................................................................................................96

2.6. Creation of the transformation.....................................................................................................97 2.6.1. Create the transformation .............................................................................................98 2.6.2. Save and close the project ........................................................................................ 101

3. Geometric description of the sensor....................................................................................103 3.1. Create a Flux project for the sensor......................................................................................... 105

3.1.1. Create and name a new project for the sensor ......................................................... 106 3.2. Strategy and tools for geometric description of the sensor...................................................... 107

3.2.1. Available geometric tools and analysis before geometry description........................ 108 3.2.2. Main stages for geometric description....................................................................... 109

3.3. Importation of the wheel base object and building the whole wheel........................................ 111 3.3.1. Import the wheel base object..................................................................................... 112 3.3.2. Geometry building process of the wheel.................................................................... 113 3.3.3. Propagate the face (tooth) ......................................................................................... 114 3.3.4. Extrude the line .......................................................................................................... 117 3.3.5. Create an arc ............................................................................................................. 119 3.3.6. Propagate the arc ...................................................................................................... 121 3.3.7. Build faces ................................................................................................................. 123

3.4. Importation of the probe objects and positioning of the wheel and probes.............................. 125 3.4.1. Import the first probe object ....................................................................................... 126 3.4.2. Modify the parameters ............................................................................................... 128 3.4.3. Import the second probe object ................................................................................. 129

3.5. Completing the domain ............................................................................................................ 131 3.5.1. About an infinite box .................................................................................................. 132 3.5.2. Add an infinite box ..................................................................................................... 133 3.5.3. Build faces ................................................................................................................. 134

4. Mesh generation of the sensor............................................................................................135 4.1. Strategy and tools for mesh generation of the sensor ............................................................. 137

4.1.1. Available meshing tools and analysis before mesh generation................................. 138 4.1.2. Main stages for mesh description .............................................................................. 139

4.2. Meshing the sensor with aided mesh....................................................................................... 141 4.2.1. Change to the mesh context...................................................................................... 142 4.2.2. About the mesh context ............................................................................................. 143 4.2.3. About Aided mesh...................................................................................................... 144 4.2.4. Synchronize Aided mesh value and mesh lines and faces ....................................... 145

4.3. Optimize the mesh ................................................................................................................... 149 4.3.1. About mesh tools ....................................................................................................... 151 4.3.2. Modify the Aided relaxation on lines and faces ......................................................... 154 4.3.3. Modify the mesh points.............................................................................................. 155 4.3.4. Assign mesh points to points ..................................................................................... 156 4.3.5. Create a mesh point................................................................................................... 158 4.3.6. Assign the mesh point to points................................................................................. 159 4.3.7. Create a mesh line..................................................................................................... 161 4.3.8. Assign meshline to lines ............................................................................................ 163 4.3.9. Mesh lines and faces ................................................................................................. 165 4.3.10. Save the project and close the Flux2D window......................................................... 167

Flux TABLE OF CONTENTS

Geometry and mesh tutorial PAGE C

5. Annex...................................................................................................................................169 5.1. Use of command files................................................................................................................171

5.1.1. About command files and the Python language.........................................................172 5.1.2. Execute command file ................................................................................................173

TABLE OF CONTENTS Flux

PAGE D Geometry and mesh tutorial

Flux Part A: General information:

Geometry and mesh tutorial PAGE 1

Part A: 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 9

Part A: General information Flux

PAGE 2 Geometry and mesh tutorial



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 device description in Flux: which strategy? 6 Main stages for geometry description 7



1.1. Introduction

Introduction Flux is 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 done in the Flux standard mode. The user will have to close the Sketcher 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 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.



1.2. 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



1.3. The device description in Flux: which strategy?

Problem How to describe the device in Flux?

Reminder: we only are interested in geometrical construction and generation of the mesh.

Geometric structure

The device consists of: one cogged wheel with three teeth two probes with a magnet and a coil around

PROBE 2

COIL 2-

COIL 2+

MAGNET 1

COIL 1-

COIL 1+

WHEEL

MAGNET 2

PROBE 1

Strategy Two strategies of description exist:

one-phase description: - description of the whole device in only one Flux project

two-phase description: - independent description of separated parts of the device in several Flux

projects - import of the independent projects (PROBE_2D.FLU and

WHEEL_BASE_2D.FLU) into one main project SENSOR_2D.FLU

The second strategy is selected in this tutorial.

Of course, the geometry can be built in ways other than the presented one. The sensor geometry is defined in this particular way in order to introduce you to the most used Flux2D features.

Continued on next page



1.4. Main stages for geometry description

Process (general aspects)

An outline of the general construction process is given in the two following blocks: the first process (1) is presented for ease of understanding the second process (2) is the real building process used in this document.

Process (1) An outline of the logical process of the geometry description is given in the

table below.

Phase Description 1 Probe description

2 Cogged wheel description

3 Sensor description

4 Addition of air around the device and closing of the domain

by the technique of the Infinite Box




Process (2) An outline of the real process of the geometry description, used in this tutorial,

is given in the table below.

1 Probe description Project: PROBE_2D.FLU

2 Wheel base object description (elementary pattern) Project: WHEEL_BASE_2D.FLU

3 Sensor description Project: SENSOR_2D.FLU

Importation of the elementary pattern (WHEEL_BASE_2D)

Building of the whole wheel

Importation of a probe object (PROBE_2D)

Rotation of the probe and rotation of the cogged wheel

Importation of a probe object (PROBE_2D)

Addition of an Infinite Box



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 § 1.1.2 About the Flux2D window.


Topic See Page Start the Flux Supervisor 11 About the Flux Supervisor 12 Open Flux2D 13



2.1. Start the Flux Supervisor

Goal Starting Flux involves opening the Flux Supervisor.

Action To start Flux from the Windows taskbar:

Start Program Cedrat Flux

Result The Flux Supervisor window opens.



2.2. About the Flux Supervisor

The Flux Supervisor window

The Flux Supervisor organizes all the modules for both Flux2D and Flux3D.

The Flux Supervisor window is divided into several areas. These areas are identified in the following figure and described in the table below.

Menu bar

Tool bar

Program manager

Modules

Project files

Geometry view

Directory manager

Most recent used files

Area Function Modules to list and launch all the Flux modules (Flux2D,

Circuit, etc.) Directory manager to show the computer’s complete directory Project files to display all Flux projects in the selected directory Program manager contains shortcuts to the Dos Shell and the Explorer Geometry view to display a preview of the geometry, if a project is

selected Recent files To display most recent used

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.



2.3. Open Flux2D

Goal The preprocessor Flux2D will be opened to manage the geometry building of

the device and mesh generation.

Action To open Flux2D from the Flux Supervisor:

1. Click on the Flux2D tab

2. Select the directory of the project

3. Double-click on Geometry&Physics




Result The PreFlux window for Flux 2D applications is opened.

There are two menus in the PreFlux window: Project and Help*.

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

Flux Part B: Geometry and mesh description of the studied device:


Part B: Geometry and mesh description of the studied device

Introduction This part B contains the description of the studied device and provide when

needed some information about the Flux software.

Contents This part contains the following topics:

Topic See Page Geometric description of the probe object 17 Geometric description of the wheel base object 75 Geometric description of the sensor 103 Mesh generation of the sensor 135 Annex 169

Part B: Geometry and mesh description of the studied device Flux




1. Geometric description of the probe object

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

data required to describe the probe geometry.

The probe object is presented in the figure below.

COIL

MAGNET


Topic See Page Create a Flux project for the probe 19 Strategy and tools for geometry description 27 Creation of geometric tools 31 Creation of points and lines for the probe base 52 Building faces for the probe 61



1.1. Create a Flux project for the probe

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 new project for the probe 20 About the Flux2D window 21 About the Help menu / User guide 22 About the geometry context 24 Name the project 25



1.1.1. Create a new project for the probe

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. The new project is temporarily named ANONYMOUS. The Flux2D window for Flux 2D applications is opened directly in the Sketcher context as below.

Action Close the sketcher context in order to describe the geometry in Flux.



1.1.2. About the Flux2D window

Flux2D window The Flux2D project window opens in the Geometry context. The Flux2D

project window has the complete set of the tools to build the geometry of the device, to mesh the computation domain and to visualize the device during different steps of the construction.

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

areas can be resized or hid by using the arrows.

Graphic scene Data tree

History zone

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

expanded using the key Graphic scene displays the graphic entities History zone prints Python command instructions

Menus and toolbars

All Flux2D commands are in the menus. Toolbars include icons that are shortcuts to the most useful commands.

Menus

Toolbars



1.1.3. 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 To open the complete user’s guide in the Flux Supervisor from the …

Help menu:

1. Click on Manual…

OR

Help toolbar: 1. Click on the icon

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

1. Click on Contents

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.



1.1.4. About the geometry context

Presentation There are three contexts in Flux2D:

Context Function Geometry to build the geometry of the device Mesh to mesh the computation domain Physics* to define the materials, sources and to prepare the

regions

* The icon corresponding to the Physics context appears after the definition of the physical application

Tools of the geometry context

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

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

1 2 3 4 5

6

Geometry context toolbars Function 1 to create geometric entities 2 to propagate / extrude points, lines, etc. 3 to build faces 4 to compute geometric values 5 to check the geometry 6 to display point and line reference numbers



1.1.5. Name the project

Goal The new project, temporarily named ANONYMOUS, will be renamed and

saved.

Action To rename the project from the …

Project menu: 1. Click on Save or

Save as…

OR


2. Type PROBE_2D as project name

3. Click on Save

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.



1.2. Strategy and tools for geometry description of the probe

Introduction This section shows:

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

selected strategy


Topic See Page

Available geometric tools and analysis before geometry description

28

Main stages for the probe geometry description 30

Reading advice This section presents an outline of the geometry building process of the

probe. Details on the different contents - definition of new concepts, explanation on the use of different tools, etc.- are given in the following sections.



1.2.1. Available geometric tools and analysis before geometry description

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

coordinate systems and transformations.

Geometric tool Function geometric parameter to allow the dimensional parameter setting of parts coordinate system to facilitate the relative positioning of parts transformation to allow the construction by propagation or extrusion

Device analysis and choice of construction 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.

In order to… …it is planned to… …as show in the figure below

enter the coordinates of the points

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




Device analysis and choice of construction tools (continued)

In order to… …it is planned to… …as show in the figure below

locate the probe in the final project (anticipation)

create a MAIN_CS Cartesian coordinate system

(the PROBE_CS coordinate system will be attached to this coordinate system) create an ANGLE

parameter to define the angular position of the MAIN_CS coordinate system

MAIN_CS

PROBE_CS

ANGLE

simplify the geometry building

create a MIRROR transformation of the affinity type to build faces by propagation

MIRROR



1.2.2. Main stages for the probe geometry description

Outline An outline of the geometry building process is presented in the table below.

Stage Description

1 De-activation of Aided mesh

As the PROBE.FLU will be later imported in Sensor_2D.FLU it is necessary to de-activate the Aided mesh*

2 Creation of 6 geometric parameters

Inner radius of the coil: COIL_IR = 2.8 mm Outer radius of the coil: COIL_OR = 3.5 mm Height of the coil: COIL_H = 16 mm Radius of the magnet: MAG_R = 2.5 mm Height of the magnet: MAG_H = 20 mm Angle for the probe angular position

in the final device: ANGLE = 0°

3 Creation of 2 coordinate systems

Cartesian coordinate system: MAIN_CS (Global coordinate system for the probe positioning in the final device)

Cartesian coordinate system: PROBE_CS (Local coordinate system for the probe description)

4 Creation of points and lines for the probe base

5 Building faces for the probe base

6 Creation of 1 transformation

Affine transformation for the probe: MIRROR

7 Building faces by propagation (and preparation of the mesh generator*)

* Explanation concerning this subject is presented in “ About mesh tools” on Linked Mesh Generator)



1.3. Creation of geometric tools

Introduction The geometry building begins by the creation of geometric tools to build the

probe geometry: geometric parameters and coordinate systems.

The parameters and coordinate systems required to describe the geometry of the probe are presented in the figure below.

MAG_H

COIL_H MAG_R

COIL_IR

COIL_OR

MAIN_CS

PROBE_CS ANGLE


Topic See Page Deactivate aided mesh 32 About creation an entity 33 About geometric parameters 35 Create the geometric parameters 36 About the undo command 38 About selection of graphic entities 39 About modification and deletion of an entity 41 About graphic view 44 Change the background color 46 About coordinate systems 47 Create the coordinate systems 49



1.3.1. Deactivate Aided mesh

Definition Aided mesh is a tool box that permits the user to quickly realize a good

quality mesh. The aided mesh (global adjustment) is activated by default on all flux projects (See About Aided mesh).

Aided mesh and imported Flux project

Aided mesh assigns specific global tool on all entities of a new project. In order not to interfere during project import to the main project, it is needed to de-activate aided mesh on project that will be imported later.

Action To deactivate the Aided mesh, from the Menu:

1. Edit the aided mesh box

2. Select “Inactivated” in the State of aided mesh field



1.3.2. About creation of an entity

Definition of entity

An entity is an object in the database of a Flux project. It can be: a point, a line, a coordinate system, etc. in the Geometry context a mesh point, a mesh line, etc. in the Mesh context a line region, a volume region, etc. in the Physics context

Creating process

An outline of the creating process is presented in the table below. The different steps are detailed in the blocks describing the creation of project entities.

Step Description 1 Activating the New command 2 Definition of entity attributes

Access the “New” command

The access to the New command can be carried out: from the Geometry menu bar (1) using icons from the Geometry toolbar (2) from the data tree (3)

These three methods to access the New command are presented in the following figure (with the example of creation of a geometric parameter) and described in the table below.

1

3

2

Method Description 1 point on the entity-type and click on New 2 click on the corresponding icon 3 double-click on the entity-type or right click and click on New




Dialog box The interaction with the database is done using dialog boxes. The user can

enter information relating to the data in this box.

Entity-type: Geometric parameter

Name Comment

Characteristics

Title bar

On-line help concerning the entity

The required fields (necessary and sufficient for the definition of the entity) are marked by an asterisk *.



1.3.3. 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.



1.3.4. Create the geometric parameters

Goal Six parameters, required to describe the geometry of the probe, are presented

in the figure below.

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 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

Geometry toolbar: 1. Click on the icon

2. Type COIL_IR as name 3. Type Inner radius of the coil as

comment 4. Type 2.8 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:

Notice too, that as you move your cursor over the parameter names, the comments are displayed to help you to identify the parameters.



1.3.5. 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

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

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



1.3.6. About selection of graphic entities

Overview of selection modes

Selection of entities can be done with the following selection modes: graphic selection (with the mouse)

- in the data tree for all entities - in the graphic scene for graphic entities

identifier selection (by name / by number) advanced selection (by criterion / by choice)

Graphic selection process

An outline of the selection process for graphic entities is presented in the table below. The different steps are detailed in the blocks describing the creation of project entities.

Step Description 1 Activating of the selection filter 2 Selection of the entity in the graphic scene

Selection filter A selection filter makes possible to identify the selectable entity-type.

For the graphic entities, the selection filter can be activated by the commands from the Selection menu or from the Selection toolbar.

Selection menu/ toolbar

The choices in the Selection menu or in the Selection toolbar relate to the graphic entities; they are presented in the figure and described in the table below.

Noselection

Freeselection

Select points / lines / faces / volumes

Select face regions / volume regions

Choice Description No selection nothing selectable

Free selection all is selectable The first entity, selected by the user, determines the entity-type selectable

Select points the points are selectable … …




Step 1: activating of the selection filter

The activating of the selection filter can be carried out: from the Select menu (1) using icons from the Select toolbar (2)

These two methods to activate the selection filter are presented in the following figure and described in the table below.

1

2

Step 2: selection in the graphic scene

Click on the specific graphic entity to select the entity in the graphic scene. The selected entity is highlighted.



1.3.7. About modification and deletion of an entity

Modification / deletion process

An outline of the modification / deletion process is presented in the table below.

Step Description

1 Activating the command (Edit, Edit array, Delete, Force delete) and selection of entities

2 Modification of the entity characteristics / Validation of the entity deletion

Access the commands

For the commands Edit / Edit array / Delete / Force delete, which require data selection, the access to the command, can be carried out: from the menu

- activation of the command and then selection via a selection box (1) from the data tree:

- activation of the command and then selection via a selection box (2) - direct selection of an entity and then activation of the command (2’)

from the graphic scene (only for graphic entities)

These methods to access the command are presented in the following figure (with the example of editing the ANGLE geometric parameter) and described in the table below.

1

2

Selection via

a selection box

2’

Selection via

a selection box

Method Description 1 point on the entity-type and click on the command

select entities via a Selection box 2 right click on the entity-type and click on the command

select entities via a Selection box 2’ double-click on the entity

or right click on the entity and click on the command 3 right click on the graphic entity* and click on the command

* The corresponding selection filter must be first activated.




Edition mode To check the data, the user needs to edit (and modify if necessary) the entities

created.

There are two modes of edition: the edition in a dialog box is used to check and to modify the

characteristics of one entity

Entity-type

Name Comment

Type (1)

Characteristics

Entity

Type (2)

On-line help concerning the entity

the edition in a data array is used to check and to modify the characteristics of a group of entities

Entity-type

Name Comment

Type (1)

Characteristics

Entities: [CORE], [MAIN]

Type (2)

Structure(Database)

Information relating to the

group of entities

Information relating to the entity [CORE]

Information relating to the entity [MAIN]




Deletion mode The user sometimes needs to delete entities. He can easily delete an entity if it

is an independent entity. However, very often, the entity is connected to other entities and the deletion of the entity can cause the deletion of all the connected entities.

There are thus two modes of deletion: the simple deletion:

is carried out on independent entities (non connected with other entities) the in force deletion :

is carried out on any entity.

These two modes are described in the table below:

Mode Destroyable entity What is destroyed simple independent selected entity in force any selected entity + entities connected to it



1.3.8. About graphic view

Introduction When referring to the graphic representation of a device, we are interested in:

the different entities and their appearance: points and their visibility, lines and their color, faces, surface elements, etc.

the type of displayed view: side view, top view, bottom view, global view, etc. and its position and dimensions in the graphic display zone.

How to modify a view

There are three methods to modify the view in the graphic scene. The modifications can be made: from the View menu (1) using icons from the View toolbar (2) using the mouse (3)

1

3

2




Using the View menu / icons

Flux2D offers modes to modify the view using commands from the View menu or icons from the View toolbar. They are described in the table below.

Command Icon Mode Mode activation Zoom all To set total view click on the command / icon Zoom out - To reduce the view click on the command Zoom in + To enlarge the view click on the command

Zoom region

To enlarge a part of view

click on the command / icon and select the rectangular zone to enlarge using the mouse

4 views mode

To set unset the 4 views mode

click on the command / icon

Full device To display or not the full device

click on the command / icon

Using the mouse

Flux2D offers modes to modify the view using the mouse, described in the table below. User can determine the active mode by the different cursors.

Mode Mode activation Cursor

Displacement (to translate the view)

click on the view with the right button of the mouse and drag the view to the new location, keeping the right button pressed

Dimension (to resize the view)

click on the graphic scene with the left button of the mouse and resize the view with the scrolling wheel of your mouse

Predefined views

It is possible to choose one view from predefined views available in Flux.

The different commands to set predefined views and their corresponding icons are presented in the table below.

View command Icon Description

Standard view Flux2D predefined view (default one)

Background color

It is possible to swap the background color from black to white and vise versa by using the Reverse video command.



1.3.9. Change the background color

Goal To better visualize the geometry, the background color will be changed.

Action To change the background color from the View menu:

1. Click on Reverse video



1.3.10. 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.

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, )

y

x

p

r

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

x

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



1.3.11. Create the coordinate systems

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

presented in the figure below.

MAIN_CS

PROBE_CS

32 mm

Data The tables below describe the coordinate systems.

Cartesian coordinate system type defined with respect to the Global system

Origin coord.

Rotation angle Name Comment Units

X Y About Z

MAIN_CS Main coordinate system

millimeter/ degree

0 0 ANGLE

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 systems from the …


on Coordinate system

OR


2. Type MAIN_CS as name of coordinate system

3. Type Main coordinate system as associated comment

4. Select Cartesian as type of coordinate system

5. Select Global as definition of coordinate system

6. Select MILLIMETER as length unit

7. Select DEGREE as angle unit 8. Type 0 as first coordinate 9. Type 0 as second coordinate

10. Type ANGLE as rotation angle

about Z axis 11. Click on OK




12. Type PROBE_CS as name of coordinate system

13. Type Probe coordinate system as comment

14. Select Cartesian as type 15. Select Local as definition of

coordinate system 16. Select MAIN_CS as parent

coordinate system

17. Type 32 as first coordinate 18. Type 0 as second coordinate 19. Type 0 as rotation angle about Z

axis 20. Click on OK


Result The two new coordinate systems are … listed in the data tree: displayed in the graphic scene*:

PROBE_CSMAIN_CS

* use the Zoom all command or (see § About graphic view).



1.4. Creation of points and lines for the probe base

Introduction The next step of the geometry description is the creation of points and lines to

build the probe.

The next figure describes the geometry of the probe.

MAG_H

COIL_HMAG_R

COIL_IR

COIL_OR


Topic See Page About points 53 Create points for the probe base 54 About display of entities in the graphic scene 56 About lines 57 Create lines for the probe base 58



1.4.1. About points

Points A point can be created:

as a set of coordinates in a specified coordinate system as an image of an existing point through a geometric transformation within the propagation or extrusion from other entities

Point coordinates

A point could be defined by its coordinates in a coordinate system (see § About coordinate systems).

Point defined by propagation

A point could be defined by propagation from another point using a transformation.

translation

origin point

created point

Point number The number to identify the point is automatically allocated by Flux during the

point creation.



1.4.2. Create points for the probe base

Goal Eight points are required to build the probe base, as presented in the figure

below.

Point 1 MAG_H

COIL_H

Point 2 Point 3

Point 4

PROBE_CS

Point 5 Point 6 Point 7

Point 8

MAG_R COIL_IR

COIL_OR

Data The table below describes the points for the probe base.

Points defined by its parametric coordinates

Coordinates No

Coordinate system X Y

1 -MAG_H/2 0 2 -MAG_H/2 MAG_R 3 MAG_H/2 MAG_R 4 MAG_H/2 0 5 -COIL_H/2 COIL_IR 6 -COIL_H/2 COIL_OR 7 COIL_H/2 COIL_OR 8

PROBE_CS

COIL_H/2 COIL_IR




Action To create the points from the …

Data tree: 1. Double-click on Point

OR

Geometry toolbar:


2. In the Geometric Definition tab

select Point defined by its parametric coordinates as type of point

3. Select PROBE_CS as coordinate system

4. Type -MAG_H/2 as first coordinate

5. Type 0 as second coordinate

6. Click on OK

7. Repeat steps 4 to 7 in the new dialog, entering data for the remaining entities (see the table on the previous page)

…


Result The points are … listed in the data tree:

displayed in the graphic scene:



1.4.3. About display of entities in the graphic scene

Introduction The graphic representation of objects is not the same during the different

steps of building the device model.

From one step to the next, we are interested in: representation of points and lines during geometry building representation of nodes and surface elements during mesh generation

Possibilities to modify the visualization

To control the graphic representation, Flux provides default settings, but the user can also modify this representation.

To do so, the following commands are available: the Display commands, which manages the list of entities to display, the Edit command, which allows the modification of the entity appearance

(characteristics of visibility and color)

How to display entities

There are two methods to display entities in the graphic scene. The modifications can be made: from the Display menu (1) using icons from the Display toolbar (2)

1

2



1.4.4. About lines

Lines Lines can be created: manually (choice of line type – segment or arc - and entering extremity

points) by propagation from existing lines using a transformation by extrusion from existing points using a transformation within the propagation or extrusion from other entities

Segments Segments are defined by starting and ending points. It does not matter if you

swap the starting and ending points.

Circle arcs Circle arcs can be defined in different ways:

either in a coordinate system: The arc is included in a plane parallel to the XOY plane. It is counter-clockwise oriented around an axis parallel to the OZ axis.

starting point

ending point

center point

radius

angle

or by three points: The arc is drawn around a triangle defined by three points. It is oriented in the direction imposed by three points.

ending point

starting point

middle point

Number The number to identify the line is automatically allocated by Flux during the line creation.



1.4.5. Create lines for the probe base

Goal Eight straight segments are required to connect each point and create closed

outlines of the magnet and coil bases.

The order to create the lines is presented in the figure below.

Line 1 Line 3

Line 4

Line 6 Line 7 Line 8

MAGNET base

COIL base

Line 2

Line 5

Data The table below describes the lines for the probe base.

Segment defined by starting and ending points

No Starting point Ending point 1 1 2 2 2 3 3 3 4 4 4 1 5 5 6 6 6 7 7 7 8 8 8 5




Action To create the lines from the …

Data tree: 1. Double-click on Line

OR

Geometry toolbar:


2. In the Geometric Definition tab

select Segment defined by starting and ending points as type of the line

3. Click on Point 1 in the graphic scene

=> its reference number enters as starting point

4. Click on Point 2 in the graphic scene=> its reference number enters as ending point

5. Repeat steps 3 to 4 in the new reduced dialog, entering data for the remaining entities (see the table on the previous page)

…


Result The lines are … listed in the data tree:




1.5. Building faces for the probe

Introduction The next step of the geometry description is building faces for the probe.

The probe geometry is presented in the figure below.


Topic See Page About automatic construction 62 Build faces of the probe base 63 About transformations 64 Create the geometric transformation 66 About propagation and extrusion 68 About selection by criterion 69 Propagate faces 70 Save and close the project 73



1.5.1. About automatic construction

Introduction The faces are automatically created and identified using the algorithms of

automatic construction.

Principle: overview

The principle of automatic face construction: First, Flux computes all the existing surfaces and determines which surfaces

the points and the lines belong to. (In Flux; a surface is defined by two lines connected to a shared point.)*

Next, the automatic face construction is carried out by a method of identification of closed contours. (In Flux, a face is defined by his contour and from one surface.)

About faces The faces created by Flux using the automatic construction algorithms are

faces contained by planar, cylindrical or conical surfaces. These faces are named automatic faces.

* In Flux2D, there is only one surface which is the 2D plane.



1.5.2. Build faces of the probe base

Goal The faces will be automatically built by Flux2D.

Action To build faces from the …

Geometry menu: 1. Point on Build and click on Build faces

OR


Result The faces are … listed in the data tree:




1.5.3. About transformations

Principle of use Transformations are geometric functions that allow the creation of new

objects from existing objects.

Various functions

The various available functions are: translation rotation affinity helix composed

Note: Only the transformation functions used in this tutorial are described here. Refer to the User’s guide for more information about transformations.

Rotation A rotation is defined by a rotation axis and an angle.

The figure below describes the creation of a new point using the rotation transformation defined by an angle and a pivot point (its coordinates or reference number)

rotation angle

original point

y

x

created point

pivot point

rotation axis is defined by: - a working coordinate system - and a pivot point

rotation angle is defined about Z axis

Note: The positive value of an angle corresponds to a counter-clockwise rotation



Affinity Affinity is defined with respect to a point or to a straight line.

The result of this transformation application depends on the affinity ratio, as presented in the table below.

Ratio Result k = -1 symmetry k = 1 identity k = 0 projection k >1 increasing (increasing affinity) 0< k < 1 reducing (reducing affinity) k < -1 increasing (increasing negative affinity) -1< k < 0 reducing (reducing negative affinity)

The examples below describe the creation of new lines using two different affinity transformations: Affine transformation with respect to a point

y

original line

center point of the affinity

(0.5)

x

(1)

(-1)

(-0.5)

(0)

Caution: Applying an affinity transformation with respect to a point with the scaling factor equal 0 causes an error, because the line is degenerated and reduced to a point.

Affine transformation with respect to a line defined by two points

(-1)

(-0.5)

(0)

original line

(1)

affinity line

y

x



1.5.4. Create the geometric transformation

Goal An affine transformation with respect to a line defined by 2 points is

required to build the probe geometry.

The points, defined the symmetry line of the transformation, are shown in the following figure:

Point 4 Point 1

Symmetry line

Data The characteristics of the transformation are shown in the following table:

Affine transformation with respect to a line defined by 2 points

Name Comment 1st point 2nd point Scaling factor

MIRROR Symmetry transformation for the probe

1 4 -1




Action To create the transformation from the …


on Transformation

OR


2. Type MIRROR as name 3. Type Symmetry transformation

for the probe as comment 4. Select Affine transformation with

respect to a line defined by 2 points as type

5. Type 1 as first point of straight line6. Type 4 as second point of straight

line 7. Type -1 as scaling factor 8. Click on OK


Result The transformation is listed in the data tree:



1.5.5. About propagation and extrusion

Definition The construction by propagation / extrusion is a building method that constructs new geometric entities, based on existing entities, by using a geometric transformation like translation, rotation, etc.

We deal with: propagation, when the image object, generated by transformation, is not

connected by lines to the source object extrusion, when the image object, generated by transformation, is

connected by lines to the source object

Examples In the figures below, the line is built by propagation / extrusion of the existing

line (source) using a translation vector.

Construction by propagation:

translation

source line

image line

Construction by extrusion:

translation

source line

connection elements

image line

Building options

Some building options are provided in order to simplify the user’s work and to carry out a certain number of repetitive tasks semi-automatically.

The building options for construction by propagation, classified in three categories, are presented in the table below.

The options … allow … for geometric building

to define the geometric entities (points, lines, faces) created during the propagation

for mesh preparation

to create the linked mesh generator associated to the transformation

to assign the linked mesh generator to the entities created by transformation

for preparation of regions

to create surface regions to assign the created regions to the geometric entities

created by transformation

The building options for construction by extrusion, classified in two categories, are presented in the table below.

The options … allow …

for geometric building

to define the form of connection elements to define the geometric entities (points, lines, faces)

created during the extrusion

for mesh preparation

to create the extrusion mesh generator associated to the transformation

to assign the extrusion mesh generator to the entities created by transformation



1.5.6. About selection by criterion

Definition / use One speaks about selection by criterion when the selection is carried out by

the intermediary of the existing relations between the various entities (points belonging to a line, ...) or characteristics, common to several entities (faces with the same color, faces on the same surface, ...).

Operation mode

The selection by criterion is available on the level of selection boxes and is carried out in two stages as presented in the table below.

Stage Description 1 From a selection box:

opening the criteria list (with the button ) and selection of a criterion

2 From a specific (with logical operators) selection box: selection of entities (graphic selection, by identifier or criterion) with applying selection operators to the group of entities

Selection criteria

The selection criteria are presented in the tables below.

General criteria The option … allows …

Select all selection of all entities Clean selection unselection of all the entities previously selected Select last instance selection of the last selected entity Selection by coordinates

selection of the nearest entity to the entered coordinates

Specific criteria (implying the use of the operators) The selection by … allows the selection of all the entities …

line / face / volume belonging to a line / face / volume surface belonging to a surface (defined by a face) linear / face / volume region belonging to a linear / face / volume region mechanical set belonging to a mechanical set color defined by a color visibility defined by a visibility (visible or invisible) nature defined by a nature (standard, in air, no exist) discretization defined by a discretization (point or line)

Selection operators

To manage the logical operations on the groups of the selected entities, the user disposes the selection operators introduced in the table below.

Operator Function Exclude to remove entities from the list Union to add entities in the list Intersect to carry out the intersection of two groups of selection



1.5.7. Propagate faces

Goal The MIRROR transformation will be applied once to propagate two faces, as

shown in the following figure.

Face 1

Face 2




Action To propagate the face from the …

Geometry menu: 1. Point on Propagate

and click on Propagate faces

OR


2. Click on 3. Click on Select all

=> face reference numbers enter 4. Select MIRROR as transformation5. Type 1 as number of times to apply

the transformation 6. Select Add Faces, Lines and

Points as building options for propagation

7. Click on OK





Result The faces are … listed in the data tree:




1.5.8. Save and close the project

Goal The current project will be saved and closed.

Action To save and close the PROBE_2D.FLU project from the …

Project menu: 1. Click on Close

OR


2. Click on Yes



2. Geometric description of the wheel base object

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

data required to describe the wheel base geometry.

The wheel base object is presented in the figure below.

TOOTH


Topic See Page Create a Flux project for the wheel base 77 Strategy and tools for geometry description of the wheel base object

79

Creation of geometric tools 83 Creation of points and lines for the wheel base 89 Building the face for the wheel base 95 Creation of the transformation 97



2.1. Create a Flux project for the wheel base




Topic See Page Create and name a new project for the wheel base 78



2.1.1. Create and name a new project for the wheel base

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

new project will be renamed and saved.

Action 1 To create a new project from the …


OR


Result 1 A new project named ANONYMOUS opens in the Geometry context by

default. The Geometry context icon is depressed, as shown in the following figure.

Action 2 To rename the project from the …


Save as…

OR


2. Type WHEEL_BASE_2D as project name

3. Click on Save



2.2. Strategy and tools for geometry description of the wheel base object


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

selected strategy


Topic See Page


80

Main stages for the wheel base geometric description 82




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

coordinate systems and transformations.

Device analysis and choice of construction 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.

The operations … it is planned …

to easily enter the coordinates of the points (elementary pattern)

to create a WHEEL_CS cylindrical coordinate system specific to the

wheel base (to anchor the wheel

center)

WHEEL_CS

to easily change dimensions of the wheel (elementary pattern)

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

BETA

TOOTH_IR

TOOTH_OR

WHEEL_R

to position the wheel in the final project (anticipation)

to create an ALPHA parameter to define the angular position of the WHEEL_CS coordinate system

ALPHA




Device analysis and choice of construction tools (continued)


to simplify the geometry building

to create a TOOTH_N parameter to define the number of teeth to create a ROTZ_WHEEL transformation of the rotation type to build the wheel base by propagation

ROTZ_WHEEL



2.2.2. Main stages for the wheel base geometric description

Outline An outline of the geometry description process to build the wheel base

geometry is presented in the table below.

Caution: the geometric tools will be prepared for building the whole wheel, but we will build only the elementary pattern. The construction of the whole wheel will be carried out with the sensor construction!!!

Stage Description

1 De-activation of Aided mesh

As the WHEEL_BASE.FLU will be later imported in Sensor_2D.FLU it is necessary to de-activate the Aided mesh*

2 Creation of 6 geometric parameters

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° Wheel radius: WHEEL_R = 10 mm Angle for the wheel angular position

in the final device: ALPHA = 0°

3 Creation of 1 coordinate system

Cylindrical coordinate system: WHEEL_CS (global coordinate system for the wheel description and positioning in the final device)

4 Creation of points and lines for the wheel base

5 Building the face for the wheel base

6 Creation of 1 transformation Rotation transformation for the wheel base: ROTZ_WHEEL

7 The next stages of building the whole wheel by propagation / extrusion will be carried out in the final project (SENSOR_2D.FLU)

* Explanation concerning this subject is presented in § About Aided mesh.



2.3. Creation of geometric tools

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

parameters and a coordinate system.

BETA

TOOTH_IR

TOOTH_OR

WHEEL_RALPHA

WHEEL_CS


Topic See Page Deactivate aided mesh 84 Create the geometric parameters 85 Create the coordinate system 87



2.3.1. Deactivate aided mesh

Definition Aided mesh is a tool box that permits the user to quickly realize a good

quality mesh. The aided mesh (global adjustment) is activated by default on all flux projects.

Aided mesh and imported Flux project

Aided mesh assigns specific global tool on all entities of a new project. In order not to interfere during project import to the main project, it is needed to de-activate aided mesh on project that will be imported later.

Action To deactivate the Aided mesh, from the Menu:

1. Edit the aided mesh box

2. Select “Inactivated” in the State of aided mesh field



2.3.2. Create the geometric parameters

About geom. parameters

See § 1.3.3 About geometric parameters.

Goal Six parameters are required for the geometry description of the wheel.

The parameters, required to build the wheel base object, are presented in the next figure.

BETA

TOOTH_IR

TOOTH_OR

WHEEL_RALPHA

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

Geometric parameters

Name Comment Expression TOOTH_IR Inner radius of the tooth 12.5 TOOTH_OR Outer radius of the tooth 21.5 TOOTH_N Number of teeth 3 WHEEL_R Radius of the wheel 10 ALPHA Wheel angle 0 BETA Tooth angle 15




Action To create the geometric parameters from the …


on Geometric parameter

OR


2. Type TOOTH_IR as name 3. Type Inner radius of the tooth as

comment 4. Type 12.5 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)

…


Result The geometric parameters are listed in the data tree:



2.3.3. Create the coordinate system

About coord.inate systems

See § 1.3.10 About coordinate systems.

Goal A cylindrical coordinate system is required to describe the geometry of the

wheel, as presented in the figure below.

WHEEL_CS

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




Action To create the coordinate system from the …


on Coordinate system

OR


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 as angle unit

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


Result The coordinate system is listed in the data tree:



2.4. Creation of points and lines for the wheel base

Introduction The next step is the creation of points and lines for the wheel base object.

The next figure describes the geometry of the wheel base object.

BETA

TOOTH_IR

TOOTH_OR

WHEEL_R


Topic See Page Create the points for the wheel base 90 Create the lines for the wheel base 92



2.4.1. Create the points for the wheel base

About points See § 1.4.1 About points.

Goal Six points are required to build the wheel base outline, as presented in the

figure below.

Point 1

BETA Point 2

Point 3

Point 4

Point 5

Point 6

TOOTH_IR

TOOTH_OR

WHEEL_R

Data The table below describes the points for the wheel base.

Points defined by its parametric coordinates

Coordinates* No

Coordinate system R �

1 0 0 2 WHEEL_R 0 3 TOOTH_IR BETA 4 TOOTH_IR -BETA 5 TOOTH_OR BETA 6

WHEEL_CS

TOOTH_OR -BETA

* Coordinates in cylindrical coordinate system: R, (see § 1.3.10 About coordinate systems).




Action To create the points from the …

Data tree: 1. Double-click on Point

OR

Geometry toolbar:


2. In the Geometric Definition tab select Point defined by its parametric coordinates as type of point

3. Select WHEEL_CS as coordinate system

4. Type 0 as first coordinate 5. Type 0 as second coordinate 6. Click on OK

7. Repeat steps 4 to 7 in the new dialog, entering data for the remaining entities (see the table on the previous page)

…


Result The points are … listed in the data tree:

displayed in the graphic scene*:

* use the Zoom all command or to visualize all points



2.4.2. Create the lines for the wheel base

About lines See § 1.4.4 About lines.

Goal Three straight segments and two arcs are required to construct the wheel base

outline.

The order to create the lines is presented in the figure below.

Line 1

Line 2

Line 3

Line 5 Line 4

Note: It does not matter which are the starting and ending points of the straight segments. The arc is counter-clockwise oriented, so it is not possible to swap the starting and ending points during the creation of the arcs.

Data The tables below describe the lines for the wheel base:

Segment defined by starting and ending points

No Starting point Ending point 1 1 2 2 3 5 3 4 6

Arc defined by its radius, starting and ending points

No Coordinate system Radius Starting point

Ending point

4 TOOTH_IR 4 3 5

WHEEL_CS TOOTH_OR 6 5




Action 1 To create the straight lines from the …


OR

Geometry toolbar:


2. In the Geometric Definition tab select Segment defined by starting and ending points as type of the line

3. Click on Point 1 in the graphic scene



5. Repeat steps 3 to 4 in the new reduced dialog to create the remaining segments(see the table on the previous page)

…


Result The lines are displayed in the graphic scene:




Action 2 To create the arcs from the …


OR

Geometry toolbar:


2. In the Geometric Definition tab select Arc defined by its radius, starting and ending points as type of the line


4. Type TOOTH_IR as arc radius 5. Click on Point 4 in the graphic scene



7. Repeat steps 4 to 6 in the new dialog to create the second arc (see the table on page before the previous page)

…


Result The lines are … listed in the data tree:




2.5. Building the face for the wheel base

Introduction The next step is building the face for the wheel base object.


Topic See Page Build the face 96



2.5.1. Build the face

Goal The face will be automatically built by Flux2D.

Action To build the face from the …


OR


Result The face is … listed in the data tree:




2.6. Creation of the transformation

Introduction The whole wheel will be built by means of a transformation. The last step is

the creation of this transformation.


Topic See Page Create the transformation 98



2.6.1. Create the transformation

About transforma-tions

See § 1.5.3 About transformations.

Goal One rotation transformation is required to build the wheel geometry, as

shown in the following figure.

360/TOOTH_N

Point 1

Data The characteristics of the transformation are shown in the following table:

Rotation defined by angles and existing pivot point

Name Comment Coord. system

Pivot point

Rotation about Z axis

ROTZ_WHEEL

Rotation transformation for the wheel

WHEEL_CS

1 360/TOOTH_N




Action To create the transformations from the …


on Transformation

OR


2. Type ROTZ_WHEEL as name 3. Type Rotation transformation

for the wheel as comment 4. Select Rotation defined by

angles and existing pivot point as type


6. Select point 1 in the list or in the graphic scene as pivot point

7. Type 360/TOOTH_N as rotation angle about Z axis

8. Click on OK


Result The transformation is listed in the data tree:



2.6.2. Save and close the project

Goal The current project will be saved and closed.

Action To save and close the project WHEEL_BASE_2D.FLU from the …

Project menu: 1. Click on Close

OR


2. Click on Yes



3. Geometric description of the sensor

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

required to describe the sensor geometry.

The sensor is presented in the figure below.

WHEEL PROBE 1

PROBE 2

INFINITE BOX


Topic See Page Create a Flux project for the sensor 105 Strategy and tools for geometric description of the sensor 107 Importation of the wheel base object and building the whole wheel

111

Importation of the probe objects and positioning of the wheel and probes

125

Completing the domain 131



3.1. Create a Flux project for the sensor




Topic See Page

Create and name a new project for the sensor 106



3.1.1. Create and name a new project for the sensor

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

new project will be renamed and saved.

Action 1 To create a new project from the …


OR


Result 1 A new project named ANONYMOUS opens in the Geometry context by

default.

Action 2 To rename and save the project from the …


Save as…

OR


2. Type SENSOR_2D as project name

3. Click on Save

* Caution: Probe_2D.FLU and Wheel_base_2D.Flu must be in the same directory than Sensor_2D.



3.2. Strategy and tools for geometric description of the sensor


the tools of objects management available in Flux (Flux object importation) the selected strategy for the geometry building of the sensor


Topic See Page


108

Main stages for geometric description 109

Reading advice This section presents an outline of the sensor geometry building process.

Details on the different contents - definition of new concepts, explanation on the use of different tools, etc.- are given in the following sections.




Strategy: reminder

The main principle of geometric construction adopted in this tutorial is the following: description of elementary parts of the structure (Flux objects) in

independent Flux projects: probe, base wheel construction of the whole sensor in a new Flux project by using of existing

Flux objects

Device analysis The analysis of the device and the construction tools chosen within the

framework of this tutorial are summarized in the table below.

The operations …

it is planned …

to easily build the wheel base geometry

to use the ROTZ_WHEEL transformation of

rotation type to build the wheel by means of propagation/extrusion

construction

to position the wheel and the probe

to use the ALPHA and ANGLE parameters to rotate the wheel and the probe

ALPHA

ANGLE



3.2.2. Main stages for geometric description

Outline An outline of the geometry description process to build the sensor geometry

is presented in the table below.

Stage Description

1 Importation of the elementary pattern (WHEEL_BASE_3D)

2 Building the whole wheel (see details in § 3.3.2 Geometry building process of the wheel)

3 Importation of a probe object (PROBE_3D)

4 Rotation of the probe and rotation of the cogged wheel

5 Importation of a probe object (PROBE_3D)

6 Addition of an Infinite Box



3.3. Importation of the wheel base object and building the whole wheel

Introduction The geometry description of the sensor begins by the importation of the wheel

base object and building the whole wheel.

The wheel base object and the whole wheel are presented below.

Wheel base Wheel


Topic See Page

Import the wheel base object 112 Geometry building process of the wheel 113 Propagate the face (tooth) 114 Extrude the line 117 Create an arc 119 Propagate the arc 121 Build faces 123



3.3.1. Import the wheel base object

Goal The wheel base object will be imported into the current project.

Action To import the wheel base object from the Project menu:

1. Point on Import and click on Import FLUX object

2. Click on

3. Select WHEEL_BASE_2D.FLU

4. Click on Open

5. Click on OK

Result The wheel base object is displayed in the graphic scene.



3.3.2. Geometry building process of the wheel

Process The main steps of the geometry description process to build the whole wheel are presented in the table below.

Step Action 1 Propagate the face

(tooth) (and preparation of the mesh generator*)

2 Extrude the line

3 Create an arc

4 Propagate the arc

5 Build faces

* Refer to section “ About mesh tools” on Linked Mesh Generator



3.3.3. Propagate the face (tooth)

About propagation / extrusion

See § 1.5.5 About propagation and extrusion.

Goal The ROTZ_WHEEL transformation will be applied twice to propagate the

face (tooth), as presented in the figure below.

Face 1




Action To propagate the face from the …


and click on Propagate faces

OR


2. Select the face in the graphic scene: click on Face 1

=> its reference number enters 3. Select ROTZ_WHEEL as

transformation 4. Type 2 as number of times to apply

the transformation 5. Select Add Faces, Lines and Points

as building options for propagation 6. Click on OK





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

* use the Zoom all command or .



3.3.4. Extrude the line



Goal The ROTZ_WHEEL transformation will be applied three times to extrude

the line, as presented in the figure below.

Line 1




Action To extrude the line from the …

Geometry menu: 1. Point on Extrude and click on Extrude lines

OR


2. Select the line in the graphic scene:

click on Line 1

=> line reference number enters 3. Select ROTZ_WHEEL as

transformation 4. Type 3 as number of times to apply

the transformation 5. Select Standard as type 6. Select Add Faces, Lines and Points

as building options for extrusion 7. Click on OK


Result The next figure is displayed in the graphic scene.



3.3.5. Create an arc

About lines See § 1.4.4 About lines.

Goal One arc is required to connect points 3 and 10 to complete the wheel

geometry, as presented in the figure below.

Point 3

Point 10

Data The table below describes the characteristics of the line to create for the

wheel.

Arc defined by its radius, starting and ending points

No Coordinate system Radius Starting point Ending point 19 WHEEL_CS TOOTH_IR 3 10




Action To create the line from the …


OR

Geometry toolbar:


2. In the Geometric Definition tab select Arc defined by its radius, starting and ending points as type of the line


4. Type TOOTH_IR as arc radius 5. Click on Point 3 in the graphic scene


6. Click on Point 10 in the graphic scene => its reference number enters as ending point





3.3.6. Propagate the arc



Goal The ROTZ_WHEEL transformation will be applied twice to propagate the

line, as presented in the figure below.

Line 19




Action To propagate the line from the …


and click on Propagate lines

OR


2. Select the line in the graphic scene:

click on Line 19

=> its reference number enters 3. Select ROTZ_WHEEL as transformation

4. Type 2 as number of times to apply the transformation

5. Click on OK





3.3.7. Build faces




OR


Result The next figure is displayed in the graphic scene:



3.4. Importation of the probe objects and positioning of the wheel and probes

Introduction The next stages of geometry building are:

the importation of the first probe object, the positioning of the wheel and the first probe by modifying the geometric

parameters the importation of the second probe object


Topic See Page

Import the first probe object 126 Modify the parameters 128 Import the second probe object 129



3.4.1. Import the first probe object

Goal The probe object will be imported into the current project.




Action To import the probe object from the Project menu:


2. Click on

3. Select PROBE_2D.FLU

4. Click on Open

5. Click on OK




3.4.2. Modify the parameters

Goal Two geometric parameters will be modified:

ALPHA, corresponding to the angle of the wheel position ANGLE, corresponding to the angle of the probe position

ALPHA

ANGLE

Action To modify the ALPHA and ANGLE parameters from the Data tree:

1. Click on ALPHA and ANGLE

keeping the Ctrl key pressed 2. Right click to open the contextual menu

and click on Edit array

3. Type 75 as ALPHA

expression 4. Type 30 as ANGLE

expression 5. Click on OK




3.4.3. Import the second probe object

Goal The second probe object will be imported into the current project.




Action To import the probe object from the Project menu:


2. Click on

3. Select PROBE_2D.FLU

4. Click on Open

5. Click on OK




3.5. 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 132 Add an infinite box 133 Build faces 134



3.5.1. About an infinite box

Infinite box technique

In the Flux software, using a mathematical transformation to model an infinite domain is called the infinite box technique.

The exterior domain (infinite) is linked to an image domain (called the infinite box) through a space transformation.

Principle of use The use of the infinite box implicitly assumes a null field at infinity.

The boundary conditions on the corresponding boundaries of the infinite box are set automatically in the physical module.

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.



3.5.2. Add an infinite box

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

Data The main characteristics of the infinite box are shown in the following table.

Infinite box of Disc type

Internal radius External radius 60 70

Action To create the infinite box from the …


on Infinite box

OR


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:



3.5.3. Build faces




OR





4. 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 137 Meshing the sensor with aided mesh 141 Optimize the mesh 149



4.1. 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 138 Main stages for mesh description 139



4.1.1. Available meshing tools and analysis before mesh generation

Local / global mesh adjustments

Two solutions are offered to users for the mesh adjustment: the global adjustment (automatic) and / or the local adjustment (manual).

The global adjustment permits to adjust the automatic mesh (triangles elements) of the whole domain taking into account certain geometry constraints (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 the Aided Mesh tool box.

The local adjustment permits to locally adjust the mesh near an entity (point, line) or a group of entities defined by the user (creation and assignment of mesh tools).

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.


to control the node density of the infinite box

to modify 2 predefined mesh

points LARGE and MEDIUM

MEDIUM

LARGE



4.1.2. 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 mesh points

Outer size infinite box mesh point: LARGE = 8 mm 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




8 Meshing: meshing lines meshing faces



4.2. Meshing the sensor with aided mesh

Introduction The first step of mesh generation of the sensor is meshing lines and faces with

aided mesh preset values.


Topic See Page Change to the mesh context 142 About the mesh context 143 About Aided mesh 144 Synchronize Aided mesh value and mesh lines and faces 145



4.2.1. 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



4.2.2. About the mesh context

Tools of the mesh context

After having activated the Mesh context, toolbars dedicated to the mesh description appear in the Flux2D window.

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



4.2.3. About Aided mesh

Introduction The global adjustment permits to adjust the automatic mesh (triangles

elements) of the whole domain taking into account certain geometry constraints (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 the Aided Mesh tool box.

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 Usually, it is advised to first mesh the device with the 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.

Note! If there is global and local adjustment on the same project, the local adjustment has the priority on global adjustment. In this case, the global adjustment information will be assign on entities that are free of local mesh information (free points, free lines and free faces.



4.2.4. Synchronize Aided mesh value and mesh lines and faces

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

and meshing faces.

Action (1) As we have imported Flux objects, it necessary to synchronize with aided

mesh preset values.

Mesh menu:

1. Point on Aided Mesh and click on Edit




Action 2 To mesh lines from the …

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

OR

Mesh toolbar: 1. Click on the icon

Result 1 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 --> 7237

Surface elements : Number of elements not evaluated : 0 % Number of excellent quality elements : 98.28 % Number of good quality elements : 1.64 % Number of average quality elements : 0.08 % Number of poor quality elements : 0 % meshDomain executed




Comments To optimize the mesh, it is advised to have at least a two elements large

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).



4.3. 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 150 Modify the Aided relaxation on lines and faces 154 Assign mesh points to points 156 Create a mesh point 158 Assign the mesh point to points 159 Create a mesh line 161 Assign meshline to lines 163 Mesh lines and faces 165 Save the project and close the Flux2D window 167



4.3.1. 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 distributes nodes on the lines based on a subdivision of the line length.

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

distribution of nodes) nodes distributed in a geometrical progression (non-uniform distribution of

nodes) It is also possible to take into account the node distribution on curved lines with the Mesh line of the deviation type (repartition of nodes in function of a deviation criteria)

Mesh generators

The different mesh generators are the following: generic mesh generators:

- automatic - mapped - none (no mesh)

users mesh generators (associated with a transformation): - linked - extrusion

The automatic mesh generator is used by default in Flux2D.

Mesh generator Function automatic to create triangular elements on the surfaces and

tetrahedral elements on the volumes (option to apply deviation on faces in 3D)

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 Relaxation enables the creation of triangular or tetrahedral good quality

elements as big as possible depending of the size of geometrical entity. The mesh 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

Medium relaxation on lines

High relaxation on lines

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

enables to take into account the proximity of disconnected objects.



4.3.2. Modify the Aided relaxation on lines and faces

Action Edit the Aided mesh box and modify the relaxation on lines and faces as

below.

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

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

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

for faces

5. Click on OK



4.3.3. 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



4.3.4. Assign mesh points to points

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

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

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 new dialog to assign the LARGE mesh point to points(see the figure on the previous page)

…




4.3.5. 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:



4.3.6. Assign the mesh point to points

About selection by criterion

See § 1.5.6 About selection by criterion.

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 points

OR





2. Click on 3. Click on Selection by

face

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

5. Click on Union

=> point reference numbers enter 6. Select MAG_MP as mesh point 7. Click on OK


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

magnets



4.3.7. 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:



4.3.8. Assign meshline to lines

About selection by criterion

See § 1.5.6 About selection by criterion.

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:

1 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 view maintaining Ctrl key pressed

3. Select meshline_1 4. Click OK




4.3.9. 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






Action 2 To mesh faces from the …

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

OR



The output is displayed in the History zone: Total number of nodes --> 15707

Surface elements : Number of elements not evaluated : 0 % Number of excellent quality elements : 99.49 % Number of good quality elements : 0.5 % Number of average quality elements : 0.01 % Number of poor quality elements : 0 % Number of abnormal elements : 0 % meshFaces executed



4.3.10. Save the project and close the Flux2D window

Goal The current project will be saved and the Flux2D window will be closed to

return to the Flux Supervisor 11.1.

Action 1 To save the SENSOR_2D.FLU project from the …

Project menu: 1. Click on Save

OR


Action 2 To close the Flux2D window from the …

Project menu: 1. Click on Exit

OR




5. Annex

Introduction This chapter describes the utilization of command files.


Topic See Page Use of command files 171



5.1. Use of command files

Introduction This section describes the use of command files.


Topic See Page About command files and the Python language 172 Execute command file 173



5.1.1. 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 your place automatically (like a WORD or EXCEL macro).

Command file: definition

A command file is a series of Flux commands and instructions written in the Python language intended to execute a series automatically.

Interest A command file is useful for:

accelerating the most frequent operations combining several commands performing a complex series of tasks



5.1.2. 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

geometry and mesh tutorial / first steps in using flux

Documents