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CEDRAT News - N° 64 - February 2013
New functionalities in Flux 11.1 thanks to macros.
Patrick Lombard - CEDRAT.
Flux
by CEDRAT
M
acros have been available under Flux® since 2008. A macro
brings the possibility of adding a new functionality to
Flux. Macros allow a set of commands to be executed,
using pyFlux command language, once questions have been
asked of the user.
Questions can include the possibility of graphically selecting Flux®
components such as points, face regions … as well as existing files
opening a Windows® Explorer. The goal of a macro is to automate
some tasks, and make using Flux® easier.
Flux® is delivered with a list of ready-defined macros. The full list of
macros is available in the “C:\Cedrat\Extensions\Macros” directory,
with the “macros_list_EN.pdf” file. You will find more macros on
the CEDRAT gate (https://gate.cedrat.com).
In this paper, we will present some of the macros available:
• CreatePathFromLineRegion
• Extrude motor in 3D
• Compute force on motor teeths for vibro-acoustic analysis
Create a path from line region
The name of this macro is “CreatePathFromLineRegion”. The main
application is for electrostatic analysis, when you want to display
electric field along a boundary, to check that the maximum value
is below the disrupting field (to avoid dielectric breakdown).
Usually, the potentials are defined through line regions, and it is
convenient to use the same line regions to check the maximum
values of the electric field.
Figure1: Example on how to load a macro.
Figure 2: Interface of
CreatePathFromLineRegion
macro.
Figure 3: Magnitude of electric field along LOWELEC line region
on both sides (up and down).
When the macro is loaded, you can execute it (by double clicking
on a new icon in the task bar). You are asked different questions:
Question
Answer
Name of path to create
Give a specific name
Select one line region
Select one line region
First line of path
The goal is to orient the path (when more than
one line)
Discretisation type: 1 = interval,
2 = point number, 3 = distance
Select mode of discretising points along the
path
Value of discretisation
Number of points
Yes = discretisation on the entire path, no
= discretisation value line
Select if number of points is for the whole path
or for each line
As a result Flux will try to create 2 paths, one corresponding to
each side of the path, allowing quantities to be displayed on both
sides. If the path is on the boundary of the domain, only one path
will be created.
In this example, we can display the magnitude value of the
electric field along the path on both sides by superposing the
curves coming from 2 separate paths. In this example from
our electrostatic tutorial, two paths are created: COMPPATH_
LOWELEC_AIR and COMPPATH_LOWELEC_LIQUID (AIR and LIQUID
being name of existing face regions).
Extrude 2D motor in 3D
A set of macros has been created to simplify the creation of motor
starting from 2D files. The goal is to benefit from 2D face regions
in order to build 3D volumes, and at the same create time 3D
volume regions, and assign them to new volumes automatically.
Let us see through an example how this works: a motor describing
a rear view mirror motor, coming from one of our technical papers
in 3D. The challenge here is that the rotor length is different from
the magnet length and the stator length.
The procedure for building the whole motor is described in the
next table:
Step
Actions
1
Open Flux 3D project
2
Open the Flux 2D project (after removing 2D infinite box)
3
Create transformation of translation for initial rotor extrusion
4
Run the ExtrudeFaceRegion macro
5
Create transformation of translation for extra magnet extrusion
6
Run the ExtrudeFaceWithVolumeRegion macro
7
Run the ExtrudeFaceAndAssignSameVolumeRegion macro
8
Create transformation of translation for extra stator extrusion
9
Run the ExtrudeFaceWithVolumeRegion macro
10
Run the ExtrudeFaceAndAssignSameVolumeRegion macro
Figure 4: Initial geometry in 2D.
Figure 5: Interface of
ExtrudeFaceRegion macro.
(see continued on page 7)
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CEDRAT News - N° 64 - February 2013
The next step is to extrude the magnet and the frame. When you
select the faces, you want the new volumes to have the same
volume region as the volume below the initial faces. This is what
the ExtrudeFaceWithVolumeRegion macro will do.
Compute force on motor teeth for
vibro-acoustic analysis
The aim of this macro is to automatically create sensors on each
stator or rotor tooth, in order to compute force vs. time. This force,
analysed in one round, can be used for another analysis in vibroacoustic software.
Figure 6: Intermediate step.
For the region in the middle, what you want is to extrude the faces,
and to assign the new volumes to a specific volume region, for
instance ROTOR_AIR.
You can redo the same procedure for extrusion of the frame.
The next step is to extrude the centre and assign it to the STATOR_
AIR region.
Figure 9: Interface of
CreateSensorFor2DMotorSlotForce macro and
resulting sensors.
The macro will automatically generate 24 sensors, allowing the
force on each stator tooth to be displayed. Each sensor will integrate
force density (called DFMAG in Flux) on the line facing the airgap.
It is then possible to display force vs. position on each tooth for
a healthy motor, or for a motor in which a minor eccentricity has
been introduced, because of some mechanical failure or default.
As an example, we propose to use the SPM magnet motor
corresponding to one of our technical papers. Due to the eccentricity
analysis, the whole motor has been described. We have performed
a dynamic eccentricity on the rotor. We display the force on one
tooth on one round of the motor, when the rotor is centred and
when it is not.
Figure 7: Interface of ExtrudeFace
AndAssignSameVolumeRegion macro.
The result is given in the next figure, with the new aided mesh
(automatic mesh created by Flux with no user input).
Figure 8: Mesh
of the resulting
motor.
Figure 10: Superposition of force on one teeth in
healthy and unhealthy motor.
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