File Import Flux

File > Import > Solver Input File

Dialog Box

This dialog has the options used in importing Flux input file.

Why an Abaqus Flux Import

Since several releases of Flux, the Flux teams works a lot to integrate the various applications in SimLab. The main goal of this integration are the homogenization of the easy GUI of all Altair's softwares, and the easy to use to be able to do multiphysics modeling (NVH, Thermal, Electromagnetic, Electrostatic...).

To ensure a smooth transition for Flux users to SimLab, we are working on an export of Flux projects in an Abaqus format. The resulting file can then be imported into SimLab.

We're working hard to convert as much of a Flux project as possible to a SimLab database, but there will be some limitations.

A beta version has been delivered with the last release 2025 of Flux (for Abaqus export) and SimLab (for Abaqus Import) with several limitations. The work continued on this release 2025.1, and several limitations has been managed.

Flux
SimLab
Restriction: Some restrictions due to the technological differences between Flux and SimLab:
  • Exporting a Flux project produces a “Ready to solve” project in SimLab. As a result, the simulation results obtained in Flux are not migrated into SimLab, and you will have to re-solve the project from SimLab.

  • Parametrization methods are radically different between Flux and SimLab and no direct correspondence is possible between these 2 methods. As a consequence, if a Flux project contains parametrized geometry, after the Abaqus export from Flux and the Abaqus import to SimLab, the geometric parametrization is lost (More detail in Parameters management).

Workflow



  1. Open the Flux project which you want export
  2. In the menu Project select Export > Export project > Export project to SimLab
  3. Choose the Output directory
  4. Click on OK

    → The main files flux_simlab_init.inp is created with a folder called includes containing all needed secondary files

    → Some internal modifications of Flux project are needed before to perform the Abaqus export (More detail about Flux project: required modifications).

    Step 2 Result Step 4
    Note: If the chosen directory is not empty, a message appear to propose to erase or the content of the directory (YES) or to choose another directory (NO → go to step 1, and choose another directory at the step 3))

  5. Open SimLab
  6. Import the master abaqus file *.inp:
    1. Open the Import dialog box by selecting File > Import > Solver Input File
    2. Choose the extension of the import as Flux (*.inp) in the bottom right corner:
      Step 6a Step 6b
      → the folder is filtered and only the flux_simlab_init.inp is displayed

    3. Select the file "flux_simlab_init.inp" and validate by clicking on OK.

      → a first dialog box "Import Flux Abaqus" is dispalyed only with the information of Input file unit system used.

    4. Click on OK

      → Some Warnings could be displayed

      → The Flux project is imported in SimLab and the database SimLab is created with all corresponding Bodies, LBC,...

      → A log is opened with the list of missing entities and other informations

    5. Step 6c 6d

      → The log file "AbaqusImport_log.txt" is stored in the user scratch directory define in Preference of SimLab. By defaut it's:

      C:\Users\"NameOfUser"\AppData\Local\Temp\SimLab\SimLab_2025\Temp\temp_x

EM Solutions available

Here is a table to show you the state of migration of Flux applications into SimLab Solutions:

DIMENSION EM SOLUTION
MS MT MAC ES
2D
Skew (option in 2D solution)
3D

EM Solutions supported by Abaqus import

Here is a table to show the EM solutions which support the Abaqus import.

DIMENSION Supported solutions by Abaqus import
MS MT MAC ES
2D (works, but not fully qualified) (works, but not fully qualified) (works, but not fully qualified)
Skew (option in a 2D solution) - - -
3D
CAUTION: As the work involved in porting from one software package to another is very extensive, we have focused on 3D magnetic applications. We are aware that there are a number of restrictions, including the following:
  • Abaqus Import of coupled applications is not supported
  • For Electric solutions, only the Abaqus import of Electrostatic 3D is supported (not yet the Electrostatic 2D)
  • Abaqus Import is not supported for Skew applications
  • Magnetic 2D solutions can be imported, but there was not a full validation, some case could be not managed
  • 3D solutions can be imported a validation has been done

Export/Import Abaqus: Functionality status

Functionality 2D 3D Comments
Mesh Improvements 2025.1: 2nd order pyramid element type is now supported by SimLab.
Infinite box The bodies of infinite box are exported from Flux and imported into SimLab

+ an Infinite Region LBC is created.

More details about Infinite Region management.
Coordinate Systems Improvements 2025.1 for Abaqus Export (Flux) /Import (SimLab):
  • coordinate system dependent of another coordinate system.
  • propagated coordinate system
  • coordinate systems created with custom units
Symmetry
Periodicity In 3D:
  • Rotation type OK
  • Translation type: not yet available in SimLab 3D solution (available in 2D)
Material

In Flux, all material models are exported in Abaqus files.

During Import in SimLab,only material models implemented in SimLab are managed.

Some models has been added.

(see tables below)
Motion Only Motion type implemented in SimLab (see table below).

Improvements 2025.1: The case of a motion created with a coordinate system depending of another coordinate system is now supported.

Limitation: in SimLab, the user can only define one motion.
Magnet
  • Flux side: Material with a "Magnet" model + a command dedicated to define the orientation + one option in the material model for the demagnetisation.
  • SimLab side: Material with a "Magnet" model + Magnet Loads

    (contains the definition of the orientation and the demagnetisation).
Circuit

Some diode models are not managed, only diode model implemented in SimLab (see table below).

Improvements 2025.1:

  • The Abaqus export and import is now managed for each diode models:
    • for model supported in SimLab OK
    • for model unsupported in SimLab, the diode is imported with the model supported with all parameters set to 0 . The user must define the model.
  • The squirrel cage component has been added in MAC2D solution, the abaqus export and import has been manage fr this new component.
Solid Conductor Solid conductor in circuit OK

Passive solid conductor: OK
Coil Conductor Coil conductor in circuit OK

Imposed current Coil: OK

Limitation: several regions assigned to the same coil conductor is not supported. The solution in SimLab is to merge the different bodies into one body and assign this body in the coil conductor.
Non-Meshed Coil - Only types implemented in SimLab (see table below).
Sheet Lamination Linked with material model.
Cut (Magnetic and Electric) - No "manual" cuts managed for this release → only managed during the SimLab solving by using automatic cuts algorithm.
Temperature

LBC to define Default working temperature (Linked with Material with Thermal option).

More details
Parameters Geometric and Physics (I/O) parameters managed and created in SimLab.

The geometric parameters, used in the definition of the Flux geometry, are lost the link with the geometry after import, because only the mesh is imported (the Flux geometry has not equivalence in SimLab.

Several mathematics functions using in Flux not yet managed in SimLab → The equivalent value is imported with the expression of the formula in comment.

More detail about Parameters management

See tables below for the mathematics functions already managed in SimLab.

Note: Spatial density / spatial parameters are not managed in SimLab, and so not manage in the Abaqus export from Flux.
Scenario The parameters of scenario are defined on the solution dialog box.

The abaqus export from Flux of scenario is not managed, so the abaqus import in SimLab is not also managed.

Limitations:

  • multi parameter unmanaged (only one parameter),
  • multi intervals unmanaged (only one interval),
  • only Step value type for the interval definition is managed (Step number (lin), Step number (log), List of steps, Adaptative step types are not managed)
Magnetic 3D Face Regions - Implemented in SimLab like "Thin region" LBC.

See table of correspondences of Flux 3D Magnetic Face Region to SimLab LBC.
Magnetic 3D Volume Region - See table of correspondences of Flux 3D Magnetic Volume Region to SimLab LBC.
Magnetic 2D Line Regions - No yet equivalences in SimLab → Abaqus export and import are not managed.

See table to consult the list of Line Regions.
Magnetic 2D Face Regions - See table of Correspondences of Flux 2D Magnetic Face Region to SimLab LBC.
Electric 3D Volume Region - Implemented in SimLab for Electrostatic 3D solution.

See table of Correspondences of Flux 3D Electric Volume Region to SimLab LBC.
Electric 3D Face Regions - Implemented in SimLab for Electrostatic 3D solution.

See table of Correspondences of Flux 3D Electric Face Region to SimLab LBC.
Electric 2D Face Regions Implemented in SimLab for Electrostatic 2D solution.

There are equivalences in SimLab, but the Abaqus export from Flux and Abaqus import in SimLab are not managed.

See table of Correspondences of Flux 3D Electric Volume Region to SimLab LBC.
Electric 2D Line Regions Implemented in SimLab for Electrostatic 2D solution.

There are equivalences in SimLab, but the Abaqus export from Flux and Abaqus import in SimLab are not managed.

See table of Correspondences of Flux 3D Electric Volume Region to SimLab LBC.

Flux project: required modifications

For compatibility reason with SimLab, when you execute the command "Export project to SimLab in Flux, some needed modifications are applied in background before to export to be able to convert to a corresponding SimLab Database:

  • When a field is defined by a formula (which could be defined also by other parameters), a new parameter is created with the same formula and exported. The initial field is modified and filled this new intermediate parameter.

    All these intermediate parameters are listed in a txt file: ..\includes\parameters\flux_parameters.txt

    Flux project SimLab database
  • About Infinite box, some Flux configurations require to identify the Infinite Region and the Air Region (which can contains several volumes of air around the device) before to export to be compatible with the Infinite Region LBC in SimLab, which is linked to the 2 bodies called Infinite Region_Inner and Infinite Region _Outer

The modification are internally done before the export, but there are no impact for the initial Flux project, no save is performed

Material models implemented in SimLab

Flux contains a lot of models of material. At this time the properties migrated in SimLab are B(H), J(E) and D(E). For each properties only few main models of materials have been implemented.

B(H) Flux Model SimLab Model Export/Import Abaqus

Linear isotropic

 Soft Magnetic - Analytical
Linear isotropic*exponential function of T Soft Magnetic - Analytical

with Thermal dependence option
Linear anisotropic
Linear isotropic complex
Linear anisotropic complex
Isotropic analytic saturation Soft Magnetic - Analytical

with Saturation option

Isotropic analytic saturation*exponential function of T Soft Magnetic - Analytical

with Saturation option

with Thermal dependence option
Isotropic analytic saturation + knee adjustment Soft Magnetic - Analytical

with Saturation option

with Knee adjustment option
Isotropic analytic saturation + knee adjustment*exponential function of T Soft Magnetic - Analytical

with Saturation option

with Knee adjustment option

with Thermal dependence option
Isotropic spline saturation Soft Magnetic - Raw data
Linear magnet described by the Br module Hard Magnetic - Linear
Linear magnet described by the Br module, with Br linear function of the temperature Hard Magnetic - Linear

with Thermal dependence option
Linear magnet described by cartesian vector Br
Linear magnet described by cylindrical vector Br
Linear magnet described by spherical vector Br

Nonlinear magnet described by HcB, HcJ and Br module

 Hard Magnetic - Nonlinear
Nonlinear magnet described by Hc and Br module + knee adjustment
Non Linear magnet described by a spline Hard Magnetic - Raw data
Isotropic parabola + straight line
Linear isotropic, tabulated function of T
Isotropic analytic saturation, tabulated function of T
User magnetic properties
Spatial linear isotropic
Spatial anisotropic linear by tensor
Spatial anisotropic linear
Spatial linear magnet
Isotropic hysteretic, Preisach model described by 4 parameters of a typical cycle
Isotropic hysteretic, Preisach model identified by N triplets
Isotropic hysteretic, Jiles-Artherton model
Sheet iron described by LS model
Iron Losses Flux Model SimLab Model Export/Import Abaqus

Modified Bertotti model (taken into account with the B(H) model chosen)

3 coefficients and 3 exponents

Option of the Soft Magnetic Materials
J(E) Flux Model SimLab Model Export/Import Abaqus
Insulator
Isotropic resistivity Electric properties → Electric resistivity
Isotropic resistivity, linear function of T

Electric properties → Electric resistivity (with Thermal option)
Isotropic resistivity, exponential function of T
Anisotropic resistivity
Anisotropic resistivity, linear function of T
Anisotropic resistivity, exponential function of T
Isotropic Superconductivity (power law)
Isotropic spline
Linear anisotropic complex
Isotropic resistivity, tabulated function of T
User resistivity
Spatial isotropic resistivity
D(E) Flux Model SimLab Model Export/Import Abaqus
Linear isotropic

Dielectric properties → Linear
Linear anisotropic
Linear isotropic with losses (tan (delta))
Linear anisotropic with losses (tan (delta))
Isotropic spline

Dielectric properties → Spline
User
Spatial linear isotropic

Default Working Temperature

For Thermal models, the Default working temperature is differently defined in Flux or SimLab:
  • In Flux: the default working temperature is defined in the material model
  • In SimLab the default working temperature is not defined in the material but via the creation of an LBC called Temperature assigned to expected body/bodies. The material must be assigned to the same body /bodies to validated the thermal model.
In Flux In SimLab


Mechanical set types implemented in SimLab

Mechanical set (Flux) Motion (SimLab) Export/Import Abaqus
Rotation around one axis Motion Rotation type
Translation along one axis Motion Translation type
Compressible Option (Immersion in the air) in the motion defined in SimLab
Fixed All bodies without motion (sliding option = without compressible)

All bodies not in contact with bodies in movement (immersion option = with compressible)
6 degrees freedom
Free movement

Diode model implemented in SimLab

Flux Diode Model (Flux) SimLab Diode Model Export/Import Abaqus
ON state resistance and OFF state resistance *
Exponential function depending on VF0, Rb and Is
Exponential function depending on Is, Ut and Rs *
Note: *
The Abaqus export and import is now managed for each diode models:
  • for model supported in SimLab OK
  • for model unsupported in SimLab, the diode is imported with the supported model and all parameters are set to 0. The user must redefine the model

Non-Meshed Coil types implemented in SimLab

Non-Meshed Coil (Flux) Non-Meshed Coil (SimLab) Export/Import Abaqus
Circular coil Circular coil : Disc section

Circular coil: Rectangular section
Rectangular coil Rectangular coil : Disc section

Rectangular coil: Rectangular section
Composed coil Composed coil : Disc section

Composed coil: Rectangular section
Composed coil by import
Multi saddle
Saddle

Mathematics functions implemented in SimLab

Trigonometric Functions (Flux) SimLab equivalence Export/Import Abaqus
Sin(x) Sine of the angle x expressed in radians SIN
Cos(x) Cosine of the angle x expressed in radians COS
Tan(x) Tangent of the angle x expressed in radians TAN
Asin(x) Arcsine in radians of the expression x; x ∈ [-1,1]
Acos(x) Arccosine in radians of the expression x; x ∈ [-1,1]
Atan2(x,y) Arctangent in radians of the expression (x/y) ATAN
Sind(x) Sine of the angle x expressed in degrees
Cosd(x) Cosine of the angle x expressed in degrees
Tand(x) Tangent of the angle x expressed in degrees
Asind(x) Arcsine in degrees of the expression x; x ∈ [-1,1]
Acosd(x) Arccosine in degrees of the expression x; x ∈ [-1,1]
Atan2d(x,y) Arctangent in degrees of the expression (x/y)
Sinh(x) Hyperbolic sine of the expression x
Cosh(x) Hyperbolic cosine of the expression x
Tanh(x) Hyperbolic tangent of the expression x
Asinh(x) Arcsine hyperbolic of the expression x; x ∈ [-1, ∝[
Acosh(x) Arccosine hyperbolic of the expression x; x ∈]-∝ , ∝[
Atan2h (x,y) Arctangent hyperbolic of the expression (x/y); x ∈ [-1,1]
Mathematical Functions (Flux) SimLab equivalence Export/Import Abaqus
Sqrt(x) Square root of the expression x SQRT
Abs(x) Absolute value of the expression x ABS
Exp(x) Exponential function of the expression x EXP
Log(x) Natural logarithm of the expression x LOG
Log10(x) Common logarithm of the expression x LO10
Int(x) Integral part of the expression x INT
Modulo(x,x1) Remainder of the division of x by x1
Min(x1,x2) Minimum of the expressions x1 and x2 MIN
Max(x1,x2) Maximum of the expressions x1 and x2 MAX
Sign(x) Sign of the expression x
Functions for "Complex Quantities" (Flux) SimLab equivalence Export/Import Abaqus
ModC(z) Complex modulus of the complex expression z
Arg(z) Argument (in radians) of the complex expression z
Inst(z,t) Value at the instant t (in degrees) of the complex expression z
Real(z) Real part of the complex expression z
Imag(z) Imaginary part of the complex expression z
Conj(z) Conjugate of the complex expression z
Cmplx(x,y)

Complex expression built starting from the real expressions x and y
Functions for "Vector" (Flux) SimLab equivalence Export/Import Abaqus
ModV(v) Vector modulus of the vector expression v
Comp(i,v) Component i of the vector expression v
PVec(v1,v2) Vector product of 2 real vector expressions
Vec2(x,y) 2D vector built starting from the real expressions x and y
Vec3(x,y,z) 3D vector built starting from the real expressions x, y and z
Mod(x) General modulus of the expression x: Mod(x)=ModV(ModC(x))
Other Functions (Flux) SimLab equivalence Export/Import Abaqus
Trapezper(x, x1, x2, x3, x4, x5, x6, x7) Trapezper(TIME, A, B, Tp, T1, T2, T3, Td)
  • TIME is the time parameter
  • A is the minimal value
  • B is the maximal value
  • Tp is the period
  • T1 is the time interval of linear increase of the function
  • T2 is the time interval of constant value of the function
  • T3 is the time interval of linear decrease of the function
  • Td is the value of initial time delay
Valid(x,x1,x2)
  • if x1 ≤ x<x2 → Valid(x,x1,x2) = 1
  • else → Valid(x,x1,x2) = 0
Trapez(x, x1, x2, x3)
  • if x1 ≤ x ≤ x1+x2 → Trapez(x,x1,x2,x3) = 1
  • if x<0 or x>x1+x2+x3 → Trapez(x,x1,x2,x3) = 0

Magnetic 3D Face Region correspondences

Face Region (Flux 3D) SimLab correspondences Export/Import Abaqus
Air Gap Thin Region LBC : AirGap type
Magnetic Non Conducting Region Thin Region LBC : Magnetic Non Conducting type
Perfect Insulator in conductor medium Thin Region LBC : Magnetic Perfect Insulator in Conductor type
Boundary condition: tangential magnetic field (normal current)
Boundary condition: normal magnetic field (tangential current)

Only for Magnetic AC

Thin conducting region (hyperbolic current density through the thickness)		 Thin Region LBC : Hyperbolic current conductor type

Only for Magnetic AC

Surface impedance region		 Option in Conductor component (Circuit Designer)

Option in Passive Solid Conductor LBC
Inactive region /

Magnetic 3D Volume Region correspondences

Volume Region (Flux 3D) SimLab correspondences Export/Import Abaqus
Air or vacuum region Bodies with Material "Air" assigned
Magnetic Non Conducting Region Bodies with Soft Magnetic Material assigned
Coil Conductor Region Imposed Current Coil LBC

Coil component in Circuit designer
Solid Conductor Region Passive Solid Conductor LBC

Conductor component in Circuit designer (2 and N terminals)

Only for Magnetic AC

Solid Conductor Region described by surface impedance		 Option in Passive Solid Conductor LBC

Option in Conductor component in Circuit designer (2 and N terminals)
Laminated magnetic non conducting region Sheet Lamination LBC
Inactive region /

Magnetic 2D Line Region correspondences

Line Region (Flux 2D) SimLab correspondences Export/Import Abaqus
Air or vacuum region
Coil Conductor Region
Solid Conductor Region
Region with current density
Boundary condition: tangential magnetic field (normal current)
Boundary condition: normal magnetic field (tangential current)
Boundary condition: imposed magnetic flux
Inactive region

Magnetic 2D Face Region correspondences

Face Region (Flux 2D) SimLab correspondences Export/Import Abaqus
Air or vacuum region Bodies with Material "Air" assigned
Magnetic Non Conducting Region Bodies with Soft Magnetic Material assigned
Coil Conductor Region Imposed Current Coil LBC

Coil component in Circuit designer
Solid Conductor Region Passive Solid Conductor LBC

Conductor component in Circuit designer (2 and N terminals)
Region with current density
Laminated magnetic non conducting region Sheet Lamination LBC
Inactive region /

Electric 3D Volume Region correspondences

Volume Region (Flux 3D) SimLab correspondences Export/Import Abaqus
Air or vacuum region Bodies with Material "Air" assigned
Dielectric with source charge density Electric charge LBC
Boundary condition: Perfect conductor (floating potential + imposed potential) Electric Potential
Inactive region /

Electric 3D Face Region correspondences

Face Region (Flux 3D) SimLab correspondences Export/Import Abaqus
Air or vacuum region Bodies with Material "Air" assigned
Dielectric with source charge density source Thin Region LBC
Charge Electric Charge
Boundary condition: tangential electric field Electric Field
Boundary condition: normal electric field Electric Field
Boundary condition: imposed electric potential Electric Potential
Inactive region /

Electric 2D Face Region correspondences

Face Region (Flux 2D) SimLab correspondences Export/Import Abaqus
Air or vacuum region Bodies with Material "Air" assigned
Dielectric with source charge source Electric Charge LBC
Boundary condition: perfect conductor Electric Potential LBC
Inactive region /

Electric 2D Line Region correspondences

Line Region (Flux 2D) SimLab correspondences Export/Import Abaqus
Charge Electric Charge LBC
Boundary condition: imposed electric potential Electric Potential LBC
Boundary condition: tangential electric field Electric Field LBC
Perfect conductor: normal electric field Electric Field LBC
Inactive region