Abaqus Export (Flux) and Abaqus Import (SimLab)

Introduction

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.

The work is in progress but the functionality is already available in Flux 2025 (export part) and SimLab 2025 (Import part) with several limitations.

Flux
SimLab

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

   → Files are created. The main file is *.inp

   Step 2	Result Step 4

   CAUTION: Please note that the contents of the selected directory will be erased. This is a known issue in release 2025, which will be fixed in 2025.1.
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 dialog box with some options is opened

   4. Unselect Split face option and click on OK

      → 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

      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 in Flux 2025

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)
3D

Export/Import Abaqus: Functionality status in 2025 release

Functionality	2D	3D	Comments
Mesh			Limitation: 2nd order pyramid element type is not yet supported by SimLab
Infinite box			The bodies of infinite box are exported from Flux and imported into simLab + an Infinite Region LBC is created
Coordinate Systems			Some limitations: there are still cases of dependency between coordinate systems to manage. the import of coordinate systems created with custom units is not yet supported
Symmetry
Periodicity			In 3D: rotation type OK Translation type: not yet available in SimLab
Material			Only Material models implemented in SimLab (see tables below)
Motion			Only Motion type implemented in SimLab (see table below) Limitation: The case of a motion created with a coordinate system depending of another coordinate system is not managed. 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 (to define the orientation and the demagnetisation)
Circuit			Some diode models are not managed, only diode model implemented in SimLab (see table below)
Solid Conductor			Solid conductor in circuit OK Passive solid conductor: OK Unmanaged case: several regions assigned to the same solid conductor
Coil Conductor			Coil conductor in circuit OK Imposed current Coil: OK Limitation: unmanaged case with several regions assigned to the same solid 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 temperature (Linked with Material with Thermal option). Not managed in this release.
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. See table below for the mathematics functions already managed in SimLab.
Scenario			The parameters of scenario are defined on the solution dialog box. 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 Face Region to SimLab LBC
Magnetic 3D Volume Region	-		See table of correspondences of Flux 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 Face Region to SimLab LBC

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 Linear
Linear isotropic*exponential function of T
Linear anisotropic
Linear isotropic complex
Linear anisotropic complex
Isotropic analytic saturation
Isotropic analytic saturation*exponential function of T
Isotropic analytic saturation + knee adjustment	Soft Magnetic Non Linear
Isotropic analytic saturation + knee adjustment*exponential function of T	Soft Magnetic Non Linear (with Thermal option)
Isotropic spline saturation	Soft Magnetic Spline
Linear magnet described by the Br module	Permanent Magnet Linear
Linear magnet described by the Br module, with Br linear function of the temperature	Permanent Magnet Linear (with Thermal 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 Hc and Br module*	Permanent Magnet Non Linear*	*
Nonlinear magnet described by Hc and Br module + knee adjustment
Non Linear magnet described by a spline	Permanent Magnet Spline
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 Material

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
Spatia linear isotropic

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

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