FE simulation: CAD import

Joel Cugnoni, LMAF / EPFL

March 7, 2012

Joel Cugnoni, LMAF / EPFL FE simulation: CAD import

CAD Import in Abaqus

1 ABAQUS and most other simulation codes allows you toimport CAD geometry from standard file formats like STEP(.stp), IGES (.igs) or ACIS (.sat) for example

2 It is also possible to import directly CATIA geometries but Ido not have much experience with this option

3 Geometry can be of different types: Solid (volume), Shell(surface) or Wire (lines)

4 Be extra careful with units; always check your modeldimension after import

5 Model can be scaled during import to convert geometry toanother system of units

6 Importing an assembly is also supported. It will just generateseveral parts in Abaqus without constraints between them.The relative position between the parts should normally bepreserved.

Joel Cugnoni, LMAF / EPFL FE simulation: CAD import

Export a model from Catia

Exporting a model from Catia is very simple:

Importing a CAD model in Abaqus is also very simple:

Load your Part or Assembly (CATPart or CATProduct)

Go to File → Save As

Specify a file name and choose the file format in the dropdown list

STEP format is recommended for volumes and assemblies,IGES tend to work better for shells

Press Save and that’s all

Joel Cugnoni, LMAF / EPFL FE simulation: CAD import

Import a CAD geometry in Abaqus CAE

Importing a CAD model in Abaqus is also very simple:

Go to File → Import → Part

Choose the file format in the drop down list and select your file

In the import dialog, choose the type of output geometry(Solid / Shell / Wire)

It is recommended to select also ”Convert to XX” and”Stitch” options whenever available

In the Part Attribute tab, define the modeling space andspecify if the part is deformable (usual case) or rigid

In the Scale tab, enter a scale factor to convert the geometryto your destination set of units (see comment after)

Press OK

Joel Cugnoni, LMAF / EPFL FE simulation: CAD import

Checking a CAD geometry in Abaqus CAE

Right after import you should :

Check if the units of length are OK; Go to Tool → Query →Distance and verify that the overall size of the part isconsistent with your set of units. If the dimensions are notOK, delete the part and reimport it with the right Scale factor

Check the part validity: go to Tools → Query → Geometrydiagnostics and check ”Invalid entities” (severe) and”Imprecise entities” (mild problem)

If Invalid / Imprecise entities are found, go to Tools →Geometry repair. In ”Part” choose ”Convert to precise”

(optional) it may help to use Tools → Geometry repair →Part → Convert to analytical (but it may fail)

If all is fine, check also for small edges and small faces as itmay create problems with meshing (in Tools → Query →Geometry diagnostics)

Joel Cugnoni, LMAF / EPFL FE simulation: CAD import