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CAD Import

COMSOL Multiphysics 4.0 Product Line

LIVELINK FOR

PRO/ENGINEER

LIVELINK FOR

AUTODESK

INVENTOR

CAD IMPORT

MODULE

LIVELINK FOR

MATLAB OPTIMIZATION

MODULE

MATERIAL

LIBRARY

LIVELINK FOR

SOLIDWORKS

COMSOL MULTIPHYSICS

AC/DC

MODULE

RF

MODULE

MEMS

MODULE

PLASMA

MODULE (BETA)

STRUCTURAL

MECHANICS MODULE

ACOUSTICS

MODULE

HEAT TRANSFER

MODULE

CFD

MODULE (BETA)

CHEMICAL

ENGINEERING

MODULE

BATTERIES & FUEL

CELLS MODULE (4.0A)

EARTH SCIENCE

MODULE

REACTION

ENGINEERING

MODULE

FILE IMPORT

FOR CATIA

V5

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Kernels or Geometry Engines

COMSOL Geometry Kernel

Parasolid

Unigraphics NX, SolidWorks, SolidEdge,

ACIS

Alibre Design, MicroStation, IronCAD

Granite

Pro/Engineer

Shape Manager

Autodesk Inventor, developed from ACIS

Catia V5

Catia V4

Faceted CAD Data

Formats: STL and VRML

Main purpose: visualization

no real CAD data

Geometrically only

approximation

No topological information

has to be calculated by COMSOL

at import

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Trimmed Surface Data

Formats: IGES and VDA-FS

Main purpose: CAD exchange

in the early days

can not represent features of

modern geometry kernels

Accurate geometric description

No topological or connectivity

information

has to be calculated by COMSOL

at import

Boundary Representation (B-rep) Data

Formats: Parasolid, SAT, STEP, and other kernel formats

Main purpose: modern CAD exchange same representation as

modern geometry kernels

Accurate geometric description

Topological and connectivity information

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File Import: Supported Formats

Format Extension Version

Parasolid .x_t, .x_b up to V22

SAT (ACIS) .sat, .sab up to R20

STEP .step, .stp AP203, AP214

IGES .igs, .iges up to 5.3

Autodesk Inventor part .ipt 6 11, 2008 2010

Autodesk Inventor

assembly

.iam 11, 2008 2010

Pro/ENGINEER .prt, .asm 16 to Wildfire 4.0

SolidWorks .sldprt, .sldasm 98-2009

CATIA V5* .CATPart, .CATProduct R6 to R19

* Needs license for File Import for CATIA V5

LiveLink for CAD products

Available for Pro/ENGINEER , SolidWorks and Autodesk

Inventor

In addition to 3D CAD file import includes a bidirectional interface

Supported packages:

Autodesk Inventor 2010, 2011

Pro/ENGINEER Wildfire 4.0, Wildfire 5.0

SolidWorks 2009, 2010

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LiveLink for CAD Products: Functionality and

Benefits

A bidirectional interface

Associative geometry transfer

Parameter update in CAD file with automatic model regeneration

Automated parameter studies

Tools for traditional CAD import

File import of both standard and propriatery 3D CAD file formats

Interactive and automatic repair and defeaturing

CAD program

assembly or part

COMSOL

Multiphysics

Geometry

Parameters Updated geometry

Form a union

Assemblies

Continue modeling by:

with Imprints without imprints

Greater freedom in meshing

Form an assembly

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CAD Representations

COMSOL Multiphysics lets you choose between two different

representations of a solid CAD model:

Form Union (default setting)

Form an Assembly

A union object is a single object consisting of multiple subdomains

The geometry, mesh, and physics are automatically glued together at internal

boundary interfaces.

An assembly consists of disjoint composite geometry objects

The geometry, mesh, and physics needs to be manually joined at internal

boundary interfaces.

Pros and Cons

Composite geometry pros: Automatic continuity in physics at material discontinuities

Automatic high accuracy solution across material interfaces

Automatic conforming mesh elements and nodes at material interfaces

Composite geometry cons: Finer mesh more memory consuming

Meshing of large CAD models more difficult

Assembly pros: Define (intentional) physics discontinuities at material interfaces, such as

contact resistance

Easier meshing of large CAD models

Coarser mesh quicker (but less accurate) results

Assembly cons: Requires more manual interaction

Could require more attention to mesh density at boundaries to ensure high-enough accuracy

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Importing CAD Files

Choose file

Click Import

Continue with meshing and modeling

as usual

Import Procedure

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Automatic Repair During Import

Removing short edges, small faces, sliver faces

Healing gaps

Removing self-intersections, spikes and discontinuities

Correcting invalid topology

Absolute import tolerance 10-5 m

Remove C5, C6

Modify C1 or C4

C4

C3

C1

C2

C3

C1 C2

C5

C6

C4

Example: spike

Defeaturing tools

After the import you can

interactively search for and

remove

Fillets

Small faces

Sliver faces

Spikes

Short edges

Advanced defeaturing

allows removal of selected

details

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Tips and Tricks CAD Import and Mesh

CAD design for FEA

During export of CAD files:

Avoid older file formats like IGES.

Check and set the export tolerance in the CAD software, if possible.

Import back your file into the CAD program.

During import into COMSOL Multiphysics:

For large assemblies test import and meshing of individual parts.

Use meshing as a tool for locating problem regions.

General tips:

Start with a simple geometry, add more features later.

If decomposition of the assembly fails:

Check for proper alignment of parts

Use assembly mode instead

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Hands-on Exercise

Import of 3D CAD file of engine

piston:

Compare 3D CAD models suitable for

Finite Element Analysis (FEA) versus

design.

Import of an IGES file:

Use repair functionality to create a

solid.

Hands-on Exercise

Import of 3D CAD file of engine

piston assembly:

Test available methods to prepare 3D

CAD assemblies for FEA.

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Hands-on Exercise

Assembly with gaps and

dimensional discrepancies

between parts:

Learn how to diagnose problem

regions by meshing.

Learn how to remove features with the

advanced defeaturing tools.

CAD Import