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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