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FRANC3D Training Workshop:
Part III
Drs. Bruce Carter, Paul “Wash”
Wawrzynek, Tony Ingraffea, and
Omar Ibrahim
February - 2016
Fracture Analysis Consultants, Inc.
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• General introduction to FRANC3D:
- capabilities and limitations
• Present theories and approaches to computational
fracture mechanics built into software
• Hands-on sessions give participants time to use
software
• Opportunity for participants to ask questions
Objectives
Part III
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Workshop Agenda
• Part I: Introduction to Fracture Mechanics Analysis
• Part II: Introduction to FRANC3D
• Part III: FRANC3D FE model import - demo & hands-on
• Part IV: Crack Insertion Process – demo & hands-on
• Part V: Crack Growth and Fatigue Life – Theory, Rules & Models
• Part VI: FRANC3D crack growth, SIF history & fatigue life
- demo & hands-on
• Part VII: FRANC3D Session Log, Playback, Command Line & Python
• Part VIII: Known issues & what to do if something goes wrong
• Part IX: Capabilities coming soon
Part III
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FE Model Import
Part III
FRANC3D FE Model Import
• FRANC3D support the following input
finite element files:
– ANSYS: *.cdb files
– ABAQUS: *.inp files
– NASTRAN: *.bdf(or *.nas) files
5 Part III
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FRANC3D FE Model Import
FRANC3D has three options for importing uncracked FE Models
• Import a complete model
• Import and divide the model in FRANC3D
• Import an already divided model
Depending on selection, different dialogs will be displayed next.
Part III
FRANC3D FE Model Import
• After importing the finite element into FRANC3D, Select Retained BC
Surfaces dialog is displayed
• Any surface that has boundary conditions will be highlighted in blue
• Using the Select All button, the blue surfaces will be colored red
7 Part III
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Importing full model
Part III
NOTE: do not retain facets where a crack will be inserted.
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Import and Divide the Model in FRANC3D
• After importing the full
FE Model, the Define a
Local Submodel dialog
box will appear
• FRANC3D supports
several options for
extracting the sub-model
• After extracting the sub-
model, the Select
Retained BC Surfaces
dialog if the sub-model has
boundary conditions or
node sets or surfaces
Part III
Import and Divide the Model in FRANC3D
• Cropping Options
– Allow one to specify which ‘side’ of the
selection plane or box is selected
– selected elements are colored red
10 Part III
Import and Divide the Model in FRANC3D
• Relative to a principal plane:
– Allows one to choose a plane that is aligned
with the Cartesian axe
– Plane can be offset from the origin
11 Part III
Import and Divide the Model in FRANC3D
• Plane normal and offset
– Allows one to define a plane that is normal to the
unit vector defined by the x, y and z coordinates
– Plane can be offset from the origin
12 Part III
Import and Divide the Model in FRANC3D
• Plane from three points
– Allow one to define a plane based on the selection of
three points
– Use the (cross) cursor to pick the point; three points of
a triangle define the plane
13 Part III
Import and Divide the Model in FRANC3D
• Rubberband box
– Allows one to define a box using the left-mouse
button to drag the outline of a box on the screen
14 Part III
Import and Divide the Model in FRANC3D
• Element by element
– Allows one to select (or unselect) individual elements
– User presses the Select button and then uses the left-
mouse button to select elements one at a time
15 Part III
Import and Divide the Model in FRANC3D
• By material
– Allows one to select elements based on the
material id
16 Part III
Import and Divide the Model in FRANC3D
• By element group
– Allows one to select elements based on an
element group name
17 Part III
Import and Divide the Model in FRANC3D
• Retained from file
– Allows one to select element id’s from a .txt file
– Useful for re-selecting elements that were selected during
a previous import
18 Part III
Import and Divide the Model in FRANC3D
• Crop, Undo and Redo – The three buttons at the bottom on the left side perform the actual
cropping operation
– Once the selection has been made using one of the options discussed,
the selected elements are cropped by pressing the Crop button
– Un-selected elements are removed.
– User can Undo or Redo the cropping operation
– Multiple selections and crops can be performed in sequence
19 Part III
Import Already Divided Model
• If the user has divided the entire FE model
into global and local model (portion that
will cracked) files
• Files can be imported into FRANC3D
20 Part III
Export Model • File Export menu item can be used to save the FE model data
without saving the FRANC3D .fdb
• User selects the analysis FE model type and enters the file name
• Used to convert FE model files from one type to another
21 Part III
Reading Analysis Results
• File Read Results menu item allows the user to choose the
analysis results file to be read
• For ANSYS, FRANC3D reads
– *.dtp file (contains displacements, temperatures ) that is created using the
FRANC3D & macros
– *.dsp file (contains nodal listing of displacements).
• For ABAQUS, FRANC3D reads
– *.dtp file (contains displacements, temperatures ) that is created using the
FRANC3D & Python script
– *.fil file (contains nodal listing of displacements).
– ABAQUS CAE Report file format.
• For NASTRAN, FRANC3D reads
– *.pch file (contains displacements, temperatures )
22 Part III
Reading Analysis Results
• Read results file dialog
23 Part III
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Demo: FE Model Import
Part III
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FRANC3D Tutorial 1
ANSYS ABAQUS NASTRAN
• 10x10x10 cube; units of length are mm
• subdivide edges for meshing using 10 to 20 subdivisions
• use quadratic brick or tetrahedral elements
• material properties: E=10000 MPa and n=0.3
• uniform traction (a negative pressure) on the top surface of 10 MPa
• bottom surface constrained in the y-direction, bottom left edge is also constrained in the
x-direction, and the point at the origin is also constrained in the z-direction
FRANC3D Tutorial 1
Part III
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FRANC3D Tutorial 1
Step 1: Build the FE model or use pre-made model
Step 2: Extract local sub-model portion from full model – create node component/set for cut-surface(s)
– write local and global portions as separate model files
– ensure local and global FE data self-consistent (does not contain extraneous data)
Step 3: Import sub-model portion into FRANC3D
Local and
global
defined in
FE code
Local and
global
defined in
FRANC3D
Part III
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FRANC3D Tutorial 1 – Import FE Model
For Step 2 when using FRANC3D:
Import and divide
full ANSYS model
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Submodel Tool:
• elements shown in dark grey are
retained when the model is Cropped
• Rubberband Box tool demonstrated
FRANC3D Tutorial 1 – Import FE Model
Part III
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FRANC3D Tutorial 1 – Import FE Model
Submodel Tool:
• Local and global portions saved along with list of retained
elements; the latter allows for scripted restarts (e.g., reanalysis).
Note that there are no
boundary conditions on
local model.
Cut-surface mesh facets retained
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FRANC3D Tutorial 1 – Import FE Model
Importing full model into FRANC3D:
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FRANC3D Tutorial 1 – Import FE Model
Surface mesh facets are retained where boundary conditions applied and
selected. If a crack is to be inserted into a surface that has boundary conditions,
do not select that surface to be retained.
Surface with boundary conditions has
mesh facets retained
Part III
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FRANC3D Tutorial 1 – before you start
Saved
camera
positions
provide
easy way
to show
different
views.
Default view control:
Left mouse button – rotate
Center mouse button – pan
Right mouse button – zoom and spin
Center mouse button + SHIFT key:
front clipping plane
Right mouse button + SHIFT key:
back clipping plane
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FRANC3D Tutorial 1 – before you start
Allows user to cut away a portion
of the model based on cutting
planes aligned with the global
Cartesian axes.
Controls the speed of rotation, translation and zooming
when “moving” the model with the mouse.
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FRANC3D Tutorial 1 – before you start
Clipping
Recenter
Visual display of
front and back
clipping planes.
Default center
of rotation is
the center of
the model.
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FRANC3D Tutorial 1 – before you start
Set preferences for the FE analysis code,
such as location of executable, etc.
Select Accept to save settings – best to restart after.
Settings are saved to text file in users’ home folder: foxrc/FAC/Franc3D.ini
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Hands On: Import FE Model
Part III
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