MATS23702
An Introduction to Modeling in Abaqus
Workshop 1: Intro Tutorial 1
The notes for this tutorial have been adapted from the official Abaqus tutorials found in
the v6.14 Abaqus/CAE User's Guide.
You can download a pdf of this here:
https://www.dropbox.com/s/ah0fsc9nhpmlpc2/Abaqus_v6.14_user_guide.pdf?dl=0
Sections in this document are referred to at various points in this tutorial, as a source of
further information (optional, if you want to find out more).
• You will work as individuals for this tutorial (and for the remaining
introductory tutorials).
• Open Abaqus CAE through the start menu.
It should be in a folder called
Dassult Systems SIMULIA Established Products 2020.
• Select the option to create a Standard/Explicit model.
This first tutorial involves the modeling of a simple cantilever beam-bending
scenario. These notes will lead you through the Abaqus/CAE (Complete Abaqus
Environment) modeling process by visiting each of the modules and showing you
the basic steps to create and analyze a simple model. To illustrate each of the
steps, you will first create a model of a steel cantilever beam and load its top
surface:
You will then submit the model for analysis and plot the resulting stresses and
displacements.
/
The following topics are covered:
• “Understanding Abaqus/CAE modules,” Section 1
• “Understanding the Model Tree,” Section 2
• “Creating a part,” Section 3
• “Creating a material,” Section 4
• “Defining and assigning section properties,” Section 5
• “Assembling the model,” Section 6
• “Defining your analysis steps,” Section 7
• “Applying a boundary condition and a load to the model,” Section 8
• “Meshing the model,” Section 9
• “Creating and submitting an analysis job,” Section 10
• “Viewing the results of your analysis,” Section 11
Learning Outcomes:
By the end of this tutorial, you should be able to:
• Use Abaqus to create a simple model of beam bending.
• Identify the various modules that Abaqus comprises, and what they do.
1 Understanding Abaqus/CAE modules
Abaqus/CAE is divided into modules, where each module defines an aspect of
the modeling process; for example, defining the geometry, defining material
properties, and generating a mesh. As you move from module to module, you
build the model from which Abaqus/CAE generates an input file that you submit
to Abaqus/Standard or Abaqus/Explicit (these are types of FE solver) for
analysis. For example, you use the Property module to define material and
section properties and the Step module to choose an analysis procedure. The
Abaqus/CAE postprocessor (for analyzing results) is called the Visualization
module.
You enter a module by selecting it from the Module list in the context bar:
In the following cantilever beam tutorial, you will enter the following Abaqus/CAE
modules and perform the following tasks:
Part: Sketch a two-dimensional profile and create a part representing the
cantilever beam.
Property: Define the material properties and other section properties of the
beam.
Assembly: Assemble the model and create sets.
Step: Configure the analysis procedure and output requests.
Load: Apply loads and boundary conditions to the beam.
Mesh: Mesh the beam.
Job: Create a job and submit it for analysis.
Visualization: View the results of the analysis.
Although the Module list in the context bar lists the modules in a logical
sequence, you can move back and forth between modules at will. However,
certain obvious restrictions apply; for example, you cannot assign section
properties to geometry that has not yet been created.
A completed model contains everything that Abaqus/CAE needs to generate an
input file and start the analysis. Abaqus/CAE uses a model database to store
your models. When you start Abaqus/CAE, the Start Session dialog box allows
you to create a new, empty model database in memory. After you start
Abaqus/CAE, you can save your model database to a disk by selecting File
Save from the main menu bar; to retrieve it from a disk, select File
Open.
For further information on related topics, see:
For a complete listing of which module generates a particular keyword, see
“Abaqus keyword browser table,” Section A.1 of the Abaqus/CAE User's Guide.
For information on other related topics, see:
Part II, “Working with Abaqus/CAE model databases, models, and files,” of the
Abaqus/CAE User's Guide
“What is a module?,” Section 2.3 of the Abaqus/CAE User's Guide
2 Understanding the Model Tree
The Model Tree provides a visual description of the hierarchy of items in a
model. The figure on the next page shows a typical Model Tree.
Items in the Model Tree are represented by small icons; for example, the Steps
icon, . In addition, parentheses next to an item indicate that the
item is a container, and the number in the parentheses indicates the number of
items in the container. You can click on the “+” and “–” signs in the Model Tree to
expand and collapse a container. The right and left arrow keys perform the same
operation.
The arrangement of the containers and
items in the Model Tree reflects the order in
which you are expected to create your
model. As noted earlier, a similar logic
governs the order of modules in the module
menu - you create parts before you create
the assembly, and you create steps before
you create loads. This arrangement is fixed -
you cannot move items in the Model Tree.
The Model Tree provides most of the
functionality of the main menu bar and the
module managers. For example, if you
double-click on the Parts container, you can
create a new part (the equivalent of
selecting Part
Create from the main
menu bar).
The instructions for the example that follows
will focus on using the Model Tree to access
the functionality of Abaqus/CAE. Menu bar
actions will be considered only when
necessary (e.g., when creating a finite
element mesh or postprocessing results).
3 Creating a part
You can create parts that are native to Abaqus/CAE, or you can import parts
created by other applications either as a geometric representation or as a finite
element mesh.
The CAD capabilities of Abaqus are somewhat limited, so for
complex geometries a specialist package like SolidWorks could be used and
then the shape imported.
For these tutorials, however, we will stick to using
Abaqus.
You will start the cantilever beam tutorial by creating a three-dimensional,
deformable solid body. You do this by sketching the two-dimensional profile of
the beam (a rectangle) and extruding it. Abaqus/CAE automatically enters the
Sketcher when you create a part.
Abaqus/CAE often displays a short message in the prompt area indicating what it
expects you to do next:
Click the Cancel button to cancel the current task. Click the Previous button to
cancel the current step in the task and return to the previous step.
To create the cantilever beam:
1. If you have not already, start Abaqus/CAE. Resize your windows so that you
can follow the tutorial and see the Abaqus/CAE main window.
2. From the Create Model Database options in the Start Session dialog box
that appears, select With Standard/Explicit Model. If you are already in an
Abaqus/CAE session, select File
New from the main menu
bar. Abaqus/CAE enters the Part module. The Model Tree appears in the
left side of the main window. Between the Model Tree and the canvas is the
Part module toolbox. A toolbox contains a set of icons that allow expert users
to bypass the menus in the main menu bar. For many tools, as you select an
item from the main menu bar or the Model Tree, the corresponding tool is
highlighted in the module toolbox so you can learn its location.
3. In the Model Tree, double-click
the Parts container to create a
new part. The Create Part
dialog box appears. Abaqus/CAE
also displays text in the prompt
area near the bottom of the
window to guide you through the
procedure. You use the Create
Part dialog box to name the part;
to choose its modeling space,
type, and base feature; and to
set the approximate size. You
can edit and rename a part after
you create it; you can also
change its modeling space and
type but not its base feature.
4. Name the part Beam. Accept the
default settings of a three- dimensional, deformable body
and a solid, extruded base
feature. In the Approximate size
text field, type 300.
5. Click Continue to exit the Create Part dialog box. Abaqus/CAE automatically
enters the Sketcher. The Sketcher toolbox appears in the left side of the
main window, and the Sketcher grid appears in the viewport. The Sketcher
contains a set of basic tools that allow you to sketch the two-dimensional
profile of your part. Abaqus/CAE enters the Sketcher whenever you create or
edit a part.
The Sketcher grid helps you position the cursor and align objects in the viewport.
• Dashed lines indicate the X- and Y-axes of the sketch and intersect at the
origin of the sketch.
• A triad in the lower-left corner of the viewport indicates the relationship
between the sketch plane and the orientation of the part.
• When you select a sketching tool, Abaqus/CAE displays the X- and Y- coordinates of the cursor in the upper-left corner of the viewport.
6. To sketch the profile of the cantilever beam, you need to select the rectangle
drawing tool . The rectangle drawing tool appears in the Sketcher
toolbox with a white background indicating that you selected it. Abaqus/CAE
displays prompts in the prompt area to guide you through the procedure.
7. In the viewport, sketch the rectangle using the following steps:
• You will first sketch a rough approximation of the beam and then use
constraints and dimensions to refine the sketch. Select any two points as
the opposite corners of the rectangle.
• Press [esc] to exit the rectangle tool (can also use the scroll button on
your mouse). (Tip:
Like all tools in Abaqus/CAE, if you simply position the
cursor over a tool in the Sketcher toolbox for a short time, a small window
appears that gives a brief description of the tool. The following aspects of
the Sketcher help you sketch the desired geometry)
• The Sketcher automatically adds constraints to
the sketch (in this case the four corners of the
rectangle are assigned perpendicular constraints
and one edge is designated as horizontal).
• Use the dimension tool
to dimension the top
and left edges of the rectangle. The top edge
should have a horizontal dimension of 200 mm,
and the left edge should have a vertical
dimension of 20 mm. When
dimensioning each edge, simply
select the line, click the left mouse
button to position the dimension
text, and then enter the new
dimension in the prompt area.
• Press F6 or the
icon if you wish to auto-fit the viewing window.
• The final sketch is:
• Note that you could also have defined your sketch using coordinates (as
opposed to mouse clicking then using the dimension tool). When creating
a sketch you might have seen the following in the prompt window, which
would have allowed you to do this:
8. If you make a mistake while using the Sketcher, you can delete lines in your
sketch, as explained in the following procedure:
• From the Sketcher toolbox, click the Delete tool, .
• From the sketch, click a line to select it. Abaqus/CAE highlights the
selected line in red.
• Press [Return]
to delete the selected line.
• Repeat steps b and c as often as necessary.
• Press [esc] to finish using the Delete tool.
• Note:
You can also use the Undo tool
and the Redo tool
to
undo and redo your previous operations.
9. From the prompt area (near the bottom of the main window), click Done to
exit the Sketcher. Note:
If you don't see the Done button in the prompt area,
continue to press [esc] in the viewport until it appears.
10. Because you are creating an extruded part,
Abaqus/CAE displays the Edit Base
Extrusion dialog box for you to select the
depth. Optional parameters to modify the
extrusion shape are also available. In the
Depth field, erase the default value and type
a value of 25.0. Click OK to accept this
value. Abaqus/CAE displays an isometric
view of the new part:
• To help you orient the cantilever beam during the modeling process,
Abaqus/CAE displays a triad in the lower-left corner indicating the
orientation of the global coordinate system.
11. Before you continue the tutorial, save your model in a model database file.
• From the main menu bar, select File
Save. The Save Model Database
As dialog box appears.
• Type a name for the new model database in the File Name field, and click
OK. You do not need to include the file extension; Abaqus/CAE
automatically appends .cae to the file name. Abaqus/CAE stores the
model database in a new file and returns to the Part module. The title bar
of the Abaqus/CAE window displays the path and name of the model
database. You should always save your model database at regular
intervals (for example, each time you switch modules).
Note: if you were concerned about computational times, it would have been
possible to run this simulation as a 2D problem (i.e., you would have drawn a
simple 2D beam and not extruded it).
You are able to do this since the results
should not change through the beam thickness (z-direction).
It is often very important in FE simulations to exploit the symmetries of
problems to reduce their complexities and computing requirements. For instance,
instead of simulating the compression of a cylinder in full 3D, you could use a 2D
slice of the cylinder and apply axis-symmetric boundary conditions.
Here, however, we’ll stick to 3D because the computing times are so short (and
because the results look prettier!)
For further information on related topics, see:
Chapter 11, “The Part module,” of the Abaqus/CAE User's Guide
Chapter 20, “The Sketch module,” of the Abaqus/CAE User's Guide
“Customizing the Sketcher,” Section 20.9 of the Abaqus/CAE User's Guide
“Editing a feature,” Section 65.4.1 of the Abaqus/CAE User's Guide
4 Creating a material
For this cantilever beam tutorial, you will create a single linear elastic
material with value for the Young's modulus of 200 GPa and a Poisson's
ratio of 0.3.
To define a material:
1. In the Model Tree, double-click the Materials container to create a new
material. Abaqus/CAE switches to the Property module, and the Edit
Material dialog box appears.
2. Name the material Steel. Use the menu bar under the browser area of the
material editor to reveal menus containing all the available material options.
Some of the menu items contain submenus; for example, the options
available under the Mechanical Elasticity menu item are:
When you select a material option, the appropriate data entry form appears
below the menu.
3. From the material editor's menu bar, select Mechanical
Elasticity Elastic. Abaqus/CAE displays the Elastic data form.
4. The units of elasticity are in MPa.
Enter 200.E3 MPa for Young's
modulus and a value of 0.3 for
Poisson's ratio in the respective
fields. Use [Tab] to move between
cells.
5. Click OK to exit the material editor.
For further information on related topics,
see:
“Creating materials,” Section 12.4.1 of
the Abaqus/CAE User's Guide
4.1 Aside: Units in Abaqus
Abaqus, like many finite element programs, does not consider the units of
quantities.
It is up to the user to make sure units are consistent.
You should
examine your problem and chose your units such that the input quantities are
close to 1.
This helps to minimize round-off errors associated with the solver.
For instance, it’s much better to work in µm steps, rather than use steps of
0.000001 m.
Example 1: SI Units
Base dimensions:
[Length] = m
[Force] = N
[Time] = s
[Mass] = kg
The following dimensions therefore need to be used:
[Pressure (stress and Young’s modulus)] = N m-2 = Pa
[Velocity] = m s-1
[Acceleration] = m s-2
[Volume] = m3
[Density] = kg m-3
[Energy] = N m = J
Example 2: SI Units (small parts – for this tutorial)
Base dimensions:
[Length] = mm
[Force] = N
[Time] = s
[Mass] = kg
The following dimensions therefore need to be used:
[Pressure (stress and Young’s modulus)] = N mm-2 = 1e6 Pa = MPa
[Velocity] = mm s-1 = 1e-3 m s-1
[Acceleration] = mm s-2 = 1e-3 m s-2
[Volume] = mm3 = 1e-9 m3
[Density] = kg mm-3 = 1e9 kg m-3
[Energy] = N mm = 1e-3 J = mJ
Therefore, if you want to enter the Young’s modulus value, you need to use its
value in MPa.
Example 3: SI Units (small loads and small parts)
Base dimensions:
[Length] = µm
[Force] = µN
[Time] = s
[Mass] = kg
The following dimensions therefore need to be used:
[Pressure (stress and Young’s modulus)] = µN µm-2 = 1e6 Pa = MPa
[Velocity] = µm s-1 = 1e-6 m s-1
[Acceleration] = µm s-2 = 1e-6 m s-2
[Volume] = µm3 = 1e-18 m3
[Density] = kg µm-3 = 1e18 kg m-3
[Energy] = µN µm = 1e-12 J = pJ
5 Defining and assigning section properties
You define the properties of a part through sections. After you create the
section, you can use one of the following two methods to assign the section to
the part in the current viewport:
• You can simply select the region from the part and assign the section to
the selected region.
• You can use the Set toolset to create a homogeneous set containing the
region and assign the section to the set.
For the cantilever beam tutorial you will create a single homogeneous solid
section that you will assign to the beam by selecting the beam from the viewport.
The solid section will contain a reference to the material Steel that you created.
5.1 Defining a homogeneous solid section
A homogeneous solid section is the simplest section type that you can define; it
includes only a material reference and an optional plane stress/plane strain
thickness definition.
To define the homogeneous solid section:
1. In the Model Tree, double-click the Sections
container to create a section. The Create
Section dialog box appears.
2. In the Create Section dialog box:
• Name the section BeamSection.
• In the Category list, accept Solid as the
default category selection.
• In the Type list, accept Homogeneous as the default type selection.
• Click Continue. The Edit Section dialog
box appears.
3. In the dialog box:
Accept the default selection
of Steel for the Material associated with the
section. Click OK.
5.2 Assigning the section to the cantilever beam
The section BeamSection must be assigned to the part.
To assign the section to the cantilever beam:
4. In the Model Tree, expand the branch for the part
named Beam by clicking the “+” symbol to expand the
Parts container and then clicking the “+” symbol to
expand the Beam item.
5. Double-click Section Assignments in the list of part
attributes that appears. Abaqus/CAE displays
prompts in the prompt area to guide you through the
procedure.
6. Click anywhere on the beam to select the region to
which the section will be applied. Abaqus/CAE
highlights the entire beam.
7. Click Done in the prompt area to accept the selected geometry. The Edit
Section Assignment dialog box appears containing a list of existing
sections.
8. Accept the default selection of BeamSection as the section, and click
OK. Abaqus/CAE assigns the solid section to
the beam, colors the entire beam aqua to
indicate that the region has a section
assignment, and closes the Edit Section
Assignment dialog box.
Note:
When you assign a section to a region of
a part, the region takes on the material
properties associated with the section.
For further information on related topics, see:
“Creating and editing sections,” Section 12.13 of the Abaqus/CAE User's Guide
“Assigning a section,” Section 12.15.1 of the Abaqus/CAE User's Guide
6 Assembling the model
Each part that you create is oriented in its own coordinate system and is
independent of the other parts in the model. Although a model may contain many
parts, it contains only one assembly. You define the geometry of the assembly
by creating instances of a part and then positioning the instances relative to
each other in a global coordinate system. An instance may be classified as
independent or dependent. Independent part instances are meshed
individually while the mesh of a dependent part instance is associated the mesh
of the original part.
For this tutorial you will create a single instance of your cantilever beam.
Abaqus/CAE positions the instance so that the origin of the sketch that defined
the rectangular profile of the beam overlays the origin of the assembly's default
coordinate system.
To assemble the model:
1. In the Model Tree, expand the
Assembly container. Then double- click Instances in the list that
appears. Abaqus/CAE switches to
the Assembly module, and the
Create Instance dialog box
appears.
2. In the dialog box, select Beam and
click OK. Abaqus/CAE creates an
instance of the cantilever beam
and displays it using an isometric
orientation. In this example the
single instance of the beam defines
the assembly. A second triad in the
viewport indicates the origin and
orientation of the global coordinate
system.
3. In the View Manipulation toolbar, click the rotate view manipulation tool,
. When you move the mouse back into the viewport, a circle appears.
4. Drag the mouse in the viewport to rotate the model and examine it from all
sides. You can also pick a center of rotation by clicking Select in the prompt
area; your selected center of rotation is retained for the current object and
viewport. Click Use Default to return to the default (center of viewport)
rotation method. Press [esc] to exit rotate mode.
5. Several other tools (pan , magnify , zoom , and auto-fit ) are
also available in the View Manipulation toolbar to help you examine your
model. Experiment with each of these tools until you are comfortable with
them. Use the context-sensitive help system
to obtain any additional
information you require about these tools. Direct view manipulation is
available using the 3D compass. The compass allows you to pan or rotate
your model by clicking and dragging on it. For example:
• Click and drag one of the straight axes of the 3D compass to pan along an
axis.
• Click and drag any of the quarter-circular faces on the 3D compass to pan
along a plane.
• Click and drag one of the three arcs along
the perimeter of the 3D compass to rotate
the model about the axis that is
perpendicular to the plane containing the
arc.
• Click and drag the free rotation handle (the
point at the top of the 3D compass) to rotate
the model freely about its pivot point.
• Click the label for any of the axes on the 3D
compass to select a predefined view (the selected axis is perpendicular to
the plane of the viewport).
• Double-click anywhere on the 3D compass to specify a view.
For further information on related topics, see:
Chapter 13, “The Assembly module,” of the Abaqus/CAE User's Guide
7 Defining your analysis steps
Now that you have created your part, you can define your analysis steps. For
the cantilever beam tutorial the analysis will consist of two steps:
• An initial step, in which you will apply a boundary condition that
constrains one end of the cantilever beam.
• A general, static analysis step, in which you will apply a pressure load
to the top face of the beam.
Abaqus/CAE generates the initial step automatically, but you must create the
analysis step yourself. You may also request output for any steps in the analysis.
7.1 Creating an analysis step
Create a general, static step that follows the initial step
of the analysis.
To create a general, static analysis step:
1. In the Model Tree, double-click the Steps container
to create a step. Abaqus/CAE switches to the Step
module. The Create Step dialog box appears with
a list of all the general procedures and a default
step name of Step-1. General procedures are
those that can be used to analyze linear or
nonlinear response.
2. Name the step BeamLoad.
3. From the list of available general procedures in the
Create Step dialog box, select Static, General if it
is not already selected and click Continue. The
Edit Step dialog box appears with
the default settings for a general,
static step.
4. The Basic tab is selected by
default. In the Description field,
type Load the top of the
beam.
5. Click the Incrementation tab, and
accept the default time
incrementation settings.
6. Click the Other tab to see its
contents; you can accept the default
values provided for the step.
7. Click OK to create the step and to
exit the Edit Step dialog box.
7.2 Requesting data output
When you submit your job for analysis, Abaqus/Standard or Abaqus/Explicit
writes the results of the analysis to the output database. For each step you
create, you can use the Field Output Requests Manager and the History
Output Requests Manager to do the following:
• Select the region of the model for which Abaqus will generate data.
• Select the variables that Abaqus will write to the output database.
• Select the section points of beams or shells for which Abaqus will
generate data.
• Change the frequency at which Abaqus will write data to the output
database.
When you create a step, Abaqus/CAE generates a default output request for the
step. For the cantilever beam tutorial,
you will simply examine the output
requests and accept the default
configuration.
To examine your output requests:
8. In the Model Tree, right click on
the Field Output Requests
container and select Manager
from the menu that
appears. Abaqus/CAE displays
the Field Output Requests
Manager. This manager displays
an alphabetical list of existing output requests along the left side of the dialog
box. The names of all the steps in the analysis appear along the top of the
dialog box in the order of execution. The table formed by these two lists
displays the status of each output request in each step.
9. Review the default output request that Abaqus/CAE generates for the Static,
General step you created and named BeamLoad. Click the cell in the table
labeled Created; that cell becomes highlighted, and the following information
related to the cell appears in the legend at the bottom of the manager:
• The type of analysis procedure carried out in the step in that
column. (The Step procedure)
• The list of output request variables (Variables).
• The output request
status (Status).
10. On the right side of the Field
Output Requests Manager,
click Edit to view more detailed
information about the output
request. The field output editor
appears. In the Output
Variables region of the dialog
box, a text box lists all the
variables that will be output. If
you change an output request,
you can always return to the
default settings by clicking
Preselected defaults above the
text box.
11. Click the arrows next to each
output variable category to see
exactly which variables will be
output. The check boxes next to
each category title allow you to
see at a glance whether all
variables in that category will be
output. A black check mark on a
white background indicates that all variables will be output, while a dark gray
check mark on a light gray background indicates that only some variables will
be output. Based on the selections shown at the bottom of the dialog box,
data will be generated at every default section point in the model and will be
written to the output database after every increment during the analysis.
12. Click Cancel to close the field output editor, since you do not wish to make
any changes to the default choice.
13. Click Dismiss to close the Field Output Requests Manager.
Note:
What is the difference between the Dismiss and Cancel buttons?
Dismiss buttons appear in dialog boxes that contain data that you cannot modify.
For example, the Field Output Requests Manager allows you to view output
requests, but you must use the field output editor to modify those requests.
Clicking the Dismiss button simply closes the Field Output Requests Manager.
Conversely, Cancel buttons appear in dialog boxes that allow you to make
changes. Clicking Cancel closes the dialog box without saving your changes.
14. Review the history output requests in a similar manner by right clicking on the
History Output Requests container in the Model Tree and then opening the
history output editor.
Note: You use field output
requests to request output of
variables that should be written
at relatively low frequencies to
the output database from the
entire model or from a large
portion of the model. Field
output is used to generate
deformed shape plots, contour
plots, and animations from
your analysis results.
Abaqus/CAE writes every
component of the variables to
the output database at the
selected frequency.
You use history output
requests to request output of
variables that should be written
to the output database at a
high frequency from a small
portion of the model; for
example, the displacement of
a single node. History output is
used to generate X–Y plots
and data reports from your
analysis results. When you
create a history output request, you must select the individual components of the
variables that will be written to the output database.
For further information on related topics, see:
Chapter 14, “The Step module,” of the Abaqus/CAE User's Guide
“Understanding output requests,” Section 14.4 of the Abaqus/CAE User's Guide
8 Applying a boundary condition and a load to the model
Prescribed conditions, such as loads and boundary conditions, are step- dependent, which means that you must specify the step or steps in which they
become active. Now that you have defined the steps in the analysis, you can
define the following prescribed conditions:
• A boundary condition that constrains one end of the cantilever beam in the X-,
Y-, and Z-directions; the boundary condition is applied during the initial step.
• A load that you apply to the top face of the beam; the load is applied during
the general analysis step.
8.1 Applying a boundary condition to one end of the cantilever
beam
Create a boundary condition that constrains the cantilever beam to be built-in at
one end of the beam.
To apply boundary conditions to one end of the cantilever beam:
1. In the Model Tree, double-click the BCs container. Abaqus/CAE switches to
the Load module, and the Create Boundary Condition dialog box appears.
2. In the Create Boundary Condition dialog box:
• Name the boundary condition Fixed.
• From the list of steps, select
Initial as the step in which
the boundary condition will
be activated.
• In the Category list, accept
Mechanical as the default
category selection.
• In the Types for Selected
Step list, accept Symmetry/
Antisymmetry/ Encastre as
the default type selection,
and click Continue. Abaqus/CAE displays prompts in the prompt area to
guide you through the procedure.
3. You will fix the face at the left end of the cantilever beam; the desired face is
shown below. Selecting the region on which to apply a boundary condition.
• Rotate the view in order to select the face. Click OK to confirm your
choice.
4. Click Done in the prompt area to indicate that you have finished
selecting. The Edit Boundary Condition dialog box appears.
5. In the dialog box:
• Toggle on ENCASTRE.
• Click OK to create the boundary
condition and to close the dialog box.
Abaqus/CAE displays arrows at each
corner and midpoint on the selected face
to indicate the constrained degrees of
freedom. Single-headed arrows
represent a constraint that is applied to a
translational degree of freedom. Double- headed arrows represent a constraint that is applied to a rotational degree
of freedom. An ENCASTRE boundary condition constrains all available
degrees of freedom.
6. In the Model Tree, right click on the BCs container and select Manager from
the menu that appears. Abaqus/CAE displays the Boundary Condition
Manager. The manager indicates that the boundary condition is Created
(activated) in the initial step and is Propagated (continues to be active) in the
general analysis step BeamLoad.
• Click Dismiss to close the
Boundary Condition
Manager.
8.2 Applying a load to the top of the cantilever beam
Now that you have fixed one end of the cantilever beam, you can apply a
distributed load to the top face of the beam. The load is applied during the
general, static step you created earlier.
You will apply a pressure that is unique to you (this is for purposes of the
mini-assessment) of 0.XX MPa, where XX are the last two digits of your
university ID number (not including your card issue number, which is
usually an un-bold O).
Use the ID number of the person who is currently operating the computer.
You will re-run the simulation (it’s very quick) for the other person in your
pair at the end of the tutorial (see the assessment information in Section
13).
To apply a load to the top of the cantilever beam:
7. In the Model Tree, double-click the Loads container. The Create Load dialog
box appears.
8. In the Create Load dialog box:
• Name the load Pressure.
• From the list of steps, select
BeamLoad as the step in which the
load will be applied.
• In the Category list, accept
Mechanical as the default
category selection.
• In the Types for Selected Step
list, select Pressure, and click
Continue. Abaqus/CAE displays
prompts in the prompt area to
guide you through the procedure.
9. In the viewport, select the top face of the beam as the surface to which the
load will be applied. The desired face is shown below.
Selecting the region
on which to apply a pressure load.
10. Click Done in the prompt area to indicate that you have finished selecting
regions. The Edit Load dialog box appears.
11. In the dialog box:
• Enter a magnitude of 0.XX MPa for
the load (0.5 MPa is used in the
example figure).
• Accept the default Distribution
selection –Abaqus will apply the load
uniformly over the face.
• Accept the default Amplitude
selection –Abaqus will ramp up the
load during the step.
• Click OK to create the load and to
close the dialog box. Abaqus/CAE
displays downward-pointing arrows along the top face of the beam to
indicate the load applied in the negative Y-direction.
12. Examine the Load Manager and note that the new load is “Created”
(activated) in the general analysis step BeamLoad.
13. Click Dismiss to close the Load Manager.
For further information on related topics, see:
Chapter 16, “The Load module,” of the Abaqus/CAE User's Guide
“What are step-dependent managers?,” Section 3.4.2 of the Abaqus/CAE User's
Guide
9 Meshing the model
You will now generate the finite element mesh. You can choose the meshing
technique that Abaqus/CAE will use to create the mesh, the element shape, and
the element type. Abaqus/CAE uses a number of different meshing techniques.
The default meshing technique assigned to the model is indicated by the color of
the model when you enter the Mesh module; if Abaqus/CAE displays the model
in orange, it cannot be meshed without assistance from you.
9.1 Assigning mesh controls
In this section you will use the Mesh Controls dialog box to examine the
technique that Abaqus/CAE will use to mesh the model and the shape of the
elements that Abaqus/CAE will generate.
To assign the mesh controls:
1. In the Model Tree, expand the
Beam item underneath the
Parts container and double-click
Mesh in the list that
appears. Abaqus/CAE switches
to the Mesh module. The Mesh
module functionality is available
only through menu bar items or
toolbox icons.
2. From the main menu bar, select Mesh
Controls. The Mesh Controls
dialog box appears. Abaqus/CAE colors the regions of your model to indicate
which technique it will use to
mesh that region.
Abaqus/CAE will use
structured meshing to mesh
your cantilever beam and
displays the beam in green.
3. In the dialog box, accept Hex
as the default Element
Shape selection.
4. Accept Structured as the
default Technique selection.
5. Click OK to assign the mesh controls and to close the dialog
box. Abaqus/CAE will use the structured meshing technique to create a mesh
of hexahedral-shaped elements.
9.2 Assigning an Abaqus element type
In this section you will use the Element Type dialog box to assign a particular
Abaqus element type to the model. Although you will assign the element type
now, you could also wait until after the mesh has been created.
To assign an Abaqus element type:
6. From the main menu bar, select Mesh
Element Type. You will be
prompted to select the regions to be assigned the element types.
Select the
beam and click Done.
The Element Type dialog box will then appear.
7. In the dialog box, accept the following default selections that control the
elements that are available for selection:
• Standard is the default Element Library selection.
• Linear is the default Geometric Order.
• 3D Stress is the default Family of elements.
8. In the lower portion of the dialog box, examine the element shape options. A
brief description of the default element selection is available at the bottom of
each tabbed page. Since the model is a three-dimensional solid, only three- dimensional solid element
types – hexahedral on the
Hex tabbed page,
triangular prism on the
Wedge page, and
tetrahedral on the Tet
page – are shown.
9. Click the Hex tab, and
choose Incompatible
modes from the list of
formulation options. A
description of the element
type C3D8I appears at the
bottom of the dialog box.
Abaqus/CAE will now associate C3D8I elements with the elements in the
mesh.
10. Click OK to assign the element type and to close the dialog box.
9.3 Creating the mesh
Basic meshing is a two-stage operation: first you seed the edges of the part
instance, and then you mesh the part instance. You select the number of seeds
based on the desired element size or on the number of elements that you want
along an edge, and Abaqus/CAE places the nodes of the mesh at the seeds
whenever possible. For the cantilever beam tutorial the default seeding will
generate a mesh with square hexahedral elements.
To mesh the model:
11. From the main menu bar, select Seed
Part to seed the part instance (this
can also be selected from the
icon). The Global Seeds dialog box
appears. The dialog box displays the default element size that Abaqus/CAE
will use to seed the part instance. This default element size is based on the
size of the part instance.
12. In the dialog box, enter an approximate
global size of 10.0 and click OK.
13. Click Done in the prompt area to indicate
that you have finished the seed
definition. Abaqus/CAE applies the seeds
to the part instance. You can gain more
control of the resulting mesh by seeding
each edge of the part instance
individually.
14. From the main menu bar, select Mesh Part to mesh the part instance (or
click the
icon).
15. In the prompt area, click Yes to confirm that you want to mesh the part
instance. Abaqus/CAE meshes the part instance and displays the resulting
mesh, as shown below.
10 Creating and submitting an analysis job
Now that you have configured your analysis, you will create a job that is
associated with your model and to submit the job for analysis.
To create and submit an analysis job:
1. In the Model Tree, double-click the
Jobs container to create a
job. Abaqus/CAE switches to the Job
module, and the Create Job dialog box
appears with a list of the models in the
model database.
2. Name the job Deform.
3. Click Continue to create the job. The
Edit Job dialog box appears.
4. In the Description field, type
Cantilever beam tutorial.
5. Click the tabs to review the default
settings in the job editor. Click OK to
accept all the default job settings and to
close the dialog box.
6. In the Model Tree, expand the Jobs
container; right click on the job named
Deform, and select Submit from the
menu that appears to submit your job
for analysis.
After you submit your job, information appears
next to the job name indicating the job's status.
The status of the cantilever beam tutorial shows
one of the following:
• Submitted while the analysis input file is
being generated.
• Running while Abaqus analyzes the model.
• Completed when the analysis is complete,
and the output has been written to the output database.
• Aborted if Abaqus/CAE finds a problem with the input file or the analysis
and aborts the analysis. In addition, Abaqus/CAE reports the problem in
the message area.
You can also right click on the job and select Monitor for more detail.
7. When the job completes successfully, you are
ready to view the results of the analysis with the
Visualization module. In the Model Tree, right
click on the job named Deform and select
Results to enter the Visualization module.
Abaqus/CAE enters the Visualization module,
opens the output database created by the job,
and displays the undeformed model shape.
For further information on related topics, see:
Chapter 17, “The Mesh module,” of the Abaqus/CAE User's Guide
“Advanced meshing techniques,” Section 17.14 of the Abaqus/CAE User's Guide
“Seeding a model,” Section 17.16 of the Abaqus/CAE User's Guide
11 Viewing the results of your analysis
You use the Visualization module to read the output database that Abaqus/CAE
generated during the analysis and to view the results of the analysis. Because
you named the job Deform when you created the job, Abaqus/CAE names the
output database Deform.odb.
For this tutorial you will view the undeformed and deformed shapes of the
cantilever beam model and create a contour plot.
To view the results of your analysis:
1. After you select Results in the Model Tree, Abaqus/CAE enters the
Visualization module, opens Deform.odb, and displays the undeformed shape
of the model in bright green
The title block (text overlay on the screen, top half) indicates the following:
• The job description.
• The output database from which Abaqus/CAE read the data.
• The release of Abaqus/Standard or Abaqus/Explicit that was used to
generate the output database.
• The date the output database was generated.
The state block (text overlay on the screen, bottom half) indicates the
following:
• The step name and the step description.
• The increment within the step.
• The step time.
• When you are viewing a deformed plot, the deformed variable and the
deformation scale factor.
By default, Abaqus/CAE plots the last step and the last frame of your
analysis. Buttons that allow you to control which analysis results are plotted
are available in the top right of the screen
(they sometimes also appear in the prompt
area).
2. From the main menu bar, select Plot Deformed Shape to view a deformed
shape plot.
3. Click the auto-fit tool
so that the entire plot is rescaled to fit in the
viewport
4. From the main menu bar, select Plot Contours On Deformed Shape to
view a contour plot of the von Mises stress.
5. For a contour plot the default variable displayed depends on the analysis
procedure; in this case, the default variable is the von Mises stress. From the
main menu bar, select Result Field Output to examine the variables that
are available for display. Abaqus/CAE displays the Field Output dialog box;
click the Primary Variable tab to choose which variable to display and to
select the invariant or component of interest. By default, the Mises invariant
of the Stress components at integration points variable is
selected. Tip:
You can also use the Field Output toolbar to change the
displayed field output variable.
6. Click Cancel to close the Field Output dialog box.
For further information on related topics, see:
Part V, “Viewing results,” of the Abaqus/CAE User's Guide
Chapter 43, “Plotting the undeformed and deformed shapes,” of the Abaqus/CAE
User's Guide
Chapter 44, “Contouring analysis results,” of the Abaqus/CAE User's Guide
You have now finished this tutorial.
Continue reading for details of how to
submit your mini-assignment.
There is also an extension section (optional)
that you may want to explore.
12 Extension (optional, not assessed)
• Can you design a beam with the same length and total volume as the
beam modeled above, but which does not bend as much?
Keep the
cross-section fixed.
• Explore what happens when you change the mesh size used in the
models – what are the advantages and disadvantages of using different
mesh sizes?
13 Summary
• When you create a part, you name it and choose its type, modeling space,
base feature, and approximate size.
• Abaqus/CAE automatically enters the Sketcher when you create or edit a
part. You use the Sketcher to draw the two-dimensional profiles of parts.
• Press [esc] in the viewport (or click Done in the prompt window) to indicate
you have finished selecting items or using a tool.
• You can create a material and define its properties and create a section and
define its category and type. Since the section refers to the material, the
material must be defined first.
• A model contains only one assembly. The assembly is composed of
instances of parts positioned in a global coordinate system.
• Abaqus/CAE generates the initial step automatically, but you must create
analysis steps. You use the step editor to define each analysis step.
• When you create a step, Abaqus/CAE generates a default output request for
the step. You use the Field Output Requests Manager and the History
Output Requests Manager to examine which categories of data will be
output.
• You invoke the field and history output editors from the Field Output
Requests Manager and the History Output Requests Manager to select
the variables that Abaqus/CAE will write to the output database during the
analysis, as well as the frequency at which they are written and the regions
and section points from which they are written.
• Prescribed conditions, such as loads and boundary conditions, are step- dependent objects, which means that you must specify the step or steps in
which they become active.
• Managers are useful for reviewing and modifying the status of prescribed
conditions in each step.
• You create loads and define where the load is applied to the assembly in the
Load module.
• Although you can create a mesh at any point after creating the assembly, you
typically do it after configuring the rest of the model, since items such as
loads, boundary conditions, and steps depend on the underlying geometry,
not the mesh.
• You can assign the element type either before or after you create the mesh.
The available element types depend on the geometry of your model.
• You use seeds to define the approximate position of nodes in your final mesh.
You select the number of seeds based on the element size or on the number
of elements that you want along an edge.
• You can use the Model Tree to submit jobs and to monitor the status of a job.
• In the Visualization module you read the output database generated by your
analysis and view the results. You can select the variable to display from the
data in the output database, and you can also select the increment being
displayed.
• You can display the results in several modes – undeformed, deformed, and
contour. You can control the appearance of the display in each mode,
independent of other modes.
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