AUTODESK INVENTOR FEA ANALYSIS TUTORIAL
AUTODESK INVENTOR FEA ANALYSIS TUTORIAL
By: Jonathan DeRoner
This tutorial is to serve the purpose of performing calculations
within the stress analysis environment of Autodesk Inventor
Professional. While the environment may slightly change in terms of
layout during each release, this will give the basics on how to set
up the different types of calculations that can be performed. This
tutorial is being written using Autodesk Inventor Professional
2014.
Getting Started
You will first want to begin by opening the desired part in
Inventor. For this part of the tutorial we will be using a simple 1
X 2 inch rectangular beam that is 12 inches long. Name: FEA
Tutorial Bar
A- Defining Material
Inventor has a very large library of materials to choose from
for your parts that you produce. By applying these materials, this
will make calculations that we will be doing as accurate as
possible. For this part we will be applying Mild Steel as our
material to the rectangular beam.
Step 1: Click on the dropdown list above and locate Steel, Mild
in the list. You will notice that once you select the material that
the color of the part changes to a brighter gray color. This means
the part is now made of mild steel in Inventor.
Tip: If you cant find the material you are looking to apply to a
part in the basic drop down list of materials, the Autodesk
Material Library at the bottom of the dropdown list will update the
current list and will give you a much wider array of materials to
choose from. You can also check the physical properties of the
material by clicking the material icon next to the dropdown
list.
This will bring open the Material Browser menu where you can
check the physical properties of every material. You can even edit
existing materials and create your own new ones relative to what
will be used in the part you are producing.
B- Getting Setup in Stress Analysis Environment
Now that we have our material defined, we can begin FEA analysis
in the Stress Analysis environment.Step 2: Click on the
Environments tab and then the Stress Analysis Icon.
This will take you to the Stress Analysis environment where we
can begin setting up our simulation. We first need to create a
simulation however.
Step 3: Click on the Create Simulation icon. A menu to set up
the simulation will then appear. Simply click OK to accept the
default setup. You will then notice a new array of tools to use
.
As of now, this is what your screen should look like.
C- Applying Constraints
Applying constraints properly is very critical in the Stress
Analysis environment. Improper application could result in improper
and incorrect calculations as the end result. You ALWAYS want to
double-check and make sure you have everything constrained the way
a part would be as close in relation to the real life scenario the
part will be used for as possible.
For this simulation we will be simulating the 12 inch long Mild
Steel Beam as if it were welded to the side of an existing
structure. Even though we have no other structure in place, our
constraints will help us simulate the situation. There are 3 types
of constraints to choose from, however, for this tutorial, we will
only be using Fixed constraints.Step 4: In the Constraints tab,
click on the Fixed constraint icon.
You will then be prompted with a menu to select a location for
the constraint. For this simulation, select the back, 1 X 2 inch
face of the beam. You will have to rotate the beam to select the
face.
Once you have selected the face, click OK. This will then close
the menu. You will notice in the simulation browser on the left
that in the constraints dropdown, there is now a fixed constraint
in the browser on the face we selected.
Make sure to rotate the view of the part to the original view we
began with after the constraint has been placed.
E- Applying Proper Physical Forces
When applying forces, its best to research the type of force
that will be acting upon the part before applying the force to
proper area of the part. You will notice in the menu there are 5
different forces to choose from in the Loads menu.
You have Force, Pressure, Bearing, Moment, and Gravity.
Typically every situation will have gravity as a factor so we can
define gravity easily by selecting the gravity icon.
Step5: Click on the Gravity icon and the following menu will
appear.
The amount shown is Earths default gravity. We then need to
select the direction gravity will be acting on the part.
Step 6: Select one of the vertical edges of the part.
Notice an arrow will appear relative to the direction of the
edge shown. If the arrow is not pointing in the direction desired,
this can be flipped or adjusted with the gravity menu as shown by
simply flipping the direction, or adjusting the XYZ coordinates of
direction in the gravity dropdown.
Once gravity is set properly, click OK the arrow for the
direction of gravity will remain shown on the part. Gravity now
will also appear under the Loads dropdown in the simulation
browser.
Now we can add our force that will directly be acting on the
part. For this simulation, we will have a 25 lbs of force (NOTE:
Not Pressure/PSI) on the top face of our rectangular block.
Step 7: Click on the Force icon in the loads tab.
The following menu will appear asking us to select a
location.
Step 8: Select the top face of the rectangular block. Then in
the magnitude tab, type in 25. The force tab will recognize that it
is 25 lbforce.
Click OK when finished.
Your screen should look like the image below when finished this
step.
In any simulation we may create, there are 3 very critical steps
to complete before we run any simulation. We need to define our
material the parts will be made out of, define the constraints of
the part, and the loads that will be acting on the part. We have
now completed all 3 basics and are now ready to run our
simulation.
F- Running the Simulation
Up to this point, we have completed all the basics to running a
simulation in the Stress Analysis Environment. We have defined the
material of our part, defined the constraints, and the loads that
will be acting on the part. Now we can run the simulation.Step 9:
Click on the Simulate icon.
The following menu will then appear. When it does, click Run and
then Inventor will generate the simulation. This may take a few
minutes to complete.
Your screen will look something like the image below when the
simulation is complete.
This means the simulation is finished and we can see the results
of our simulation. The 3 types of results you will want to check
are the Von Mises Stress, Displacement, and Safety Factor.
The Von Mises Stress is the amount of stress occurring on the
part at a time during the simulation and is the default result
always shown. Your results should be similar to those shown
below.
We can then check the displacement and safety factor as
well.
Step 10: Double-click on the Displacement result in the
simulation browser and this will then show the displacement
results.
While the results seem exaggerated compared to what they really
are, there is only a displacement of .001 inches which is very
little. We can change the level of exaggeration of the resulting
image under the display tab.
Step 11: Click on the display dropdown and select Actual. The
image will then change and the actual level of displacement can be
seen on the part. You will notice that there is very little change
in the image now.
Never be quick to judge what you see in the results right off
the bat. Inventors default representation is to multiply the
effects in the image shown so you can see what the results of the
forces are doing to the part in the simulation.The next thing we
will want to check is the Safety Factor.
Step 12: Double-click on the Safety Factor result in the
simulation browser and the screen should look like the image
below.
The safety factor isnt listed because it is well above the range
listed. So to see a safety factor, we are going to adjust the
amount of force acting on the beam.
Step 13: Double-Click on Force 1 in the simulation browser and
change the force to 500 lbforce and click OK
We need to update the simulation so we will run the simulation
with the new force acting on the beam.
Step 14: Click the Simulate icon and then click run.
The simulation is now updated and there are new results listed
under the Von Mises Stress, Displacement, and Safety Factor.
Step 15: Double-Click on Safety Factor results in the simulation
browser. Your screen should show similar results to those shown
below.
Now that we can see the Safety Factor, this beam maintains a
Safety Factor of approximately 3.55 with 500 lbforce pressing down
on the top face. As long as a part has a Safety Factor above 1, it
is ok to use. The higher the results are above 1, the better. If
the results are ever below 1, the design would likely fail and be a
safety hazard if used in the real world for the intended purpose.
This is the end of part 1 of the tutorial. G- Making Calculations
Precise
In many cases, we usually only want a force to apply to a
specific part on the face of an object. If we know where that force
will be precisely and how much there will be, we can edit the part
itself to reflect where the force will be acting. In this
simulation, we will be seeing the results of force acting on the
end of the beam in a 2 X 2 inch region at the very end of the
rectangular block. Step 1: Open the FEA Tutorial Bar and create a
sketch on the top face. (Note: If you have the FEA Tutorial Bar
still open from the steps before, close the file. Do NOT save any
changes to the part and re-open the original)
Make sure to create a 2 X 2 inch rectangle at the end of the top
face as shown. Once this is complete, click Finish Sketch
We will then want to split the face of the rectangle.Step 2:
Click on the Split tool in the modify tab and follow the
instructions below.
Step 3: Inventor prompts us to select a split tool. So in this
step, select the rectangle we sketched previously.
You will then need to select the face of the object to be split.
Click on the Faces tool and select to the top face. Then click
OK
The top face of the rectangle has now been split into 2 separate
faces on the screen as you can see in the image below.
To make the faces easer to distinguish in the FEA environment,
we are going to change the color of the new split face to
beige.
Step 4: Click on the new split face and then click the Color
Wheel icon in the top left of the screen.
The following menu of colors from Inventors library will appear.
Click on the color Beige and upload it to the parts face by
clicking the icon and then the Add appearance to document command
that will appear just below the icon. You can always select other
colors also. Once finished, close the browser.
Your part should look like the image below.
Now we are ready to run the simulation again. Follow the
directions as listed previously for applying material of mild steel
to our part before moving on to the Stress Analysis
environment.Step 5: Under the Environments tab click on the Stress
Analysis icon and then create a new simulation. Accept all the
defaults given.
Your screen should look similar to the image below when
finished.
We are now ready to apply the constraints and loads just like we
did before. Only this time, the load will be placed on the face
that is colored beige instead.Step 6: Apply a fixed constraint to
the back face of the rectangle.
The constraint will appear in the Simulation browser like we
have seen before.
Now we are ready to apply the force to the split face of the
rectangle.
Step 7: Click on the Force icon and then select the beige face
of the rectangle. Notice that the force is now only being
designated to the face we have created.
Change the force amount to 500 lbforce and then click OK
Note: Make sure to define gravity after applying the 500 lbforce
by selecting the edge like we did previously.
Your screen should look like this when all these steps have been
completed.
Now we are ready to run the simulation again since we have the 3
essentials for any simulation. We have defined our material, our
constraints, and our loads.Step 8: Click the Simulate icon and then
run the simulation.
You will now notice a great difference in the results as they
now relate to the force only acting on the 2 X 2 inch face rather
than the whole top face of the rectangular block. Your results
should be very similar to the ones listed below.Von Mises
Stress
Displacement
Safety Factor
Even with the 500 lbforce now being more concentrated at the end
of the rectangular block in relation to where it is fixed in the
simulation, it is still able to hold a safety factor above 1.
H- ConclusionMaking sure that a simulation is run as close in
relation to what a part will be doing in real life is very
important and having knowledge of how these simulations work is key
to getting the correct results that would also be relative to those
we would otherwise perform hand calculations to obtain. Always make
sure when running simulations that you have the 3 factors that need
to be defined before jumping to conclusions of the results that are
given. 1. Always define a parts material. 2. Always make sure the
constraints are defined correctly in relation to where a part will
be and what it will be doing. 3. Always make sure the forces acting
on a part are input correctly and as precise as possible. Even to
obtain maximum precision, some small edits need to be made to a
part to relate to what a part is supposed to do in many cases.
These simulations will help save time when determining the
capabilities of parts and also help determine if a part is safe for
use before it is even produced.