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Any referenced datasets can be downloaded from "Module downloads" in the module overview.
Transcript
00:08
Welcome to the Getting Started with Inventor Nastran module.
00:11
In this first unit, we're going to be looking at an introduction to Finite Element Analysis as well as the Inventor Nastran analysis types.
00:22
In the Digital Prototyping process, there are several stages.
00:25
And a Finite Element Analysis tool like Inventor Nastran can be used in any one of them.
00:30
You will often see it used in the Design & Engineering stage as a way to explore different geometries and materials,
00:37
in order to optimize a product.
00:40
However, you may also see it at the test and validation stage,
00:44
alongside physical testing as a way to make sure products will perform as expected,
00:49
while making physical prototypes less expensive.
00:53
And lastly, it can be used in the Manufacturing & Production stage as a way to validate manufacturing processes,
00:59
as well as explore failures and determine their root cause.
01:06
FEA softwares allow users to take their three-dimensional model and subject it to forces, vibrations,
01:13
thermal loads and other effects to see how it would respond before producing an actual physical prototype.
01:19
With FEA, you'll take a three dimensional model and break it up into a series of nodes and elements.
01:26
This mesh that's created can then be constrained and loaded in order to generate results.
01:32
The results are typically your stresses and displacements,
01:36
but you can also calculate other things like velocity and acceleration in a dynamic analysis.
01:42
Once the actual solution has been generated, you can then determine how much the part is going to yield,
01:48
how much it might displace or deform, and whether or not it's going to wear out under a series of cycles.
02:04
Once that model has been imported, the first step in any Inventor Nastran analysis is going to be creating an idealization.
02:13
An idealization contains two things, the material and the element type that will be used to represent the solid in the mesh.
02:21
The three different element idealization types are Solids, Shells and Lines,
02:27
and these can be used individually or combined in an assembly level analysis.
02:34
After defining an Element type, the next step in the process will be defining a material for that idealization to use.
02:41
Inventor Nastran has a very large library for its users to pull from, as well as several different ways to define materials for the FEA.
02:49
One of the most common material types is going to be an Isotropic material.
02:53
Isotropic materials behave with the same strength and stiffness characteristics in each direction.
02:59
An example of this would be aluminum or steel.
03:02
Orthotropic 2D and 3D materials behave with different strength and stiffness characteristics in each direction.
03:09
An example of that would be a wood material where the strength with the grain versus against the grain might be slightly different.
03:18
For a linear static analysis, you will be working with a linear material.
03:22
However, if you would like to perform a nonlinear analysis, you can also input the nonlinear material data.
03:28
This is going to be the stress and strain data beyond the yield strength of a material.
03:34
Having these different ways to define a material,
03:36
give the user the ability to appropriately model the characteristics of their actual design and get accurate results.
03:46
After all the idealizations and materials have been defined, the next step in the process is going to be generating a finite element mesh.
03:53
Inventor Nastran has several global Mesh Settings including Element Size,
03:58
Element Order, and whether or not to use Continuous Meshing.
04:02
Inventor Nastran also has the ability to apply local mesh controls to accurately control the size of elements in key regions.
04:10
A default mesh size will be created automatically based off of a bounding box size of the model,
04:16
but that can be refined further as the analysis progresses.
04:22
Boundary Conditions is a term that FEA solvers use to represent constraints and loads that are added into an FEA problem.
04:31
Constraints are going to represent your true supports or contacting geometry.
04:35
Anything that is going to restrict the number of degrees of freedom available to a component.
04:41
Loads are used to simulate a force, pressure, thermal load,
04:46
or maybe even an acceleration that's going to be applied to the mesh that will generate a displacement or a stress.
04:53
It's important to correctly define these boundary conditions,
04:56
in order to accurately represent the physics that your model is going to undergo.
05:04
Inventor Nastran is embedded into the Autodesk Inventor platform.
05:08
It acts as a preprocessor that allows you to set up the FEA problem with your mesh, constraints, loads and materials,
05:16
and then it will be exported to the Autodesk Nastran Solver to actually create a result.
05:23
Once the solver is finished, it will take the results file and import it back into Inventor Nastran,
05:28
where the actual contours and data points can be reviewed.
05:34
The advantage of having an embedded FEA tool within the CAD platform is that you are able to make changes to the CAD model,
05:41
and then update the mesh and resolve without having to start over every single time a change is made.
05:49
FEA solvers allow users to predict many different physical effects.
05:53
The most common result is going to be your Von Mises stress, as well as your displacement or your amount of deformation.
06:01
However, other things can be analyzed as well.
06:03
Some of these include vibration and acceleration, as well as fatigue and how well something will perform after a series of cycles.
06:11
You can also look at more dynamic problems like motion and buckling as well as thermal analysis such as heat transfer.
06:19
The reason that Inventor Nastran has so many different study types is so that a user can find the study,
06:25
that most accurately represents the physics that their problem requires.
06:30
This slide shows some of the basic analysis types that Inventor Nastran has for its users.
06:35
The default analysis type for all studies is going to be your Linear Static analysis.
06:40
You can also perform eigenvalue and eigenvector analysis or your Normal Modes analysis.
06:45
Buckling is a great way to troubleshoot geometric instability and determine failure points,
06:51
and then Prestress Static and Prestress Normal Modes are the same as your statics and normal modes,
06:56
except you can apply a preload in a separate sub case.
06:59
You'll also see Linear Steady State Heat Transfer and Thermal Stress available in this software as well.
07:06
Some of the more advanced analysis types include your Nonlinear.
07:09
This can be your Nonlinear Statics or your Nonlinear Transient Studies to look at things like Impact.
07:14
An automated Impact Analysis tool is also included for Drop Testing.
07:19
If a more dynamic analysis is required,
07:21
you can perform a Direct and Modal Frequency Response to determine how something responds to a driven input frequency.
07:29
Linear dynamics can also be performed, and that would be something like a Random Response or a Shock Response Spectrum.
07:37
And Nonlinear Steady State Heat Transfer and Transient Heat Transfer can also be performed within an Inventor Nastran.
07:45
When choosing a static analysis, it's important to understand the difference between Linear and Nonlinear.
07:51
Linear static studies assume that the displacements and rotations are going to be fairly small.
07:58
This means you will not see a significant amount of bending or rotation in the final result.
08:03
It also assumes that your supports do not move or settle under load.
08:08
That means you typically won't have constraints allowing sliding or geometric instability.
08:14
The material itself should remain linear, meaning that you will be in the linear working range of the material.
08:19
All stresses should be below the yield strength and stress is going to remain directly proportional to strain at all times.
08:27
The last assumption is that loads in their orientation, magnitude and distribution are going to remain constant at all times.
08:36
This means that if a part deforms, the load vector will remain the same.
08:41
It will not follow that deformation and the distribution of the load will remain the same throughout as well.
08:48
There are three effects that would make a user consider using a nonlinear study instead of a linear one.
08:54
The first of these is called geometric nonlinearity.
08:57
This is when you're seeing large amount of displacement or strain.
09:02
The nonlinear solver is able to break up the load into increments and update the stiffness matrix,
09:08
which will more accurately capture the effect of a large amount of bending.
09:14
Material nonlinearity is when you go beyond the yield strength of a given material.
09:18
This will create what's called permanent or plastic deformation,
09:22
and a nonlinear stress/strain curve is required in order to accurately capture that data.
09:28
The last nonlinear effect is boundary condition nonlinearity.
09:33
This would be when a load or a constraint might be changing orientation or direction,
09:38
as well as more complex contact interactions in things like impact analysis.
09:48
Opening up a part here in Autodesk Inventor Professional 2024, you will see the Model Tree on the left hand side,
09:55
as well as your typical 3D modeling tools along the top.
09:58
One thing to note with this model is that if you look at the material properties, Mild, Steel has already been defined.
10:05
If you define a material with an Inventor,
10:07
it'll automatically be copied over to the idealization within Inventor Nastran So if I go to the Environments tab,
10:15
once I've installed Inventor Nastran, it'll automatically be embedded into this panel.
10:22
I can go ahead and open it up.
10:24
And what you'll see right away is it brings in the model.
10:27
And on the left hand side, you'll see the Analysis 1.
10:30
It is a Linear Static analysis shown in parentheses there and then Solid 1 is the first idealization that's been created.
10:38
And if I expand it, you'll notice that Mild, Steel is automatically added.
10:42
So that's done when you first import a model.
10:45
If you have not defined the material with an Inventor,
10:47
this material will show up as generic and you'll want to make sure that you update that idealization.
10:54
Another thing that you will notice right away is that beneath the analysis tree is the Model Tree.
10:60
If you were to expand this, you will see that there's a separate set of settings and options below the analysis tree.
11:07
One thing to keep in mind is that the analysis tree will contain all of the items that will go into the Solver.
11:14
This includes your idealizations, materials, mesh, loads and constraints.
11:20
The Model Tree is a backup or a library of all the resources you create during your studies.
11:26
So if you have multiple analyses that you create over time, a backup of those resources will automatically be created in the Model Tree.
11:33
However, nothing in the Model Tree will be given to the Nastran Solver when you click "Run".
11:40
So let's say that we want to change the Analysis type.
11:43
All you have to do is double click on "Analysis 1".
11:47
This will open up this dialog box here where you can choose an analysis name as well as the type of study that you'd like to perform.
11:55
Hitting this drop-down menu, you will see Linear Static, which is the default analysis type.
11:60
But you can also perform a Normal Modes analysis to calculate natural frequencies, Linear Buckling to look at geometric instabilities,
12:08
Preloaded Static and Preloaded Normal Modes, which require an additional sub case,
12:14
and then your Nonlinear Statics and Nonlinear Buckling.
12:16
Most of these analyses in this first chunk here are going to be your Statics or Buckling.
12:22
The next section here contains your Dynamic Analyses.
12:25
This would be your Transient Response, your Frequency Response Impact Analysis and then your Linear Dynamics,
12:32
which would be Random Response and Shock Response Spectrum.
12:35
Down further, you have your Fatigue Studies, Heat Transfer and then Explicit Dynamics or Quasi-Static.
12:42
So they're grouped into these five categories.
12:45
And once you change the analysis type and you select, "Okay", you will notice each analysis has different requirements.
12:51
For instance, normal modes will require a Modal Setup in addition to Idealizations, Loads and Constraints.
12:60
The analysis is saved with the Inventor part file or the Inventor assembly file,
13:04
which means if you were to Finish the Autodesk Inventor Nastran environment,
13:10
and go back to the 3D modeling environment and then you click "Save",
13:14
the next time you open this part. When you open up Inventor Nastran, all of your changes will automatically be saved.
13:20
So any analysis that you create will show up in there without having to create a separate file.
Video transcript
00:08
Welcome to the Getting Started with Inventor Nastran module.
00:11
In this first unit, we're going to be looking at an introduction to Finite Element Analysis as well as the Inventor Nastran analysis types.
00:22
In the Digital Prototyping process, there are several stages.
00:25
And a Finite Element Analysis tool like Inventor Nastran can be used in any one of them.
00:30
You will often see it used in the Design & Engineering stage as a way to explore different geometries and materials,
00:37
in order to optimize a product.
00:40
However, you may also see it at the test and validation stage,
00:44
alongside physical testing as a way to make sure products will perform as expected,
00:49
while making physical prototypes less expensive.
00:53
And lastly, it can be used in the Manufacturing & Production stage as a way to validate manufacturing processes,
00:59
as well as explore failures and determine their root cause.
01:06
FEA softwares allow users to take their three-dimensional model and subject it to forces, vibrations,
01:13
thermal loads and other effects to see how it would respond before producing an actual physical prototype.
01:19
With FEA, you'll take a three dimensional model and break it up into a series of nodes and elements.
01:26
This mesh that's created can then be constrained and loaded in order to generate results.
01:32
The results are typically your stresses and displacements,
01:36
but you can also calculate other things like velocity and acceleration in a dynamic analysis.
01:42
Once the actual solution has been generated, you can then determine how much the part is going to yield,
01:48
how much it might displace or deform, and whether or not it's going to wear out under a series of cycles.
02:04
Once that model has been imported, the first step in any Inventor Nastran analysis is going to be creating an idealization.
02:13
An idealization contains two things, the material and the element type that will be used to represent the solid in the mesh.
02:21
The three different element idealization types are Solids, Shells and Lines,
02:27
and these can be used individually or combined in an assembly level analysis.
02:34
After defining an Element type, the next step in the process will be defining a material for that idealization to use.
02:41
Inventor Nastran has a very large library for its users to pull from, as well as several different ways to define materials for the FEA.
02:49
One of the most common material types is going to be an Isotropic material.
02:53
Isotropic materials behave with the same strength and stiffness characteristics in each direction.
02:59
An example of this would be aluminum or steel.
03:02
Orthotropic 2D and 3D materials behave with different strength and stiffness characteristics in each direction.
03:09
An example of that would be a wood material where the strength with the grain versus against the grain might be slightly different.
03:18
For a linear static analysis, you will be working with a linear material.
03:22
However, if you would like to perform a nonlinear analysis, you can also input the nonlinear material data.
03:28
This is going to be the stress and strain data beyond the yield strength of a material.
03:34
Having these different ways to define a material,
03:36
give the user the ability to appropriately model the characteristics of their actual design and get accurate results.
03:46
After all the idealizations and materials have been defined, the next step in the process is going to be generating a finite element mesh.
03:53
Inventor Nastran has several global Mesh Settings including Element Size,
03:58
Element Order, and whether or not to use Continuous Meshing.
04:02
Inventor Nastran also has the ability to apply local mesh controls to accurately control the size of elements in key regions.
04:10
A default mesh size will be created automatically based off of a bounding box size of the model,
04:16
but that can be refined further as the analysis progresses.
04:22
Boundary Conditions is a term that FEA solvers use to represent constraints and loads that are added into an FEA problem.
04:31
Constraints are going to represent your true supports or contacting geometry.
04:35
Anything that is going to restrict the number of degrees of freedom available to a component.
04:41
Loads are used to simulate a force, pressure, thermal load,
04:46
or maybe even an acceleration that's going to be applied to the mesh that will generate a displacement or a stress.
04:53
It's important to correctly define these boundary conditions,
04:56
in order to accurately represent the physics that your model is going to undergo.
05:04
Inventor Nastran is embedded into the Autodesk Inventor platform.
05:08
It acts as a preprocessor that allows you to set up the FEA problem with your mesh, constraints, loads and materials,
05:16
and then it will be exported to the Autodesk Nastran Solver to actually create a result.
05:23
Once the solver is finished, it will take the results file and import it back into Inventor Nastran,
05:28
where the actual contours and data points can be reviewed.
05:34
The advantage of having an embedded FEA tool within the CAD platform is that you are able to make changes to the CAD model,
05:41
and then update the mesh and resolve without having to start over every single time a change is made.
05:49
FEA solvers allow users to predict many different physical effects.
05:53
The most common result is going to be your Von Mises stress, as well as your displacement or your amount of deformation.
06:01
However, other things can be analyzed as well.
06:03
Some of these include vibration and acceleration, as well as fatigue and how well something will perform after a series of cycles.
06:11
You can also look at more dynamic problems like motion and buckling as well as thermal analysis such as heat transfer.
06:19
The reason that Inventor Nastran has so many different study types is so that a user can find the study,
06:25
that most accurately represents the physics that their problem requires.
06:30
This slide shows some of the basic analysis types that Inventor Nastran has for its users.
06:35
The default analysis type for all studies is going to be your Linear Static analysis.
06:40
You can also perform eigenvalue and eigenvector analysis or your Normal Modes analysis.
06:45
Buckling is a great way to troubleshoot geometric instability and determine failure points,
06:51
and then Prestress Static and Prestress Normal Modes are the same as your statics and normal modes,
06:56
except you can apply a preload in a separate sub case.
06:59
You'll also see Linear Steady State Heat Transfer and Thermal Stress available in this software as well.
07:06
Some of the more advanced analysis types include your Nonlinear.
07:09
This can be your Nonlinear Statics or your Nonlinear Transient Studies to look at things like Impact.
07:14
An automated Impact Analysis tool is also included for Drop Testing.
07:19
If a more dynamic analysis is required,
07:21
you can perform a Direct and Modal Frequency Response to determine how something responds to a driven input frequency.
07:29
Linear dynamics can also be performed, and that would be something like a Random Response or a Shock Response Spectrum.
07:37
And Nonlinear Steady State Heat Transfer and Transient Heat Transfer can also be performed within an Inventor Nastran.
07:45
When choosing a static analysis, it's important to understand the difference between Linear and Nonlinear.
07:51
Linear static studies assume that the displacements and rotations are going to be fairly small.
07:58
This means you will not see a significant amount of bending or rotation in the final result.
08:03
It also assumes that your supports do not move or settle under load.
08:08
That means you typically won't have constraints allowing sliding or geometric instability.
08:14
The material itself should remain linear, meaning that you will be in the linear working range of the material.
08:19
All stresses should be below the yield strength and stress is going to remain directly proportional to strain at all times.
08:27
The last assumption is that loads in their orientation, magnitude and distribution are going to remain constant at all times.
08:36
This means that if a part deforms, the load vector will remain the same.
08:41
It will not follow that deformation and the distribution of the load will remain the same throughout as well.
08:48
There are three effects that would make a user consider using a nonlinear study instead of a linear one.
08:54
The first of these is called geometric nonlinearity.
08:57
This is when you're seeing large amount of displacement or strain.
09:02
The nonlinear solver is able to break up the load into increments and update the stiffness matrix,
09:08
which will more accurately capture the effect of a large amount of bending.
09:14
Material nonlinearity is when you go beyond the yield strength of a given material.
09:18
This will create what's called permanent or plastic deformation,
09:22
and a nonlinear stress/strain curve is required in order to accurately capture that data.
09:28
The last nonlinear effect is boundary condition nonlinearity.
09:33
This would be when a load or a constraint might be changing orientation or direction,
09:38
as well as more complex contact interactions in things like impact analysis.
09:48
Opening up a part here in Autodesk Inventor Professional 2024, you will see the Model Tree on the left hand side,
09:55
as well as your typical 3D modeling tools along the top.
09:58
One thing to note with this model is that if you look at the material properties, Mild, Steel has already been defined.
10:05
If you define a material with an Inventor,
10:07
it'll automatically be copied over to the idealization within Inventor Nastran So if I go to the Environments tab,
10:15
once I've installed Inventor Nastran, it'll automatically be embedded into this panel.
10:22
I can go ahead and open it up.
10:24
And what you'll see right away is it brings in the model.
10:27
And on the left hand side, you'll see the Analysis 1.
10:30
It is a Linear Static analysis shown in parentheses there and then Solid 1 is the first idealization that's been created.
10:38
And if I expand it, you'll notice that Mild, Steel is automatically added.
10:42
So that's done when you first import a model.
10:45
If you have not defined the material with an Inventor,
10:47
this material will show up as generic and you'll want to make sure that you update that idealization.
10:54
Another thing that you will notice right away is that beneath the analysis tree is the Model Tree.
10:60
If you were to expand this, you will see that there's a separate set of settings and options below the analysis tree.
11:07
One thing to keep in mind is that the analysis tree will contain all of the items that will go into the Solver.
11:14
This includes your idealizations, materials, mesh, loads and constraints.
11:20
The Model Tree is a backup or a library of all the resources you create during your studies.
11:26
So if you have multiple analyses that you create over time, a backup of those resources will automatically be created in the Model Tree.
11:33
However, nothing in the Model Tree will be given to the Nastran Solver when you click "Run".
11:40
So let's say that we want to change the Analysis type.
11:43
All you have to do is double click on "Analysis 1".
11:47
This will open up this dialog box here where you can choose an analysis name as well as the type of study that you'd like to perform.
11:55
Hitting this drop-down menu, you will see Linear Static, which is the default analysis type.
11:60
But you can also perform a Normal Modes analysis to calculate natural frequencies, Linear Buckling to look at geometric instabilities,
12:08
Preloaded Static and Preloaded Normal Modes, which require an additional sub case,
12:14
and then your Nonlinear Statics and Nonlinear Buckling.
12:16
Most of these analyses in this first chunk here are going to be your Statics or Buckling.
12:22
The next section here contains your Dynamic Analyses.
12:25
This would be your Transient Response, your Frequency Response Impact Analysis and then your Linear Dynamics,
12:32
which would be Random Response and Shock Response Spectrum.
12:35
Down further, you have your Fatigue Studies, Heat Transfer and then Explicit Dynamics or Quasi-Static.
12:42
So they're grouped into these five categories.
12:45
And once you change the analysis type and you select, "Okay", you will notice each analysis has different requirements.
12:51
For instance, normal modes will require a Modal Setup in addition to Idealizations, Loads and Constraints.
12:60
The analysis is saved with the Inventor part file or the Inventor assembly file,
13:04
which means if you were to Finish the Autodesk Inventor Nastran environment,
13:10
and go back to the 3D modeling environment and then you click "Save",
13:14
the next time you open this part. When you open up Inventor Nastran, all of your changes will automatically be saved.
13:20
So any analysis that you create will show up in there without having to create a separate file.
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