- [Instructor] Now we're going to set up
a plane strain analysis, which as we've described earlier,
is a special type of static analysis.
And in SolidWorks simulation, a 2D section is created
of the required datum plane.
We're also going to be carrying out meshing of the section.
So we start off by opening.
And the file that we want is lug3d_begin.
Now the SolidWorks model shown is a lug component.
There is a single bolt attachment at the top of the lug,
and then eight bolting point attachments
at the bottom of the lug where it forks into two.
The objective of this analysis is to use plane strain
to simplify the modeling,
again making it much cheaper and faster to run.
Now the main question is whether the stress flow
through the 3D lug can be represented
by a plane strain analysis.
The introductory notes in the previous video
showed how the presence of the bolt hole
will influence the stress distribution locally.
The stress concentration factor,
which we're going to see here at the fillet radius,
can be represented using plane strain.
The stress concentration factor
is the increase in the peak stress around about this region
over the nominal stress which we'll see
around about in this region.
So let's click on Simulation.
And we go to New Study.
We make sure that the default static analysis type is set.
And then there's a check box here for Use 3D Simplification.
We're going to name this as Plane Strain one
and check OK.
Now we get a further dialogue box
with options for plane strain, plane stress
and axi-symmetric.
And the little videos in here are actually quite useful,
giving a preview of what's happening.
Now the one we want is plane strain.
For a moment, if we look at the video,
we can see there's the depth we talked about,
infinite depth.
We'll take a 2D slice through,
essentially doing a 2D slice analysis
of what is a 3D structure.
So a simple reminder, it's actually
quite a useful little animation there.
Now we have to choose a section plane
that we want to do the cut through.
Now what we're going to try first
is to cut through the front plane.
So if we come here and choose our views,
there's the front plane,
which is running nicely down the center line
of the structure.
So I choose that.
You can see we get a preview of the section
that will form the slice.
Now unfortunately, that's not going to be workable for us,
because there's a cutout where the bolt hole
goes straight through there.
So we would have a disconnected structure.
So what we need to do is to choose a different plane.
Now one way we can do that is to,
if we just for the moment click the Axi-symmetric,
that allows us to re-pick a plane.
And we can pick this plane in here.
So that's the plane I've picked.
Now I don't want to do axi-symmetric,
so come back to Plane Strain, and it remembers that.
So there's a little trick to actually
be able to change your mind there.
I can't find any other way of doing it,
but this little trick, which is quite useful.
Now the depth of 3dlug is two inches.
What we need here is an arbitrary section depth
of our plane strain analysis.
And normally we would keep this as unit depth,
but it does give us the opportunity,
within SolidWorks Simulation,
to actually put in a variation on that.
So I can actually put two inches in.
And that's quite convenient, because then that
will enable me to match the load from the full 3D model
to the load applied into the plane strain model,
and also I can check reactions in the same way.
So it's actually a very convenient little option there.
So that's everything set up there.
We can just click OK.
Use the View option to come to the front view.
Now we can right mouse click on Mesh, choose Create Mesh.
Under the Mesh parameters, at the moment,
we have a fairly coarse mesh control set up here.
If we open up Mesh parameters,
we can see that we've got a default size
around about 0.061 inch.
Now that's quite a coarse mesh for a plane strain model.
The lower walls here are only
a quarter of an inch thick, 0.25 inches.
So if we use this size,
it will only give us four elements through thickness.
And one of the big advantages of doing a 2D model
is the analysis time is far quicker
than working with 3D models.
So we can easily afford to drop this mesh size right down
and really put many, many more elements
than implied in here.
So we're going to move the Mesh Density bar
all the way to the right.
Now we have a much finer mesh in here.
So let's just click OK.
And we can see there's a very fine mesh in here.
If we zoom into the area around that radius,
we can see a lot of elements around there.
Now this is where
we're anticipating the stress concentrations,
so in fact we can do better than this,
again, with this idea that we've got a good budget
of elements now.
Let's come over to Mesh, right mouse click,
and say Apply Mesh Control.
We can pick this feature here, which is the edge.
As we slice through, this is the route radius
it's picked out.
So as drawn in here, we can see a preview
of the number of elements, the element size,
but again, it's quite coarse.
So again, let's move the slider bar
all the way to the right.
And we mustn't forget to pick the lower shoulder as well,
so we just move down here,
make sure we also grab this guy,
and apply the same to that.
So we've now got a very fine mesh density.
So again, the emphasis on plane strain analysis
is to really swamp any feature like this with elements,
almost as cheap to run,
and really extraordinarily fine meshes can be created
using this method.
So let's click OK.
Now we need to re-mesh, so I create the mesh.
Now we can see the influence of the very fine mesh.
That's exactly what we're looking for.
So let's zoom in again.
And that's really the level of fidelity
that we're looking for.
And we can even push that further,
if we wanted to, without any big penalty,
particularly on the run time.
Now before we finish,
we need to give the component a material property.
So right mouse click on the part name
and select Apply Material.
We're going to use the Alloy Steel.
So we apply that value, then we close it out.
Now this has the material property in there.
Now one of the curious things is the part name
shows the part analysis that we defined,
but also it's got Length for forces equals,
if I just hover there, 50.8 millimeters,
which equates to the two inches that we defined.
This is the plane strain thickness we're going to use.
Now in my installation it's reported as 50.8 millimeters,
your installation might be reported in meters,
they're all related to inches.
All the defaults and options in the model
are set to inch, pounds, seconds.
So it may be that this is just a SolidWorks feature.
As long as that relates to the length you defined,
even though the units are different,
there won't be a problem with that.
So at that point, let's save our SolidWorks model.
We'll save this as lug3d_end, SolidWorks part.
It's asking if we want to copy the results files.
This is implying that the mesh is being defined
isn't actually a result, but the definition for the mesh
is in one of the files that's appended to the database.
So the answer to this is Yes.
And we can rebuild and save the document.
So in summary, in this video,
we saw how to define a static analysis
as being a plane strain analysis type.
We saw how the plane section can be created
using a 2D slice and then meshed with 2D elements.