- [Instructor] In this video,
we're going to set up loads and boundary conditions
for the plane strain analysis.
So let's go and open up the file.
We're going to change to the simulation study tab here,
the plane strain one we set up before.
And just to remind ourselves,
let's go and show the mesh.
Now we're going to constrain the bottom end of the bracket
down here and down here.
In practice, the loads are going to be carried
in the 3D model by the lower bolts.
But we're going to be focusing on the shoulder region,
so it doesn't really matter that we constrain down here.
The load path, we assume
the stress flow is going to be the same
whether we constrain here
in our 2D plane strain model,
or using bolts in the 3D model.
So as long as we've got that similar load path,
that is quite acceptable.
So let's click on the fixtures icon.
Go for fixed geometry.
And then the two regions we want are this region here
and this region here.
Now it turns out we also have to
constrain the splits here and here.
Because the way the geometry was set up,
this actual portion of the structure is
disconnected from this portion here.
It's one of the limitations of the fast geometry creation
when we do the plane strain analysis
when it creates this sector for us.
We don't have too much control over that.
So I'm going to,
in addition, therefore constrain these bottom ends.
Same approach applies.
We're basically going to isolate this bottom portion in here.
There won't be any stresses.
So this becomes our effective constraint point
here and here.
Again, from a modeling perspective, that really is no issue.
So let's click OK to constrain those sections there.
So let's change the name here.
And we're going to call this bracket end.
Now we want to apply our loads,
so let's right mouse click on external loads.
You notice in the list here,
there is no option to apply a bearing load.
Now, we don't use a bearing load in this particular case,
but it's important to just note that that's absent,
so we'd have to think of another way
of applying a load into a bolt hole
if we want to model a bolt hole.
or a similar kind of hole in a 2D plane strain.
So then we're going to choose force,
and we choose the top edge of the bracket just here.
We choose the normal direction
that's convenient for us here.
You can see the arrows indicating that.
And we want to use IPS system,
and we want to be applying 12,000 pounds force.
Per item, we've only got one item,
so that's not relevant there.
You notice the direction is wrong,
so we just flip the direction here.
And now we're applying a tensile load to the top end.
Just check OK.
Now, the 12,000-pound force that we applied here
is, in fact, the total load applied to the 3D model.
But when we set up the plane strain analysis,
we actually selected a two-inch depth
rather than unit depth.
So that means that the loads to the 3D model
match the loads to the 2D plane strain model,
which is quite a useful technique.
So let's just rename this.
We're going to call this bracket top.
So at that point, let's save off our model.
We're going to call this lug3d_lbc_end.
LBC for loads and boundary conditions.
Again, we copy the result file
because they will contain the mesh definitions.
So in conclusion, the loads and boundary conditions
are applied in the normal way.
The only exception is that we don't have
the bearing distribution available in plane strain,
so it's something to be aware of.
And also, because we set our default depth
of the plane strain to be two inches,
that matches the total load that we apply to our 3D model.