In this lesson, we go over how to refine a simulation mesh.

After completing this lesson,

you'll be able to use local mesh refinement.

At this point, we've created a simulation.

We've taken a look at the results.

We see where the stress is going from the motors.

We see where the deflection is and how much it is.

Now we want to start to modify things and see how it affects the results.

Now, it's a good idea for you guys to play around with the model, make some changes,

maybe come in and thicken this area and see how you can increase the rigidity,

maybe just in the top section not in the bottom

because we are going to be using it to pass cables through.

But there are different ways that you can modify this.

Now as we're looking at the stress,

I think it's important for us to make a couple of notes here.

The stress again is being carried across these ribs.

And as we look at the center section here coming from

the motor into where we're mounting the component tray,

it's starting to actually make use of the center section of that IBM cross-section.

It's not for a while but we do start to

use some of this material as well, but not as much.

So this is telling me that we could potentially leave the area

open without any sort of detrimental effects.

Or instead of leaving it open,

we could put some small ribs from side to side or do a generative type mesh shape

inside there without really having

any major negative effects on the strength of the design.

But for right now, I'm going to leave it.

That's a great practice example that we're going to talk about for you guys to play with.

But for right now, what I want to focus on is mesh refinement.

After the first pass using all the default settings to create a mesh,

there are a few things that we can do to help

make sure that we completely understand the results.

So under the managed section,

we have local mesh control and adaptive mesh refinement.

Now remember, if we take a look at the mesh,

we can see that it already did some adaptive meshing.

Now, what I mean by this is the mesh element size on these smaller areas

like these fillets are smaller than the faces next to them.

We can see on the top here that the larger the face, the broader the face,

the larger the mesh element size gets,

and over here in

our generative mesh area that we actually have some fairly small elements.

We can also get a good idea of the actual need for the generative type design here.

You can see that some of these are carrying load in this V-shaped pattern.

And that is consistent with the loading path from the motors.

It's carrying them along those axes.

While the rest of these aren't really carrying much load,

it's still staying fairly close to the minimum amount.

But we can take a look at this design and we can see areas where we might need

to increase if we were using this as a fairly rigid structural member.

And we can see areas where we might want to maybe get rid of

elements altogether if we need more air flow or something along those lines.

So this is a great way for us to focus in on these results.

But under manage, let's go and take a look at local mesh control.

And this is going to allow us to

designate a mesh element size in certain areas if we want to

focus on a fillet or a face or

a certain area where we know that we're going to have load concentration,

and we want to get a better idea on how that handles.

So we're going to take a look at face edge selection and we want to come

in here and we're going to select these internal faces in this corner.

I'm going to rotate it around,

I want to grab all of these,

and I also want to grab some of these faces inside.

You have to be careful with the faces,

the specific faces that you select because you don't want to

have a very fine mesh over a large area.

Now in our case, again,

we're focusing on just the top here for right now,

and we're focusing on these internal faces.

And whenever we reduce the mesh size in this area,

it's also going to translate out to the surrounding faces.

So we're going to reduce the mesh element size to one millimeter.

We're going to say OK, and then we need to regenerate the mesh.

So you can see that the mesh now has a caution symbol next to it,

and we have this local mesh control.

So what happens is it pre-passes or does

the mesh like we originally set up using our default settings,

and the local mesh control will then happen after the fact.

We've only got a single local mesh control.

We could select more faces,

but I really just want to show you how this process works.

So we're going to right click, we're going to regenerate that mesh.

We're going to take a look at how the local mesh control is going to affect

the overall resolution of the stress in this area.

Now that the mesh has been generated,

let's take a look at the results.

So you can see the faces that we selected have that one-millimeter mesh element size.

And you can see that as it goes up over the edge,

it has smaller mesh elements in the faces where it connects,

and they get larger as they get farther away.

So now that we have this smaller mesh element size,

the results are out of date and we need to resolve this study.

Again, we're going to solve it on the cloud,

and go ahead and allow it to solve.

And we'll take a look at it when it's complete.

Now that we have the results for you, let's take a look.

You can see that the factor of safety change

slightly but we're still within the same range.

Now if we take a look at the results,

really what we're looking for is to see the stress concentration in these areas.

Now this is a great example because the sparre or

the structure on the left-hand side is

identical to the stuff on the right-hand side in terms of the loading,

the geometry, and we can see that we have

a better idea of the location of stress points when we have a finer mesh.

So as we zoom in here, you can see these small areas of stress concentration.

As we rotate this around,

we can take a look on the inside as well.

These areas tell me that this could potentially benefit from a larger radius fillet,

if we want to make sure that we reduce the stress in those areas.

But again, we're really talking about very small amounts.

So you can see, as we look at the refined mesh,

we have a larger concentration of stress than we do in the unrefined mesh.

As we drag the color bar slider up,

there's going to be a point where the stress concentration on the unrefined one

disappears and the stress concentration

on the refined one still stays for just a little bit.

Now these are minute differences in our design,

but they could make a big difference in a different design.

So just keep that in mind that the mesh refinement can give you

a better idea of the stress concentration and how we're getting from

the loading points of the motor mount all the way down to

the area where we're locking the geometry down using the component tray.

At this point, I'm happy with my results.

So I'm going to go ahead and save the file so we can move on to our next step.

Refine a mesh simulation

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