How to Model Surface Coating Stress in Ansys Mechanical
Presenter: Ming Yao from Ozen Engineering, Inc.
Introduction
In this video, I'll demonstrate how to set up a simulation with a coating or film using Ansys Mechanical. We will start with a basic static structural analysis. Companies often inquire about modeling films or thin coatings, as these can introduce residual stress that causes deformation in thin features like glass plates or very thin films.
Model Setup
We will create a thin piece of geometry with the following specifications:
- Dimensions: 80 mm by 30 mm
- Thickness: 1 mm
To add a film, use Ctrl + C and Ctrl + V to create a surface on top of the solid. This can be put into a single component with shared topology to ensure a conformal mesh between the surface and the solid, allowing us to treat the shell or surface as a coating.
Material Properties
We will set the properties for the parts as follows:
- Solid: ABS plastic
- Coating: 10-micron layer of copper
The parts will be connected node by node, sharing nodes between them. We will use a slightly darker gray for the plastic and a bluish gray for the copper.
Meshing and Simulation
For the copper layer, we will use a sweep method to create three layers through the thickness. We will turn on weak springs to hold the part in place and apply a temperature change to introduce pre-stress:
- Initial Temperature: 100°C
- Delta Temperature: -100°C
This temperature change will cause the top surface to contract, pulling the rest of the part upwards, resulting in a "smiling" shape.
Analysis
We can analyze the total deformation, stresses, and strains on the surface and film. The model allows for varying the thickness of the surfaces, from microns to nanometers.
Advanced Modeling
We can also model curved surfaces. By revolving the geometry, we can create a dome shape and apply the same analysis techniques. Using shared topology, we ensure the mesh is consistent across the assembly.
Exporting Results
The results, including stress and deformation data, can be exported as an STL file for further processing.
Conclusion
This method demonstrates how to model deformation in solids with thin coatings that have significant residual stress. For more information, please visit Ozen Engineering, Inc.
If you found this video helpful, please like and subscribe to our channel. Thank you and have a great day!
Hi everyone, this is Ming Yao from Ozen Engineering. In this video, I'll be showing you how to set up a simulation with a coating or a film. Let's start with a basic static structural analysis.
Often times, companies ask me about how to model films of thin coatings because, for thin sheets of geometry, having a thin coating can greatly affect the part and introduce a residual stress, which causes deformation on thin features like glass plates or very thin films.
So, that's discovery modeling. We're going to create a thin piece of geometry. Let's make it 80 by 30. We'll create a fairly high aspect ratio part, just one millimeter in thickness. And, if we want to add a film, I do Ctrl+C, Ctrl+V to create a surface on top of the solid.
We can put this into a single component. And, we can turn on shared topology. So, shared topology will ensure that the surface and the solid are meshed with the conformal mesh, and that means we can treat the shell or the surface as a coating. Here's our model.
We want to go ahead and set the properties of all of these parts. So, I'm going to look for some plastics, and then we'll be taking a look at the material. So, I'm going to look for some plastics. For my solid. For my solid.
Which, if I go down here, you can see, there are various types of ABS, HDP, PE, and polyamides. So, let's go ahead with an ABS plastic here, and let's say we're going to do a 10-micron layer of copper.
So, let's go ahead with an ABS plastic here, and let's say we're going to do a 10-micron layer of copper. So, let's go ahead with an ABS plastic here, and let's say we're going to do a 10-micron layer of copper. There we go. We'll go for a basic copper alloy here.
You can see, there are no connections between the parts because they are going to be connected node by node. Slightly darker gray for the copper. Slightly darker gray for the plastic, and this bluish gray for the copper. We can also display... We can also display... the node numbers.
You can see that the node, each node in the corner, has just a single number, so these are sharing the nodes between the parts. Turn that off. Now, we want probably three layers of thickness of elements in the copper, so I'm going to put in a method here.
Go for a sweep method, and we'll do three layers through the thickness. Now, we have a model here. I'm going to turn on weak spring, which will tend to hold the part in place. Select the blue section, and I'm going to put a temperature on there.
This will allow me to specify a pre-stress of the part. So, if initially, let's say, this is 100 degrees, and we cool it down, let's say, a delta temperature change of minus 100 degrees. This will tend to contract. That will pull the rest of the part upwards. So, we should have a smiling shape here.
The benefit of this method is we can make the difference between the two layers. So, we can make the surfaces as thin as we like. Right now, it's just a tenth of a micron, but you can, I mean, 10 microns, but you can make it a nanometer if you'd like here. Let's look at the total deformation.
All right, so it's behaving the way we'd expect, with the top surface contracting, pulling it downwards. We can also look at the stresses on the surface. On the film, if we wish. And the strain. Let's grab these results. Okay. So, that's the top and bottom stress distribution and elastic strain.
So, they're very similar. Because we can assign material properties to the surface, you can see there's a lot of different stresses. So, you can see that the surface is a little bit more elastic. So, we can also look at the surface. So, you can see that the surface is a little bit more elastic.
So, I'm going to make it a little bit more elastic. So, you can see there's stiffness options for membrane only, membrane bending, or stress evaluation only for that shell. We can also make it non-linear if we wish. So, that's a simple model here. Let's say we get rid of this part.
And we make let's say a curved surface. So, we can see that the surface is a little bit more elastic and costs there for the main structure. So, without this, there's a lot of stress. Here's the mechanism we use to create the lower preparers.
So, each of our abrasive grains, we apply auditory ABS and secondary abrasive, we apply 3M abrasive, and a schematic rescuer. Like stress because we once applied it, cigar stretch, MVaz D, around the stated area.
So, we place it here as a sign, which is supposed to stop these areas because, at this point, the carbide is very, very, wrap being involved, constant heat, and generation super-dang the heat from the rescued material that's because the temperature is short of the heat field, so figure off that cute bishop, increasing volume of air conveyed, clicking the switched surface right now.
Since now gas is stuck on top, very great corner, to turn away here, so you know these things, and uh... going to do it off, so here, so rather than having a straight piece, I want to show you how we can do the same model but with a curved section.
Yes, if you hit the P button to pull, we're going to revolve this around this one and we're going to just have it go around the whole circle, so now, rather than a flat piece, we have a dome. So, let's see what happens when we have a dome, and I'm going to copy-paste it.
We have a surface here on top of our dome, and this time, I'm going to make the whole analysis whole assembly with shared topology, so I'm going to update my model, telling me hey, there's all these things that need to be changed. So, let's go ahead and fix the changes.
That's the sweet body, say 100 microns. We're going to do copper and ABS again. Let's go ahead and generate the mesh. So, maybe we do instead of sweep, automatic. We'll do a thin automatic, thin see, this does a better job of meshing it.
Okay, so it's got the surface as well as a solid mesh, and we're going to do a thin mesh, and we're going to do a thin mesh, and we're going to do a thin mesh, so that it has a solid mesh on the inside. We're going to select our orange color surface here and solve this simulation.
So, you can see the way that this particular film surface causes the plastic to deform. We can look at the stretch here, the stress. This is the stress on all the bodies. So, I can reduce that to just the stress on the surface itself, as well as the stress on the solid.
So, that's the stress on the surface and the solid. We can export this to a form shape as an STL file for further work on it or further processing if needed.
So, that's a quick example of how we set up a film stress simulation, pretending that if you either painted or coated a solid with a very thin layer of another material. How do we model the deformation when that thin layer has a significant amount of residual stress?
Hopefully, you found this video interesting. If you have any questions, please reach out to us at ozeninc.com. If you like this video, please like and subscribe to our channel. Thank you, and have a great day. Bye-bye.
