Wire Drawing Process Simulation with Plastic and Frictional Heating in Ansys Mechanical

Hi everyone, this is Ming Yao from OZ Engineering. In this video, I will continue my previous analysis of the wire pulling simulation. This simulates pulling a wire through a diamond die, a way to make the wire slightly thinner depending on how aggressive you want to be.

There's a lot of plastic deformation. The additional concern as wires deform this way is that you could have temperature issues. There's a lot of friction going on at the interface and there's significant metal deformation, permanent plastic deformation, which could generate heat.

ANSYS, in addition to being an easy-to-use tool, also gives you full coupled physics simulation capabilities. So to include the heating effects of friction as well as plastic deformation, we can use a coupled field static structural simulation here, static analysis, or transient if you wish.

This will link the static simulation, use the same material, geometry, and mesh, and allow us to set up a brand new coupled physics simulation. In this region, the purple areas, we're going to include both structural and thermal physics.

You can see we can also include electrical as well as acoustics if we want to, but for now, we'll leave it as coupled physics. We'll set the settings similar to what we did previously. So I'm going to give it a hundred sub steps here and a million as a maximum number of sub steps.

We'll make sure to turn on large deflection and on the output side, you can see there's a lot of things we can output, including heat flux, stress, strain, back stress, as well as nonlinear data, etc. So maybe heat generation rate could be helpful too. Next, we want to select plastic heating.

So this part will be heated due to plasticity, and this is a plastic work fraction, which means what's the fraction of the plastic work that will get converted into heat.

This is probably very material dependent and maybe even somewhat circumstances dependent, but I'm going to just show you an example here. Let's say 20% of the plastic work in this part will get turned into heat. That's all I have to do.

We're going to, I ran this previously to make sure it works, but we're going to grab all of these property boundary conditions and move it into our analysis system here. And the other part is we want to ensure that we capture the frictional heat generation as well.

So, for this plastic work, we can specify frictional heat generation using a couple of commands here.

We're going to modify a real constant on the contact side with two of them, 15 and 18. 15 is a real constant that specifies the fraction of the frictional dissipated energy that gets converted into heat. One means we're going to convert all of it into heat.

And then this one here is a weight factor of the distribution factor. So, this one here is the weight factor of the distribution factor. So, I can check where's the distribution of heat between the contact and the target surface.

So, which side will the heat be applied on and you can choose either contact or target. Having 0.5 means that it's evenly distributed across the two surfaces. So, that's pretty much what we need to do here. We do seem to have a question mark. Let's see when I run it, what does it say here?

Oh, I need thermal constraints. Of course, right now, I only have thermal constraints, because I only have thermal constraints. So, that's not going to be the same thing here. Let's just say that all this heat is distributed evenly across the surface. It's going to be evenly distributed.

So, that's going to be even. So, that's worth that. constraints, of course. Right now I only have force constraints, structural constraints. Because I'm adding heat now, I need to have some sort of thermal constraint.

So let's select the wire as well as the outer edge of my die and say these are our thermal energy dissipation areas, and I'm going to use a value of 5 watts per meter squared degrees Celsius as my convection coefficient. So these are the areas that I want to lose energy from.

So let's go ahead and solve our simulation. It says here I should be changing my units. Let's go ahead and do that and switch the millimeters. It's often a good idea to listen to the warnings ANSYS provides. So I'm going to do that. There it is.

Now I can do this in kind of a controlled time range, 60 seconds including the instruments. So the parameters then again do not come up very pretty for the data. For the label, and of course for the spectra.

That's the scientific measurement and the information solution, so again I chose our simulation as the input, the sources. While running here we can look at our temperature plot to see at each position what the temperature is.

So we've heated up from 22 degrees to 36 degrees Celsius and this is the temperature distribution inside of my wire. It's pretty uniform 36.6 to 36.4 but so it's roughly a constant temperature here. Okay, so the simulation is completed. We can look at uh let's look at the temperature plot first.

So here is the temperature rise. You can see that it goes from 22 degrees Celsius up to 58 degrees Celsius. We can look at the strain. The plastic strain like we looked at earlier. The strain energy. Uh, which is generating heat. And then we can look at thermal flux, heat flux.

So where is heat being generated? It's right near the contact, which is where both the plastic strain as well as the friction heating is coming into effect. So that shows you the ability of ANSYS to quickly analyze, a structural simulation as we pull a wire through the die.

But also expand that to a couple field analysis where we look at plastic heating as well as frictional heating to include the, uh, to attempt to predict the temperature of this, of the system as these forming operations are carried out. Hopefully this is of interest to you.

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