Piezoelectric Flexure Simulation using Ansys Mechanical

Hi everyone, this is MingYao from Ozen Engineering and in this video I'll be looking at how we set up a piezoelectric actuator. In the past few years, Ancestor has really made doing piezoelectric analysis easy. I'm taking a real-life example from Thorlabs.

Thorlabs has a wide range of piezoelectric actuators, including amplified ones. The nice thing about this is that you are able to download the CAD model of these amplified piezo actuators. We can put it into Ancestor to see how they work. So let's get on with it.

I'm going to drag and drop a step file of the piezoelectric actuator geometry. And I'm going to drag and drop a step file of the piezoelectric actuator geometry. And we're going to use some of these coupled field harmonic analysis blocks for our simulation.

The coupled field elements built into Workbench now allow us to combine electric, mechanical, and thermo-acoustic solvers. So we have the ability to do full piezoelectric analysis. Even more conveniently, we have a wide range of piezoelectric materials already defined here.

We can use something like lithium niobate, or we can do a PZT-8, PZT-4, etc. I added a couple of piezoelectric materials. Now we can go ahead and set up this simulation. Harmonic analysis means we're driving the piezo stack at a certain frequency and looking at the structural response due to that.

Okay, here's the system. We have a casing here, which we don't need. I'm going to suppress this. We have a piezo stack. I've taken the liberty of removing the connecting wires. There used to be these wiggling wires connecting through it. And then we have the flexure that will be actuated.

I'm going to suppress this here as well. So we're going to move our way down here. So let's go ahead and select all of these bodies. And I'm going to make these pieces... These pieces are PZT- 8. I'm going to hide it. And everything else right now is structural steel.

And maybe I'll just leave it that way. We can always go to a particular part. Maybe we'll go to one of these parts. And I can make it, say, a titanium type of material. This has a huge library of materials available for selection. Maybe I need to type out the entire word here.

And it'll search for titanium alloy. So we have various grades of titanium alloy. I'm going to pick one of them at random to set for this. It is important when we're looking at piezoelectric materials to assign the right orientation.

So we want the PZT stack to be aligned...the z-axis of the PZT stack to be aligned along the x-axis.

So if we go and look at our material property here for PZT-8, you'll see that the first two x and y are the same and z is in a different orientation for both the elastic matrix as well as the primitivity matrix. So to do that, we define a coordinate system. Right click, insert.

Let's put in a new coordinate system here. And we want to align the z-axis along the global x-axis. So we're going to again select all of these PZT components. We're going to go find them in the tree and assign a coordinate system to align it in the right direction.

So that's all we have to do for that. The meshing, we can do lots of fancy meshing if we wanted to. But I'm going to skip that for the sake of this analysis. And we're going to specify a frequency sweep. So I'm going to sweep from 900 to 1500 Hz. We'll do 100 solution intervals.

We can do finer or user-defined methods as well. Automatically, ANSYS will take into account and use variational technology to speed up the simulation if it can. And we're going to add maybe a little bit of depth. A couple percentage of damping.

Physics on the entire system will cover structural and electric charge. Now we just have to specify some boundary conditions. So this particular area will be held stationary. So I'm going to select these two areas and assign let's say frictional support.

This will cause the entire system to be able to turn those. Maybe let's just do a basic fixed support here. And we want to specify the PZT stack. So let's hide everything else. There's a few ways to... We want to kind of alternating plus or minus across this PZT stack.

If I click on a surface here... I have to pick surface. I can see they're all stacked up. But it can be a little bit difficult. It's difficult to figure out which surface is which. So what I tend to do is I'll kind of hide every other one of these. I'll right click and hide bodies.

Then I'll select these. And we'll add electric voltage here. We'll do 75 volts. Right now it's millivolts. So let's do 75,000 millivolts. And then we'll do ground on the other side. It's a harmonic analysis. So the excitation will be in phase. We can always adjust the phase angle if needed.

So that'll be ground. I'm going to show everything now. And we're going to now kind of do the same thing we did last time here. We'll hide everything else. Looking at my voltage here, I'm going to select all the blocks that I've already loaded. And then do the same thing. So this one we can...

Let's go ahead here. We can add to it. So I'm going to add the same eight more. And then the ground, we'll add eight more. Now while you're doing your CAD work, if you want, you can specify these as well. So you can just pick a name selection to do it.

So that's all we need to do to set up the simulation. Go ahead and run this analysis. Okay, simulation has completed. Let's take a look at a frequency response. This is an actuator. So we want to see, let's say this surface. We can go for the maximum deformation in the global z-axis. Okay.

So we have excitation here at 1368 hertz. Let's select the source phase. We can take a look at the deformation at 1368. Let's turn off the mesh here. We can always refine the mesh to get, oh this is a little too much. Let's go with, maybe we'll exaggerate by 100 times. See how that works.

So, that's the actuator moving. We can see all of the springs working properly to excite the actuator. And when we run this, you can see there's a maximum deflection of about 100 microns, 0.1 millimeter based on this current design here. We can also look at our electric voltage potential.

This will show you the... Oh, sorry. Sorry. Sorry. Sorry. Sorry. Sorry. Sorry. Sorry. Sorry. Sorry. Sorry. Sorry. Sorry. Sorry. Sorry. Sorry. Let's change this to 1368. Show the 75 volt deformation. And we can plot a variety of other results as needed. Stress can be very important.

So, we also want the stress at 1368. Okay.

and we can look at the maximum stress as zero phase or we can say at this particular frequency but maximum over the phase so now here we can see where the maximum stress is going to occur right in that location depending on you can see there's a fillet here to try to relieve the stress and how you mass some stress right there is probably a refined measure helps understand the actual maximum stress better so that's a really quick example of how we set this up you can take this a lot further in essence almost every value you can see for example my driving voltage my results frequency and maximum amplitude can all be parameterized whenever I see an amplitude can all be parameterized whenever I see an antivox here in addition the material property and geometry can be parametric so here I can set up a modal and a couple here field harmonic analysis with a wide range of input parameters and output parameters from these parameters I can do a response surface to look at the how different parameters interact how the input parameters and output parameters are correlated and this allows us to do a design optimization where I can specify for each parameter what the goals are and then have have the computer run different design parameters to get the right performance so if I'm trying to achieve a specific resin frequency I can change the thickness and size of the springs maybe how long they are I can change the thickness and size of my flexure and also anything about the material property itself so lots of options available for you to use and I hope you found this video helpful if you did please make sure to subscribe to our channel and hit the bell icon so you don't miss any of our future videos and we'll see you next time on our next video so thank you very much for watching this video if you like this video please like and subscribe to our channel if you have any questions on how to do answer simulations for example these piezo electric devices feel free to reach out to us at ozink.com thanks and have a great day you