Videos > Battery Pack Impact and Submodeling in Workbench LS-Dyna
Dec 2, 2020

Details

Battery Pack Impact and Submodeling in Workbench LS-Dyna

Hi everybody, my name is Adam Remmel. I am an application engineer at Ozen Engineering, Inc., and today I'm going to give you a brief overview of how to perform a battery pack drop test.

Introduction to Impact Analysis Using Workbench LS-Dyna

Simulating all of the physics and geometry in detail can be challenging and time-consuming, so some simplifications are necessary. As shown in the image, I'm using a simplified geometry of a battery pack. The model involves an explicit dynamic simulation of a battery pack impacting a rigid surface using ANSYS Workbench LS-Dyna. The impact analysis is then transferred to a submodel for more detailed analysis on a specific region of interest.

Boundary Conditions

  • The battery pack is given an initial velocity of 10 meters per second.
  • All battery cells have frictionless contacts within the frame.
  • The connectors are bonded to the battery cells.
  • The rigid surface has a fixed support applied to it.

Simulation Results

The simulation shows significant stress and deformation in the battery pack, with the highest stress located on the connector nearest to the point of impact. Due to the complexity of battery packs, they are initially meshed coarsely. Once a region of high stress is identified, submodeling is used to isolate and analyze that part more closely.

Submodeling Process

  1. Create a name selection around your submodel boundary. For example, if interested in a connector, create a name selection on its surface.
  2. Use LS-Dyna's name selections manager to assign a unique ID to the name selection.
  3. Create a keyword snippet with two keywords:
    • Interface Component Segment: Assign the same unique ID as the name selection.
    • Interface Component File: Specify the file where displacements are saved, ensuring it has the .isfl file extension.

Submodel Setup

  1. Suppress all bodies not part of the submodel if geometry blocks are linked in Workbench.
  2. Create the same name selection as in the global model, ensuring it is on the same geometry.
  3. Assign the same user ID to the name selection using the name selections manager.
  4. Create another keyword snippet with two keywords:
    • Interface Linking Segment: Specify the user IDs for the name selections.
    • Interface Linking File: Use the same file as in the global model to import displacements.

Mesh Refinement and Results

In my example, the mesh was refined from 63 nodes in the global model to 572 nodes in the submodel. This refinement increased the maximum equivalent stress from 65 to 96, a 50% increase. Refining the mesh in areas of high stress is crucial for accurate stress resolution.

Conclusion

This concludes the brief overview of battery pack drop tests. At Ozen Engineering, Inc., we use physics-based simulation to solve multidisciplinary engineering problems, specializing in FEA, CFD, and electromagnetics. For more information about our company, ANSYS software, or consulting services, please contact us at:

[This was auto-generated. There may be mispellings.]

Hi everyone, my name is Adam Remmel. I am an application engineer at Ozen Engineering, and today I'm going to give you a brief overview into how to do a battery pack drop test. So first, a little bit about impact analysis using Workbench LS-Dyna.

Simulating all of the physics and the geometry and all of its detail would be very challenging and time-consuming, so some simplifications are definitely going to be needed. As you can see in the image here, I'm using a pretty simplified geometry of a battery pack.

The model consists of an explicit dynamic simulation of a battery pack impacting a rigid surface. I'm going to be using ANSYS Workbench LS-Dyna to set up and simulate this model.

The impact analysis is then transferred to a submodel so that I can do a more detailed analysis on one specific region of interest within my model.

Some of the boundary conditions for this are: * The battery pack is given an initial velocity of 10 meters per second. * All of the battery cells have frictionless contacts within the frame. * The connectors are bonded to the battery cells. * My rigid surface has a fixed support applied to it.

Looking at the results of this simulation, you can see that the battery pack undergoes quite a bit of stress and deformation. Because battery packs are usually pretty large, complex models, we mesh them rather coarsely initially.

But once we see this region of very high stress in one specific part of the geometry, submodeling becomes a good strategy for being able to isolate that part of the geometry and look at it a little more closely without causing any damage.

I'm going to use ANSYS Workbench LS-Dyna to simulate this model a little more closely. Now, let's take a quick look at a modifier that works within this submodeling wrapping.

Here are some of the functions that some of you may want to use: * By default, the reasons are identical from 39m to 77m, fast to slow from zero to style to 1m. * Then from two museums to 3x whole. * Pista gear displace smooth. * Then from b to nonlinear hazel identities where all prices don't divide late. * The і can Paddy go onward suddenly to make labor slot patients when the battery pack turns the onto environment trær all the prec secured and chips. * And then to make the region much more finely than you would in your global model, as well as include some more geometric detail that you simplify in your global model.

You can link the engineering data and the geometry between these two simulations, but make sure not to link the model and anything below that.

A couple of steps that you need to do in order to include a submodel are: 1. Create a name selection around your submodel boundary. 2. Use LS-Dyna's name selections manager to give that name selection a unique ID. 3. Create a keyword snippet. The snippet is pretty simple. It's just two keywords.

The first one being "interface component segment" and the second one being "interface component file." This is the file where the displacements of your submodel are going to be saved.

Under the interface component file, you just put in anywhere, it doesn't matter where this file is or what you name it. The only thing that matters is that it includes the .isfl file extension type.

In the submodel, if you did link the geometry blocks in Workbench, you'll need to suppress all of the bodies that are not going to be part of your submodel. Then, create the name selection in the same way you did in the global model. Finally, create another keyword snippet.

Again, just a simple quick snippet, two keywords. The first one being "interface linking segment" and the second one being "interface linking file." This is just the exact same file that you wrote out in the global model. Then, you're ready to solve the submodel.

No other boundary conditions are necessary for the submodel because all those boundary conditions are held and stored in this linking file that links your global model to the submodel. In my example, I refined the mesh from 63 nodes in the global model mesh to 572 nodes in my submodel.

This caused the maximum equivalent stress to go from 65 to 96, so about a 50% increase. It is very important to do, especially in an area of high stress, to try to refine the mesh in that area to make sure you're resolving that stress correctly.

That's it for the brief overview on battery pack drop tests. Once again, I work for Ozen Engineering. We use physics-based simulation to solve multidisciplinary engineering problems. We specialize in FEA, CFD, and high and low frequency electromagnetics.

If you'd like to learn more about our company, learn some more about ANSYS software or our consulting services, you can email us at [info@ozeninc.com](mailto:info@ozeninc.com), call our office phone number, or visit our website at [www.ozeninc.com](http://www.ozeninc.com).

Title of the talk: Battery Pack Impact and Submodeling in Workbench LS-Dyna.

View on YouTube