Thin-Wall Rectangular Pressure Vessels Simulation

Most pressure vessels are designed to be cylindrical for a reason. It minimizes deformation and stress concentration and is the optimal shape for maximum pressure load relative to material volume. But sometimes, other concerns drive designs toward thin-wall rectangular pressure vessels. When we have to design with a rectangular shape, we have to set aside what we know about standard pressure vessels, especially when the wall gets thin.

PADT’s Alex Grishin encountered this for a project when working on a lithium-ion battery pack that, during a thermal runaway event, can become a thin-wall rectangular pressure vessel. After doing both hand calculations and simulations, he summarized his findings about stress in thin-wall rectangular pressure vessels with the presentation below.

The PDF contains the following:

1. Background on thin-wall rectangular pressure vessels
2. An Ansys Mechanical model , 1/4 symmetry, of a thin-wall rectangular pressure vessel for a lithium-ion battery pack during thermal runaway.
3. An estimation of maximum deflection without and with non-linearities included, using the assumption that the geometry will deform into a cylinder.
4. An estimation of maximum stress without and with non-linearities included, using equations and an Ansys Mechanical model.

We have included the spreadsheet and Ansys mechanical models that were used to represent the thin-wall rectangular pressure vessel.

Presentation: Thin-Wall Rectangular Pressure Vessels Simulation

Here is a link to a zip file with the Ansys Mechanical models and Excel spreadsheet:

This presentation is an example of how PADT’s engineering team combines an understanding of fundamental engineering principles with the leading simulation tools from Ansys. It would be easy to just import the CAD model, put some pressure loads on, and run it. However, an approach that includes some looks at some basic equations can help us make sure we are modeling the real situation.

This is one of the many reasons why companies around the world use PADT’s simulation consulting team to supplement their own engineering teams. Reach out today and let’s talk about how we can help.