# HYPERFOAM Model Issue
**URL:** https://calculix.discourse.group/t/hyperfoam-model-issue/4115
**Category:** Analysis issues
**Created:** [September 23, 2026, 11:12am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115 "2026-09-23T11:12:54Z")
**Posts on this page:** 13
**Page:** 2
### Author:  [@fgr](https://calculix.discourse.group/u/fgr)
#### Post date: [September 24, 2026, 7:15am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/21 "2026-09-24T07:15:09Z")
@Viertelstein I believe you misunderstod when I wrote to input material parameters twice
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### Author:  [@Viertelstein](https://calculix.discourse.group/u/Viertelstein)
#### Post date: [September 24, 2026, 7:33am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/22 "2026-09-24T07:33:03Z")
I’m sorry, maybe I’m too stupid to follow your advice. I did it (again) but it’s not working.
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### Author:  [@Calc\_em](https://calculix.discourse.group/u/Calc_em)
#### Post date: [September 24, 2026, 7:44am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/23 "2026-09-24T07:44:00Z")
This is with my model. It was different (prepared before you shared yours). Try this material card with your original model.
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### Author:  [@Viertelstein](https://calculix.discourse.group/u/Viertelstein)
#### Post date: [September 24, 2026, 7:54am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/24 "2026-09-24T07:54:58Z")
> [@fgr](#):
>
> `0.02, 3.0, 0.02, 3.0, 0.05, 0.05`
Just running the other model. To be 100% sure, I would like to run your INP on my laptop.
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### Author:  [@Calc\_em](https://calculix.discourse.group/u/Calc_em)
#### Post date: [September 24, 2026, 8:00am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/25 "2026-09-24T08:00:00Z")
You can also try with the single element model from here: [HYPERFOAM Model Issue - #10 by Calc\_em](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/10)
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### Author:  [@Viertelstein](https://calculix.discourse.group/u/Viertelstein)
#### Post date: [September 24, 2026, 8:01am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/26 "2026-09-24T08:01:57Z")
Yes, finally !!!
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### Author:  [@JuanP74](https://calculix.discourse.group/u/JuanP74)
#### Post date: [September 24, 2026, 8:05am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/27 "2026-09-24T08:05:22Z")
Now you have to fit your data with the hyperfoam model N=2 to identify the actual parameters that best fit your model.
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### Author:  [@Viertelstein](https://calculix.discourse.group/u/Viertelstein)
#### Post date: [September 24, 2026, 8:27am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/28 "2026-09-24T08:27:16Z")
For the moment thanks a lot to everybody. 🥰
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### Author:  [@Disla](https://calculix.discourse.group/u/Disla)
#### Post date: [September 24, 2026, 8:45am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/29 "2026-09-24T08:45:34Z")
> [@fgr](#):
>
> A quick workaround for you could be just to add the material parameters twice like this:
Using the N=1 parameters twice is a great idea but I would like to add an small correction. One would be doubling de energy U=U1+U2=U1+U1=2U1.
First parameter should be divided by 2.
```markdown
u1/2, 3.0, u1/2, 3.0, 0.05, 0.05
```
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### Author:  [@JuanP74](https://calculix.discourse.group/u/JuanP74)
#### Post date: [September 24, 2026, 9:10am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/30 "2026-09-24T09:10:47Z")
you can check CCX results with the model and data provided here (is a model with N=3).
[4.22. Hyperfoam Model — LAMÉ Manual](https://www.sandia.gov/files/sierra/SM_LAME_5_26/main/models/hyperfoam.html#tab-hyper1)
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### Author:  [@Calc\_em](https://calculix.discourse.group/u/Calc_em)
#### Post date: [September 24, 2026, 9:18am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/31 "2026-09-24T09:18:12Z")
Bug reported: [Hyperfoam material model showing incorrect deformation with no stresses · Issue #188 · Dhondtguido/CalculiX · GitHub](https://github.com/Dhondtguido/CalculiX/issues/188)
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### Author:  [@Calc\_em](https://calculix.discourse.group/u/Calc_em)
#### Post date: [September 24, 2026, 9:24am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/32 "2026-09-24T09:24:33Z")
There are some great resources for such material models within the Dassault Systemes SIMULIA community, but you need to register there to access them. This post summarizes resources for the hyperfoam model in Abaqus (of course, in addition to its documentation): [3DSwym](https://r1132100503382-eu1-3dswym.3dexperience.3ds.com/community/swym:prd:R1132100503382:community:39?content=swym:prd:R1132100503382:communitypost:pIYYFtvjSvmQNN6oHO6XlA)
Btw. it also says there:
> If you base a \*Hyperfoam material model on only uniaxial compression test data, it is likely that the simple shear behavior of the material model will be very wrong - orders of magnitude wrong. The 2006 paper by Petre and Erdemir point this out very clearly.
And mentions the Kossa & Berezvai 2016 paper too.
Dassault offers a cloud app that can calibrate such materials.
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### Author:  [@Calc\_em](https://calculix.discourse.group/u/Calc_em)
#### Post date: [September 24, 2026, 9:28am UTC](https://calculix.discourse.group/t/hyperfoam-model-issue/4115/33 "2026-09-24T09:28:01Z")
And you may want to check this project too: [SimTK: Determination of elastomeric foam parameters for simulations of complex loading: Project Home](https://simtk.org/projects/elastomericfoam)
Or this thesis:
_Petre, M. T. Determining material parameters for multi-axial simulations of elastomeric foams, MSc Thesis, Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA, 2005._
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