# Nlgeom missing from the dynamic step

**URL:** <https://prepomax.discourse.group/t/nlgeom-missing-from-the-dynamic-step/891>\
**Category:** Bug Reports\
**Created:** [May 26, 2023, 9:11am UTC](https://prepomax.discourse.group/t/nlgeom-missing-from-the-dynamic-step/891 "2023-05-26T09:11:34Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [May 26, 2023, 9:11am UTC](https://prepomax.discourse.group/t/nlgeom-missing-from-the-dynamic-step/891/1 "2023-05-26T09:11:34Z")

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Hi,

maybe it’s not a bug in a typical sense but I’ve noticed that the essential Nlgeom parameter is missing from the dynamic step definition window in v1.4.0 dev:

 ![dynamic](https://global.discourse-cdn.com/free1/uploads/prepomax/original/2X/e/e98ccc0e299aebb5759ecc2f1e46165efe12db77.png)

I guess that it’s just a matter of setting

`_dctd.GetProperty(nameof(Nlgeom)).SetIsBrowsable(false);`

to

`_dctd.GetProperty(nameof(Nlgeom)).SetIsBrowsable(true);`

in `ViewDynamicStep.cs`. I could try to send a merge request but is this parameter currently disabled in the dynamic step for a reason or was it just overlooked ?

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**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\
**Post date:** [May 26, 2023, 12:10pm UTC](https://prepomax.discourse.group/t/nlgeom-missing-from-the-dynamic-step/891/2 "2023-05-26T12:10:05Z")

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Hmm, I disabled it on purpose since I think it is not possible to have a dynamic analysis without nonlinear effects. So I thought it makes no sense to show it to the user.

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<div class="post-metadata">

**Author:** ![FEAnalyst](https://yyz2.discourse-cdn.com/free1/user_avatar/prepomax.discourse.group/feanalyst/32/688_2.png) [@FEAnalyst](https://prepomax.discourse.group/u/FEAnalyst)\
**Post date:** [May 26, 2023, 12:22pm UTC](https://prepomax.discourse.group/t/nlgeom-missing-from-the-dynamic-step/891/3 "2023-05-26T12:22:10Z")

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But it seems that currently Nlgeom is not added to the \*Step keyword before \*Dynamic, meaning that it’s disabled by default and all dynamic analyses are performed without geometric nonlinearity.

Personally, I would prefer to have it enabled by default for dynamic analyses but still with an option to disable it for some benchmark/verification studies. In Abaqus, Nlgeom is even disabled by default for implicit dynamics and enabled by default (with an option to disable it) for explicit dynamics. I recall a few cases when I had to disable it for some more thorough investigations regarding the solver’s behavior.

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<div class="post-metadata">

**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\
**Post date:** [May 26, 2023, 12:59pm UTC](https://prepomax.discourse.group/t/nlgeom-missing-from-the-dynamic-step/891/4 "2023-05-26T12:59:43Z")

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I was not aware of this possibility. So I think my assumption was wrong, and I will enable the activation of the Nlgeom parameter to the user. I will have to do some tests about it to see how it affects the results.

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<div class="post-metadata">

**Author:** ![Matej](https://avatars.discourse-cdn.com/v4/letter/m/a698b9/32.png) [@Matej](https://prepomax.discourse.group/u/Matej)\
**Post date:** [June 7, 2023, 7:28pm UTC](https://prepomax.discourse.group/t/nlgeom-missing-from-the-dynamic-step/891/5 "2023-06-07T19:28:18Z")

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Closed on June 7, 2023, 7:28pm UTC