# Distributing coupling constraints

**URL:** <https://calculix.discourse.group/t/distributing-coupling-constraints/2396>\
**Category:** Uncategorized\
**Created:** [September 4, 2024, 6:23am UTC](https://calculix.discourse.group/t/distributing-coupling-constraints/2396 "2024-09-04T06:23:10Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![zhnanli](https://avatars.discourse-cdn.com/v4/letter/z/57b2e6/32.png) [@zhnanli](https://calculix.discourse.group/u/zhnanli)\
**Post date:** [September 4, 2024, 6:23am UTC](https://calculix.discourse.group/t/distributing-coupling-constraints/2396/1 "2024-09-04T06:23:10Z")

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Dear all,  
Does CalculiX support geometric nonlinearity for distributing coupling constraints or dcoup3d element, thanks!

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**Author:** ![Calc\_em](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\
**Post date:** [September 4, 2024, 8:09am UTC](https://calculix.discourse.group/t/distributing-coupling-constraints/2396/2 "2024-09-04T08:09:52Z")

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Not much is explained about that in the CalculiX documentation:

> Coupling constraints generally lead to nonlinear equations. In linear calculations (without the parameter NLGEOM on the \*STEP card) these equations are linearized once and solved. In nonlinear calculations, iterations are performed in each of which the equations are linearized at the momentary solution point until convergence.

You can find this and more details regarding the implementation of distributing coupling constraints (\*COUPLING followed by \*DISTRIBUTING) in the documentation chapter _6.7.4 Kinematic and Distributing Coupling_.

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<div class="post-metadata">

**Author:** ![zhnanli](https://avatars.discourse-cdn.com/v4/letter/z/57b2e6/32.png) [@zhnanli](https://calculix.discourse.group/u/zhnanli)\
**Post date:** [September 4, 2024, 9:37am UTC](https://calculix.discourse.group/t/distributing-coupling-constraints/2396/3 "2024-09-04T09:37:23Z")

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Thanks for your reply

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**Author:** ![xyont](https://yyz2.discourse-cdn.com/free1/user_avatar/calculix.discourse.group/xyont/32/3553_2.png) [@xyont](https://calculix.discourse.group/u/xyont)\
**Post date:** [September 4, 2024, 11:23am UTC](https://calculix.discourse.group/t/distributing-coupling-constraints/2396/4 "2024-09-04T11:23:41Z")

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some problem exist in beam and shell element due to imposed rotational dof’s and large deformation. However `*Distributing coupling` and `dcoup3d` element seems not to have any problem since only translation allowed.

i’m testing on original example file `distcoup.inp` by activating NLGeom and multiplied loads 100 times.

 ![2024-09-04 19_04_26-CalculiX GraphiX](https://global.discourse-cdn.com/free1/uploads/calculix/original/2X/7/71feee4dd678a237071e43af1b0952dca7975b59.png)