# Corrugated tube (bellow) - problem with analytical verification

**URL:** <https://calculix.discourse.group/t/corrugated-tube-bellow-problem-with-analytical-verification/3774>\
**Category:** Analysis issues\
**Created:** [February 9, 2026, 3:33pm UTC](https://calculix.discourse.group/t/corrugated-tube-bellow-problem-with-analytical-verification/3774 "2026-02-09T15:33:01Z")\
**Posts on this page:** 1\
**Showing post:** 3

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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:** [February 9, 2026, 11:49pm UTC](https://calculix.discourse.group/t/corrugated-tube-bellow-problem-with-analytical-verification/3774/3 "2026-02-09T23:49:33Z")

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> [@xyont](#):
>
> can analytical plot deformed shapes and shown its magnitude?

The only analytical solution I have for the displacement is just the total stretch value from a formula. But I can try different BC configurations (so far none helped) later and share the screenshots of the corresponding deformed shapes.

> [@xyont](#):
>
> i suspect the model FE is over constrained

I also suspect that. After all, if stiffness is too high, it’s almost always a fault of overconstraining BCs. Maybe I will try with symmetry in a 3D model and try to figure out the assumptions made by the author of the original paper.

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