# Doubt about userbeam.inp (U1) from ccx test

**URL:** <https://calculix.discourse.group/t/doubt-about-userbeam-inp-u1-from-ccx-test/668>\
**Category:** Uncategorized\
**Created:** [July 8, 2021, 6:16pm UTC](https://calculix.discourse.group/t/doubt-about-userbeam-inp-u1-from-ccx-test/668 "2021-07-08T18:16:45Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ginda](https://avatars.discourse-cdn.com/v4/letter/g/e68b1a/32.png) [@ginda](https://calculix.discourse.group/u/ginda)\
**Post date:** [July 8, 2021, 6:16pm UTC](https://calculix.discourse.group/t/doubt-about-userbeam-inp-u1-from-ccx-test/668/1 "2021-07-08T18:16:45Z")

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Hi all,

Using `userbeam.inp` from `ccx` `test` I have a doubt or a misunderstanding of this CalculiX user type `U1` feature.

If in `userbeam.inp` example I change `*CLOAD` argument from `2,2,1.` to `2,3,1.` I expected to obtain the same absolute values for displacements and section forces (sign and _position_ may change). For displacements this effectively happens, but not for sections forces. I expected the same absolute results because properties given in `*BEAM SECTION` are symmetrical (same moment of inertia for local `1-direction` and local `2-direction`).

Am I misunderstanding something?

Regards  
Gregorio

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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:** [August 9, 2021, 1:09pm UTC](https://calculix.discourse.group/t/doubt-about-userbeam-inp-u1-from-ccx-test/668/2 "2021-08-09T13:09:34Z")

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I can confirm this. It seems to be a bug. Here are the results for the first case (load in 2nd direction):

 ![beam1](https://global.discourse-cdn.com/free1/uploads/calculix/original/1X/cfd9c2a8e2af76f0db8fce441776b31f336f9492.png)

And here are the results for the second case (load in 3rd direction):

 ![beam2](https://global.discourse-cdn.com/free1/uploads/calculix/original/1X/19bc122bb34b75dba69c055bf84892b02dd340e7.png)

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<div class="post-metadata">

**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 30, 2021, 9:32am UTC](https://calculix.discourse.group/t/doubt-about-userbeam-inp-u1-from-ccx-test/668/3 "2021-09-30T09:32:34Z")

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Apparently, this bug is fixed in CalculiX 2.18. Unfortunately, the other one related to this element type (link below) still persists.

> [@Problem using U1 element (general beam section)](https://calculix.discourse.group/t/problem-using-u1-element-general-beam-section/600):
>
> Hi, I ran into an issue with the general beam section (element type U1). I tried to make a simple test but aparently failed. So far I tried with ccx 2.15 and 2.17. The example is the following, describing a cantilever with weight at the tip (I think I found a similar example elsewhere): \*NODE, NSET=Nall 1,0.,0.,0. 2,10.,00.,00. 3,20.,00.,00. 4,30.,00.,00. 5,40.,00.,00. 6,50.,00.,00. 7,60.,00.,00. \*ELEMENT, TYPE=U1, ELSET=Eall 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, …