# QUE8 with shell behaviour **URL:** \ **Category:** Uncategorized\ **Created:** [December 13, 2021, 12:23am UTC](https://calculix.discourse.group/t/que8-with-shell-behaviour/904 "2021-12-13T00:23:16Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![dichtstoff](https://avatars.discourse-cdn.com/v4/letter/d/dec6dc/32.png) [@dichtstoff](https://calculix.discourse.group/u/dichtstoff)\ **Post date:** [December 13, 2021, 12:23am UTC](https://calculix.discourse.group/t/que8-with-shell-behaviour/904/1 "2021-12-13T00:23:16Z")
is it possible, to use QUE elements for thin-shell structure like a tube, silo or a cylindrical structure? wbr dichtstoff ---
**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:** [December 13, 2021, 8:10am UTC](https://calculix.discourse.group/t/que8-with-shell-behaviour/904/2 "2021-12-13T08:10:47Z")
What are these elements ? I can’t find them in the documentation or anywhere else. ---
**Author:** ![dichtstoff](https://avatars.discourse-cdn.com/v4/letter/d/dec6dc/32.png) [@dichtstoff](https://calculix.discourse.group/u/dichtstoff)\ **Post date:** [December 13, 2021, 8:36am UTC](https://calculix.discourse.group/t/que8-with-shell-behaviour/904/3 "2021-12-13T08:36:54Z")
these are quadrangle plain strain elements, generated with “elty all QU8E” you get \*ELEMENT, TYPE=CPE8, ELSET=Ecircle wbr & thnx ---
**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:** [December 13, 2021, 9:15am UTC](https://calculix.discourse.group/t/que8-with-shell-behaviour/904/4 "2021-12-13T09:15:16Z")
All right, so those are actually regular 8-node plane strain elements. They are meant for long structures so tube or other cylindrical vessel could be modeled with these elements. You just have to make sure that the section being analyzed has sufficiently dense mesh which might be a bit more difficult for thin-walled structures. However, the gain in computation time thanks to the omission of the third dimension makes even very dense meshes easy to use. You just have to make sure that the loading is applicable to plane strain condition (acts at the whole length of the structure) and be careful with boundary conditions (use symmetry whenever possible). ---
**Author:** ![dichtstoff](https://avatars.discourse-cdn.com/v4/letter/d/dec6dc/32.png) [@dichtstoff](https://calculix.discourse.group/u/dichtstoff)\ **Post date:** [December 15, 2021, 1:47pm UTC](https://calculix.discourse.group/t/que8-with-shell-behaviour/904/5 "2021-12-15T13:47:33Z")
Hello, thx for your help. I have tried to apply a boundary with _RIGID BODY, but these is not working with plane strain elements? Is these correct? Maybe because the CPE_ elements are internal expanded? wbr ---
**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:** [December 15, 2021, 2:54pm UTC](https://calculix.discourse.group/t/que8-with-shell-behaviour/904/6 "2021-12-15T14:54:58Z")
Rigid body constraint works with plane strain elements as well, I just checked it to make sure. Did you get any error messages ? ---
**Author:** ![dichtstoff](https://avatars.discourse-cdn.com/v4/letter/d/dec6dc/32.png) [@dichtstoff](https://calculix.discourse.group/u/dichtstoff)\ **Post date:** [December 15, 2021, 7:37pm UTC](https://calculix.discourse.group/t/que8-with-shell-behaviour/904/7 "2021-12-15T19:37:12Z")
Hello, no error, i fixed the refnode with but there was still displacement. I’ll check again. thnx a lot, if i don’t get it fixed, I’ll post my file. thnx a lot.