# Truss element one direction

**URL:** <https://calculix.discourse.group/t/truss-element-one-direction/1653>\
**Category:** Uncategorized\
**Created:** [May 12, 2023, 10:09pm UTC](https://calculix.discourse.group/t/truss-element-one-direction/1653 "2023-05-12T22:09:47Z")\
**Posts on this page:** 1\
**Showing post:** 23

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**Author:** ![Disla](https://yyz2.discourse-cdn.com/free1/user_avatar/calculix.discourse.group/disla/32/3548_2.png) [@Disla](https://calculix.discourse.group/u/Disla)\
**Post date:** [May 15, 2023, 11:58am UTC](https://calculix.discourse.group/t/truss-element-one-direction/1653/23 "2023-05-15T11:58:27Z")

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> [@dichtstoff](#):
>
> with spring constant, and with the relativ displacement i get my force.

Right. Maybe someone knows a ccx comand to get the tension on the spring directly but I’dont. I need to measure elongation and then extract the Force form simple interpolation on the curve.

> [@dichtstoff](#):
>
> I know why i prefere a truss element

Why? You have the same problem ¿isn’t it?. You comment you also need to measure the force inidectly through the stress\*Area.

> [@dichtstoff](#):
>
> can use \*RIGID BODY

I don’t see why not. The spring will go from REF node to REF NODE.

> [@dichtstoff](#):
>
> dimensional spring (SPRING1)

> [@Is nonlinear stiffness allowed for SPRING1 elements?](https://calculix.discourse.group/t/is-nonlinear-stiffness-allowed-for-spring1-elements/412/6):
>
> I have managed to set up a nonlinear SPRING1 element. I’m imposing a sinusoidal vertical displacement to test the whole positive and negative response range. Reactions follow the Force-Elongation shape but values for the reaction forces are wrong. Should be Rz=504=200N I get Rz=1254=500N For prescribed displacements it gives this warning but ccx can finish the analysis: “\*INFO in cascade: linear MPCs and nonlinear MPCs depend on each other common node: …

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