Rotational spring

[gabrifio]

Dear STKO team, I have modelled this beam in a 2d solid continuous. It has a nodal force at the top.

How can I add an elastic simple rotational spring at the top of the beam? I have tried with a zero-length element and material but it doesn’t seem to work.

Please find attached the model.
Thank you

[STKO Team]

From the model, I don't fully understand what you are trying to model.
Could you please post a sketch of what you want to represent?

[gabrifio]

Hi, thank you for the response. Here is a sketch. It is a simple 2D model of a pile in an elastic medium. The only force is the horizontal force at the top node. The top node of the pile can be either free to rotate or fixed against the rotation if I add the fixed constraint, but I would like to insert a rotational spring to determine the degree of fixity of the top of the pile.

Please let me know if you need more details.

Pile spring.png (53.4 KiB) Viewed 3125 times

[STKO Team]

Ok so in this case what you have to do is:

1. Create an auxiliary node, coinciding with the Pile Head.
2. Fix it in all DOFs
3. Create an interaction (node-to-node, master = Auxiliary node, slave = Pile head)
4. Add the zero-length with rotational spring to the interaction

fix pile rot.png (92.6 KiB) Viewed 3113 times

Here's what you get with K=1 (Left) and K = 1.0e8 (Right)

fix pile rot 2.png (62.67 KiB) Viewed 3113 times

Here's the modified file:

ModifiedASP_spring.zip

(157.11 KiB) Downloaded 258 times

[gabrifio]

Hi STKO Team, thank you very much!

[STKO Team]

You're welcome