single-degree-of-freedom (SDOF) model

[mazen]

Hello,

I am working on creating a simple single-degree-of-freedom (SDOF) model using two zero-length elements to represent stiffness and damping. For this, I used the Steel01 material type for stiffness and the Viscous material type for damping.

Upon running the model, I didn't encounter any convergence issues. However, when I recorded the forces and deformations in the two zero-length elements, I observed unexpected behaviors:

stiffness.png (40 KiB) Viewed 493 times

Damping.png (103.04 KiB) Viewed 493 times

I am not able to understand these results. Shouldn't the first element display the behavior characteristic of the Steel01 material and the second element exhibit the typical response of a viscous damper?

model.rar

(97.96 KiB) Downloaded 91 times

Thank you for the support!


Best regards,
Mazen

[STKO Team]

Check material.stress vs material.strain in the post processor using the gauss plot. In this case you can see each material response.
Not that I had to increase the ground motion a lot to see these results:
stiffness:

zl_1.png (32.31 KiB) Viewed 415 times

damping:

zl_2.png (53.26 KiB) Viewed 415 times