rotational springs in 3D problems

[papaloo]

Hi dear...

Is there any difference between 2D & 3D problems in the rotational springs modelling?If yes,:

1)Which command helps me define a rotational spring in 3D problem?
My model has 2 rotational spring.One of them belongs to -dir5 and the other to -dir6

2)By which command,I can apply the rotational stiffness to the spring?

Thanks a lot for your help.

[vesna]

1) When defining a spring you are defining a direction of it in 3D. So no matter if in 3D or 2D you will apply your spring in directions 5 and 6. zeroLength element should be used to define springs: http://opensees.berkeley.edu/wiki/index ... th_Element.

2) to define the stiffness of the spring you can use one of the uniaxial materials. If your spring is fully elastic you can use elastic uniaxial material: http://opensees.berkeley.edu/wiki/index ... l_Material

[Prafullamalla]

i have a question in similar topic. If I am using a translational spring in 2 directions , X and Y directions. Aren't the material properties independent to each others. For example, I apply large displacement in X -direction and the material becomes in plastic stage. Now, if I apply displacement in Y direction from this point, does the material starts from the plastic phase or from the elastic phase>

Thank you