Forum for OpenSees users to post questions, comments, etc. on the use of the OpenSees interpreter, OpenSees.exe
Moderators: silvia, selimgunay, Moderators
-
imancivil
- Posts: 55
- Joined: Mon Feb 11, 2008 11:15 pm
- Location: Kerman
Post
by imancivil » Sat Nov 29, 2008 7:50 am
Hi all,
I want to use unidirectional element with nonlinear generalized force-deflection capability that can be used in any analysis. The element is defined by a generalized force-deflection curve.
How can I define an optional force-deflection curve?
Thanks.
-
susan
- Posts: 110
- Joined: Sun Mar 02, 2008 12:10 am
Post
by susan » Sat Nov 29, 2008 9:21 am
Dear iman,
You raise an interesting question. i have the same question about this. Although I know in ANSYS it is possible to define a specific force-deflection curve for elements, but in opensees i don't know.
Can anyone help us?
Thanks!
-
silvia
- Posts: 3909
- Joined: Tue Jan 11, 2005 7:44 am
- Location: Degenkolb Engineers
-
Contact:
Post
by silvia » Sat Nov 29, 2008 4:22 pm
why not use the truss element where you define the section response via the uniaxial section?
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
-
imancivil
- Posts: 55
- Joined: Mon Feb 11, 2008 11:15 pm
- Location: Kerman
Post
by imancivil » Sat Nov 29, 2008 10:47 pm
Daer silvia & susan,
thanks a lot for your consideration. i think i could not mention my purpose clearly.
i have the force-deflection (F-D) curve for the a specific element:
D=-100mm at F=-250 KN
D=-60mm at F=-360 KN
D=-36mm at F=-460 KN
D=-24mm at F=-550 KN
D=-16mm at F=-800 KN
D=-8mm at F=-1100 KN
D=-5mm at F=-2140 KN
D=0mm at F=0 KN
D=0.458mm at F=2525.76 KN
D=2mm at F=2525.76 KN
(F<0 are compression forces and F>0 are tension forces)
how can i apply this behavior to element?
thnx
Iman Mansouri
PhD Candidate
University of Kerman
-
silvia
- Posts: 3909
- Joined: Tue Jan 11, 2005 7:44 am
- Location: Degenkolb Engineers
-
Contact:
Post
by silvia » Sun Nov 30, 2008 9:38 am
use the hysteretic material for the section, defining A=1, the section stiffness becomes the force-deformation behavior, right?
otherwise, use a zero-length element.....
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
-
imancivil
- Posts: 55
- Joined: Mon Feb 11, 2008 11:15 pm
- Location: Kerman
Post
by imancivil » Sun Nov 30, 2008 10:41 am
Dear silvia,
Thanks for your help.
Iman Mansouri
PhD Candidate
University of Kerman
-
esi_opensees
- Posts: 93
- Joined: Mon Apr 14, 2008 10:53 pm
Post
by esi_opensees » Tue Dec 02, 2008 5:44 am
Dear silvia,
would you please tell me why A=1? the area may be greater,equal or less than 1.
-
silvia
- Posts: 3909
- Joined: Tue Jan 11, 2005 7:44 am
- Location: Degenkolb Engineers
-
Contact:
Post
by silvia » Tue Dec 02, 2008 6:29 am
to make the stress equal to the force....
i may be wrong...
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
-
imancivil
- Posts: 55
- Joined: Mon Feb 11, 2008 11:15 pm
- Location: Kerman
Post
by imancivil » Tue Dec 02, 2008 8:23 am
i agree with silvia; because first we define the properties analysis (section, material,…) for a single element and capture the force-deflection curve; we repeat this step for all the types of elements; then in the next step we apply the data which obtained from the curve on the whole of structure. A=1 causes the stress = force, right?
Iman Mansouri
PhD Candidate
University of Kerman
-
esi_opensees
- Posts: 93
- Joined: Mon Apr 14, 2008 10:53 pm
Post
by esi_opensees » Tue Dec 02, 2008 8:34 am
Dear silvia&iman
According to your notions when we applying the behavior of material (Hysteretic material) for entire of structure the value of area is independent (each value is correct). isn’t it?
-
silvia
- Posts: 3909
- Joined: Tue Jan 11, 2005 7:44 am
- Location: Degenkolb Engineers
-
Contact:
Post
by silvia » Tue Dec 02, 2008 8:44 am
you've got to work throught the modeling with someone in person with pen and paper in front of you.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
-
silvia
- Posts: 3909
- Joined: Tue Jan 11, 2005 7:44 am
- Location: Degenkolb Engineers
-
Contact:
Post
by silvia » Tue Dec 02, 2008 9:33 am
no, it is really difficult to work through this via this forum.
i was making the recommendation i give everyone who is trying to figure out how to define a model.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
-
esi_opensees
- Posts: 93
- Joined: Mon Apr 14, 2008 10:53 pm
Post
by esi_opensees » Tue Dec 02, 2008 10:04 am
thanks, you are very kind.
now, would you plz tell me the imancivil's opinion is true or false?
tnx.
-
silvia
- Posts: 3909
- Joined: Tue Jan 11, 2005 7:44 am
- Location: Degenkolb Engineers
-
Contact:
Post
by silvia » Tue Dec 02, 2008 10:40 am
for uniaxial response, yes, where stress=force/area
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104