The OpenSees Community

as far as I know - none has ever received the code.

But looks like many users are interested - perhaps it could become part of the standard OpenSees material library?

Hi all,

I am running Time-Histories on SDoF model with 1 transnational spring with the Hysteretic material (see source code below by signature).

I've realized something strange in the output hysteretic curves:

-in the non-linear range, after the unloading, the reloading shows "jump" of forces (almost vertical lines as infinite stiffness) - it is shame i cant upload figures here.

I havent found this info explicitly in the documentation, but I assume that the model is a modified takeda and hence in the unloading/reloading if performs the following check on the stiffnesses:

S = max(S_sec, So (dy/dm)^beta) from (https://dianafea.com/manuals/d95/MatLib/node402.html).

I've done some hand calcs on the ouput hysteresis, and indeed it looks like that the unloading follows the "So (dy/dm)^beta" stiffness even if it is lower than the "S_sec". and consequently, the material suddenly realizes that the stiffness is too small, and so it jumps back abruptly (to the force that it would have predicted if it were to follow S_sec).

I've used this model extensively before with different backbones and was not causing issues. Indeed I've tryied to use a different backbone (but same pinching, damage, and beta), and does not cause the same odd behavior. I've tried with several different EQ recs, and with static displacement control.

Is it really an unlucky combination of the input param's that triggers the issue?

Any idea of what could have gone wrong?

Thanks a lot,
Gio

PS: I am using V 3.1.0 64-bit.

#source code

# build the backbone

set s1p 250.
set e1p 0.002
set s2p 500.
set e2p 0.01
set s3p 500.
set e3p 0.036

set s1n [expr -$s1p]

set e1n [expr -$e1p]

set s2n [expr -$s2p]

set e2n [expr -$e2p]

set s3n [expr -$s3p]

set e3n [expr -$e3p]

#uniaxialMaterial Hysteretic 2 $s1p $e1p $s2p $e2p $s3p $e3p $s1n $e1n $s2n $e2n $s3n $e3n 1 1 0.0 0.0 0.75

selimgunay wrote:
> You can probably follow the instructions for 32-bit on a 64-bit machine. In
> a 64-bit machine, you don't necessarily need to use 64-bit software, you
> can use 32-bit software as well.

Indeed, i ve sorted it out changing ghe set up for x64 in Visual Studio, and it worked fine.

The OpenSees x32 in my x64 machine does not work. It crashed as soon as i click the exe .

Cheers

nilz wrote:
> Hi
> I really appreciate if it is possible for you to send me the video which
> you have

https://www.youtube.com/watch?v=BaxFLF6A8Rg&t=977s

Hi guys,

I ve got the .cpp and .h file ready for a new simple, but I am struggling with the setting up of Visual Studio, building the solution and stuff.

is there any of you who would be up for a call (or skype call) to help me with this setting up part?

I ve followed the video but cant get the basic example working either...

Happy to share the source code with you all!

Cheers,

Hi all,

I am following the video about how to add my own code to opensees. in the video everything (visual studio and opensees) is set to x32, but I ve got a x64 machine.

Are in this case different steps to be taken?

Cheers,

CMiculas wrote:
> @giovannimilan, files were sent with wetransfer.com!

I have seen it! thanks a lot!

rafal wrote:
> svn co svn://peera.berkeley.edu/usr/local/svn/OpenSees/trunk OpenSees
>
> see the link:
>
> http://opensees.berkeley.edu/OpenSees/developer/svn.php

Thanks for the prompt reply.

Thats the one which does not work for me. I keep on getting the message: You don't have permission to access /WebSVN/listing.php on this server.

CMiculas wrote:
> Hello,
> I received the files a couple of days ago from another user, so, give me
> your mail address and I will send them!
> BR
> Cristian


giovanni1.milan@gmail.com

Hi all,

The source code link in the opensees webside does not work for me.

Is it the same for you?

Can someone please attach the current link of the source code?

Cheers,

Hi all,

I trying to model a rocking behavior with non-lin rotational springs. The flag-shape model (Self centering) is the way to go, but I would need to have different yielding force in the 2 direction.

Has anyone worked in something similar? Suggestions in an eventual coding procedure?

Cheers,

I myself did it in the post processing phase... summing up (python script or even excel) the values of the accel nodal recorder (relative) with the GM accelleration values, making sure that the time-step of the two is the same. It worked fine!

wuhaoshrek wrote:
> giovannimilan wrote:
> > wuhaoshrek wrote:
> > > fmk wrote:
> > > > transformation handler cnnot handle one node constrained to another
> > > > constrained to another. you should have been seeing warning messages.
> try
> > > > Penalty method, but you may have numerical problems due to
> conditioning as
> > > > some of the penalty factors are going to add up if your values are
> poorly
> > > > chosen.
> > >
> > > I see rigidDiaphragm command can only be used for 3D problem. What if I
> want to
> > model
> > > the rigidDiaphragm effect in a 2D problem? Other than using elastic element
> with
> > > large stiffness, if there any options? thanks.
> >
> > Maybe with the rigidLink beam.
> that's incorrect cause rigid link will constraint translationnal DOFs.

I am quoting the wiki page

$type beam both the translational and rotational degrees of freedom are constrained.

source: http://opensees.berkeley.edu/wiki/index ... nk_command

wuhaoshrek wrote:
> fmk wrote:
> > transformation handler cnnot handle one node constrained to another
> > constrained to another. you should have been seeing warning messages. try
> > Penalty method, but you may have numerical problems due to conditioning as
> > some of the penalty factors are going to add up if your values are poorly
> > chosen.
>
> I see rigidDiaphragm command can only be used for 3D problem. What if I want to model
> the rigidDiaphragm effect in a 2D problem? Other than using elastic element with
> large stiffness, if there any options? thanks.

Maybe with the rigidLink beam.

Why do you wanna use transient for gravity?

I usually for static, based on the example I found in opensees wiki.

Have you seen them? like dynamic analysis on 2d steel frame