Example for Lysmer+free field boundary model

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yuweihwang
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Joined: Wed Apr 29, 2020 4:54 am

Example for Lysmer+free field boundary model

Post by yuweihwang » Thu Jun 25, 2020 11:48 pm

Hello,

I saw ASDEA demonstrated the Lysmer+free field boundary model in your youtube video
(https://youtu.be/0BTug_4or6g?t=109)
Is there any tutorial or can you provide the scd file of this example for us to learn how to implement this boundary?

Thanks for your help,
Yu-Wei Hwang

STKO Team
Posts: 168
Joined: Tue Oct 29, 2019 8:45 am

Re: Example for Lysmer+free field boundary model

Post by STKO Team » Fri Jun 26, 2020 8:41 am

Hi Yu-Wei,

That example is quite old, I don't have that exact SCD file anymore. However we recently gave a webinar about SSI with absorbing boundaries which is exactly the same, but more generic (it is a 3D example)

On our website you can visit the e-learning wepage were we keep track of all previous webinars with links to the video recordings and to download the input files:

https://asdeasoft.net/?stkowebinars-for-opensees
ssi.png
ssi.png (61.61 KiB) Viewed 657 times
If you instead need exactly that 2D example, I could replicated it as soon as possible.

yuweihwang
Posts: 9
Joined: Wed Apr 29, 2020 4:54 am

Re: Example for Lysmer+free field boundary model

Post by yuweihwang » Fri Jun 26, 2020 3:41 pm

Hello,
Thank you for your information. It will be really nice if we can have a demo for 2D model!
Thank you for all your help!

STKO Team
Posts: 168
Joined: Tue Oct 29, 2019 8:45 am

Re: Example for Lysmer+free field boundary model

Post by STKO Team » Fri Jun 26, 2020 5:45 pm

dear User,
of course, we will prepare it.
Have a nice day

yuweihwang
Posts: 9
Joined: Wed Apr 29, 2020 4:54 am

Re: Example for Lysmer+free field boundary model

Post by yuweihwang » Fri Jul 03, 2020 2:06 am

Thank you!!

Clarabella
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Joined: Wed Jul 08, 2020 3:50 pm

Re: Example for Lysmer+free field boundary model

Post by Clarabella » Tue Jul 28, 2020 1:30 pm

Dear Yu-Wei,
please dowload Vukkumus' model modified by STKO:
viewtopic.php?f=36&t=1662#p2134

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vokumus
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Re: Example for Lysmer+free field boundary model

Post by vokumus » Sat Aug 01, 2020 9:28 pm

Clarabella wrote:
Tue Jul 28, 2020 1:30 pm
Dear Yu-Wei,
please dowload Vukkumus' model modified by STKO:
viewtopic.php?f=36&t=1662#p2134
Dear Clarabella and Yu-Wei;

In this model, there was some strange results. For example dynamic analysis starts with very high accelerations. I have managed to get correct results making loadconst selected and psuedo time zero in relax analysis after the initial stage analysis.

I don't know why this happened. I couldn't run OpenSeesMP in my computer and changed some analysis parameters to use normal OpenSees. It does not make sense but maybe this could be the culprit.

Anyway, model is working fine now.
Vefa OKUMUS
MSc. Structural Engineer
PhD candidate.
Software Developer.
Istanbul - Turkey

Clarabella
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Joined: Wed Jul 08, 2020 3:50 pm

Re: Example for Lysmer+free field boundary model

Post by Clarabella » Mon Aug 03, 2020 7:00 am

Dear Vokumus,
we usually add an analysis after the vertical analysis, in particular when we perform nonlinear TH. Just add an analysis with damping to be sure to not have spurious accerelation before starting the TH, this is a suggestion both for implicit and explicit analysis and it does not depend on the software used.
Regards

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vokumus
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Re: Example for Lysmer+free field boundary model

Post by vokumus » Mon Aug 03, 2020 9:25 am

Clarabella wrote:
Mon Aug 03, 2020 7:00 am
Dear Vokumus,
we usually add an analysis after the vertical analysis, in particular when we perform nonlinear TH. Just add an analysis with damping to be sure to not have spurious accerelation before starting the TH, this is a suggestion both for implicit and explicit analysis and it does not depend on the software used.
Regards
Yes I know. But the problem is; if you don't select loadconst and pseudo time = 0 for this relaxation analysis you mentioned, you get some weird results in TH analysis.
Vefa OKUMUS
MSc. Structural Engineer
PhD candidate.
Software Developer.
Istanbul - Turkey

Clarabella
Posts: 17
Joined: Wed Jul 08, 2020 3:50 pm

Re: Example for Lysmer+free field boundary model

Post by Clarabella » Mon Aug 03, 2020 10:20 am

Yes, you are perfectly right the load must be constant and you need to set to 0 the pseudo time.

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