What does this stress output for quad element mean?

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bayram_aygun
Posts: 109
Joined: Sat May 05, 2007 12:28 pm
Location: Houston, TX

What does this stress output for quad element mean?

Post by bayram_aygun »

Hi,

While I was trying to get some sort of stress output in previous versions, I produced a stress output file for one quad element (v1.7.5Beta). My toy model consists of 1 quad element,1 pile,1 PyLiq1 Spring. The recorder command I used looks like:

recorder Element -ele 1 -time -file PressurePDMY.out material 3 stress

where material 3 is the pressure dependent multi yield material.

The weird thing with the output file is this: It has 6 columns, the first being the the time steps. Do you have any idea what the other 5 columns represent?

0.0025 -2.00236e-005 -0.00919024 -2.79097e-008 3.18891e-006 0.0152104
0.005 -0.000448881 -0.0401242 -0.000429611 2.95748e-006 0.0644439
0.0075 -0.00343411 -0.0890313 -0.00341712 2.40216e-006 0.134397
0.01 -0.00951481 -0.146497 -0.00950023 1.98453e-006 0.20637
........................

Thanks,
Bayram Aygun
Graduate Student, Civil&Env. Eng.
Rice University
rjaeger
Posts: 102
Joined: Thu Aug 31, 2006 9:57 pm
Location: UC Davis

Post by rjaeger »

Hi Bayram,

Here is what I see in the source code for the stress recorder (found in the getresponse and then getcommittedstress functions)

static Vector temp5(5);
workV6 = currentStress.t2Vector();
temp5[0] = workV6[0];
temp5[1] = workV6[1];
temp5[2] = workV6[2];
temp5[3] = workV6[3];
temp5[4] = scale;

So these would be your 5 columns after the time. currentStress is a t2vector so you just need to determine what each of the components of the t2vector are. Perhaps one of the authors, Frank or Silvia could shed some light on this.

This should give you a start: http://opensees.berkeley.edu/OpenSees/a ... tml#l00132

Robbie
bayram_aygun
Posts: 109
Joined: Sat May 05, 2007 12:28 pm
Location: Houston, TX

Post by bayram_aygun »

Hi,

I'm trying to understand the examples in <http://cyclic.ucsd.edu/opensees >. Let's consider Example 15: Single quadrilateral element, subjected to sinusoidal base shaking.

I look at the outputs and the post-processing Matlab files but it's really confusing. What are this "%integration point 1 excess pore water pressure" or "%integration point 3 confinement p VS. deviatoric q relation" figures under the "MATLAB Plotting File" link? Where is this integration point 1?

It's probably an easy thing to understand for a geotech. student but I'm puzzled at the moment.

Anyone, out there?
Bayram Aygun
Graduate Student, Civil&Env. Eng.
Rice University
jaugalde
Posts: 17
Joined: Sun Jan 21, 2007 12:04 am
Location: Fugro

Re: What does this stress output for quad element mean?

Post by jaugalde »

Hope this helps.

From the manual...

For 2D problems, the stress output follows this order: sxx, syy, szz, sxy, hr, where hr is the ratio
between the shear (deviatoric) stress and peak shear strength at the current confinement
(0<= hr<=1.0). The strain output follows this order: exx, eyy, gxy.
For 3D problems, the stress output follows this order: sxx, syy, szz, sxy, syz, szx, hr, and the strain output
follows this order: exx, eyy, ezz, gxy, gyz, gzx.







bayram_aygun wrote:Hi,

While I was trying to get some sort of stress output in previous versions, I produced a stress output file for one quad element (v1.7.5Beta). My toy model consists of 1 quad element,1 pile,1 PyLiq1 Spring. The recorder command I used looks like:

recorder Element -ele 1 -time -file PressurePDMY.out material 3 stress

where material 3 is the pressure dependent multi yield material.

The weird thing with the output file is this: It has 6 columns, the first being the the time steps. Do you have any idea what the other 5 columns represent?

0.0025 -2.00236e-005 -0.00919024 -2.79097e-008 3.18891e-006 0.0152104
0.005 -0.000448881 -0.0401242 -0.000429611 2.95748e-006 0.0644439
0.0075 -0.00343411 -0.0890313 -0.00341712 2.40216e-006 0.134397
0.01 -0.00951481 -0.146497 -0.00950023 1.98453e-006 0.20637
........................

Thanks,
bayram_aygun
Posts: 109
Joined: Sat May 05, 2007 12:28 pm
Location: Houston, TX

Post by bayram_aygun »

Thanks a lot.
Bayram Aygun
Graduate Student, Civil&Env. Eng.
Rice University
dkkim
Posts: 9
Joined: Fri Sep 22, 2006 9:29 pm
Location: Seoul National University

Post by dkkim »

Hi~

I saw your other posts..
And I have same problems... like "update material.."

By the way you said that ver. 1.7.5 beta was fine.

How do you get the ver. 1.7.5 beta??
I'd like to test my SSI model with the version.

Thanks,

DK
bayram_aygun
Posts: 109
Joined: Sat May 05, 2007 12:28 pm
Location: Houston, TX

Post by bayram_aygun »

jaugalde,

I checked the (.pdf) manual and the online manual, but I didn't come across a passage where the stress outputs are explained. Can you tell me where you found this information?

One more thing, as far as what you wrote, we can't monitor the vertical stresses in the quad elements, is that it? I need to double-check the pore pressure ratio output I get, that's why I need to get the vertical stresses before after the ground shaking.

Thanks for your time,
Bayram Aygun
Graduate Student, Civil&Env. Eng.
Rice University
edjefzz
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MNC3333
Posts: 1
Joined: Mon Nov 21, 2011 11:27 am

Re:

Post by MNC3333 »

bayram_aygun wrote:
> jaugalde,
>
> I checked the (.pdf) manual and the online manual, but I didn't come across
> a passage where the stress outputs are explained. Can you tell me where you
> found this information?
>
> One more thing, as far as what you wrote, we can't monitor the vertical
> stresses in the quad elements, is that it? I need to double-check the pore
> pressure ratio output I get, that's why I need to get the vertical stresses
> before after the ground shaking.
>
> Thanks for your time,

This may be outdated, but I was also wondering where you found the stress output information.
andybrinson38
Posts: 1
Joined: Fri Feb 03, 2012 4:26 pm

Re: What does this stress output for quad element mean?

Post by andybrinson38 »

thanks for the info...
smith8890
Posts: 3
Joined: Mon Feb 06, 2012 10:45 pm

Re: What does this stress output for quad element mean?

Post by smith8890 »

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