topics on rolling resistance modeling granular media

Asked by wangxiaoliang

Many body here seems interested in the rolling moment type model for granular media, including me.

however, as I have read some of the talking in this launchpad, I am not satisfied with the answers and also I have never realized

one modeling using rolling model.

As I know, at least 2 model could be used for modeling rolling resistance

1) Ip2_CohFrictMat_CohFrictMat_CohFrictPhys() + Law2_Scgeom6D_cohFrictPhys_cohFrictPhys_CohesionMoment()

    which can model compression shear rolling and twisting, but I have tested that as linran(one of the yade user) did, in one of the interactions, I found bending moment and twisting moment are both 0.

    As for this contact law, anybody have tested it, and how to use this one to model rolling resistance?

2) Ip2_FrictMat_FrictMat_MindlinPhys() + Law2_ScGeom_MindlinPhys_Mindlin()
    as talked by Christian Jacob last time by add parameters in this contact law krot eta and includeMoment=True

    I have also tested this scheme, rolling moment could be added , the problem is the maxmum rolling moment is larger than the plastic bending moment if I set eta=1.0, I guess eta plays no role here. Have Jacob tested eta?

   Also I have questions about the 2nd way, if I have set krot and eta, the initial state (after isotropic compression) is really difficult to control, at least kn ks frictionangle krot and eta should be tested. however, In Plassizrd's paper used SDEC, he just used kn ks and frictionangle to control the isotropic compression process, and then add rolling moment to the contact, but I never realized that in yade, which I have found only friction angle could be easily changed.

    Anybody have realized the rolling moment model in yade using either the method I mentioned or other scheme?

I am glad to talk with all of u interested in rolling resistance moment model

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Bruno Chareyre (bruno-chareyre) said :
#1

Hi Wang,
I tested 1).
You can find an example of a problem with bending-twisting moments in examples/test/chained-cylinder/chained-cylinder-spring.py. This example is not using spheres but it makes no difference for the Ip functor and the contact law.

Thank you for opening this discussion. It suggests there is a need for an example script of the triaxial type with cohesive contacts and moments.

As for how to model rolling resistance, it is by introducing bending moments. Rolling and bending are two names for more or less the same thing in my opinion.

Revision history for this message
Bruno Chareyre (bruno-chareyre) said :
#2

I just commited a new example script with cohesion and rolling friction.

See:
https://github.com/yade/trunk/blob/dbfa0cd01b7634292762d3a2177025ff1fa2134b/examples/test/triax-cohesive.py

Revision history for this message
wangxiaoliang (wangxiaoliang) said :
#3

thanks Chareyre for your comment
I tested script u commited, luckily it works. I have printed one of the interaction results show below
here c is one of the interaction

Yade [7]: c.phys.cohesionBroken
 -> [7]: False
Yade [8]: c.phys.kn
 -> [8]: 7653241.2717035133
Yade [9]: c.phys.kr
 -> [9]: 1593844.2946957101
Yade [10]: c.phys.ks
 -> [10]: 3061296.5086814053
Yade [11]: c.phys.ktw
 -> [11]: 1593844.2946957101
Yade [12]: c.phys.moment_bending
 -> [12]: Vector3(-105.4878453405061,512.93976974058694,129.58686704922914)
Yade [13]: c.phys.maxRollPl
 -> [13]: 0.050906805758850759
Yade [14]: c.phys.maxTwistMoment
 -> [14]: Vector3(0,0,0)
Yade [15]: c.phys.moment_twist
 -> [15]: Vector3(300.29038157157754,-753.75279141536646,3237.7950631480908)

Obviously, norm of c.phys.moment_bending is a bit larger than c.phys.maxRollPl ( I think this should be the plastic rolling threshold value ), so I think etaRoll plays no roll here, Why?

Also I found this kind of phenomena in the 2nd way I mentioned in my question using
Ip2_FrictMat_FrictMat_MindlinPhys() + Law2_ScGeom_MindlinPhys_Mindlin()

Chareyre, Jokob or others, could u explain that

Revision history for this message
Bruno Chareyre (bruno-chareyre) said :
#4

Comparing moment to maxRollPl is like comparing shear force to friction angle.
maxRollPl is only the coefficient of rotational friction, it has to be multiplied by normal force to give strength.

>luckily it works
I was also surprised that random typing resulted in a functional script . ;)

Revision history for this message
wangxiaoliang (wangxiaoliang) said :
#5

I see, great help of u, Chareyre!

Another comment about yade, somebody juest want to add a rolling moment to the classic Cundall model to model sand or gravel

in which there is no cohesion phys.

I remember months ago, there is phys and law named MomentMat phys , Law2_Scg_MomentPhys_CohesionlessMomentRotation.

why do u remove MomentMat Phys and its Ig, law ?

Revision history for this message
Chiara Modenese (chiara-modenese) said :
#6

Hi Bruno,
Thank you for your new script. I have not tested it but I would add a comment to lines 83, 88 and 90 (O.engines[2].lawDispatcher.functors[1].always_use_moment_law = True, O.engines[2].physDispatcher.functors[1].setCohesionNow = True). If I am not wrong, these instructions will add a moment/cohesion only to newly created contacts whereas existing interactions will not be affected by. It is a detail but it would be good to add a comment in the script about it (so that users do not forget it).
Chiara

On 19 Sep 2012, at 17:31, Chareyre wrote:

> Question #208965 on Yade changed:
> https://answers.launchpad.net/yade/+question/208965
>
> Chareyre proposed the following answer:
> I just commited a new example script with cohesion and rolling friction.
>
> See:
> https://github.com/yade/trunk/blob/dbfa0cd01b7634292762d3a2177025ff1fa2134b/examples/test/triax-cohesive.py
>
> --
> You received this question notification because you are a member of
> yade-users, which is an answer contact for Yade.
>
> _______________________________________________
> Mailing list: https://launchpad.net/~yade-users
> Post to : <email address hidden>
> Unsubscribe : https://launchpad.net/~yade-users
> More help : https://help.launchpad.net/ListHelp

Revision history for this message
Bruno Chareyre (bruno-chareyre) said :
#7

Wang (is that your name?),
I don't remember this specific law you are mentionning. If we removed it, then it was probably unmaintained and unsafe to use.
There is no need for a "cohesionless" law. As you see in the example script (2nd loading), Law2_ScGeom6D_CohFrictPhys_CohesionMoment can do that.

Chiara,
always_use_moment_law=1 means that bending moment is always present with or without cohesion.
setCohesionNow=1 means that all existing contacts will have cohesive/moment properties initialized at the next step.
Newly created will not be cohesive because setCohesionOnNewContacts=0 by default.

Feel free to add comments (attributes doc could be better to...), else I'll do it eventually but not today.

Revision history for this message
Chiara Modenese (chiara-modenese) said :
#8

On 20 Sep 2012, at 10:20, Chareyre wrote:

> Question #208965 on Yade changed:
> https://answers.launchpad.net/yade/+question/208965
>
> Chareyre proposed the following answer:
> Wang (is that your name?),
> I don't remember this specific law you are mentionning. If we removed it, then it was probably unmaintained and unsafe to use.
> There is no need for a "cohesionless" law. As you see in the example script (2nd loading), Law2_ScGeom6D_CohFrictPhys_CohesionMoment can do that.
>
>
> Chiara,
> always_use_moment_law=1 means that bending moment is always present with or without cohesion.
> setCohesionNow=1 means that all existing contacts will have cohesive/moment properties initialized at the next step.
> Newly created will not be cohesive because setCohesionOnNewContacts=0 by default.

Excellent, sorry I have never used this law and I did not properly check the details in code/documentation. Then I think that the script is fine as details are (or should be) already explained in documentation.
Chiara

>
> Feel free to add comments (attributes doc could be better to...), else
> I'll do it eventually but not today.
>
> --
> You received this question notification because you are a member of
> yade-users, which is an answer contact for Yade.
>
> _______________________________________________
> Mailing list: https://launchpad.net/~yade-users
> Post to : <email address hidden>
> Unsubscribe : https://launchpad.net/~yade-users
> More help : https://help.launchpad.net/ListHelp

Revision history for this message
wangxiaoliang (wangxiaoliang) said :
#9

Hi Chiara, as I again test the script u give, warning list is shown below

WARN /home/michael/yadeLatest/yade081/yade-trunk-2954021/pkg/dem/CohesiveFrictionalContactLaw.cpp:149 go: If :yref:`CohesiveFrictionalContactLaw::useIncrementalForm` is false, then plasticity would not be applied correctly (the total formulation would not reproduce irreversibility)

either I turn useIncrementalForm true or false, I always got this warning, and the calculation won't go to the end. The two yade versions I used is 0.80.1 and yade point 2971.

Revision history for this message
Bruno Chareyre (bruno-chareyre) said :
#10

I fixed this warning recently.
You need the daily snapshot or updated sources to get rid of it.

Revision history for this message
wangxiaoliang (wangxiaoliang) said :
#11

which updated version, 0.80.1 still has this problems, would u please show the webpage of the updated source here? thanks

> -----原始邮件-----
> 发件人: Chareyre <email address hidden>
> 发送时间: 2012年9月24日 星期一
> 收件人: <email address hidden>
> 抄送:
> 主题: Re: [Yade-users] [Question #208965]: topics on rolling resistance modeling granular media
>
> Question #208965 on Yade changed:
> https://answers.launchpad.net/yade/+question/208965
>
> Status: Open => Answered
>
> Chareyre proposed the following answer:
> I fixed this warning recently.
> You need the daily snapshot or updated sources to get rid of it.
>
> --
> You received this question notification because you are a member of
> yade-users, which is an answer contact for Yade.
>
> _______________________________________________
> Mailing list: https://launchpad.net/~yade-users
> Post to : <email address hidden>
> Unsubscribe : https://launchpad.net/~yade-users
> More help : https://help.launchpad.net/ListHelp

Revision history for this message
Bruno Chareyre (bruno-chareyre) said :
#12

Do you compile yade usually? If not, you need the "daily" package (see installation instructions).
Else, simply update your sources.

If you plan to check the webpage for fixing the problem manually instead of simply updating, don't do that, really.
It is a very bad idea in the long run.

Revision history for this message
wangxiaoliang (wangxiaoliang) said :
#13

Well, I never install yade successful via the yade-daily, I installed yade by download yade source and use scons, Ubuntu version of mine is 9.10.

sudo add-apt-repository ppa:yade-pkg/stable shows error below

Executing: gpg --ignore-time-conflict --no-options --no-default-keyring --secret-keyring /etc/apt/secring.gpg --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --keyserver keyserver.ubuntu.com --recv 7241D8E316D8283220948D3CB58448722AFBE6B7
gpg: download key ‘2AFBE6B7’,from hkp server keyserver.ubuntu.com
gpg: key 2AFBE6B7:“Launchpad PPA for Yade packagers” never changed

and sudo apt-get update also show errors.

Revision history for this message
wangxiaoliang (wangxiaoliang) said :
#14

Btw, I also used the 2nd way I mentioned, say
Ip2_FrictMat_FrictMat_MindlinPhys() + Law2_ScGeom_MindlinPhys_Mindlin() to simulate triaxial compression

luckily ,there exists rolling moment . Very Strangely, model with rolling moment results a much smaller than model without rolling moment?

Can anybody tell me why?

Revision history for this message
Anton Gladky (gladky-anton) said :
#15

> Well, I never install yade successful via the yade-daily, I installed
> yade by download yade source and use scons, Ubuntu version of mine is
> 9.10.

Version 9.10 Ubuntu Karmic is not supported any more since April 2011 [1].
Please upgrade Ubuntu to a newer version or compile Yade from source.

Scons has been also dropped recently [1]. Use Cmake for compilation.

Anton

[1] http://en.wikipedia.org/wiki/List_of_Ubuntu_releases#Ubuntu_9.10_.28Karmic_Koala.29
[2] https://launchpad.net/yade/+announcement/10328

Revision history for this message
Bruno Chareyre (bruno-chareyre) said :
#16

Hi Anton,
I'm receiving the launchpad questions twice at the moment. One with
header Re: [Yade-users] [Question #208965]:, the other with header Re:
[Question #208965]:
Do you save the same behavior? Any change recently in the settings of
launchpad? It is a annoying a little bit...

Have a nice day :)

Bruno

On 25/09/12 07:15, Anton Gladky wrote:
> Question #208965 on Yade changed:
> https://answers.launchpad.net/yade/+question/208965
>
> Status: Open => Answered
>
> Anton Gladky proposed the following answer:
>> Well, I never install yade successful via the yade-daily, I installed
>> yade by download yade source and use scons, Ubuntu version of mine is
>> 9.10.
> Version 9.10 Ubuntu Karmic is not supported any more since April 2011 [1].
> Please upgrade Ubuntu to a newer version or compile Yade from source.
>
> Scons has been also dropped recently [1]. Use Cmake for compilation.
>
> Anton
>
> [1] http://en.wikipedia.org/wiki/List_of_Ubuntu_releases#Ubuntu_9.10_.28Karmic_Koala.29
> [2] https://launchpad.net/yade/+announcement/10328
>

--
_______________
Bruno Chareyre
Associate Professor
ENSE³ - Grenoble INP
Lab. 3SR
BP 53
38041 Grenoble cedex 9
Tél : +33 4 56 52 86 21
Fax : +33 4 76 82 70 43
________________

Revision history for this message
Chiara Modenese (chiara-modenese) said :
#17

Hi Wang,
We cannot help you further unless you provide us with an example. We used the law you mention successfully here and we did not find any strange results.
Chiara

On 25 Sep 2012, at 02:41, wangxiaoliang wrote:

> Question #208965 on Yade changed:
> https://answers.launchpad.net/yade/+question/208965
>
> wangxiaoliang gave more information on the question:
> Btw, I also used the 2nd way I mentioned, say
> Ip2_FrictMat_FrictMat_MindlinPhys() + Law2_ScGeom_MindlinPhys_Mindlin() to simulate triaxial compression
>
> luckily ,there exists rolling moment . Very Strangely, model with
> rolling moment results a much smaller than model without rolling moment?
>
> Can anybody tell me why?
>
> --
> You received this question notification because you are a member of
> yade-users, which is an answer contact for Yade.
>
> _______________________________________________
> Mailing list: https://launchpad.net/~yade-users
> Post to : <email address hidden>
> Unsubscribe : https://launchpad.net/~yade-users
> More help : https://help.launchpad.net/ListHelp

Revision history for this message
wangxiaoliang (wangxiaoliang) said :
#18

I reinstall my Ubuntu, now the version becomes 12.04. And problems using cohesive materials are solved.

I will open another page to talk about the 2nd way simulating rolling resistance for sand via
Ip2_FrictMat_FrictMat_MindlinPhys() + Law2_ScGeom_MindlinPhys_Mindlin()

thanks all guys, especially Chareyre

Revision history for this message
Anton Gladky (gladky-anton) said :
#19

Hi Bruno,

it probably happens, when I answer the question through email, using
<email address hidden> as email address. I do not know,
how to fix it as there are no any settings on "Answer" section on Launchpad.

Sorry for inconvenience,

Anton

2012/9/25 Chareyre <email address hidden>:
> Question #208965 on Yade changed:
> https://answers.launchpad.net/yade/+question/208965
>
> Chareyre proposed the following answer:
> Hi Anton,
> I'm receiving the launchpad questions twice at the moment. One with
> header Re: [Yade-users] [Question #208965]:, the other with header Re:
> [Question #208965]:
> Do you save the same behavior? Any change recently in the settings of
> launchpad? It is a annoying a little bit...
>
> Have a nice day :)
>
> Bruno