Build remote interaction for WireMat

Hi Alex,

you are right. The interactionDetectionFactor is used to initialise the remote interactions for the WireMat. Nevertheless, it is a general option of the Ig2 functor and is independent of the material since it just enlarges the bounding box for the interaction detection. Note that you have to set the aabbEnlargeFactor for the bounding box as well (see [1] or WireMat examples). You can use it to initialise interactions as done for the WireMat or to define distant interactions, i.e. particle which are not in contact but in within the specified range will interact. In the first case you have to reset the interactionDetectionFactor after the links have been created.

linkThresholdIteration is material specific and in case of the WireMat it defines a threshold until when links can be created. I don't think it is implemented for any other material. For the WireMat, this means that interactions can only be created by default in the first iteration.

HTH
Klaus

[1] https://yade-dem.org/doc/user.html?highlight=interactiondetectionfactor#creating-interactions

Hi Klaus
Thank you for your detailed explanation. I have some other questions.

In your example wirecontacttest.py, I notice that there are two Ip2 functor and two Law2 functors defined for the WireMat and the FrictMat (which obeys Cundall’s constitutive law) respectively. Is that correct that the Ip2 and Law2 functors of FrictMat also work for the interaction between the dropping sphere block and the wire net?

Hi Alex,

you are correct. WireMat is derived from FrictMat (as most of the material classes in Yade, see [1]) and, hence, you can have interactions between WireMat and FrictMat where the WireMat is basically treated as a FrictMat. So you need Ip2_FrictMat_FrictMat_FrictPhys and Law2_ScGeom_FrictPhys_CundallStrack for contact between the block and the mesh.

HTH
Klaus

[1] https://yade-dem.org/doc/yade.wrapper.html#material

Thank you Klaus.

Looking forward to seeing your recent progress on Yade-DEM development in the upcoming Yade seminar.

Regards,

Alex

Hi Klaus,

I still have some questions about WireMat-FrictMat interaction.

I understand WireMat inherits FrictMat so that CundallStrack law can work for the interactions between WireMat and FrictMat. What if I want to use Hertz-Mindlin law instead?

I tried to do that by simply replacing the lp2 and law2 functors by Ip2_FrictMat_FrictMat_MindlinPhys and Law2_ScGeom_MindlinPhys_Mindlin, but it didn't work and gave me the following error report:

FATAL FATAL /home/alexcheng/myYade/trunk/pkg/common/InteractionLoop.cpp:142 action: None of given Law2 functors can handle interaction #19133+19132, types geom:ScGeom=1 and phys:FrictPhys=3 (LawDispatcher::getFunctor2D returned empty functor)

Could you please give some advices on this?

btw, what do geom:ScGeom=1 and phys:FrictPhys=3 mean?

Regards,

Alex

Hi, jduriez

Thanks for the remarks. I am simulating uniaxial compression on a woven textile sand bag. I choose WireMat for modeling the bag and FrictMat for the soil inside the bag. Here is my script for the engine parts (sorry for not pasting the whole script, it's too long).

My script worked this time. Problem seems to be that I built remote links before defining the interaction loop. Anyway, thank you very much.

##################################
## Defining engines ##
##################################

O.engines=[
 ForceResetter(),
 InsertionSortCollider([Bo1_Sphere_Aabb(label='Sphaabb'),Bo1_Box_Aabb(label='Wallaabb')]),
 InteractionLoop(
  [Ig2_Sphere_Sphere_ScGeom(label='Ig2ssGeom'),Ig2_Box_Sphere_ScGeom(label='wall')],
  [Ip2_WireMat_WireMat_WirePhys(label='wovenbag'),
   Ip2_FrictMat_FrictMat_MindlinPhys(
   krot=kr,
   ktwist=kr,
    label='soilsphere')],
  [Law2_ScGeom_WirePhys_WirePM(label='Law_wvbg'),
    Law2_ScGeom_MindlinPhys_Mindlin(
    includeMoment=True,
   label='Law_ssph')]
 ),
 NewtonIntegrator(damping=0.2,gravity=[0,0,-9.81],label='newton'),
 GlobalStiffnessTimeStepper(timeStepUpdateInterval=100)
]

Thanks Jérôme Duriez, that solved my question.