Yade

Can tensile and compressive modulus be separately defined for GridConnection?

Asked by Hongyang Cheng

Hi guys,

I have two questions regarding deformable elements, i.e. chainedcylinder and gridConnection.
1) Can tensile modulus (internal behavior) and compressive modulus (e.g. sphere-gridNode contact) be separately defined for deformable elements? I can only see one modulus given for each material in this newly added example [1].
2) Is chainedcylinder deprecated?

[1] https://github.com/yade/trunk/blob/549f14efe6d2409b5ffb647d5f1e510681749450/examples/grids/CohesiveGridConnectionSphere.py#L40

Cheers

Alex

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Klaus Thoeni
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Best Klaus Thoeni (klaus.thoeni) said : 		#1

Hi Alex,

1) In the specific script gridNodeMat, i.e., the material used to create the gridNodes, defines the properties of the internal behaviour of the gridConnection or cylinder. gridCoMat, i.e., the material used to create the gridConnection, defines the properties for the interactions with external bodies, e.g., interaction of a cylinder and a sphere.

2) I was talking to Bruno about this, and yes at some stage we are going to remove the chainedCylinder. I already added similar examples to examples/grid. Nevertheless, note that the constitutive behaviour of chainedCylinder and gridConnection are not exactly the same. There are some differences in the preprocessing of the Ip2 parameters.

BTW, in the latest trunk version you need to use "from yade.gridpfacet import *" for importing the functions for chainedCylinder and grids. See as well the updated examples.

HTH
Klaus

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Hongyang Cheng (alex-cheng) said : 		#2

Hi Klaus,

Thanks for the details and the examples to study. I understand how the grid element works now.

One last thing to confirm. Does relpos in the Ig2 functors, e.g. Ig2_Sphere_GridConnection_ScGridCoGeom, work as the barycentric coordinates in Anna's paper?

Cheers

Alex

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Hongyang Cheng (alex-cheng) said : 		#3

Thanks Klaus Thoeni, that solved my question.

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Klaus Thoeni (klaus.thoeni) said : 		#4

Yes, I guess you can see it this way. "relpos" defines the location of the contact in "local" coordinates. So for a cylinder it should be between 0 and 1.

K