ABAQUS PYTHON SCRIPTING. Node order not preserved while creating a node set

[Brij_raj_]

I will explain this without going too much into the theoretical background. Now lets say I have a cube and I have meshed it. on each of the 6 surfaces of my cube I have some nodes. i have identified the surfaces as xmin, xmax, ymin, ymax, zmin, zmax. and I have created a set of nodes in each of these 6 surfaces. Now inorder for me to gain any valuable insights for my project I need to have the arrangement of nodes in xmin-xmax, ymin-ymax, zmin-zmax in a particular order. Now let me explain this in terms of my xmin and xmax surface. each node in my xmin surface will have a periodic equivalent in the xmax surface. Now I have the nodes in xmin and xmax in a certain order which Abaqus has done it to be in ascending order. Suppose the first node in my xmin node set has a periodic equivalency with the 5th node in the xmax node set, so I will sort my xmax nodes (a new sorted_x_max set) such that the 5th node is now at the first position. and then continue with the second node in xmin set identifying its periodic equivalent in the the xmax set and adding it to the sorted x set. Now all of this is done and I have me sorted_x_max_Set exactly in the order I want it to be. Now when I try making a node set with this sorted_x_max_set and run the simulation upon inspecting the input script the new Sorted set is still in the same order as my original xmax set. I have tried debugging it for 5 days but still the same results. the node labels are how I want them, the identification criteria is working everything Is working but as soon as I create a set from these sprted nodes it will assume its original positions.

below I have provided the nodesets

*Nset, nset=RVE_AG_NegX_AGSORT

3, 4, 5, 6, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52

53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68

69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84

85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100

101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116

*Nset, nset=RVE_AG_PosX_AGSORT

7, 8, 9, 10, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147

148, 149, 150, 151, 152, 153, 154, 193, 194, 195, 196, 197, 198, 199, 200, 201

202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 231, 232, 233, 234, 235, 236

237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252

253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268

*Nset, nset=Sort

7, 8, 9, 10, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147

148, 149, 150, 151, 152, 153, 154, 193, 194, 195, 196, 197, 198, 199, 200, 201

202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 231, 232, 233, 234, 235, 236

237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252

253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268

also below are the node labels of the identified periodic copies( the total number of nodes might not match because I did not copy the entire thing)

Node_labels

10, 7, 8, 9, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 241,

 

[rb1957]

I don't know Abaqus or python and tend to very simple if labourious solutions ... here goes ...

it is easy to identify the node pairs, yes?

initially I'd choose node numbering to make this easy to notice

even if you can't do it by review of your model, it should be easy enough to sort through the list of node co-ordinates and pick nodes on the +ve x face and the -ve x face.

Then I'd put that into excel, a sheet for x pairs, a sheet for y pairs, and z pairs.

Now I have the node numbers organised I can sort through the abaqus output and select whatever nodal output.

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[FEA way]

So you just want matching meshes for periodic boundary conditions on RVE model ? Then check this thread:

https://www.eng-tips.com/viewthread.cfm?qid=489796

The Micromechanics plug-in would be my first choice.