# How to model 1/4 part of 3D cubic void cell (RVE) in abaqus which is subjected to combined tension and shear ?

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I want to model 1/4 part of cubic void cell which is subjected to combined tension and shear, Since its a part of RVE hence I need to apply periodic boundary conditions. I am trying to model the same model which is taken by Prof  Cihan Tekoglu in his paper "Representative volume element calculations under constant stress triaxiality, Lode parameter, and shear ratio" under same boundary conditions. I had applied all the boundary conditions mentioned in his paper in Appendix B, but still I get wierd deformed shape after simulation.

I have created nodal sets for each sets mentioned i.e. Surface Top Left,Surface Top Right, Surface Left, Surface Right etc. and then applied given equation constraints for each set.

Should I go for node to node equation constraint ?

Link for Prof  Cihan Tekoglu's paper

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### Ya node set will not work

I think node set would not work. you have to go from node to node.

It is better to use to python script with find the corresponding nodes at the edges and surfaces and then use the equation constraint to apply the boundary conditions.

If you are trying it for the first time then you may contact me again and send me the input file.

I would also recommend you to try CUBIT software which is more useful in generating the input file for abaqus.

All the best.

### Node set will work if...

Finally its working in my case,

Obviously Node to Node Equation constrains is another option if someone knows python.

But incase someone doesn't know pyhton then this could be the other way to go forward,

Node set will work subject to condition that the node set should be formed using paired nodes (Pairing of nodes can be done using a simple MATLAB code). Also while writing the input file UNSORTED option must be activated to force the ABAQUS to apply equation constraints on the nodes in sequential order (the order in which you have formed the nodal set.

For example,

*Nset, nset=Surface-Bottom-Right, instance=Part-1-1, unsorted

Regards,

Vishal