If I remove the component term “X” and update the code as (nsel,R,S,,4000), then the code works. What I want to do after selecting these nodes is to find elements that all their nodes are part of the selected list of nodes and kill these elements. However, now I have two other problems. Please let me know if you suggest creating a new post for these questions. 

My first question is why there is no correspondence between the calculated stress values and the defined criterion for selecting the nodes. I defined the stress threshold of 4000 (I am not sure if the units are Pa) for the selection of the nodes of REINF elements and performed the simulation. I expected to see that when the max principal stress of the REINF elements exceeds 4000 Pa, the solver selects these elements to apply further operations on them using the next lines of code. However, I can see that they are selected even if the stress values of the REINF elements are much lower than this threshold.

I want to perform the EKILL command on the elements that have the selected node in the previous step. So, I added the following lines to my code (esln,S,1, ekill, all). Although the ESLN command options “,1” is stating that only elements that all their nodes are selected by the NSEL command should be selected, I see that some neighboring solid264 elements are also selected, and EKILL command is performed on them as well. This is happening while before using the (nsel,R,S,,4000) I selected only REINF264 elements by (esel,s,type,,3). Type 3 elements in the ELIST are REINF264 elements. 

I can share an example case with you through ANSYS Customer portal if you deem it helpful.

Thank you in advance for any help you can provide.