Index out of bound error in AceFEM

Question

I have written an AceGEN code for a 3D element. The degrees of freedom at each point are 4, 3 spatial displacements and one additional degree of freedom that acts like temperature, i.e. for the initialization part I wrote

Xi \[DoubleRightTee] 
 SMSReal[Array[nd$$[#1 , "X" , 1] & , nNodes], 0 , 10];
Yi \[DoubleRightTee] 
 SMSReal[Array[nd$$[#1 , "X" , 2] & , nNodes], 0 , 10];
Zi \[DoubleRightTee] 
 SMSReal[Array[nd$$[#1 , "X" , 3] & , nNodes], 0 , 10];
ui \[DoubleRightTee] 
 SMSReal[Array[nd$$[#1 , "at" , 1] &, nNodes], -0.1 , 0.1];
vi \[DoubleRightTee] 
 SMSReal[Array[nd$$[#1 , "at" , 2] &, nNodes], -0.1 , 0.1];
wi \[DoubleRightTee] 
 SMSReal[Array[nd$$[#1 , "at" , 3] &, nNodes], -0.1 , 0.1];
\[Eta]bari \[DoubleRightTee] 
 SMSReal[Array[nd$$[#1 , "at" , 4] & , nNodes]];

The AceGen code compiles completely. However, when it comes to the AceFEM to do the job the following error occurs.

Index out of bounds error while executing user subroutine SKR of element 3Dpseudoelasticity (possible bug in the symbolic description of the element!!). Description : Index in expression:nd$$[..,at,j] has value: 4. Index bounds are min=1 max=3. Source code identification: \$D144\$ Version: 6.811 Windows (27 Nov 16) (MMA 10.4) Module: SMTBoundCheck

I saw the debugging session in the help documentation and it says that this is the problem of nd$$ that cannot exceed 3. So I was wondering how to fix this problem and add a new degree of freedom to the problem.

Answer 1

This is a general comment turned into an answer.

With coupled (thermo-mechanical) elements you have to be careful when setting up basic element topology and corresponding node positions, nodal DOF and node IDs. They should be specified in the beginning of AceGen element code in SMSTemplate (see its documentation page).

For example, this is an excerpt of 2D coupled element, taken from "Lectures.nb" from home page.

SMSTemplate[
  "SMSTopology" -> "Q1",
  "SMSNoNodes" -> 8,
  "SMSDOFGlobal" -> {2, 2, 2, 2, 1, 1, 1, 1},
  "SMSAdditionalNodes" -> Hold[{#1, #2, #3, #4} &],
  "SMSNodeID" -> {"D", "D", "D", "D", "T -M", "T -M", "T -M", "T -M"},
  "SMSSegments" -> {{1, 2, 3, 4}},
  ...(* other options *)

];