thermo-mechanical coupling

[BSFEAP]

Dear All,

I am solving thermo-mechanical coupling by using Part.  For the following cases, results are not equal.....
case 1:::.
batch
dt,,0.0
LOOP time 1
   TIME
   LOOP,,5
   PART,,1
      LOOP iter 5
         TANGent,,1
      NEXT,iter
   PART,,2
      LOOP iter 5
         TANGent,,1
      NEXT,iter
   NEXT 
NEXT time
end

case 2:::
batch
dt,,0.0
LOOP time 1
   TIME
   LOOP,,5
   PART,,2
      LOOP iter 5
         TANGent,,1
      NEXT,iter
   PART,,1
      LOOP iter 5
         TANGent,,1
      NEXT,iter
   NEXT 
NEXT time
end

[FEAP_Admin]

Why would you expect them to be equal?  These are non-linear flow operators that do not commute.

[BSFEAP]

Thank you..
if I use
PARTitions
1 1 1 0
0 0 0 1

which case, the results is more accurate??
first solve part,,2 or first solve part,,1

[Yaakov]

Comparison of experimental or (finite element & theory)analytical results can tell u, which one is better one.

[Prof. R.L. Taylor]

If the thermo-mechanical coupling is one way (e.g., temperatures affect strains but stress/strain does not affect temperature change) then solving the thermal problem first is best.  If you solve the mechanical one first you would not get any effect from the final temperature at this time step.  If there is two way coupling then it depends on which is the strongest effect -- usually this is still the temperature one and solving it first may be better than the other way around.