Cyclic thermal loading is applied to the TBC. At the beginning, the TBC is stress free at temperature 1000˚C.
Each thermal cycle consists of three stages:
Cooling to 0˚C
Reheating to 1000˚C
Maintaining 1000˚C
The TGO grows in the dwelling stage of the TBCs. The TGO growth is simulated using the swelling model defined via the userswstrain subroutine. Following is the swelling-evolution code used in the subroutine:
cyc = int(time/3.d0) * 1.d0 ! # of cycle
tmod = mod(time,3.d0) ! Last cycle
if(tmod.gt.2.d0) then
sweqt = c1 * cyc + c1 * (tmod - 2.d0)
else
sweqt = c1 * cyc
endif