I'm using static analysis with external thermal load and want to calculate thermal expansion dl/l. The point is that T_load goes to cryogenic temperatures where ALPHX(T) is strictly not constant and not linear with T and I get confusing results. Example:
A cube with 1mm edges
Material with ALPHX(T)=
Study -> Reference Temperature T_ref = 300K
External load -> Temperature - applied to the whole body - T_load = 65K
What I expect by physics is dl/l = SUM_i (T_ref -> T_load) [ 0.5*(ALPHX(T_i)+ALPHX(T_(i+1))) * (T_i - T_(i+1)) ] = ~0,0018 - should be UX=1.8micron
What I get is exactly dl/l = 0 / UX=0 !?
Is it possible SIMULATION does not integrate ALPHX(T) dT in order to calculate dl/l but instead uses something like dl/l = APLHX(T_load) * (T_load - T_ref)
which physicaly is not very useful.
Could somebody please verify and explain what's my mistake?