How to get the real part of a expression

I’m trying to get the real part of a expression, but I failed. It looks like this. vfTQ8 How to get the real part of a expression

Does anyone have a solution? By the way, it is quite weird because when I simplify this: CCFlu How to get the real part of a expression Mathematica returns the right answer, but I can’t tell the big difference between the two expressions.

Here is my code:

vectorVr = Array[Subscript[vr, #] &, 9];
vectorVi = Array[Subscript[vi, #] &, 9];
$  Assumptions = 
  Join[vectorVr, vectorVi] \[Element] Reals;

FullSimplify[ (0.` + 0.0576` I) (I Subscript[vi, 1] - 
  I Subscript[vi, 4] + Subscript[vr, 1] - Subscript[vr, 
  4]) (-I Subscript[vi, 1] + I Subscript[vi, 4] + Subscript[vr, 
  1] - Subscript[vr, 4]) // Expand // Re]

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