Dear GetFEM++ users,
i was wondering whether it was possible to define a scalar variable computed over a surface, namely in my case a volume bounded by surfaces.
That is to say, something along the lines of
Volume= (1/3) int_{Gamma} Det(Grad_u+Id(3)) Normal.Inv(Grad_u+Id(3)).(X+u) dGamma
where we denote by:
-Gamma, the surfaces in the undeformed configuration
-u, the displacement field
-X, the position in the undeformed configuration
Also, out of curiosity, is it possible to compute such a thing in post-processing?