First- and second-older shape sensitivity analyses in a fully nonlinea
r framework are presented in this paper. Using the fixed domain techni
que and the adjoint approach, integral expressions over the domain are
obtained. The Guillaume-Masmoudi lemma allows these expressions to be
rewritten as integrals over the domain boundary. The formalism is the
n applied to the steady creep of a bar in torsion, as an example of po
wer-law nonlinearities that occur not only in creep problems but also
in viscoplastic fluid flow. Finally, a problem with known analytical s
olution is presented in older to show the equivalence between exact di
fferentiation and the shape sensitivity approach.