Pg. Ciarlet et E. Sanchezpalencia, AN EXISTENCE AND UNIQUENESS THEOREM FOR THE 2-DIMENSIONAL LINEAR MEMBRANE SHELL EQUATIONS, Journal de mathematiques pures et appliquees, 75(1), 1996, pp. 51-67
We consider the two-dimensional membrane equations of a linearly elast
ic clamped shell, whose middle surface is uniformly elliptic. The elim
ination of the normal component of the displacement yields a reduced v
ariational problem whose strain energy vanishes for some non-zero tens
ors. The application of the theory of S. Agmon, A. Douglis and L. Nire
nberg to an auxiliary uniformly elliptic first-order system neverthele
ss allows to show that the bilinear form of the reduced problem is H-0
(1)-elliptic.