This paper considers the problem of two adherents joined by a soft thin adh
esive along their common surface. Using the asymptotic expansion method, th
e authors obtain a simplified model in which the adhesive is treated as a m
aterial surface and is replaced by returning springs. The authors show weak
and strong convergence of the exact solution toward the solution of the li
mit problem. The singularities of the limit problem are analyzed, and it is
shown that typically they are logarithmic. Furthermore, the authors invest
igate the phenomenon of boundary layer by studying the correctors, the extr
a terms, which must be added to the classical asymptotic expansion to verif
y the boundary conditions. The correctors show that, contrary to the adhere
nts, in the adhesive there are power-type singularities, which are at the b
ase of the failure of the assemblage.