ASYMPTOTICALLY EXACT JOINING CONDITIONS AT THE JUNCTION OF PLATES WITH VERY DIFFERENT CHARACTERISTIC

The phenomenon of the boundary layer which occurs when plates are join ed is studied. A procedure for deriving the asymptotically exact joini ng (transmission) conditions which associate the two-dimensional equat ions for the deformation of the plates along the joining line Gamma is developed using the method of matched asymptotic expansions. Two situ ations are discussed in which these conditions turn out to be non-stan dard: the bending moment in Gamma must disappear and the deflection ca n undergo a jump (for real values of the physical parameters, the long itudinal displacements and forces as well as the bending and the shear ing force always remain continuous). One of the situations (the joinin g of ''thick, soft'' and a ''thin, rigid'' shells) is characteristic o f a moving loudspeaker system. The results of a numerical experiment, which confirm the asymptotic analysis of the problem, are presented. ( C) 1998 Elsevier Science Ltd. All rights reserved.