Abstract: Postbuckling behavior is investigated for Reciangular Reissner’s moderately thickplates and sandwich plates. The fundamental equations and boundary conditions areevpressed in unified dimensionless form for reciangular moderaiely thick plaies andsanduich plaies. Exact solutions of series form with a number of different boundaryconditions. especially. with unsmmetrical boundary conditions. are oblained bydeveloping a new technique of mixed Fourier series in nonlinear analisis. Thenonlinear parlial differenlial equalions are reduced to an infinite set of simultaneousnonlinear algebraic equations, which are truncated by iteration in numericalcompulations.

Key words: topography with mltiple shallow circular-arc canyons, scattering series solution, postbuckling, moderately thick plates, sandwich plates