CLASSICAL VERSUS IMPROVED THIN SHELL THEORIES - A THEORETICAL ARGUMENT OR A DESIGN CONCERN

Differences in the response of thin nonshallow spherical shells result ing from the choice of the adopted shell theory (classical or improved ) are addressed analytically and through a series of representative sh ell problems. The analytical approach utilized to study the variation between the two theoretical models is based on the response resulting from singular lends, The differences are quantified in a set of proble ms that reflect on the assumptions used in formulating the analytical description of the two theories in question. The broad scope of this p aper is to examine the impact of shear deformability, introduced by th e improved theory on the stress field when amplified under specific le nding and geometric conditions, when those are of primary concern to t he engineers. Such cases associated with stress concentration around c utouts, interaction of shells with nozzles, stress field in the vicini ty of concentrated sur;face loads, etc. The mathematical formulation i s based on the derivation of appropriate Green functions and the compu tational scheme is formed upon a special type of boundary integral equ ation., Comparison solutions for stress concentration around circular cutouts of twisted and sheared shells, stress amplification in the jun ction of shell with nozzles, and local stress field induced by concent rated loads are presented for the two theories.