This paper on "Non-Linear, Finite Element Analysis of Stability and Imperfection Sensivity of Aerospace Shell Structures" was presented at the NAFEMS World Congress on The Evolution of Product Simulation From Established Methods to Virtual Testing & Prototyping - 24-28 April 2001, The Grand Hotel, Lake Como, Italy.

Introduction to Paper

Most of the 'mudules' involved in the International Space Station, ISS, are constituted by reinforced shell structures. Low weight prescriptions make these structures of thin walled type. Although the several space modules are subjected to modest loadings when in orbit, the high level of compressive loads corresponding to the launch stage, requires stability analysis, which turns out be a primary design condition of these structures.
It is well known that thin-walled structures often exhibits high sensitivity to geometrical imperfections. As it was demonstrated by pioneering work of von Karman and Tsien (1) and Cicala (2), Koiter (3) such a sensitivity analysis requires geometrical nonlinear theories and postbuckling analysis. Linearized buckling loads of perfect structures can be in fact, five-six times higher than effective 'ultimate' loadings computed or measured by nonlinear analysis of geometrically imperfect shells.
In the very past, stability design of thin shell has been done by extensive use of experimental data, see the recent survey by Singer (4). Classical and more recent design requirements in these sense can be read in the book by Bushnell (5) and in the chapter by Antona (6). Computational approaches have also been used in the recent past. Recent, interesting survey on that topics have been written by Teng (7).