ULTIMATE STRENGTH AND POSTBUCKLING STIFFNESS OF PLATE PANELS SUBJECTED TO COMBINED LOADS USING SEMI-ANALYTICAL MODELS

SUMMARY Non-linear semi-analytical buckling models are deve loped for fast and accurate buckling, postbuckling and ultimate strength assessment of thin-walled plate panels. Th e models are founded on thin-walled large deflectio n plate theory, Raleigh-Ritz discretization of the buckling deflect ion and incremental methods for solving the geometr ically non-linear equilibrium equations. By limiting the degrees of f reedom and solving the non-linear geometrical probl em, combined with hot spot stress control of the redistributed stress pattern, buckling and ultimate strength limits are estimated with good accuracy and a minimum of computer effort. The models are packed into simple user interface tools (PULS ) for easy physical interpretation of buckling characteristics . Examples are presented illustrating typical featur es of non-linear behaviour of plates subjected to combined bi-axial and shear loads and some comparisons with full blown non-linear finite element codes are included. Comparisons with existi ng Classification rules are also included for some cases.