Stochastic finite-element analysis for elastic buckling of stiffened panels

The variability of the random buckling loads of beams and plates with stoch astically varying material and geometric properties is studied in this pape r using the concept of the variability response function. The elastic modul us, moment of inertia, and thickness are assumed to be described by homogen eous stochastic fields. The variance of the buckling load is expressed as t he integral of the auto- and cross-spectral density functions characterizin g the stochastic fields multiplied by the deterministic variability respons e functions. Using this expression spectral-distribution-free upper bounds of the buckling load variability are established. Further, the buckling loa d variability for prescribed forms of the spectral density functions is cal culated. Using a local average approach, the commercial finite-element pack age ABAQUS is incorporated into the analysis of these random buckling loads . The technique is applied to study variability of the critical buckling lo ad of a stiffened steel plate used in experiments to model a barge deck.