Buckling Load Calculations of the Isotropic Shell A-8 using a High-Fidelity Hierarchical Approach

AIAA-2002-1513BUCKLING LOAD CALCULATIONS OF THE ISOTROPIC SHELL A-8USING A HIGH-FIDELITY HIERARCHICAL APPROACHJohann Arbocz*Delft University of Technology, The NetherlandsandJames H. Statues**NASA Langley Research Center, Hampton, VA 23681-001ABSTRACTAs a step towards developing a new designphilosophy, one that moves away from thetraditional empirical approach used today indesign towards a science-based designtechnology approach, a test series of 7 iso-tropic shells carried out by Arbocz andBabcock [1] at Caltech is used. It is shown howthe hierarchical approach to buckling loadcalculations proposed by Arbocz et al [2] canbe used to perform an approach often called"high fidelity analysis", where the uncertaintiesinvolved in a design are simulated by refinedand accurate numerical methods. The DelftInteractive Shell DEsign COde (short,DISDECO} is employed for this hierarchicalanalysis to provide an accurate prediction ofthe critical buckling load of the given shellstructure. This value is used later as areference to establish the accuracy of theLevel-3 buckling load predictions. As a finalstep in the hierarchical analysis approach, thecritical buckling load and the estimatedimperfection sensitivity of the shell are verifiedby conducting an analysis using a sufficientlyrefined finite element model with one of thecurrent generation two-dimensional shellanalysis codes with the advanced capabilitiesneeded to represent both geometric andmaterial nonlinearities.