STAGS models of part of a ring and stringer stiffened cylindrical shell previously optimized by PANDA2

This and the next two slides are from the paper, "Optimization of perfect and imperfect ring and stringer stiffened cylindrical shells with PANDA2 and evaluation of the optimum designs with STAGS", by David Bushnell and Charles Rankin, AIAA 43rd Structures, Structural Dynamics and Materials Conference, AIAA Paper 2002-1408, referred to in the next two slides as "2002 PANDA2 paper".

This slide shows Figs 1, 2, and 3 from the 2002 PANDA2 paper. Here is a STAGS sub-domain model of a ring and stringer stiffened, angle-ply, composite cylindrical shell under combined axial compression and in-plane shear.

Fig. 1 a,b: The starting design

Fig. 2 a,b: The design previously optimized by PANDA2

Fig. 3 Linear bifurcation buckling of the optimized shell under Load Set 1: axial compression, Nx=-700 lb/in and in-plane shear, Nxy=+40 lb/in.

A STAGS "sub-domain" model is a STAGS model of part of a stiffened shell that has previously been optimized by PANDA2 or by GENOPT/BIGBOSOR4. The boundary conditions of the sub-domain are formulated so that the prebuckling stress distribution in the sub-domain is very close to that in the complete shell.

Sub-domain STAGS models are especially useful for obtaining converged predictions of local buckling. They are frequently used in order to verify predictions of local buckling of optimized designs obtained by PANDA2 and by GENOPT/BIGBOSOR4.

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