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This is Fig. 29 from the 2007 Bushnell paper. Shown here is the nonlinear equilibrium state from the 60-degree STAGS model of the PANDA2-optimized stiffened cylindrical shell lised as Case 2 in Table 4, an optimum design obtained by PANDA2 from an unconservative model. This is the deformed state predicted by STAGS at the highest load factor PA reached in the nonlinear static run, PA = 1.02487.
This figure shows the outer fiber effective stress (psi) at axial load Nx = -3000 x 1.02487 lb/in.
Notice that the maximum effective stress, about 78000 psi, is significantly higher than that obtained from the more conservatively optimized Case 4 model, results from which are displayed in the previous two slides. In those slides the maximum effective stress is about 15 per cent less than in this less conservatively optimized panel.
Notice sidesway of the three central stringers in the region with the highest mesh density. These three central stringers are darker than the others because they have greater nodal point density over their cross sections.
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