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This is Fig. 262 from the 2009 GENOPT paper, "Minimum weight design of imperfect isogrid-stiffened ellipsoidal shells under uniform external pressure" by David Bushnell, AIAA 50th Structures, Structural Dynamics, and Materials Conference, Palm Springs, California, 2009, AIAA Paper 2009-2702, called "2009 GENOPT paper".
Shown in ths slide is a STAGS “soccerball” model of half of the optimized imperfect isogrid-stiffened equivalent ellipsoidal shell.
The optimum design, listed in columns 2 and 3 of Table 33 of the 2009 GENOPT paper, was obtained by GENOPT/BIGBOSOR4 with plus and minus axisymmetric (n=0) mode 1 and mode 2 linear buckling modal imperfection shapes with amplitude, Wimp = 0.2 inch.
This is the non-axisymmetric (2nd n=1 circumferential wave) linear buckling modal imperfection shape used as the n = 1 imperfection corresponding to the last trace in Fig. 254 of the 2009 GENOPT paper.
For viewing figures and tables referred to here but not shown here, please download the 2009 GENOPT paper from this website.
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