Example 9, Slide 27: Buckling mode and load factor of the most critical aft strut under Load Case 1

Fig. 28 from the 2013 GENOPT paper1. Load Case 1: STAGS prediction of the critical shell buckling mode for the entire length of an aft strut for the optimized long propellant tank/strut system with two sets of struts, aft and forward, 4 pairs of struts in each set. The applied compressive load from the STAGS model is 23082 lbs. and the buckling load factor corresponding to this strut shell buckling mode is 5.09, which corresponds to the third eigenvalue (mode). The first two modes correspond to buckling of the strut as a column. Compare with the strut shell buckling mode from BIGBOSOR4 shown in Fig. 20(A). The difference in the BIGBOSOR4 and STAGS prediction for the buckling load factors here and in Fig. 20(A) is primarily due to the different prediction from GENOPT/TANK and STAGS of maximum compressive load in an aft strut in Load Case 1 (axial acceleration): -22693 lbs according to GENOPT/TANK and -23082 lbs according to STAGS. [See Table 7(b).].

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