Example 9, Slide 17: Modal vibrations of the optimized strut-supported long propellant tank in which most of the energy is in the strut extension and

Fig. 16a from the 2013 GENOPT paper1. Vibration modes from GENOPT/BIGBOSOR4 for the optimized propellant tank with aft and forward sets of struts, 4 pairs of struts at each axial location. The struts are not shown because BIGBOSOR4 cannot plot springs. Compare with the predictions from STAGS shown in Figs. 25a,b. Shown here are the four vibration modes in which the propellant tank moves approximately as a rigid body. Modes (A), (C) and (D) are the most important modes because these are the modes that would be excited during launch of the propellant tank into space. The struts are not shown because BIGBOSOR4 does not have the capability to plot springs attached to shells of revolution.

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