Skin-Stringer Option Summary

Strength and stability determine the structural design. With diagonal tension designs, where we allow skin to buckle, we must calculate additional stringer and frame loads. Solid and finite-element modeling is so prevalent in today's industry that computers are important even to the first stage of die design. Still, we must not substitute computers for a thorough knowledge of the various modes of failure and the limits of our assumptions.

Cylinder geometry is key in both the monocoque and skin-stringer examples. We cube the length in the equation for bending rigidity, and use the radius prominently in calculating stability. Table 11-63 illustrates the effects of making the cylinder shorter and wider. Note that the resized cylinder has the same internal volume as the original case, so we must verify that the launch vehicle's shroud can handle the new size.

TABLE 11 -63. Cylinder Sizing Summary.

Geometry (m)



Skint (cm)

Stringer A (cm2)

Mass (kg)

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