Schematic of the joint in the payload shroud that buckled during a test

This is a schematic of one of the axisymmetric joints (the field joint at Station 468) in the segmented payload shroud and the mode in which it failed during a test. The shroud and loading are shown in the previous three slides.

The axial stiffeners are external "hats" (corrugations), cut down locally in order to give access to the joint at Station 468. The failure was caused by local non-axisymmetric buckling at the joint in a mode shown here on the right and in the next slide.

Buckling occurs partly because the compressive axial load path makes a local inward axisymmetric “dimple” in the neighborhood of the joint where the external corrugations are cut down. This inward "dimple" gives rise to combined axial compression and local hoop (circumferential) compression in the neighborhood of the joint at Station 468.

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