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Accession Number N20120014456
Title Stability Analysis of Intertank Formed Skin/Stringer Compression Panel with Simulated Damage.
Publication Date Apr 2012
Media Count 7p
Personal Author D. W. Harper R. J. Wingate
Abstract The External Tank (ET) is a component of the Space Shuttle launch vehicle that contains fuel and oxidizer. During launch, the ET supplies the space shuttle main engines with liquid hydrogen and liquid oxygen. In addition to supplying fuel and oxidizer, it is the backbone structural component of the Space Shuttle. It is comprised of a liquid hydrogen (LH2) tank and a liquid oxygen (LOX) tank, which are separated by an Intertank. The Intertank is a stringer-stiffened cylindrical structure with hat-section stringers that are roll formed from aluminum-lithium alloy Al-2090. Cracks in the Intertank stringers of the STS-133 ET were noticed after a November 5, 2010 launch attempt. The cracks were approximately nine inches long and occurred on the forward end of the Intertank (near the LOX tank), along the fastener line, and were believed to have occurred while loading the ET with the cryogenic propellants. These cracks generated questions about the structural integrity of the Intertank. In order to determine the structural capability of the Intertank with varying degrees of damage, a finite element model (FEM) simulating a 1995 compression panel test was analyzed and correlated to test data. Varying degrees of damage were simulated in the FEM, and non-linear stability analyses were performed. The high degree of similarity between the compression panel and the Intertank provided confidence that the ET Intertank would have similar capabilities.
Keywords Compression tests
Cryogenic rocket propellants
External tanks
Finite element method
Liquid oxygen
Mathematical models
Space shuttles
Structural failure

Source Agency National Aeronautics and Space Administration
NTIS Subject Category 84 - Space Technology
Corporate Author National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.
Document Type Conference proceedings
Title Note N/A
NTIS Issue Number 1307
Contract Number NNM07AB03C

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