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Development of technology for fluid-structure interaction modeling of a 1/8-scale dynamic model of shuttle External Tank (ET). Volume i: Technical reportA NASTRAN analysis of the external tank (ET) substructure of the 1/8-scale space shuttle structural dynamics model is described. The NASTRAN hydroelastic procedures were used to form a model of the liquid oxygen portion of the ET. Large computer storage requirements and running times were required unless these procedures were modified. Several possibilities were demonstrated including the substitution of the real for the complex eigenvalue routine and the use of the OMIT capability to reduce the number of fluid coordinates. A NASTRAN model of the complete ET was formed and reduced to 252 degrees of freedom. A review of the eigenvector extracted, using the unsymmetrical inverse power method, indicated that the structural OMIT's resulted in unsatisfactory modal deflections. Modifications to the NASTRAN hydroelastic capability appeared necessary to generate a successful ET model. An approach is described which, by assuming incompressibility, reduces the fluid representation to a symmetric mass matrix which can be added to the structural mass. The problem is solved using faster and more efficient eigenvalue routines. Using this approach the ET NASTRAN model was analyzed for three separate weight conditions.
Document ID
19750013287
Document Type
Contractor Report (CR)
Authors
Bernstein, M.
(Grumman Aerospace Corp. Bethpage, NY, United States)
Coppolino, R.
(Grumman Aerospace Corp. Bethpage, NY, United States)
Zalesak, J.
(Grumman Aerospace Corp. Bethpage, NY, United States)
Mason, P. W.
(Grumman Aerospace Corp. Bethpage, NY, United States)
Date Acquired
September 3, 2013
Publication Date
August 1, 1974
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
NASA-CR-132549-1
Funding Number(s)
CONTRACT_GRANT: NAS1-10635
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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