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Dynamic analysis of nonlinear rotor-housing systemsNonlinear analysis methods are developed which will enable the reliable prediction of the dynamic behavior of the space shuttle main engine (SSME) turbopumps in the presence of bearing clearances and other local nonlinearities. A computationally efficient convolution method, based on discretized Duhamel and transition matrix integral formulations, is developed for the transient analysis. In the formulation, the coupling forces due to the nonlinearities are treated as external forces acting on the coupled subsystems. Iteration is utilized to determine their magnitudes at each time increment. The method is applied to a nonlinear generic model of the high pressure oxygen turbopump (HPOTP). As compared to the fourth order Runge-Kutta numerical integration methods, the convolution approach proved to be more accurate and more highly efficient. For determining the nonlinear, steady-state periodic responses, an incremental harmonic balance method was also developed. The method was successfully used to determine dominantly harmonic and subharmonic responses fo the HPOTP generic model with bearing clearances. A reduction method similar to the impedance formulation utilized with linear systems is used to reduce the housing-rotor models to their coordinates at the bearing clearances. Recommendations are included for further development of the method, for extending the analysis to aperiodic and chaotic regimes and for conducting critical parameteric studies of the nonlinear response of the current SSME turbopumps.
Document ID
19890005078
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Noah, Sherif T. (Texas A&M Univ. College Station, TX, United States)
Date Acquired
September 5, 2013
Publication Date
October 1, 1988
Subject Category
Mechanical Engineering
Report/Patent Number
NASA-CR-183574
NAS 1.26:183574
Accession Number
89N14449
Funding Number(s)
CONTRACT_GRANT: NAS8-36293
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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