A simplified analytical method is proposed to obtain eigenfrequencies and modes of a rocket with an asymmetric configuration. This method is an extension of the symmetric beam element matrix method and utilizes asymmetric beam elements. The purpose of this simplified analysis using a FORTRAN 77 program is to prepare an analytical tool for the preliminary design phase and a rough-check tool for detailed analysis. This program has three functions: (1) to generate stiffness and mass matrices for the asymmetric beam element using Timoshenko-type beam theory, (2) to calculate the dynamical matrix from which rigid body degrees of freedom are eliminated, and (3) to calculate eigenvalues and eigenvectors. A sample analysis of the structural vibrations in a hypothetical rocket with an asymmetric configuration is conducted to demonstrate the capability of this simplified method. The results obtained agree well with those obtained by MSC/NASTRAN analysis, and this proposed method greatly simplifies the preparation of a model. Based on these findings, the proposed method is judged to be an efficient tool for the analysis of structural vibrations in an asymmetric rocket.
Simplified method of analysis of structural vibrations of asymmetric rockets
Vereinfachte Analyse der Strukturschwingungen von asymmetrischen Raketen
1998
9 Seiten, 12 Bilder, 2 Tabellen, 17 Quellen
Article (Journal)
English
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