FLUTTER AND VIBRATION ANALYSIS BY A COLLOCATION METHOD: ANALYTICAL DEVELOPMENT AND COMPUTATIONAL PROCEDURE

• Main Authors: Rodden,William P, Farkas,Edith F, Malcom,Heather A
• Format: Report
• Language: English
• Subjects: AERODYNAMIC CONFIGURATIONS; DAMPING; DATA PROCESSING; DIGITAL COMPUTERS; FLEXIBLE COUPLINGS; FLUTTER; MATRICES(MATHEMATICS); STRUCTURES; VELOCITY; VIBRATION

A collocation solution of the flutter and vibra tion problems for a multiple component system is pres The formulation utilizes structural, aerodynamic, and inertial characteristics in the form of matrices of structural and aerodynamic influence coefficients and a mass matrix, respec tively, for each component. The use of a rigid body modal matrix permits a general analysis for a system free in space with up to six rigid-body degrees of freedom. The solution also utilizes a newly developed subroutine for finding the eigenvalues and eigenvectors of a non-Hermitian matrix having close roots, and obtains the cor responding values of frequency, required struc tural damping, and velocity of the flutter system. The Aerospace IBM 7090 Computer Program No. LD005A provides the flutter or vibration solution for a system composed of as many as 20 flexible components with a maximum total of 49 collocation control points. An option is provided to vary the density as well as the reduced velocity. Another option is provided to yield the modes from a vibration analysis in a punched-card for mat for use in flutter analysis by modal methods. (Author)