NONLINEAR OSCILLATIONS OF ELASTIC PANELS IN A SUPERSONIC NONVISCOUS AIRSTREAM.
Abstract
A variational analysis is presented for the problem of a panel under the influence of both random excitation (turbulent boundary layer) and aerodynamic loading. Geometric nonlinear effects in the panel are taken into account, and a (Rayleigh-Ritz) modal approximation is used to represent the spatial variation of the displacements. The supercritical (beyond linear flutter boundaries) limit-cycle amplitude and frequency are determined by assuming a Fourier-series representation for the modal amplitudes, thereby reducing the problem to solving a set of nonlinear algebraic equations. The aerodynamic loads resulting from the panel deformation are approximated by linear piston theory. Random excitation in the form of a pressure with known spatial and temporal correlations is then introduced. The forced response is calculated with the aid of Fourier-transform techniques and a method of equivalent linearization at flow conditions below and above the stability boundary for classical panel flutter. The effect of random excitation on the supercritical response is reduced to a study of coupled nonhomogeneous Mathieu equations. The solution of these equations is determined approximately using the digital computer. The determination of the amplitude of response and the frequency of oscillation provides the necessary information for a fatigue analysis. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1968
- Accession Number
- AD0676682
Entities
People
- Franklin E. Eastep
Organizations
- Stanford University