Time Domain Method for Nonlinear Flutter of Curved Panels Under Yawed Supersonic Flow at Elevated Temperature

Abstract

There are a large number of papers dedicated towards investigation of flutter analysis of flat plates in supersonic flow regime, but very few papers address the problem of flutter of curved panels. Furthermore, many of the panel flutter investigations that include thermal effects have de alt with flat plates. Very scarce literature exists about flutter of curved panels wi th thermal effects. Hence, the objective of this paper is to develop, for the firs t time in the literature, a consistent finite element formulation and an efficient solutio n procedure to investigate nonlinear flutter of curved panels at yawed superso nic flow and at elevated temperature. A finite element time domain method is developed and presented to predict the pre/post-flutter behavior of curved pan els. The Marguerre plate theory, the von Karman large deflection theory, the quasi-s teady first-order piston theory and Quasi-static thermoelasticity are used in the f ormulation. The principle of virtual work is applied to develop the equations of motion of the fluttering system in structural degrees of freedom. These system equati ons of motion are transformed into modal coordinates, and solved by a fourth-orde r Runge-Kutta numerical scheme. Time history responses, phase plots, power spectrum density plots, and bifurcation diagram are used for better understanding of the pre/post flutter responses of cylindrical panels of different height -rises under increasing dynamic pressure and uniform or linearly varying Static The rmo-Aerodynamic Loading (STAL). The results demonstrated that the flutter d ynamic behavior, characterized by a motion map, moved directly to chaos skipping the limit cycle oscillations region, thus proving that the flutter dynamic behav iors alter significantly when temperature effects come into the picture.