Aeroelastic stability characteristics of cylindrical shells considering imperfections and edge constraint.

Abstract

Abstract : Recent wind tunnel results indicate that the existing cylindrical shell aeroelastic stability theories are generally nonconservative. Therefore, some type of destabilizing mechanism is needed in the present theory to enhance correlation with experiment. In the paper, the dynamic stability behavior of thin circular cylindrical shells subjected to a supersonic flow field is investigated theoretically and compared with existing experimental data. Combined effects of axisymmetric initial geometric imperfections, radial edge constraint, and prestability deformations are considered. The cylinder's motion is described with nonlinear Donnell type shell equations coupled with a linear 'piston theory' aerodynamic approximation. A modal type approach employing Galerkin's approximate technique is used to investigate the dynamic stability about the shell's deformed middle surface. Prestability deformations alone have been shown to have very little influence on the aeroelastic stability behavior of very thin shells. However, with the inclusion of initial imperfections, the combined effect is destabilizing. The resulting aeroelastic stability boundaries correlate quite well with existing experimental data. (Author)