Supersonic Flutter of Circular Cylindrical Shells Subjected to Internal Pressure and Axial Compression

摘要

Results of recent experiments on the flutter of circular cylindrical shells in the Mach number range 2.5-3.5 are presented. Three shells with radius-to-thickness ratios of 2000 were subjected to radial external pressure loadings and to combinations of axial compressive loading and internal pressurization while in the presence of an external axiallydirected supersonic flow. Small amounts of internal pressurization were very stabilizing with respect to flutter, but moderate amounts reduced stability to the unpressurized level. However, high internal pressures completely stabilized the shells. The axial compressive loading was slightly destabilizing for moderate amounts of internal pressurization. There was no apparent danger of destruction of models even for the most violent flutter conditions which occurred just prior to buckling under radial external pressure loading and just after buckling under axial compressive loading. Buckled portions of a shell did not flutter. It appears that the large local curvatures encountered in the buckling of a cylindrical shell have a marked stabilizing effect on the shell locally. However, it also appears that the localized buckling usually encountered in practice significantly reduces the stability of any unbuckled regions of the shell. (Author)