Summary of Research Accomplishments for the Period 1 December 1966 to 30 November 1970.
TEXAS UNIV AUSTIN DEPT OF AEROSPACE ENGINEERING AND ENGINEERING MECHANICS
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A combined theoretical and experimental research program has been carried out over the past four years to establish preliminary design criteria for estimating the aeroelastic stability and forced-response characteristics of thin-walled circular cylindrical shell structures. As a result of this study, several basic observations were made concerning the degree of sophistication required in the aerodynamic and structural modeling of this aeroelastic problem. It was found, for example, that small details in the description of the structural boundary conditions can strongly influence the aeroelastic stability of the shell. The most significant structural boundary condition effect was observed when the shell geometry and loading conditions were such that the edge disturbances were propagated well into the interior of the shell. On the other hand, when conditions were such that these edge disturbances were confined to a small boundary layer region near the ends of the shell no significant edge effects were noticed on the overall shell aeroelastic stability. Small initial deviations of the shells surface from its idealized shape were also shown to drastically reduce its resistance to panel flutter even though the deviations were only on the order of one shell thickness. Panel flutter instabilities in the presence of a laminar boundary layer profile were also found to be much less destructive to the shell than those originating in the presence of a turbulent profile. Author
- Research and Experimental Aircraft
- Fluid Mechanics