Buckling and vibration of externally pressurized conical shells withcontinuous and discontinuous rings

Abstract

External pressure buckling, free vibration, and external pressure-vibration interaction data were obtained on a sixth scale Lexan model of the Titan IV (prototype) nose cone fairing. The objectives of these experiments were to validate analytical models used in the prototype design and to provide experimental data on the effects of discontinuous circumferential rings, flexible ring-to-shell attachment, separation rails, and skin splices. In addition, a nondestructive buckling load predictive test technique based on natural frequencies was evaluated using the Lexan model. The advantage of a Lexan model is that it can be buckled without sustaining damage, thus allowing repeated buckling experiments to be performed. Correlation studies were carried out using NASTRAN finite element and BOSOR finite difference models. Buckling and frequency data showed good agreement between analysis and experiment. Pressure-vibration interaction data were obtained to investigate an experimental procedure for extrapolating the interaction curve to predict the critical buckling load. While it was found that extrapolation of these data always over predicted the buckling pressure, the data were used to develop a procedure that was successfully applied as stop-test criteria in the prototype test.