Abstract
To bridge the gap between the theoretical and experimental buckling pressures of perfect spherical shells subjected to external pressure, extensive experiments have been carried out in the course of the authors' research to make the characteristics of the buckling of shells clear. In the present paper, the outline of experiments is described first and then the buckling pressure is discussed in detail. Specimens, prepared by paying special attentions to the fabrication of perfect shells and to the realization of the ideal clamped edge condition, have been loaded pneumatically. The applied pressure and the resulting distributions of deflection and strain in shells have been recorded continuously up to the critical pressure. The buckling pressures measured are close to the classical value, and some questions about the nonlinear analyses reported so far are presented. The deformation pattern and strain distribution up to and at the critical pressure will be reported in the proceeding papers.
