Robust knockdown factors for the design of spherical shells under external pressure: Development and validation

摘要: Abstract In this paper a physically based and deterministic design procedure for spherical shells under external pressure is introduced. Within the new concept membrane energy of sphere incrementally reduced by means perturbation cutouts, until bending dominate state identified. The threshold between represents robust plateau buckling pressure. A comprehensive numerical investigation was performed in order to study influence radius-to-thickness ratio (R/t) as well dome height-to-base radius (H/r). results verify that both geometric properties ratios significantly lower-bound pressure, especially if plastic occurs. Improved shell factors are given form an simple analytic equation. corresponding KDFs were validated with large number experiments deliver much higher than currently used empirical guidelines. Based on criterion estimation tori-spherical bulkhead inner cryogenic upper stage ESC-A from European space launch-vehicle Ariane 5 determined.