Design and Analysis of Orthotrophic Ring-Stiffened Cylindrical Shells Subjected to External Hydrostatic Pressure

Three theories are presented for the analysis of ring-stiffened or monocoque cylindrical shells under hydrostatic pressure. The theories compute the stress state and the axisymmetric collapse, interbay buckling, and general instability pressures from external hydrostatic pressure loading. The theories were derived for the case of specially orthotropic material with theoretically uniform properties through the thickness; the theories apply equally to shells made of isotropic materials. A computer program, DAPS4 (Design and Analysis of Plastic Shells, Version 4), was written that incorporates these theories that can be used as an initial sizing tool or analysis of a shell's hydrostatic pressure capability. The program includes a pseudo-plastic method to account for the reduction of computed collapse pressures when the stress state is above the proportional limit of the material's stress-strain curve. The purpose of this report is to document the theories and the code. Correlation with numerous pressure tests is shown. A user manual with example problems is included. The original document contains color images.