A direct analysis approach for ejection problem of the independent escape capsule

A direct analysis approach is adopted to handle ejection problem of the independent escape capsule from submarine in still water. Motion characteristics of the capsule and the gap between the capsule and submarine for successful escape are obtained. Ejection process is mainly divided into the translational and coupling motion phases according to forces (including the hydrostatic and hydrodynamic) on the capsule and its corresponding motions. The capsule's coupling motion is solved by using the concept of contact pairs in ABAQUS, and the hydrodynamic force on the capsule is calculated with the commercial computational fluid dynamics (CFD) package Fluent and introduced into numerical model through ABAQUS/AQUA module. The numerical simulation shows that the gap is much smaller than the results obtained by the assumption that the capsule rotates around a fixed supported edge, which indicates that coupling motion is critical to the successful escape of the capsule. The hydrodynamic force prolongs the escaping time and affects the value of the gap and the motion characteristics in both translational and coupling motion phases. In addition, time and the gap are chosen as standard, under which several design parameters are investigated in order to provide suggestions for optimal design of the capsule.