Deformation numerical simulation of titanium diaphragm for spacecraft tank

A 3D numerical model for describing the deformation process of a titanium diaphragm is established according to the elastic-plasticity and large displacement nonlinear finite element method (FEM). The graduated thickness and anto-cracking process are realized by compiling two subroutines into the FEA software. The failure behaviors of hemispherical titanium diaphragm in deformation process such as drape, eccentricity, and fracture were simulated appropriately in the present work. According to the model, the deformation process of titanium diaphragm with 0.75 mm thickness and 0.55~0.8 mm thickness are simulated respectively. Subsequently, the deformation regulation and failure behaviors are analyzed based on the simulation results. The research shows that the drapes could be easily produced in the deformation process for the diaphragm with uniform thickness However, the diaphragm with graduated thickness has better inversion capability because it could suppress the production of drapes. The major defect of deformation for graduated thickness diaphragm is eccentricity. The experimental results show that the present model predicts the deformation process and failure modes accurately, and provides the reference for thickness optimizing.