航天器贮箱用钛制隔膜变形过程的数值模拟

Deformation Numerical Simulation of Titanium Diaphragm for Spacecraft Tank

基于弹塑性大位移非线性有限元理论,建立航天器贮箱用钛制隔膜变形的有限元分析模型,并对有限元软件进行二次开发,首次通过编辑子程序实现了隔膜厚度的渐进变化及失效过程中隔膜的自动开裂,准确仿真出了隔膜在翻转变形过程中发生的褶皱、偏心与破裂等失效行为。依据此模型,分别对0.75mm等厚隔膜及0.55～0.8mm变厚隔膜的翻转过程进行了仿真,并对其翻转规律及失效机制进行了分析。研究发现,等厚隔膜在翻转过程中易产生褶皱,渐变壁厚隔膜翻转性能明显优于等厚隔膜,能克服褶皱的产生,但变厚隔膜在变形过程中易产生偏心。通过与试验对比表明,数值仿真能准确预测隔膜的变形规律与失效模式,为后续优化厚度分布提供了可靠的依据。

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.