柔性飞艇主气囊不稳定构型阶段力学性能分析

为了揭示柔性飞艇主气囊不稳定构型阶段的力学性能,首先基于迭代薄膜性能法(IMP)编制可分析薄膜褶皱的子程序,通过对比不同单元类型充气管变形结果,找出一种合理的单元类型进行不稳定构型主气囊模拟.在此基础上,以9m柔性飞艇主气囊简化模型为对象,对简化模型在不同约束状态下不稳定构型阶段外形及应力进行分析.研究表明:气压梯度和模型约束是柔性飞艇主气囊在不稳定构型阶段力学性能的重要影响因素,模型从稳定构型到不稳定构型阶段开始的一段时间,形状变化不大,中间阶段模型发生较大的形状改变.不稳定构型阶段在约束部位较稳定构型时更容易发生强度破坏.研究结果对柔性平流层飞艇主气囊结构设计具有参考价值.

Mechanical Characteristic Analysis of Flexible Airship Envelop at Unstable Configuration Stage

Abstract： In order to reveal the mechanical characteristics of non rigid airship at the unstable configuration stage, ABAQUS’s user material subroutine based on the iterative membrane properties (IMP) method was proposed. A rational membrane element which was used to simulate the mechanical characteristic of the flexible airship envelop at the unstable configuration stage was chosen by comparing the model results of the engineering elastic beam theory, membrane wrinkling theory and the corresponding experiment. The shape and stress of a 9 meter simplified models of the flexible airship envelop under different constraint conditions was discussed by using the explicit contact nonlinear finite element method.The net buoyant density and boundary conditions are the key factors influencing the mechanical characteristic of the flexible airship envelop at the unstable configuration stage. The non rigid airship envelop shape varies smoothly at the initial steady state and sharply in the middle of the invariable configuration stage.In addition, the constraint parts of non rigid airship envelops are more likely to cause strength failure in the invariable configuration phase than in the stable phase.The method proposed is valuable in disclosing the mechanical characteristics of non rigid airship envelop at the invariable configuration stage.