飞艇充气囊体变形规律的探究

发布时间：2018-05-17 11:54

本文选题：充气膜结构 + 大曲率大体积柔性特性　；参考：《上海交通大学》2015年硕士论文

【摘要】：在平流层飞艇平台这一大曲率大体积柔性充气膜结构的研究中,充气膜结构的整体和局部变形分析是膜结构结构分析的重要内容之一,因为结构囊体的整体和局部变形分析不仅有助于指导囊体结构的制造,而且有利于能源系统、推进系统等外部搭载系统设备的安装,同时,在获知外部环境后,通过囊体变形能预测飞艇工作寿命。因此,探究飞艇充气囊体变形规律对于平流层飞艇的成功研制有重大的现实意义。本文选用飞艇囊体外形为一种典型的三叶玫瑰线形,以经典力学理论和商用有限元软件为两大工具,使用控制变量的方法,对影响飞艇囊体变形的四个抗力指标和三个荷载效应指标进行了探究。首先,使用经典力学理论对飞艇进行了静力学分析,确定了囊体内外压差的范围,推导了囊体应力、应变计算公式,并验证了铁木辛柯梁理论在分析充气膜结构中的正确性。其次,从飞艇囊体的大曲率大体积柔性的特点出发,结合有限单元法的基本原理,提出了解决该类问题的一般方法。由于飞艇头锥、尾锥曲率较大,数值计算时网格难以划分,即使是模型正确、网格质量优良,在计算过程中也可能出现不收敛的情况,本文针对这种情况提出了具体的解决措施;由于飞艇是悬浮在空气中的,如何确定其边界条件是其静力计算中的关键问题之一,目前针对该问题的解决方法有两种,其一是采用惯性释放技术,其二是在适当的点施加约束,本文对两种方法做了详细的分析对比,并指出了各自的应用范围。最后,利用大曲率大体积柔性充气结构的有限元方法,对材料弹性模量、泊松比、结构囊体长度、结构长细比这四个影响囊体变形的抗力指标分别作了数值计算,通过分析得出一般规律;对囊体内外压差、重力荷载、吊挂荷载这三个影响囊体变形的荷载效应指标做了数值计算,通过分析得出一般规律。
[Abstract]:In the study of stratospheric airship platform which is a flexible inflatable membrane structure with large curvature and large volume, the integral and local deformation analysis of inflatable membrane structure is one of the important contents of membrane structure analysis. Because the whole and local deformation analysis of structural thylakoids is not only helpful to guide the manufacture of thylakoid structures, but also conducive to the installation of external system equipment such as energy systems, propulsion systems, and so on. At the same time, after learning about the external environment, The working life of airship can be predicted by thylakoid deformation. Therefore, it is of great practical significance for the successful development of stratospheric airship to investigate the deformation law of airship filling airbag. In this paper, the airship thylakoid is chosen as a typical three-leaf rose shape. The classical mechanics theory and commercial finite element software are used as two tools, and the method of controlling variables is used. Four indexes of resistance and three indexes of load effect affecting the deformation of airship thylakoid were studied. Firstly, the static analysis of airship is carried out by using classical mechanics theory, the range of pressure difference in and out of capsule is determined, the calculation formula of stress and strain of capsule body is deduced, and the correctness of Temocco beam theory in the analysis of inflatable membrane structure is verified. Secondly, based on the characteristics of the large curvature and large volume flexibility of the airship thylakoid, combined with the basic principle of the finite element method, a general method to solve this kind of problem is put forward. Because of the large curvature of the head cone and the tail cone of the airship, it is difficult to divide the mesh in the numerical calculation. Even if the model is correct and the mesh quality is good, it may not converge in the calculation process. As the airship is suspended in the air, how to determine its boundary conditions is one of the key problems in static calculation. One is to use inertial release technology, the other is to impose constraints at appropriate points. In this paper, the two methods are analyzed and compared in detail, and their respective application fields are pointed out. Finally, by using the finite element method of flexible inflatable structure with large curvature and large volume, the resistance indexes of material elastic modulus, Poisson's ratio, structure thylake-length and structure aspect ratio to thylakoid deformation are calculated numerically respectively. Through the analysis, the general law is obtained, and the three indexes of load effect which affect the deformation of the capsule are calculated, such as the pressure difference inside and outside the capsule, the gravity load and the hanging load, and the general law is obtained through the analysis.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V274;V215

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