Large deployable space membrane structures are developing in recent years as Gossamer spacecraft for solar sail and sun shield, and etc. To design the deployable membrane structures, the mechanical properties of the structures are significant to examine the deployment configuration, vibrational and dynamic properties of the membrane structures. However, the initial deformation on the membrane due to the folding line and wrinkle with plastic deformation is not negligible for evaluating the mechanical properties because it is very large with respect to the membrane thickness. This paper investigates the effects of relatively large initial deformation on the vibration properties of large membrane numerically and experimentally under the assumption that the initial deformations are random that has a band range of wavelength as the deformation observed in the solar sail "IKAROS". At first the double corrugated deformation model is theoretically examined under the sinusoidal initial deformations for vibration properties. Then, FEM analyses are performed for the corrugated membrane to examine the effects of amplitude of initial deformation and wavelength on the properties of modal vibration using the FEM model for membrane model consists of 20m x 20m square membrane with thickness, t=0.1mm, and with simply supported or free boundary condition. In the numerical analyses, the normal random distribution is assumed. The effects of random initial deformation of deployable membrane on vibration properties are obtained. Finally, it is found that the vibration properties of large deployable membranes are quite sensitive for the relatively large initial deformation.
展开▼
机译：近年来，随着Gossamer航天器用于太阳帆和遮阳板等，正在开发大型可展开空间膜结构。要设计可展开膜结构，结构的机械性能对于检查其的展开构型，振动和动态特性具有重要意义。膜结构。然而，由于折叠线引起的膜上的初始变形以及具有塑性变形的褶皱对于评估机械性能而言是不可忽略的，因为相对于膜厚度而言，膜的初始变形非常大。本文假设在太阳帆“ IKAROS”中观察到的初始变形是随机的，具有一个波长带范围的假设下，通过数值和实验研究了相对较大的初始变形对大膜振动特性的影响。首先，理论上在正弦形初始变形下检查双波纹变形模型的振动特性。然后，对瓦楞膜进行有限元分析，以检查初始变形幅度和波长对模态振动特性的影响，方法是使用厚度为t = 0.1mm的20m x 20m方形膜组成的膜模型的FEM模型。具有简单支持的边界条件或自由边界条件。在数值分析中，假定正态随机分布。获得了可展开膜的随机初始变形对振动特性的影响。最后，发现较大的可展开膜的振动特性对于较大的初始变形非常敏感。
展开▼
