拉伸作用下薄膜褶皱影响因素数值分析

Numerical Analysis of Wrinkles-Influencing Factors of Membrane Under Tensile Load

薄膜因其质轻、折叠体积小及力学性能良好等优点,在航空航天领域扮演着重要的角色。但薄膜属于柔性材料,由于其厚度小、抗弯刚度小,在外部载荷较大时极易出现局部屈曲现象,从而产生褶皱。褶皱是影响空间薄膜结构性能的重要因素之一,因此研究薄膜褶皱特性及其抑制方法对薄膜结构在航空航天等领域的应用至关重要。本文主要研究薄膜的结构参数及边界条件对薄膜褶皱特性的影响。针对拉伸作用下的方形薄膜结构,采用显式动力法对该结构进行了褶皱仿真分析,并将其仿真结果与理论计算结果进行对比,验证了仿真模型和分析结果的正确性。为了探究拉力作用下褶皱特性的变化规律,以方形薄膜为研究对象,分析了薄膜长宽比、内角、夹持宽度等结构参数和边索结构对褶皱特性及变形的影响规律。结果表明:当薄膜长宽比由1.0增加至1.5时,薄膜的面外变形增大,且褶皱分布区域扩大。当薄膜中内角小于75°时,褶皱主要分布于薄膜两边夹角为锐角的角区域。此外,增大薄膜夹持宽度和增加边索结构均可有效抑制褶皱的发生。为了进一步验证分析结果,进行了不同夹持宽度下的褶皱测试,通过褶皱数量和幅值变化的趋势分析,以及与仿真结果的对比,证明了仿真模型的正确性,为薄膜结构的张拉分析提供了一定的理论依据。

Thin film plays an important role in the field of aerospace because of its advantages of light weight,small folding volume and good mechanical properties.Thin film is a flexible material with characteristics of small thickness and bending stiffness.The local buckling phenomen-on of the thin film is easy to occur at large external loads,leading to undesirable wrinkles.Folding is one of the important factors affecting the structure and properties of spatial thin films.Therefore,it is crucial to study the characteristics of film folding and its inhibition for the application of film structure in the field of aerospace.In this paper,the effects of the structural parameters and boundary conditions on the fold characteristics of thin films are studied.Aiming at square membrane structure under tensile load,wrinkling simulation analysis of the structure is carried out by using the explicit dynamic method,and the simulation results are compared with the theoretical calculation results to verify the simulation model and analysis results.In order to explore the change law of wrinkles characteristics under tensile loads,we analyze how the wrinkles characterist-ics and deformation of square membrane are affected by the structural parameters including membrane aspect ratio,internal angle,clamping width,and side cable structure.The results show that the out-of-plane deformation of membrane increases and the wrinkle distribution area expands when the aspect ratio of membrane increases from 1.0 to 1.5.The wrinkles are mainly distributed in the corner area with an acute angle between two sides of membrane when the internal angle in the membrane is less than 75°.In addition,the occurrence of wrinkles can be effect-ively suppressed by increasing the clamping width of membrane and the side cable structure.To further verify the analysis results,fold tests un-der different clamping widths were carried out.The simulation model is validated by the trend analysis of the experimental results of fold number and amplitude as well as their comparison with the simulation results,which provides a certain theoretical basis for the tensile analysis of thin film structure.