薄膜褶皱影响因素的试验研究及数值分析

发布时间：2018-06-28 06:06

本文选题：薄膜结构 + 褶皱构形　；参考：《北京交通大学》2017年硕士论文

【摘要】：薄膜以其轻质、折叠体积小以及良好的力学性能等特点,广泛应用于建筑结构领域和航空航天领域。薄膜因其厚度薄、抗弯刚度小,当外载荷产生的压应力超过临界压应力时,就会出现局部屈曲现象而形成褶皱。褶皱的出现不仅会影响薄膜结构的表面精度,还会改变结构的应力分布状态,进而影响结构的静力和动力特性。研究褶皱的影响因素及其影响机理,有利于对薄膜褶皱变形进行准确预测,有效的控制或消除褶皱变形,具有重要的意义。而已有文献尚未系统研究预张力、厚度、材料属性(泊松比和弹性模量)对薄膜褶皱变形特征的影响。本文通过受剪矩形薄膜和对角受拉方形薄膜的试验及有限元研究,系统分析了边界条件、预张力、厚度、材料属性等因素,对薄膜褶皱变形特征的影响规律,具体研究工作如下:a.设计研发了矩形薄膜受剪和方形薄膜对角受拉的试验加载装置,并借助激光位移传感测量技术系统研究了边界条件、预张位移、厚度对矩形薄膜以及边界条件、厚度对方形薄膜褶皱变形特征的影响。b.基于板壳稳定理论,采用商用有限元软件ANSYS的LS-DYNA显式算法模块,对矩形薄膜和方形薄膜褶皱进行数值分析,并将有限元结果与相应的试验结果进行对比分析,验证了本文建立的有限元模型的有效性。c.采用通过正确性和精确性验证的有限元模型,系统研究了边界条件、预张位移、厚度、泊松比和弹性模量等因素对矩形薄膜褶皱变形特征的影响,以及边界条件、厚度、泊松比和弹性模量对方形薄膜的褶皱构形的影响,并阐述了这些影响因素对薄膜褶皱变形特征的影响机理。研究结果标明:边界条件、预张力、厚度以及弹性模量对褶皱构形的影响较大,泊松比对褶皱构形的影响较小。
[Abstract]:The thin film is widely used in the field of building structure and aerospace because of its light weight, small folding volume and good mechanical properties. Because of its thin thickness and low flexural stiffness, when the compressive stress caused by external load exceeds the critical compressive stress, the local buckling will occur. The appearance of fold will not only affect the surface accuracy of the thin film structure, but also change the stress distribution of the structure, and then affect the static and dynamic characteristics of the structure. It is of great significance to study the influencing factors and the influencing mechanism of folding, which is helpful to accurately predict the deformation of thin film folds and effectively control or eliminate the deformation of folds. However, the influence of pretension, thickness and material properties (Poisson's ratio and elastic modulus) on the characteristics of film folding and deformation has not been systematically studied. In this paper, the effects of boundary conditions, pretension, thickness and material properties on the wrinkle and deformation characteristics of the thin films are systematically analyzed by means of the experiments and finite element studies on the shear rectangular and diagonal tension square films. The specific research work is as follows: A. The experimental loading device of rectangular film shear and square film diagonal tension is designed and developed. The boundary condition, pretension displacement, thickness to rectangular film and boundary condition are systematically studied by laser displacement sensing technique. The effect of thickness on the deformation characteristics of square thin films. Based on the theory of plate and shell stability, the LS-DYNA explicit algorithm module of commercial finite element software ANSYS is used to numerically analyze the rectangular and square thin film folds, and the finite element results are compared with the corresponding experimental results. The validity of the finite element model established in this paper. The effects of boundary conditions, pretension displacement, thickness, Poisson's ratio and elastic modulus on the folding and deformation characteristics of rectangular thin films are systematically studied by using the finite element model verified by correctness and accuracy, as well as the boundary conditions and thickness. The influence of Poisson's ratio and elastic modulus on the fold configuration of square thin film is discussed. The results show that the boundary conditions, pretension, thickness and elastic modulus have great influence on the fold configuration, while Poisson's ratio has little effect on the fold configuration.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU38

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