各向异性硬质薄膜/柔软基底系统的表面屈曲分析

Analysis on Surface Buckling of Anisotropic Stiff Film/Soft Substrate System

目的研究有限尺寸矩形正交各向异性薄膜/基底系统在单向压缩下的表面屈曲。方法采用Kirchhoff-Love薄板理论和von Kármán板理论分析了临界应变和后屈曲形貌演化,考察了材料的各向异性性质及薄膜的几何参数对表面屈曲行为的影响。结果一般来说,薄膜/基底系统的初始屈曲总是对应于多个波峰,在薄膜长度相同的条件下,薄膜宽度的改变可以影响波峰的数目。在薄膜的各向异性性质特别强烈的时候,薄膜/基底结构表现出一些显著的特点。其中之一是在外加应变超过临界应变之后,边缘幅值随着薄膜宽度的增大而增大,而中心幅值则急剧减小。结论中心和边缘幅值的差距越来越大,最终导致薄膜后屈曲形貌幅值在宽度方向上的巨大差异,并预示随着外加应变的逐渐增大,宽度方向可能演变出其他的屈曲模式。

The work aims to study the surface buckling of rectangular orthotropic anisotropic film/substrate system with finite length and width under unidirectional compression.The critical strain and the evolution of post-buckling morphology were analyzed by Kirchhoff-Love thin plate theory and von Kármán plate theory,and the anisotropic properties of materials and the influence of geometric parameters of thin films on surface buckling were investigated.Generally speaking,the initial buckling of the film/substrate system always happened with multiple wrinkles.Previous research demonstrated that the number of wrinkles varied with be change of the film width under the same film length.When the anisotropy of the film was very strong,the film/substrate structure showed some remarkable characteristics.One of them was that the edge amplitude increased with the rise of the film width after the applied strain exceeded the critical buckling strain,while the center amplitude decreased sharply.This phenomenon makes the difference between the edge amplitude and center amplitude larger and larger,ultimately leading to sharp change of post-buckling morphology in the width direction and indicates that other buckling pattern may appear in the width direction with the increase of the applied strain.