Analysis On Surface Buckling Of A Stiff Anisotropic Film/Soft Substrate System

This study is mainly concerned with the surface buckling of a rectangular orthotropic thin film/substrate system with finite length and width under unidirectional compression.The critical strain and the evolution of buckling morphology are analyzed by using 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 are investigated.Generally speaking,the initial buckling of the film/substrate system always corresponds with multiple wrinkles.Previous research demonstrates that the number of wrinkles varies with the width of the film when the length of it keeps the same.When the anisotropy of the film is very strong,the film/substrate structure shows some remarkable characteristics.One of them is that the edge amplitude increases with the increase of the width of the film after the applied strain exceeds the critical buckling strain,while the center amplitude decreases sharply.This phenomenon continues,making the difference between the edge amplitude and center amplitude larger and larger,ultimately leading to sharp change of buckling morphology in the width direction.It indicates that other buckling pattern may appear in the width direction with the increase of the applied strain.In addition,this paper also analyzes the post-buckling behavior of the hard film/soft substrate structure,obtaining some progress in the wrinkle mode of double-period,which lays a theoretical foundation for further research.In the final part of this paper,Abaqus simulation verification is used to compare the simulation results of the previous buckling modes with the theoretical conclusions.They are in good agreement in the aspects of both critical strain and buckling morphology.