Strain Analysis In Thin Film Of Non-uniform Stretchable Electronics Based On Origami Design

The stretchable electronics is different from the traditional electronic device.It is a new and bendable electronics.Stretchable electronics is an electronic device system which is composed of stretchable film and extensible substrate.Stretchable electronics are widely used in many fields,such as aerospace,medical monitoring,intelligent robot,large-scale equipment monitoring,basic biology and so on.Therefore,it is of great significance to study the mechanism of stretchable electronics.The traditional stretchable electronic film adopts uniform thickness design,which limits the application scale of the stretchable device.With the in-depth research and development of origami technology,the thickness of stretchable electronic film based on origami design can be changed.The non-uniform thickness of the film can adjust the stretchable electronics profile during the bending and folding process,ensuring the diversified design of the stretchable electronics,and increasing the application scale of the stretchable electronics.Therefore,this article introduces non-uniform parameters to analyze non-uniform stretchable electronics based on origami design.The stretchable electronics film can either global-buckling or local-folding to assemble stretchable electronics systems.In this article,the global-buckling and local-folding theoretical model of non-uniform stretchable electronics based on origami design is proposed.When a moderate pre-strain is applied,the stretchable electronics film is in a global-buckling deformation state.The geometric assumption of the global-buckling deformation profile is assumed by the truncated Fourier series.Using the method of energy minimization,a concise expression of the deformation profile and maximum strain of the steady-state global-buckling film is analytically determined.When a sufficiently large pre-strain is applied,the stretchable electronics film is in a local-folding deformation state.This article divides the local-folding problem into two cases,namely no-pass and pass cases,and discusses the two cases separately.Considering the joint effect of non-uniform coefficient and van der Waals interactions,and using the method of energy minimization,the concise expressions of the steady-state deformation profile and maximum strain of the local-folding film are analytically determined.In order to verify the accuracy and effectiveness of the global-buckling and local-folding theoretical model,through finite element analysis and molecular dynamics simulation,the deformation profile and maximum strain of non-uniform global-buckling and local-folding stretchable electronics are obtained and compared with the analytical solutions respectively.The comparative results show that the above theoretical model can well predict the deformation profile and maximum strain,so as to effectively control the configuration of the stretchable electronics,and prevents the structural fracture and other failures during the global-buckling and local-folding process.In addition,a series of conclusions about global-buckling and local-folding of non-uniform thickness films can be degenerated to existing uniform thickness film designs under specified cases.In summary,the research in this article is expected to provide some guidance for the diversified design of stretchable electronics.