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Theoretical Investigation And Numerical Simulation On The Interfacial Failure Of Graphene/Substrate Under Uniaxial Compression

Posted on:2018-01-11Degree:MasterType:Thesis
Country:ChinaCandidate:Z CuiFull Text:PDF
GTID:2321330542957060Subject:Solid mechanics
Abstract/Summary:PDF Full Text Request
Graphene/substrate structures have very broad application prospects in many fields,such as new micro-nano devices,nano-composite materials,and ultra-sensitive sensors.Due to the differences in material properties between the graphene and the substrate,interfacial sliding and buckling will occur in the processes,which make negative effects on the using performance and life of structures.Therefore,understanding the mechanism of interfacial failure is of great important for their design and application.In this dissertation,based on the continuum mechanics,the mechanical properties of interface and failure mechanism between graphene and substrate are investigated.By using shear-lag cohesive zone models,interfacial stress transfer of graphene on a substrate subjected to uniaxial compression is studied,and the critical strains for onset of sliding and debonding are predicted.In addition,the critical strain for onset of buckling is derived via the theory of continuum mechanics with the van der Waals(vdW)interaction between graphene and substrate surface taken into consideration.Then,the influences of interfacial adhesion energy and geometric sizes of graphene are discussed on the critical strains for the interfacial sliding and buckling.By the comparison of two critical failure strains of graphene,it is found that there exists a critical length of graphene.As the graphene length is smaller than it,there only exist interfacial sliding and debonding.Conversely,the compression will not only lead to interfacial sliding in edge area,but also cause buckling in middle area.Based on the theoretical analysis,finite element simulation is used to study the mechanical behavior of interfacial failure.The critical strains of sliding and buckling are calculated,and the effects of interfacial adhesion energy and geometric sizes on the interfacial failure are analyzed.What's more,the evolution from bonding to debonding of interface is simulated by finite element simulation.Finally,using the FE model,the influence of substrate on buckling is studied.The results of simulation show a good agreement with the theoretical results as well as the experiment results in corresponding literatures.
Keywords/Search Tags:Graphene, Interface failure, Sliding, Buckling, Adhesion energy
PDF Full Text Request
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