Studys On Tension And Buckling Instability Mechanics Of Kirigami Structure

The kirigami structure has attracted much attention due to the platform integration,widely tunable elasticity,significant deformation and rich geometric topology.Unfortunately,little work has been done on the problem of the design of curved kirigami structures that can significantly improve the in-plane tensile properties.It appears that there has been only limited research into the buckling instability of kirigami structures in tension.The problems regarding design paradigms of flexibility,stretchability,compressibility and functionality are far from being solved.In addition,the scaling correlation of the instability behavior for graphene kirigami structures needs to be further investigated.This paper focuses on the mechanical behaviors of buckling instability in kirigami structures.We focus on the kirigami structure and its buckling instability mechanics.We first analyze the in-plane tensile mechanical properties of curved kirigami structures.And then,we analyze the buckling mechanical properties of kirigami structures in tension.Next,we investigate buckling,tension and compression properties for the strain-limiting kirigami structures.Finally,we reveal the buckling instability behaviors with regard to graphene kirigami structures.The detailed demonstrations can be given as following:The in-plane mechanical properties of curved kirigami structures can be investigated firstly.The design principle regarding curved kirigami structures can be introduced.Based on thessa large-curvature curved beam(LCCB)theory,the corresponding mechanical model can be established and the close-form solutions can be obtained.Based on the numerical simulations,elasticity theory and the theory without curvature effects,the systematic and comparative analysis of proposed LLCB theory model can be performed.And then,effects of various geometry parameters on large curvature,stiffness,and stretchability can be obtained.Based on the 3D printing technology and tensile experiments,the predictions can be validated using prepared curved kirigami structures.Finally,the optimization for stretchability enhancement of curved kirigami structures is provided.The buckling instability behavior for two dimensional(2D)kirigami structures in tension is investigated.The sinusoidal beam model can be used to describe the asymmetric deformation of kirigami structure.While,the complex deformation with regard to symmetric buckling pattern for kirigami structure can be characterized using the sinusoidal beam model and opposite bending shell.Based on the energy principle and LCCB theory,the normalized flexibility,critical buckling strain can be obtained.Based on the numerical simulation,the phase diagrams of buckling kirigami structures regarding different buckling patterns can be established.Based on the scaling law and critical force,the stretchability,maximum strain,critical buckling mechanism,and postbuckling deformation response can be investigated,reflecting the accuracy of proposed mechanical model.Finally,the mechanical programmability and energy harvesting of 2D kirigami structure with the stable electomechanical convention efficiency can be demonstrated.The buckling instability,tension and compression properties of strain-limiting kirigami structure can be investigated.The design principle and preparation method for the strain-limiting kirigami structure with high flexibility,stretchability,compressibility and functionality can be proposed.Based on the plane-strain composite beam and large-curvature curved beam theory,we establish the mechanical models with respect to flexibility of strain-limiting kirigami structures.When we neglect the large curvature effects,the obtained analytical solution can be used to characterize the importance of curvature.Based on finite deformation theory and finite thickness effect,the critical conditions regarding the surface wrinkling for semiinfinite substrate with small deformation,semi-infinite substrate with large deformation,and finite substrate with finite deformation can be investigated.Global bending and local wrinkling of strain-limiting kirigami structures can be demonstrated using de-bending,de-wrinkle,and de-prestrain effects.The close-form solutions regarding stretchability can be provided.Based on the peak strain of thin film and stability analysis,the mechanical model of compressibility for strainlimiting kirigami structures can be established.Using the numerical simulations and experiments,we demonstrate the evolutions of global bending and local wrinkling for strain-limiting kirigami structures.Based on the Fourier inversion technology and optical microscope,the surface evolution pattern for strain-limiting kirigami structure can be carried out.Through the design of functional membrane structure,the strainlimiting kirigami can light up the LED stably.Simultaneously,the strain-limiting kirigami can realize the high flexibility,stretchability and compressibility.Effects of various dimensionless geometries on flexibility,stretchability and compressibility for strain-limiting kirigami structures are investigated using the theoretical model.The buckling instability behaviors regarding Cut type and Cut-Join type graphene kirigami structures can be investigated.Firstly,using molecular dynamics simulation,the post-buckling behaviors regarding in-plane shrinking and out-of-plane expansion for Cut type graphene kirigami can be investigated.Based on the tension experiments of kirigami structure,the scaling correlation for Cut type graphene kirigami can be revealed.Next,using the hybrid potential functions in molecular dynamics,the buckling instability behavior for Cut type graphene kirigami in nanocomposite can be demonstrated.The modulus,strength,and toughness of Cut type graphene kirigami in nanocomposite can be obtained from the stress-strain curves.The significant enhancement for strength and toughness of the silicon-based composite can be realized using the buckling instability of Cut type graphene kirigami structures.Finally,based on the Burgers vector and two-dimensional dislocation theory,the lattice mismatch,out-of-plane deformation,and stress field for building block of Cut-Join type graphene kirigami structure can be demonstrated.And then,the array of Cut-Join type graphene kirigami structure is established using design principles,i.e.,positive Gaussian curvature,cancellation of two Burgers vectors,and anisotropy principles.Using molecular dynamics simulations,the instability evolution of Cut-Join type graphene kirigami array can be studied.The phase diagram and energy mechanism can identify the four evolutional patterns with regard to nanoscroll,nanotube,breathing oscillation,and damping oscillation.