The mechanical properties of Miura-ori foldcore metamaterials were studied using finite element simulations.The responses of foldcores with various topological parameters to quasi-static out-of-plane compression and s...The mechanical properties of Miura-ori foldcore metamaterials were studied using finite element simulations.The responses of foldcores with various topological parameters to quasi-static out-of-plane compression and shear loading were analyzed using the relative density as a governing parameter.The non-unique relationships between the core density and the materials'strength in the examined loading directions were revealed,pointing out the strong influence of the Miura-ori topology.Linear relationships were established between the elastic moduli and relative densities of the Miura-ori metamaterials while power-law functions of the relative density with different exponent constants were established for the strength in different loading directions.It was shown that the Miura-ori materials possess the highest strength under shear in the X1-X3 plane and it increases with the increase in the relative density.However,this characteristic is strongly influenced by the sector angleα.In general,the difference between the two shear strengths increases when increasing the relative density by using thicker cell walls.It is noted that the strength of the Miura-ori materials as a function of the relative density is nearly constant with respect to the cell dimensions if the values of folding angleγ0 and sector angleαare given.The mechanical characteristics of the Miura-ori material with equal relative density,which exhibits the highest strength among the analyzed origami models,are compared with the out-of-plane compression and shear responses of prismatic hexagonal honeycomb.It is observed that compression and shear responses of the honeycomb outperform the Miura-ori foldcore in all loading directions when considering large deformations.展开更多
Origami,such as Miura-ori,is the art of folding two-dimensional materials into complex,elaborate,and multifunctional three-dimensional objects.In this paper,SMP MO sheet are prepared,and the accuracy of deployable pro...Origami,such as Miura-ori,is the art of folding two-dimensional materials into complex,elaborate,and multifunctional three-dimensional objects.In this paper,SMP MO sheet are prepared,and the accuracy of deployable process is verified by experiments.The folding and deployable process of SMP MO sheet is divided into 4 stages,and each stage is described in detail.The stiffness of smart deployable stage is characterized by an exponential decline at the beginning and a gradual decrease to 0,and this is similar to the theoretical shear equivalent modulus in the Y direction.The effects of various parameters on strain and stress are also explored.The purpose of studying these mechanical characteristics is to provide driving force reference in application;In terms of application,the flow field and electromagnetic characteristics of MO sheet in different directions are studied.The aerodynamic drag and RCS reduction of MO unit cell and graded MO sheet during the deployable process are evaluated.When the dihedral fold angle is about 45°,the RCS reduction and drag reduction characteristics of MO sheet are relatively optimal,which is most beneficial to morphing aircraft.展开更多
This paper presents a quantitative framework to analyze the complexity of folding origami structures from flat membranes.Extensive efforts have realized intricate origami patterns with desired functions such as mechan...This paper presents a quantitative framework to analyze the complexity of folding origami structures from flat membranes.Extensive efforts have realized intricate origami patterns with desired functions such as mechanical properties,packaging efficiency,and deployment behavior.However,the complexity associated with the manufacturing or folding of origami patterns has not been explored.Understanding how difficult origami structures are to make,and how much time they require to form is crucial information to determining the practical feasibility of origami designs and future applications such as robotic origami assembly in space.In this work,we develop this origami complexity metric by modeling the geometric properties and crease formation of the origami structure,from which it outputs crease and pattern complexity values and a prediction of the time to complete the pattern assembly,based on the characteristics of the operator.The framework is experimentally validated by fabricating various Miura-ori origami paper models.展开更多
基金support by Grant No.BG05M2OP001-1.001-0003-C01(2018-2023)financed by the Science and Education for Smart Growth Operational Program,BulgariaG.Lu thanks the Australian Research Council for the support through a Discovery Grant(DP210103323).
文摘The mechanical properties of Miura-ori foldcore metamaterials were studied using finite element simulations.The responses of foldcores with various topological parameters to quasi-static out-of-plane compression and shear loading were analyzed using the relative density as a governing parameter.The non-unique relationships between the core density and the materials'strength in the examined loading directions were revealed,pointing out the strong influence of the Miura-ori topology.Linear relationships were established between the elastic moduli and relative densities of the Miura-ori metamaterials while power-law functions of the relative density with different exponent constants were established for the strength in different loading directions.It was shown that the Miura-ori materials possess the highest strength under shear in the X1-X3 plane and it increases with the increase in the relative density.However,this characteristic is strongly influenced by the sector angleα.In general,the difference between the two shear strengths increases when increasing the relative density by using thicker cell walls.It is noted that the strength of the Miura-ori materials as a function of the relative density is nearly constant with respect to the cell dimensions if the values of folding angleγ0 and sector angleαare given.The mechanical characteristics of the Miura-ori material with equal relative density,which exhibits the highest strength among the analyzed origami models,are compared with the out-of-plane compression and shear responses of prismatic hexagonal honeycomb.It is observed that compression and shear responses of the honeycomb outperform the Miura-ori foldcore in all loading directions when considering large deformations.
基金the financial support from the National Natural Science Foundation of China(No.11872160)the Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special Environments(JCKYS2020603C007)。
文摘Origami,such as Miura-ori,is the art of folding two-dimensional materials into complex,elaborate,and multifunctional three-dimensional objects.In this paper,SMP MO sheet are prepared,and the accuracy of deployable process is verified by experiments.The folding and deployable process of SMP MO sheet is divided into 4 stages,and each stage is described in detail.The stiffness of smart deployable stage is characterized by an exponential decline at the beginning and a gradual decrease to 0,and this is similar to the theoretical shear equivalent modulus in the Y direction.The effects of various parameters on strain and stress are also explored.The purpose of studying these mechanical characteristics is to provide driving force reference in application;In terms of application,the flow field and electromagnetic characteristics of MO sheet in different directions are studied.The aerodynamic drag and RCS reduction of MO unit cell and graded MO sheet during the deployable process are evaluated.When the dihedral fold angle is about 45°,the RCS reduction and drag reduction characteristics of MO sheet are relatively optimal,which is most beneficial to morphing aircraft.
基金the financial support from the Pennsylvania State University startup fundsthe Haythornthwaite Foundation Research Initiation Grant from Haythornthwaite Foundation and Applied Mechanics Division of the American Society of Mechanical Engineersthe support from the National Science Foundation of US(Award number 2030579)
文摘This paper presents a quantitative framework to analyze the complexity of folding origami structures from flat membranes.Extensive efforts have realized intricate origami patterns with desired functions such as mechanical properties,packaging efficiency,and deployment behavior.However,the complexity associated with the manufacturing or folding of origami patterns has not been explored.Understanding how difficult origami structures are to make,and how much time they require to form is crucial information to determining the practical feasibility of origami designs and future applications such as robotic origami assembly in space.In this work,we develop this origami complexity metric by modeling the geometric properties and crease formation of the origami structure,from which it outputs crease and pattern complexity values and a prediction of the time to complete the pattern assembly,based on the characteristics of the operator.The framework is experimentally validated by fabricating various Miura-ori origami paper models.
