An origami shield with supporting frame structures optimized by a feature-driven topology optimization method

In this paper,the design,manufacture and testing of an origami protective shield with a supporting frame structure are presented.It consists of an origami shield surface and a deployable supporting frame structure that needs to be portable and sufficiently stiff.First,for the design of the shield surface,a threestage origami crease pattern is developed to reduce the shield size in the folded state.The shield surface consists of several stiff modular panels and layered with flexible fabric.The modular panels are made of a multi-layer composite where a ceramic layer is made of small pieces to improve durability as those small pieces enable restriction of crack propagation.Then,the supporting frame structure is designed as a chain-of-bars structure in order to fold into a highly compact state as a bundle of bars and deploy in sequence.Thus,a feature-driven topology structural optimization method preserving component sequence is developed where the inter-dependence of sub-structures is taken into account.A bar with semi-circular ends is used as a basic design feature.The positions of the bar’s end points are treated as design variables and the width of the bars is kept constant.Then,a constraint on the total length of the chain of bars is introduced.Finally,the modular panels made of multi-layer composite and the full-scale prototype of the origami shield are fabricated and tested to verify the bullet-proof performance.

Bending results of graphene origami reinforced doubly curved shell

The present work investigates higher order stress,strain and deformation analyses of a shear deformable doubly curved shell manufactures by a Copper(Cu)core reinforced with graphene origami auxetic metamaterial subjected to mechanical and thermal loads.The effective material properties of the graphene origami auxetic reinforced Cu matrix are developed using micromechanical models cooperate both material properties of graphene and Cu in terms of temperature,volume fraction and folding degree.The principle of virtual work is used to derive governing equations with accounting thermal loading.The numerical results are analytically obtained using Navier's technique to investigate impact of significant parameters such as thermal loading,graphene amount,folding degree and directional coordinate on the stress,strain and deformation responses of the structure.The graphene origami materials may be used in aerospace vehicles and structures and defence technology because of their low weight and high stiffness.A verification study is presented for approving the formulation,solution methodology and numerical results.

Design and mechanical properties analysis of a cellular Waterbomb origami structure

Cellular structures are commonly used to design energy-absorbing structures,and origami structures are becominga prevalent method of cellular structure design.This paper proposes a foldable cellular structure based on theWaterbomb origami pattern.The geometrical configuration of this structure is described.Quasi-static compressiontests of the origami tube cell of this cellular structure are conducted,and load-displacement relationship curvesare obtained.Numerical simulations are carried out to analyze the effects of aspect ratio,folding angle,thicknessand number of layers of origami tubes on initial peak force and specific energy absorption(SEA).Calculationformulas for initial peak force and SEA are obtained by the multiple linear regression method.The degree ofinfluence of each parameter on the mechanical properties of the single-layer tube cell is compared.The resultsshow that the cellular structure exhibits negative stiffness and periodic load-bearing capacity,as well as foldingangle has the most significant effect on the load-bearing and energy-absorbing capacity.By adjusting the designparameters,the stiffness,load-bearing capacity and energy absorption capacity of this cellular structure can beadjusted,which shows the programmable mechanical properties of this cellular structure.The foldability andthe smooth periodic load-bearing capacity give the structure potential for application as an energy-absorbing structure.

Experimental study of solid-liquid origami composite structures with improved impact resistance

In this paper,a liquid-solid origami composite design is proposed for the improvement of impact resistance.Employing this design strategy,Kresling origami composite structures with different fillings were designed and fabricated,namely air,water,and shear thickening fluid(STF).Quasi-static compression and drop-weight impact experiments were carried out to compare and reveal the static and dynamic mechanical behavior of these structures.The results from drop-weight impact experiments demonstrated that the solid-liquid Kresling origami composite structures exhibited superior yield strength and reduced peak force when compared to their empty counterparts.Notably,the Kresling origami structures filled with STF exhibited significantly heightened yield strength and reduced peak force.For example,at an impact velocity of 3 m/s,the yield strength of single-layer STF-filled Kresling origami structures increased by 772.7%and the peak force decreased by 68.6%.This liquid-solid origami composite design holds the potential to advance the application of origami structures in critical areas such as aerospace,intelligent protection and other important fields.The demonstrated improvements in impact resistance underscore the practical viability of this approach in enhancing structural performance for a range of applications.

A symmetric substructuring method for analyzing the natural frequencies of conical origami structures

Conical origami structures are characterized by their substantial out-of-plane stiffness and energy-absorptioncapacity.Previous investigations have commonly focused on the static characteristics of these lightweight struc-tures.However,the efficient analysis of the natural vibrations of these structures is pivotal for designing conicalorigami structures with programmable stiffness and mass.In this paper,we propose a novel method to analyzethe natural vibrations of such structures by combining a symmetric substructuring method(SSM)and a gener-alized eigenvalue analysis.SSM exploits the inherent symmetry of the structure to decompose it into a finiteset of repetitive substructures.In doing so,we reduce the dimensions of matrices and improve computationalefficiency by adopting the stiffness and mass matrices of the substructures in the generalized eigenvalue analysis.Finite element simulations of pin-jointed models are used to validate the computational results of the proposedapproach.Moreover,the parametric analysis of the structures demonstrates the influences of the number of seg-ments along the circumference and the radius of the cone on the structural mass and natural frequencies of thestructures.Furthermore,we present a comparison between six-fold and four-fold conical origami structures anddiscuss the influence of various geometric parameters on their natural frequencies.This study provides a strategyfor efficiently analyzing the natural vibration of symmetric origami structures and has the potential to contributeto the efficient design and customization of origami metastructures with programmable stiffness.

Enhancing clinical proficiency through laparoscopic training using Japanese origami

Objective This study aimed to investigate the clinical efficacy of laparoscopic training using origami,a traditional Japanese papercraft,using laparoscopic forceps to create origami cranes.Methods In this retrospective study,4 surgeons were randomly divided into 2 groups:The training group,consisting of surgeons 1 and 2,and the non-training group,consisting of surgeons 3 and 4.Over the course of a one-year study period,the training group regularly underwent laparoscopic surgery training with a dry box,wherein they folded a total of 1000 origami cranes using laparoscopic instruments.The non-training group periodically underwent common laparoscopic surgery training of techniques such as suturing and ligation.Each surgeon regularly performed the transabdominal preperitoneal approach for inguinal hernias.Each training was conducted concurrently with the surgeries.The procedure time(peritoneum detachment,mesh placement,and closure of the peritoneum),total operation time(time from peritoneum detachment to closure of the peritoneum),and surgical outcomes were examined.Results The training group showed greater improvement in the total operation time and more stable performance than the non-training group.Additionally,the time taken for peritoneum detachment was significantly shorter in the training group.Conclusion Laparoscopic training using origami has the potential to enhance laparoscopic surgical skills and improve surgical outcomes.

Atomistic simulations of graphene origami:Dynamics and kinetics

Origami offers two-dimensional(2D)materials with great potential for applications in flexible electronics,sensors,and smart devices.However,the dynamic process,which is crucial to construct origami,is too fast to be characterized by using state-of-the-art experimental techniques.Here,to understand the dynamics and kinetics at the atomic level,we explore the edge effects,structural and energy evolution during the origami process of an elliptical graphene nano-island(GNI)on a highly ordered pyrolytic graphite(HOPG)substrate by employing steered molecular dynamics simulations.The results reveal that a sharper armchair edge is much easier to be lifted up and realize origami than a blunt zigzag edge.The potential energy of the GNI increases at the lifting-up stage,reaches the maximum at the beginning of the bending stage,decreases with the formation of van der Waals overlap,and finally reaches an energy minimum at a half-folded configuration.The unfolding barriers of elliptical GNIs with different lengths of major axis show that the major axis should be larger than 242 A to achieve a stable single-folded structure at room temperature.These findings pave the way for pursuing other 2D material origami and preparing origami-based nanodevices.

可大幅度提高封装效率的Origami封装

众所周知,目前所有的信息处理与存储工作都是由硅实现的,由此可见硅材料的重要性。然而再看看电路板我们就不难发现,电路板上的大部分空间处于闲置状态,电路板空间的利用率极低。封装只能够增加体积、重量和成本,而且同时还可能降低硅的性能。幸运的是,一种新型封装技术正在改变着电路板的这种状况。 影响封装的最大因素是封装的效率,也就是硅片面积与封装引脚面积之比。

Origami结构的优化及其在桥梁工程中的应用

Origami结构作为一种新兴的材料结构,具有轻质、牢固、可展、收缩、防撞、吸能等特性,已逐渐应用于工程领域。文章基于对Origami结构的优化,探究其在桥梁工程中的两大应用:(1)可移动桥梁;(2)桥梁防撞体系。并在桥梁防撞体系中引入"蛋盒"模型,利用Pro/e和COMSOL Multi-physic进行有限元模拟仿真分析,得出"蛋盒"结构与普通的防撞结构相比,具有更加优良的吸能防撞特性,且能多角度抵抗撞击,从而增加桥梁的使用寿命。

Universal scaling law of an origami paper spring

This letter solves an open question of origami paper spring risen by Yoneda et al.(Phys.Rev.E 2019).By using both dimensional analysis and data fitting,an universal scaling law of a paper spring is formulated.The scaling law shows that origami spring force obeys power square law of spring extension,however strong nonlinear to the total twist angle.The study has also successfully generalized the scaling law from the Poisson ratio 0.3 to an arbitrary Poisson's ratio with the help of dimensional analysis.

A Stiffness Variable Passive Compliance Device with Reconfigurable Elastic Inner Skeleton and Origami Shell

Devices with variable stiffness are drawing more and more attention with the growing interests of human-robot interaction,wearable robotics,rehabilitation robotics,etc.In this paper,the authors report on the design,analysis and experiments of a stiffness variable passive compliant device whose structure is a combination of a reconfigurable elastic inner skeleton and an origami shell.The main concept of the reconfigurable skeleton is to have two elastic trapezoid four-bar linkages arranged in orthogonal.The stiffness variation generates from the passive deflection of the elastic limbs and is realized by actively switching the arrangement of the leaf springs and the passive joints in a fast,simple and straightforward manner.The kinetostatics and the compliance of the device are analyzed based on an efficient approach to the large deflection problem of the elastic links.A prototype is fabricated to conduct experiments for the assessment of the proposed concept.The results show that the prototype possesses relatively low stiffness under the compliant status and high stiffness under the stiff status with a status switching speed around 80 ms.

Unusual thermal properties of graphene origami crease:A molecular dynamics study

Graphene is a two-dimensional material that can be folded into diverse and yet interesting nanostructures like macro-scale paper origami.Folding of graphene not only makes different morphological configurations but also modifies their mechanical and thermal properties.Inspired by paper origami,herein we studied systemically the effects of creases,where sp^(2)to sp^(3)bond transformation occurs,on the thermal properties of graphene origami using molecular dynamics(MD)simulations.Our MD simulation results show that tensile strain reduces(not increases)the interfacial thermal resistance owing to the presence of the crease.This unusual phenomenon is explained by the micro-heat flux migration and stress distribution.Our findings on the graphene origami enable the design of the next-generation thermal management devices and flexible electronics with tuneable properties.

Origami meets electrospinning:a new strategy for 3D nanofiber scaffolds

Inspired by the constitution of things in the natural world,three-dimensional (3D)nanofiber scaffold/cells complex was constructed via the combination of electrospinning technology and origami techniques.The nanofiber boxes prepared by origami provided a limited space for the layer-by-layer nanofiber films,and the human fetal osteoblasts (hFOBs)seeded on the both sides of the nanofiber films were expected to facilitate the bonding,of the adjacent nanofiber films through the secretion of extracellular matrix.Specifically,the hFOBs presented 3D distribution in the nanofiber scaffold,and they can stretch across the gaps between the adjacent nanofiber films,forming the cell layers and filling the whole 3D nanofiber scaffold.Eventually,a 3D block composed of electrospun nanofiber scaffold and cells was obtained',which possesses potential applications in bone tissue engineering.Interestingly,we also created 3D nanofiber structures that range from simple forms to intricate architectures via origami,indicating that the combination of electrospinning technology and origami techniques is a feasible method for the 3D construction of tissue engineering scaffolds.

A geometry-based framework for modeling the complexity of origami folding

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.

Effect of concentration and adsorption time on the formation of a large-scale origami pattern

The arrangement of DNA-based nanostructures into the desired large-scale periodic pattern with the highest possible accuracy and control is essential for the DNA application in functional biomaterials;however, formation of a DNA nanostructure pattern without utilizing the molecular interactions in nanotechnology field remains difficult. In this article, we use the optimal concentration and adsorption time of origami to induce DNA origami in the form of a large-scale 2D pattern on mica without changing the origami itself. DNA origami structures can form a pattern by close packing of symmetric and electrostatic interactions between ions, which was confirmed by the atomic force microscopy images. Furthermore, we identified favorable conditions for the concentration of enable pattern formation with DNA origami. This work provides an insight to understand the adsorption of DNA on mica and guides researches on regular DNA nanostructure pattern, which can serve as templates for pattern formation of proteins or other biomolecules.

DNA origami-templated assembly of plasmonic nanostructures with enhanced Raman scattering

DNA origami have been established as versatile templates to fabricate plasmonic nanostructures in predefined shapes and multiple dimensions. Limited to the size of DNA origami, which are approximate to 100 nm, it is hard to assemble more intricate plasmonic nanostructures in large scale. Herein, we used rectangular DNA origami as the template to anchor two 30-nm gold nanoparticles(Au NPs) which induced dimers nanostructures. Transmission electron microscopy(TEM) images showed the assembly of Au NPs with high yields. Using the linkers to organize the DNA origami templates into nanoribbons,chains of Au NPs were obtained, which was validated bythe TEM images. Furthermore, we observed a significant Raman signal enhancement from molecules covalently attached to the Au NP-dimers and Au NP-chains. Our method opens up the prospects of high-ordered plasmonic nanostructures with tailored optical properties.

The Tessellation Rule and Properties Programming of Origami Metasheets Built with a Mixture of Rigid and Non-Rigid Square-Twist Patterns

Metamaterials constructed from origami units of different types and behaviors could potentially offer a broader scope of mechanical properties than those formed from identical unit types.However,the geometric design rules and property programming methods for such metamaterials have yet to be extensively explored.In this paper,we propose a new kind of origami metasheet by incorporating a family of different square-twist units.The tessellation rule of these metasheets is established to allow compatible mountain-valley crease assignments and geometric parameters among neighboring units.We demonstrate through experiments that the energy,initial peak force,and maximum stiffness of the metasheets can be obtained by a summation of the properties of the constitutional units.Based on this,we are able to program the mechanical properties of the metasheets over a wide range by varying the types and proportions of the units,as well as their geometric and material parameters.Furthermore,for a metasheet with a fixed number of units,all the geometrically compatible tessellations can be folded out of the same pre-creased sheet material by simply changing the mountain-valley assignments,thereby allowing the properties of the metasheet to be re-programmed based on specific requirements.This work could inspire a new class of programmable origami metamaterials for current and future mechanical and other engineering applications.

Origami结构材料在机械工程和土木工程中的应用

折纸艺术吸引了许多艺术家和科学家来研究并发现其基本原理,目前折纸技术已经在许多行业应用中得到使用,本文通过介绍Origami结构在机械工程和土木工程领域的应用现状,归纳总结其研究热点,以期为Origami结构材料应用前景的研究提供参考。

Behaviors of Bellows-Like Origami Patterned Tubes with Trapezoidal Patterns

In this paper, we show one of the possibility utilizing typical origami structures for civil engineering fields such as the bridge bearing support. We numerically investigate axial spring constants and buckling behaviors of bellows-like origami tube structures. The bellows-like origami tube structures, which can be folded because of elastic deformations, work as a kind of spring. If the initial heights of the bellows-like origami tubes are less than 90% of the height of the prismatic tubes without bellows-like folded lines, the spring constants of the bellows-like tubes are very low compared with those of the prismatic tubes. The buckling loads and patterns of the bellows-like tubes vary depending on the initial heights of the tubes.

Teaching the Non-Chinese Speaking Students Origami to Improve Their Interest and Concentration in Learning Chinese Language

The difficulties in learning Chinese faced by non-Chinese students are the subjects of concern in the education sector, especially in writing Chinese characters. We write the characters with strokes and dots, more or less strokes or dots will represent different words and different meanings. Students found these very complicated and confused, thus it leads them to lose their motivation and interest in learning Chinese language. From the beginning of the 1990s, I began using origami as one of the activities to promote the teaching of Chinese in the state school in Melbourne Australia with remarkable results. Program got widely reported by Medias. In 1995, I got the ＂National Excellence in Teaching Awards＂. After I took up the position as the curriculum development officer in University of Hong Kong in 2007, I worked closely with the teachers and students using origami as the theme base learning in Chinese. It helps to increase their understanding of the radicals and parts, so as to improve their confidence in writing Chinese characters.