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Energy absorption of thin-walled tubes with pre-folded origami patterns: Numerical simulation and experimental verification

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Abstract

Thin-walled tubes are widely used as energy absorption components. In this study, two different origami patterns were introduced to circular tubes. The influence of the origami patterns on the energy absorption capacity and the deformation mechanism of tubes under uniaxial loading were investigated both numerically and experimentally. The results showed that the initial peak force of origami tubes would be significantly reduced, while the energy absorption capacity could be improved or maintained. Brass tubes with and without origami patterns were fabricated using 3D printing and were tested to validate the finite element models.

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... (G) Axial energy-absorbing test of an origami tube [32]. (H) A crawler [33] and (I) a robotic arm based on the Kresling origami [22]. ...
... Origami can also offer a variety of geometric design options and can have the benefit of easy fabrication from a flat developable surface [53,56,57]. For example, a thin-walled tube with pre-folded Yoshimura pattern [32] and a sandwich-like structure with Kresling pattern [58] can both provide favorable energy-absorbing behaviors. However, all of these previous origami systems are passive, and the entire energy absorption performance is determined by the design geometry and material properties. ...
... In comparison with the conventional thin-walled tube of identical material cost, the proposed zipper tube shares similar loading responses as those of other origami energy absorbers [32,36]: lower peak force and more energy absorption. Moreover, the zipper tube also owns the potential to tune the energy-absorbing behavior by deploying to different extensions. ...
Thesis
Thin-walled origami-inspired tubes can be used as lightweight systems for various functional applications in engineering. Folding motions can allow for deployment, reconfiguration, and compact storage of the systems, while buckling of the thin walls can be used to tune the system properties or achieve secondary functions such as energy absorption. This thesis aims to explore the stability of morphing tubes and harness buckling for functional applications. The dissertation first explores a deployable design where origami tubes extend, lock, and absorb energy through crushing (buckling and plasticity). Numerical and experimental studies investigate the tunable stiffness and energy absorption behaviors of these systems under static and dynamic scenarios. The stiffness, peak crushing force, and total energy absorption of these origami tubes can be changed through reconfiguration. These deployable systems can increase the crushing distance between impacting bodies and can allow for on-demand energy absorption characteristics. Next, the bending stability that allows for morphing in corrugated tubes is explored (bending in drinking straws). Finite element models and a reduced-order elastic simulation package can capture the nonlinear multi-stable behaviors. Modified cross-sections for the corrugated tubes are introduced and explored to identify how geometry affects bending stability, energy barriers, and stable configurations. Results show that thinner shells, steeper cones, and weaker creases are required to achieve bending bi-stability. A bar and hinge simulation model is then used to identify and capture a unique pop-up mechanism in Kresling origami that enables shape-morphing and stiffness tuning. By buckling the valley creases, the conical Kresling will pop into a dome-like shape and the crease network will be distorted. As a result, the flexible twisting motion via crease folding is prohibited, and the cone stiffness can be increased by up-to-four orders of magnitude. Parametric studies revealed that a shallower and more twisted Kresling unit will have more significant stiffness tuning. Experimental tests were used to verify the numerical predictions of tunable stiffness. This thesis explores how buckling in thin-walled origami tubes can be harnessed for functional purposes. The mechanics of three different tubular designs are explored to give insight on how geometry, sheet thickness, and material properties affect the buckling and multi-stable behaviors. These findings can inform future designs of tubular origami for shape-morphing and other functional uses.
... This formulation is widely used for capturing origami unit cells and sheets [172][173][174][175], metamaterials [139,[176][177][178], sandwich cores [179][180][181][182], and crash boxes [183][184][185][186] when the creases are rigidly connected. ...
... References [139] and [172][173][174][175][176][177][178][179][180][181][182][183][184][185][186][187][188]. ...
... For example, Yuan et al. show one origami inspired metamaterial that can produce programmable stiffness for various engineering applications [176]. In addition, this FE model setup has been used for analyzing origami crash boxes for energy absorption applications [183][184][185][186]. For instance, Wang and Zhou [184] use this approach to study the influence of imperfection sensitivity of origami crash boxes, and Xiang et al. [182] provide a detailed review on using origami-inspired structures for energy absorption. ...
Article
Origami-inspired systems are attractive for creating structures and devices with tunable properties, multiple functionalities, high-ratio packaging capabilities, easy fabrication, and many other advantageous properties. Over the past decades, the community has created a variety of simulation techniques to analyze the kinematic motions, mechanical properties, and multi-physical characteristics of origami systems. These various simulation techniques are formulated with different assumptions and are often tailored to specific origami designs, and thus, it is valuable to systematically review the state-of-the-art of origami simulation techniques. This review presents the formulations of different origami simulations, analyzes their strengths and weaknesses, and discusses the potential application scenarios of different simulation techniques. The three major types of simulations: kinematics-based simulations, mechanics-based simulations, and multi-physics based simulations are all discussed in this work. The paper also addresses how to select appropriate simulation techniques for studying different origami-inspired systems and the potential future challenges in the field of origami simulation.
... In addition, the mean crushing force decreases with the increase in the number of buckling points. Yang et al. [20] used a 3D printing technique to manufacture the proposed tubes and investigated the influence of the origami circular tube with two different isometric origami patterns (called diamond and full-diamond patterns) on energy dissipation performance through experiments and numerical analysis. They found that the initial peak force of origami tubes would be significantly reduced, whereas its energy absorption capacity could be improved or maintained. ...
... The stressstrain relationship curve obtained by the tensile test is shown in Figure 5. Different from the previous models, the origami tube in this paper uses the full model, and the height between the layers was not equal; therefore, before the numerical model analysis, the grid density convergence test and analysis were carried out to ensure the accuracy of the results. As in the study of [17,20], it was verified using the following principle recommended by Abaqus [45]: in most processes, the kinetic energy of the deformed material does not exceed 5% of its internal energy to ensure a correct quasi-static response. The ratio of pseudo-strain energy to total energy or plastic dissipation is less than 5%; otherwise, it is necessary to increase the grid density to reduce the effect of hourglass stiffness in the results. ...
... In practice, there were two typical methods [19,20,23] to practically manufacture the designs in this paper. One used a 3D printing technique to manufacture it. ...
Article
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Thin-walled tubes are widely used as energy-absorbing components in traffic vehicles, which can absorb part of the energy in time by using the plastic deformation of the components during collision so as to reduce the damage of the vehicle body and improve the overall safety and reliability of traffic vehicles. The prefolded design of thin-walled tube components can guide it to achieve the ideal energy dissipation performance according to the preset damage path, so the related research based on origami tubes has attracted a lot of attention. Since the geometry of the origami tubes is controlled by many parameters and stress and deformation is a complex nonlinear damage process, most of the previous studies adopted the method of case analysis to carry out numerical simulation and experimental verification of the relevant influence parameters. This paper makes a new exploration of this kind of problem and focuses on solving the related technical problems in three aspects: 1. The automatic model modeling and 3D display based on parameters are proposed; 2. System integration using Python programming to automatically generate the data files of ABAQUS for finite element simulation was realized, and we sorted the finite element analysis results into an artificial intelligence analysis data set; 3. Clustering analysis of the energy consumption history of the data set is carried out using a machine learning algorithm, and the key design parameters that affect the energy consumption history are studied in depth. The sensitivity of the energy absorption performance of the origami tubes with multi-morphology patterns to the crease spacing is studied, and it is shown that the concave–convex crease spacing distribution with a distance larger than 18 mm could be used to activate specific crushing modes. In the optimal case, its initial peak force is reduced by 66.6% compared to uniformly spaced creases, while the average crushing force is essentially the same. Furthermore, this paper finds a new path to optimizing the design of parameters for origami tubes including a multi-morphology origami pattern from the perspective of energy dissipation.
... Origami-based structures can be stored in a small size when folding and used in a full size when deploying. By taking these advantages, various origami-based structures have been proposed for practical engineering applications, such as collapsible kayaks [87], pneumatic actuators [88] , space telescope lenses [89], concealand-reveal box [90], oriceps [91], energy absorption devices [92,93], medical devices [94][95][96], actuators used in soft robots [97]. The multi-stable behaviours of the origami-based structure can switch among different stable states to reduce complexity of the control architecture for improving the robot locomotion [98,99]. ...
... Kresling pattern [217], cylindrical Miura-ori base structure [218], and polygonal tubes [92,93,219]. Some other patterns have been developed according to different applications. ...
... Some other patterns have been developed according to different applications. Examples of the other patterns with compliant mechanisms and unique kinematics responses include diamond-cell [93,220], kite-shape [221], crash box cell [92,222], Kaleidocycle-inspired pattern [223], Yoshimura pattern [224], and bio-inspired morphing structures [49,[225][226][227]. ...
Article
Full-text available
Vibration and sound control is critical to many practical engineering systems in order to minimise the detrimental effects caused by unavoidable vibrations and noises. Metamaterials and origami-based structures, which have attracted increasing interests in interdisciplinary research fields, possess many peculiar physical properties, including negative Poisson’s ratios, bi- or multi-stable states, nonlinear and tuneable stiffness features, and thus offer promising applications for vibration and sound control. This paper presents a review of metamaterials and origami-based structures as well as their applications to vibration and sound control. Metamaterials are artificially engineered materials having extremal properties which are not found in conventional materials. Metamaterials with abnormal features are firstly discussed on the basis of the unusual values of their elastic constants. Recent advances of auxetic, band gap and pentamode metamaterials are reviewed together with their applications to vibration and sound mitigations. Origami, as the ancient Japanese art of paper folding, has emerged as a new design paradigm for different applications. Origami-based structures can be adopted for vibration isolation by using their multi-stable states and desirable stiffness characteristics. Different origami patterns are reviewed to show their configurations and base structures. Special features, such as bi- or multi-stable states, dynamic Poisson’s ratios, and nonlinear force–displacement relationships are discussed for their applications for vibration control. Finally, possible future research directions are elaborated for this emerging and promising interdisciplinary research field.
... Origami structures made of thin sheet material offer a promising remedy to the above two challenges [6][7][8][9][10]. Thanks to conceptual simplicity and the absence of complicated assembly, origami structures have been widely and innovatively applied in practical engineering, including metamaterials [11][12][13], energy absorption/buffering structures [14][15][16], robots [17][18][19], architectures [20][21][22], robot grippers [23][24][25], and to name only a few. The origami structure's coexisting structural properties of flexibility and rigidity provide it with an inherent superiority when applied to flexible robot grippers [26][27][28]. ...
... Putting equations (5), (15) and (18) into equation (4) gives: ...
Preprint
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Although the flexible origami gripper can handle a wide range of objects, there is a need for significant further improvement in its gripping performance. This study develops a novel nonlinear topology optimization (NTO) method to enhance the gripping performance of an origami chomper-based flexible gripper. The proposed NTO method incorporates the additive hyperelasticity technique and multi-resolution design (MRD) strategy with the advantages of being computationally efficient, having excellent convergence, and enabling refined design. The effectiveness of the proposed NTO method is validated by two compliant mechanism benchmark examples, i.e., the displacement inverter and gripper mechanisms. We apply the NTO method to the origami chomper-based flexible gripper to redistribute the material at the creases to obtain the optimized origami chomper-based flexible gripper. Several optimized origami chomper-based flexible gripper prototypes are fabricated by using laser cutter, followed by a series of experiments to test the gripping performances, including gripping range capability under an identical input load, maximum gripping ratio, gripping adaptability, and achieving richer gripping characteristics by size scaling. Results demonstrate that the optimized origami chomper-based flexible gripper can handle a wide range of objects irregularities in textures and uneven shapes;and the gripping range capability can be significantly enhanced by the NTO method. We also show that the optimized origami chomper-based flexible gripper can enable effective gripping of objects across scales from millimeters to centimeters to decimeters through size scaling.
... Four-node shell elements (S4) are employed to mesh the ZBSO metamaterial. Global element size is chosen as 1. calculated as 79 mm/s, which is much smaller than the one used in [24,26]. Thus, the effect of the stress wave is acceptable. ...
... Thus, the effect of the stress wave is acceptable. Two contact properties are set in the simulation, i.e. penalty friction with the Coulomb friction coefficient as 0.25 as suggested by [24,49] and hard contact model to character the contact pressure between surfaces. General contact is employed to simulate all contacts in the FE model, as suggested in [26]. ...
Article
Full-text available
Origami-based metamaterial has shown remarkable mechanical properties rarely found in natural materials, but achieving tailored multistage stiffness is still challenging. We propose a novel zigzag-base stacked-origami (ZBSO) metamaterial with tailored multistage stiffness based on crease customization and stacking strategies. A high precision finite element (FE) model to identify the stiffness characteristics of the ZBSO metamaterial has been established, and its accuracy is validated by quasi-static compression experiments. Using the verified FE model, we demonstrate that the multistage stiffness of the ZBSO metamaterial can be effectively tailored through two manners, i.e. varying the microstructures (through introducing new creases to the classical Miura origami unit cell) and altering the stacking way. Three strategies are utilized to vary the microstructure, i.e. adding new creases to the right, left, or both sides of the unit cell. We demonstrate that the multistage stiffness is caused by both the self-locking and asymmetrical stiffness distribution of the ZBSO metamaterial. We further reveal that the proposed ZBSO metamaterial has several outstanding advantages compared with traditional mechanical metamaterials, e.g. material independent, scale-invariant, lightweight, and excellent energy absorption capacity. The unraveled superior mechanical properties of the ZBSO metamaterials pave the way for designing the next-generation cellular metamaterials with tailored stiffness properties.
... That is why there are two types of origami structures which are used as energy absorbers: one is four folding lines such as bellows fold and the other one is six folding ones such as spiral folding. Reference [6] introduces mainly four research groups led by Lu and Chen [7], You and coauthors [8][9][10], Wang and coauthors [11,12] and Xie [13,14]. All of them use four folding line types. ...
... This is because they consider that four folding lines such as bellows fold have basically lines parallel to the top and bottom faces, and so it has lower reaction force than six folding line types which has not only the parallel lines but also the diagonal ones which contribute more for the force perpendicular to top and bottom faces. Actually, it is intended to raise force by inserting structures in the hollow cross section like a multi-cell tabular structure [13]. Anyway origami structures have been shown to be promising as a new energy absorber. ...
Article
Full-text available
Current vehicle energy absorbers face two problems during a collision in that there is only a 70% collapse in length and there is a high initial peak load. These problems arise because the presently used energy-absorbing column is primitive from the point of view of origami. We developed a column called the Reversed Spiral Origami Structure (RSO), which solves the above two problems. However, in the case of existing technology of the RSO, the molding cost of hydroforming is too expensive for application to a real vehicle structure. We therefore conceive a new structure, named the Reversed Torsion Origami Structure (RTO), which has excellent energy absorption in simulation. We can thus develop a manufacturing system for the RTO cheaply. Excellent results are obtained in a physical experiment. The RTO can replace conventional energy absorbers and is expected to be widely used in not only automobile structures but also building structures.
... Meanwhile, the SEA of the origami-based tubes remained constant or even improved. Moreover, the folding parameters have a significant influence on the EA behavior and deformation modes of thin-walled tubes; in the optimal case, origami tubes can deform into desirable collapse modes with high SEA [35][36][37]. For example, Song et al. [35] investigated the axial crushing deformation and EA behavior of thin-walled tubes with equilateral trapezoid patterns by conducting experiments and simulations. ...
Article
Full-text available
Thin-walled tubes with origami patterns exhibit good energy absorption capacity under axial tension. In this study, the tensile behavior of thin-walled tubes with pleated patterns, known as origami bellows, was first systematically investigated. A parametric study was performed to assess the impact of origami patterns and wall thicknesses on the energy absorption performance and deformation mechanism of origami bellows. The experimental and numerical results showed that a desirable tensile process without excessive initial peak force, followed by a stable and high plateau force, can be obtained. The non-rigid deployment mechanism of origami bellows under tension is observed. The specific energy absorption of the origami bellows increases as the unit width decreases provided that the value of the unit width is less than a critical value. The mean tensile force increased with the pre-folding angle, with a maximum increase of 16% in the cases studied, and increased as the wall thickness increased to a power of 1.67. This study provides a new avenue for constructing an energy absorber with good energy-absorption performance under tensile loading.
... The circular tubes with two different origami patterns were experimentally investigated using 3D printing technology [375]. It was found that the circular tubes with pre-folded origami patterns exhibit a higher specific energy absorption and a lower initial peak force compared to conventional circular tubes. ...
... Tailoring the geometric size of the unit cell and arraying it in different dimensions in space or by mutating, assembling, and stacking the unit cells make the origami structure own huge design flexibility and programmability, further creating innovative structures with extraordinary characteristics, e.g., negative Poisson's ratio, quasi-zero stiffness, bistability, tunable swelling behaviour, tailored stiffness and dynamic properties, and excellent energy absorption, to name a few [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54]. In addition to design flexibility and programmability advantages, the large-scale alteration of space volume through folding also provides a feasible solution for tunable frequency for noise suppression. ...
Article
Full-text available
Noise reduction is of critical importance in many engineering applications. One way to achieve noise reduction is using acoustic metamaterials. However, traditional acoustic metamaterials have long been criticized for the fixed and narrow frequency band in low- and medium-frequency sound attenuation. In this study, by incorporating the accordion origami into Helmholtz resonators as the side cavity, a novel origami-based acoustic metamaterial (OBAM) with tunable and broad bandwidth sound-eliminating capacities is developed. The sound attenuation properties of the proposed OBAM, quantified by transmission loss (TL), are extensively investigated by theoretical, numerical, and experimental methods. The sound attenuation of the OBAM can be readily tuned by air pressure via capitalizing on the single-degree-of-freedom property of accordion origami. The transfer matrix method is used to compute the TL of the OBAM analytically, compared with those obtained from the finite element and acoustic impedance methods. Results show that the theoretical, numerical, and experimental methods have good consistency, and the TL can be easily and quantitatively tuned by pressure in the low-medium frequency band. The working frequency bandwidth (TL larger than 10 dB), achieving an effective attenuation of more than 90% of the sound energy, can reach 500 Hz in the range of 271–790 Hz, in which the thickness of the OBAM is only 1/18–1/6 λ with λ being the working wavelength, demonstrating the powerful and broadband low-frequency sound elimination capacity of the OBAM at sub-wavelength. Moreover, the proposed OBAM allows airflow-permeating, possesses high design flexibility and programmability, and remains scale-independent, real-time tuning, and free of the complex control algorithm. This study paves the way for effective tunable and broadband sound insulation attenuation equipment with efficient ventilation.
... Yang). deformation modes for increased energy absorption and improved force response compared to conventional tubes [11][12][13][14][15][16]. An origami architecture that has received increased attention in recent years is the Kresling pattern [17][18][19][20][21]. ...
Article
Pre-folded tubes can exhibit superior energy absorption characteristics under axial crushing compared to conventional straight-walled tubes. However, their construction can be difficult to automate. In this investigation, we present a novel filament winding approach to efficiently manufacture pre-folded carbon fiber reinforced plastic (CFRP) tubes featuring the Kresling fold pattern. We experimentally study the quasi-static axial crushing behavior of three Kresling geometries and compare them to conventional tubes with a circular and square cross-section. The data from experiments is used to develop a finite element model for estimating axial crush indicators. Despite the layup sequence not orienting the fibers in the direction of loading, we obtain superior structural performance in terms of the mean force divided by the initial peak crushing force, which represents the crushing force efficiency of the structure. The tested tubes exhibit further potential to improve their energy absorption performances, while preserving enhanced manufacturability.
... In recent years, with growing interest in origami engineering technology, an increasing number of origami configurations have been developed for deformation alteration, such as Yoshimura pattern [1], Trapezoid-based pattern [2], Crash box [3][4], kite-shape pattern [5], etc. Among them, a tube patterned by curved Miura origami proposed by Liu [6] is proved to alter the deformaiton mode of the tube and hinder its global buckling. ...
Conference Paper
Full-text available
Flexural rigidity reflects the lateral deformation capacity of a structural member under bending, which is directly affected by the cross sectional inertia moment of the member. Origami-patterned tubes have intricate geometries and consequently varied cross-sections, thus making it difficult to calculate the inertia moment. As part of the endeavor to quantify the deformation capacity of a curved Miura origami-patterned tube, this manuscript develops a practical calculation method for inertia moment of the tube. Conducted on a basic tubular unit of the tube, the derivation adopts a simplified cross-section equivalent to the actual cross-section and follows the general theoretical formula for inertia moment. After substitutions and collections, a practical calculation formula expressed by six independent geometrical parameters is developed. The application of the developed formula on the tubes with different geometries reveals a zigzag distribution of the inertia moment along the tube length. By using the formula, the least inertia moment of the tube could be readily located and calculated.
... Song and Chen [14] proposed a type of tubes with equilateral trapezoid patterns, which were numerically and experimentally verified to improve the crashworthiness by successfully inducing the crushing modes of the tubes. Since then, various types of origami patterns have been designed and applied to tubes, including Miura origami pattern [15,16], Yoshimura pattern [17], crash box [18,19], kite-shape pattern [20,21], waterbomb pattern [22,23] and so on. These elaborately designed patterns significantly enhance the energy absorption capacity of the tubes. ...
Article
Full-text available
In order to improve energy absorption capacity of tubes under axial compression, this work introduces an octagon tube patterned by curved Miura origami pattern and aims at suppressing global buckling of the tube via an appropriate fold line scheme. By categorizing the fold lines of the tube into two types (hinge-like lines and continuous lines) and allocating them to different positions, four arrangement schemes of the lines are developed. Through numerical comparison in force-displacement curve, stress distribution and lateral deformation capacity among four 3-level patterned tubes under different schemes, Scheme 4 (inclined valley lines as hinge-like lines and the others as continuous lines) is found to outperform the others in suppressing global buckling by reducing the magnitude of lateral deformation by up to 59.9% and by delaying the occurrence of global buckling by up to 35.9% compared with the other schemes. To step further, the scheme is applied in a long tube and geometrically different tubes are compared. The results prove that the scheme is potentially an effective way to alleviate buckling instability of a long tube when appropriately designed.
... 第 9 期 刘杰,等: 曲线折痕折纸力学超材料可定制压缩力学特性 振等方面展现出了巨大的潜力 [7][8][9] 。 Wu 等 [10] 研究 了三浦折纸管在自由展开过程中的瞬态动力学行 为。 在此基础上,Han 等 [11] 利用三浦折纸管实现了 准零刚度特性,进而提出了一种非线性低频隔振器。 Liu 等 [12] 研究发现通过改变折叠角等参数可以大范 围地调控三浦折纸管的动力学特性。 除了三浦折纸 管外,Agarwal 等 [13] 还探讨了 Kresling 型管状折纸力 学超材料在谐波力激励下的非线性动力学行为。 虽然上述基于直线折痕的折纸超材料已展现 出了卓越的 可 定 制 力 学 特 性,但 两 点 之 间 只 能 有 一条直线折痕但可以有多条曲线折痕。 直线折痕 大大减少了 折 纸 力 学 超 材 料 的 设 计 自 由 度, 进 而 限制了 其 可 定 制 力 学 特 性 [ 14] 。 基 于 三 浦 折 纸, Gattas 等 [ 15] 提出了一种曲线折痕折纸结构建模方 法。 在此基础上,Zhai 等 [ 16] 提 出 了 一 种 曲 线 折 痕 折纸力学超材料,并证实了其在轻质机械爪、隔振 和多级刚度 响 应 等 方 面 的 应 用 潜 力;利 用 碳 纤 维 增强复合材料,Du 等 [ 17] 设计了一种复合材料曲线 折痕折纸超 材 料 夹 芯,并 发 现 通 过 改 变 夹 芯 厚 度 可实现屈 曲 和 破 坏 2 种 失 效 模 式 的 定 制。 然 而, 目前很少有研究薄壁管状的曲线折痕折纸力学超 材料,一定程 度 上 限 制 了 曲 线 折 痕 折 纸 力 学 超 材 料的实际工程应用潜能。 本文设计了一种曲线折痕圆柱折纸力学超材 料, 其二维基本单元由 Explicit 分析方法可有效求解准静态问题 [6,18] 此外,相比 w 1 = 10 mm 和 w 1 = 15 mm 的情况, 当 w 1 = 12 mm 时,力学超材料在加载初段出现的第 一次峰值力明显高很多。 这是由于 w 1 = 12 mm 时 力学超材料上半部分的扭转刚度很大,且在加载初 段主要变形模式为上半部分扭转。 由此可见,当描 述基本单元折痕图的其他参数保持不变,w 1 越小, 折纸力学超材料压缩过程中的主要变形模式为" 整 体扭转" →" 面板弯曲" ;而 w 1 越大,折纸力学超材 料压缩过程中的主要变形模式为" 上半部分扭转" 较大时,折纸力 学超材料压缩过程中的 主 要 变 形 模 式 为 " 整 体 扭 转" →" 面板弯曲" ,出现整体压扭现象;而 w 1 较大 且 w 2 较小时,主要变形模式为" 上半部分扭转" → "上半部分面板弯曲" →" 下半部分扭转" →" 下半部 分面板弯曲" ,出现局部压扭现象。 这是由于当 w 1 较小且 w 2 较大时,曲线折痕圆柱折纸力学超材料中 部扭转刚度较小,在受到轴向压缩时容易出现整体 扭转失稳;而因当 w 1 较大且 w 2 较小时,曲线折痕圆 柱折纸力学超材料中部扭转刚度较大,致使其上半 部分和下半部分更容易出现局部扭转失稳。 此外, 基于直线折痕的折纸力学超材料的变形模式一般为 " 折痕转动" 和" 面板弯曲" [4] , 且一般通过调整材 料厚度来实现不同变形模式的定制 [15] 。 而本文所 提折纸力学超材料可以通过在基本单元二维折痕图 上定制曲线折痕实现对曲线折痕圆柱折纸力学超材 料压缩力学响应和变形模式的定制,且出现了更加 丰富的变形模式。 值得指出的是,相较于直线折痕 折纸力学超材料,曲线折痕转动在力学超材料变形 过程中并不起主导作用,但会伴随其他变形模式发 生曲线折痕的转动。 2) 控制其他几何参数不变,调控 w 1 和 w 2 可实 曲线折痕圆柱折纸力学超材料变形模式的转变,即, 当 w 1 较小且 w 2 较大时,变形模式为" 整体扭转" → "面板弯曲" ( 整体压扭特性) ,而当 w 1 较大且 w 2 较 小时,变形模式变为" 上半部分扭转" →" 上半部分 面板弯曲" →" 下半部分扭转" →" 下半部分面板弯 曲" ( 局部压扭特性) ; ...
... Unlike the Miura-Ori, this pattern does not have a single degree of freedom, due to its degree-6 vertices which have three degrees of freedom [94]. The Yoshimura pattern has been used in pneumatic actuators [103], energy absorption [104], and in the development of a barrel vault [105]. ...
Article
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The field of foldable and physically reconfigurable antennas has recently attracted significant interest from diverse scientific communities, including researchers on antennas, material science, mechanical engineering and numerical modeling. Deployable, packable and multifunctional systems are very important for many applications, including satellite communications, UAVs, CubeSats as well as airborne and spaceborne communication systems. Foldable and physically reconfigurable antennas, particularly origami-based antennas, can provide new capabilities for the aforementioned applications. In this work, we present emerging research on foldable and physically reconfigurable antennas. Such antennas morph their shape to adapt and reconfigure their EM performance (e.g., frequency of operation, bandwidth, polarization, beamwidth, etc.). Also, origami antennas provide ultra-compact stowage, easy deployment, reduced weight, enhanced EM performance and multifunctional utility.
... These columns typically consist of folded sheets or intricate modules, and they exhibit some unique characteristics, such as auxetics, tunable nonlinear stiffness, and multistability. Many scholars have applied the prefolded approach to absorb energy for crashworthiness design (Yang et al., 2016(Yang et al., , 2018. A typical design approach to enhance a vehicle's crashworthiness is to install energy absorption devices that deform and absorb kinetic energy during a low-speed collision (Ma & You, 2014b). ...
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This paper reveals the mechanical behavior of thin-walled columns with pre-folded patterns subjected to compressive loading. The column specimens (Polylactic Acid) are fabricated using Fused Deposition Modeling 3D printer and subjected to quasi-static compressive loading to investigate their mechanical behavior (by modifying the specimens' cross-section patterns and folding angles). The column specimens are simulated by finite element analysis to understand how the stress distribution and local deformation affecting the stiffness, strength, and overall deformation. The experiments showed that introducing the pre-folded pattern in a thin-walled column with different cross-sections can dramatically lower its structural stiffness (85%) and compressive strength (69%), but increase its deformability (115%), which is good agreement with numerical simulation. The variation of cross-section patterns and pre-folding angle could effectively modify the compressive mechanical behavior. Moreover, the results demonstrate how the FDM 3D Printing method can be used in fabricating a thin-walled column with irregular shapes and then to modify its deformability. This finding can be useful for designing any complex structures requiring specific stiffness and deformation such as suspension devices, prosthetic devices in biomechanics, and robotic structures.
... In this regard, Li et al. [29] proposed a thin-walled polyhedral pipe liner for rehabilitation of underground smooth pipes and investigated its elastic buckling capacity under external pressure. Similar to an origami structure [30], a textured pipeline may have high impact resistance and favorable energy absorption capacity. ...
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A series of physical tests and finite element (FE) analyses are conducted to evaluate the failure of smooth (conventional) and textured (proposed concept) pipes. To do so, hydrostatic pressure tests are performed on aluminium beverage cans (ductile failure) and additively manufactured Ti6Al4V-0406 titanium pipes (brittle failure). Mechanical material properties are obtained from tensile tests of coupon samples. In absence of physical burst pressure tests, FE models are validated against experimental results of external pressure tests and are used to predict the buckle initiation (Pi) and burst pressure (Pb) capacity of the textured pipes with different number of circumferential triangles, N, and base angles, a. Results show that buckle initiation pressures of the textured concept is 2.34 and 1.80 times greater than those of the smooth aluminium cans and titanium pipes, respectively. However, the burst pressure of the textured pipe can only get 3% greater than the smooth pipe. Based on the current results a textured pipe with N=6 and a=30° is the optimum textured design.
... After understanding the folding behavior of a single-layer structure, the reachable workspace of a multi-layer structure is examined, which is an important index for robot design. Note that Yoshimura-ori structure has also been exploited for pneumatic actuation (Paez et al., 2016), energy absorption (Yang et al., 2016), and Barrel Vault (Cai et al., 2015), however, a theoretical framework of folding kinematics has not been developed. ...
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Earthworm-like robots have received great attention due to their prominent locomotion abilities in various environments. In this research, by exploiting the extraordinary three-dimensional (3D) deformability of the Yoshimura-origami structure, the state of the art of earthworm-like robots is significantly advanced by enhancing the locomotion capability from 2D to 3D. Specifically, by introducing into the virtual creases, kinematics of the non-rigid-foldable Yoshimura-ori structure is systematically analyzed. In addition to exhibiting large axial deformation, the Yoshimura-ori structure could also bend toward different directions, which, therefore, significantly expands the reachable workspace and makes it possible for the robot to perform turning and rising motions. Based on prototypes made of PETE film, mechanical properties of the Yoshimura-ori structure are also evaluated experimentally, which provides useful guidelines for robot design. With the Yoshimura-ori structure as the skeleton of the robot, a hybrid actuation mechanism consisting of SMA springs, pneumatic balloons, and electromagnets is then proposed and embedded into the robot: the SMA springs are used to bend the origami segments for turning and rising motion, the pneumatic balloons are employed for extending and contracting the origami segments, and the electromagnets serve as anchoring devices. Learning from the earthworm’s locomotion mechanism--retrograde peristalsis wave, locomotion gaits are designed for controlling the robot. Experimental tests indicate that the robot could achieve effective rectilinear, turning, and rising locomotion, thus demonstrating the unique 3D locomotion capability.
... The desire to decrease initial peak forces while increasing energy absorption capacity motivates research and development of new materials and meso-and macroscale geometries [31]. While most commercial crush tubes are made of extruded aluminum or stainless steel, there are variations. ...
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With approximately 5.9 million vehicular collisions in the United States per year, the ability of a vehicle to absorb energy during a collision is critical to reducing the likelihood and severity of injuries. A primary means to absorb energy during a collision is a crush tube, which is a predominantly-prismatic-shaped, metallic structure located at the front or rear of a vehicle intended to absorb energy by progressively buckling in addition to dissipating energy, crush tubes must be light weight to reduce vehicular green-house gas emissions, resilient to fatigue, resilient to environmental exposure, and economically feasible to manufacture. Historically, these competing objectives have been satisfied via extrusion, hydroforming, or a combination of extrusion and hydroforming manufacturing processes. Such manufacturing processes limit geometric freedom, resulting in a peak initial force significantly greater than the mean force during progressive buckling. Thus, the problem, i.e., crush tubes cause an excessively large initial deceleration due the current manufacturing process. This research seeks to address this problem via two actions: Explore fused depositional modeling (FDM) as a possible manufacturing process for energy dissipating structures. Characterize the effects of FDM processing parameters and honeycomb meso-structures on energy dissipation properties (e.g., peak initial for, mean force, total energy dissipated, slope of force-deflection curve during progressive buckling). Honeycomb structures will be subjected to quasi-static, compressive forces within a design of experiments (DOE) framework. The results of this thesis can be used to influence the design of crush tubes and energy dissipative structures made of materials that are more conductive to automotive components such as aluminum or steel. The results can also be used to categorize the physical properties of Polylactic Acid 3D printed components.
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Thin-walled tubes with origami patterns exhibit good energy absorption capacity under axial tension. In this study, the tensile behavior of thin-walled tubes with pleated patterns, known as origami bellows, was first systematically investigated. Parametric study was conducted to determine the influence of origami patterns and wall thicknesses on the energy absorption performance and deformation mechanism of origami bellows. The experimental and numerical results showed that a desirable tensile process without excessive initial peak force, followed by a stable and high plateau force, could be obtained. The non-rigid deployment mechanism of origami bellows under tension is observed. The specific energy absorption of the origami bellows increases as the unit width decreases provided that the value of the unit width is less than a critical value. The mean tensile force increased with the pre-folding angle, with a maximum increase of 16% in our cases, and increased as the wall thickness increased to a power of 1.67. This study provides a new avenue for constructing an energy absorber with excellent energy-absorption performance under tensile loading.
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An expanding energy absorber with variable thickness distribution tube is proposed and studied in this work. At first, a uniform thickness tube structure finite element (FE) model was developed and then verified by the results of an impact test. The parametric study found that outer obliquity angle β and inner obliquity angle γ have positive influence on initial peak force (Fp). While as axial distribution ratio l less than 0.1, the l has significant positive effect on Fp. The non-monotonicity of specific energy absorption (SEA) with design parameters of β and γ was found. Increasing the parameter l could obviously improve the SEA. To obtain the optimal design, an integrated optimization methodology was applied. The Pareto fronts show that there is a lot of room for improvement of original design. The optimal compromising solution increased the SEA by 12.60 % with Fp decreased by 14.24 kN comparing with that of original design. At last, the optimization result were verified. The study stated that the proposed variable thickness distribution tube of expanding energy absorber is conducive to improving the crashworthiness of rail vehicles.
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Origami has emerged as a powerful mechanism for designing functional foldable and deployable structures. Among various origami patterns, a large class of origami exhibits rotational symmetry, which possesses the advantages of elegant geometric shapes, axisymmetric contraction/expansion, and omnidirectional deployability, etc. Due to these merits, origami with rotational symmetry has found widespread applications in various engineering fields such as foldable emergency shelters, deformable wheels, deployable medical stents, and deployable solar panels. To guide the rational design of origami-based deployable structures and functional devices, numerous works in recent years have been devoted to understanding the geometric designs and mechanical behaviors of rotationally symmetric origami. In this review, we classify origami structures with rotational symmetry into three categories according to the dimensional transitions between their deployed and folded states as three-dimensional to three-dimensional, three-dimensional to two-dimensional, and two-dimensional to two-dimensional. Based on these three categories, we systematically review the geometric designs of their origami patterns and the mechanical behaviors during their folding motions. We summarize the existing theories and numerical methods for analyzing and designing these origami structures. Also, potential directions and future challenges of rotationally symmetric origami mechanics and applications are discussed. This review can provide guidelines for origami with rotational symmetry to achieve more functional applications across a wide range of length scales.
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This study involved the design of energy absorbing structures that have precisely tailored performances based on the differences between the bifurcated motions of a Tachi-Miura polyhedron (TMP) with flat-foldable and load-bearing motions. The tailored performance is explored with finite element analysis and experiments using test pieces fabricated via additive manufacturing. Significant differences are observed between the force responses of TMPs with flat-foldable and load-bearing motions. Moreover, no initial peaks of force responses and plateau forces are observed in the long-stroke range by breaking load-bearing motions. In other words, the TMPs exhibit suitable properties for energy absorption. In addition, the force responses against dynamic loading are measured by projecting an impactor with a mass of over 100 kg, where the TMP with load-bearing motion completely absorbs high-impact energy. In conclusion, these findings enable the design of energy absorption structures that can be tailored to handle several types of collision scenarios over a wide energy range.
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Most well-known classic origami patterns to date come from human inspirations. The present article is aimed to make use of the exceptional computational capabilities of computers, so as to systematically devise a routine for netting origami bearing desirable properties from a vast pool of candidates. A gene coding strategy, which is carried out through ternary strings, is introduced to enhance the portability of digital origami representation. The proposed gene codes are found highly compressible on binary infrastructures underpinning modern computers. Then a simulation scheme is then given to hunt for origami structures bearing high folding ratios, which see a potential use in solar panel design. After several hours of simulations on a standard computer, five configurations bearing high folding ratios are singled out among 1044 theoretical possibilities. One of them just coincides with a conceptual solar panel design by NASA, and the other four, as far as the authors know, have not been reported in literature yet.
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Origami patterns can be used to inspire the designs of structural materials with beneficial properties, such as low strength-to-weight ratios. This study explores the design, manufacturing, and mechanical properties of three different origami-inspired shapes, as well as three different material combinations for each shape, through dynamic impact testing and quasi-static compression testing. The commonly studied Miura origami pattern will be compared to two uncommon patterns: a square-based pattern and a triangular-based pattern. The samples are 3D printed and the material combinations include one rigid and one flexible polylactic acid (PLA) sample, and one multi-material configuration with flexible PLA crease areas and rigid PLA origami faces. The rigid square sample was the most effective at absorbing a single drop-weight impact load and the flexible Miura pattern was most effective at absorbing impact loads when multiple drops were performed on the same sample. The rigid triangular structure withstood the highest loads during the quasi-static compression testing. A finite element model of the quasi-static compression test was built to enhance the analysis of the various tested configurations.
Article
In this paper, we present a comprehensive study of mechanical characteristics of a reconfigurable origami-inspired structure using Finite Element and Artificial Neural Network (ANN) approaches. We introduce a design of crease section in the proposed reconfigurable structure, which undergoes enormous and complicated deformation in the folding and unfolding process. Although this crease design can make the deploying process more straightforward, it can jeopardize the stability and life cycle of the structure. We explore how the geometric parameters of the design affect the stability and fatigue failure, including length ratio, total height, story’s height, thickness, crease indexes, and circumscribed circle’s radius. In order to reduce the computational time, we develop an ANN employing the obtained Finite Element method (FEM) results. The ANN results demonstrate that decreasing the circumscribed circle’s radius, the length ratio, and the total height enhance the stability of the origami-inspired structure. It is found that crease indexes affect stability based on the radius of the circumscribed circle. In addition, we investigate how these parameters simultaneously contribute to this design’s buckling load and life cycle. The results provide a detailed design parameter characteristic map that can be used to optimize origami structure performance.
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In this paper, an innovative type of thin-walled structures, the convex-concave honeycomb columns (CCHCs) with transverse negative Poisson’s ratio (NPR), is proposed for energy absorbers by replacing the cell walls of square honeycomb lattice columns with sine-shaped or zigzag-shaped walls of equal mass. Numerical simulations show that, under axial impact, contrary to the conventional square honeycomb columns of equal mass, the transverse cross section of NPR CCHC shrinks inward, making the cell walls of CCHC contact and interact sufficiently with each other and thus dissipate the impact energy much more effectively. By suitably adjusting the transverse NPR, the CCHC can have the combined advantages of effective total energy absorption, high specific energy absorption and low maximum peak crushing force. The research of this paper provides a new strategy for the design of high-performance energy absorbers widely used in the engineering fields of vehicle engineering, aerospace engineering etc.
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In this study, we investigated the energy-absorption characteristics of an origami honeycomb in the out-of-plane crushing process. Accordingly, the numerical simulation results showed that, compared with conventional honeycombs, origami honeycombs exhibit a more stable folding process. Moreover, owing to the guiding effect of the creases, the deformation mode of origami honeycombs during compression is predictable. Additionally, the energy-absorption characteristics of the origami honeycombs were theoretically deduced using the super-folding method, and the error between the theoretical and simulation results was between -8.55% and 6.50%, which verifies the accuracy of the theoretical model.
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In this work, a novel layered aux-hex honeycomb (LAHH) filled tube (LAHHFT) structure is proposed and investigated. A series of LAHH and LAHHFT structures with different number of aux-hex interfaces is designed and analyzed via extensive finite element analyses (FEAs). The results indicate that the designed LAHH and LAHHFT structures possess significantly higher effective Young's modulus, mean crushing stress (MCS) and specific energy absorption (SEA) than the single honeycombs and single honeycomb filled tubes under the same relative density. Double interaction effect, i.e. aux-hex interaction and LAHH-tube interaction, contributes to the superior improvement. Quantification of the interaction effect shows that the relative improvement of the MCS and SEA due to the double interaction effect could reach up to 617% and 557% for the LAHHFT structures. Theoretical models are carried out to predict the mechanical and crushing stress properties of the proposed hybrid structures considering interaction effect, which agree well with the FEA results. Besides, the interaction also affects the deformation modes of the LAHH and LAHHFT structures, which in turn influences the energy absorption performance. Three different crushing deformation modes including global bending mode, straight folding mode and mixed deformation mode occur to the LAHHFT structures. A theoretical model is also established and provides a good explanation to the change of deformation modes. This study offers a new route and a useful guideline for the design of future high-performance light-weight materials and structures.
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Abstract Origami crash tubes have concerned nowadays due to their superior crashworthiness behavior by controlling the initial buckling force and collapse modes. In this paper, a Multi-layered origami pattern is proposed, and numerical analysis is investigated under quasi-static axial compressive loading and validated by the experimental result of the fabricated origami crash box. To compare the energy absorption efficiency of this proposed origami tube, its mechanical responses are normalized with the conventional octagonal tube. Moreover, for parametric study, the crashworthiness behavior of 64 samples is investigated for the parameters of the dihedral angle 2θ, outer layer height e, and module number M. It is demonstrated that by increasing M with a constant value of e, the critical angle of θ decreases. By increasing the value of e with constant values of M and θ, the mechanical responses of tube increase, and these trends are valid as long as θ is below the critical angle. The number of modules M, angle θ, and outer layer height e have the highest effect on the mechanical responses. Finally, the results show that by maintaining the specific energy absorption of the conventional octagonal tube, the initial peak force can be reduced by 55%. Furthermore, the proposed pattern reduces the initial peak force while maintaining the specific energy absorption, leaving designers free to design. Keywords: Origami, crash box; energy absorption; FEM; Axial crushing, quasi-static, simulation, experimental.
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Composite sandwich tubes have been widely used in aviation and automobile industries due to their high specific mechanical properties. This paper presents an experimental and numerical study on the energy absorption properties of composite sandwich tubes with pre-folded core (CSTPC) based on the full-diamond origami pattern. The CSTPC specimens were fabricated using the hot-press and vacuum-bag molding methods. Axial compression tests were carried out to obtain the mechanical properties of CSTPC with and without the inversion cap. The experiment results showed that CSTPCs with the inversion cap exhibit impressive energy absorption properties. Secondly, the FE modelling method for CSTPC with the inversion cap was developed and validated with the experiment data. An extensive parametric study on CSTPCs with various CSTPC geometries, wall thickness and composite layups and geometries of the inversion cap was conducted. Moreover, CSTPC was compared to the stand-alone straight or pre-folded composite tube and composite sandwich tube with corrugated core. The results showed that CSTPC possesses better energy absorption performance than the stand-alone tubes or the tube with corrugated core.
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In this paper, the energy absorption behavior of a novel multibody circular tube is investigated based on the experimental and numerical methods. To achieve the best design for the segments, the bell-end circular tubes, a multi-objective optimization technique was implemented using Python and MATLAB with four various objective functions such as absorbed energy, mass, peak crush force, and average crush force. Moreover, an arrangement of these bell-end tubes as a multibody structure would decrease the total length, obtain less capacity usage, and have better crashworthiness characteristics. The results elucidate an enormous decrease in the peak crush force and an increase in specific absorbed energy in comparison with the thin-walled circular tubes having the same mass. Finally, the energy absorption behavior of the optimal multibody circular tube was tested and compared to the obtained numerical results in single and double forms.
Article
Carbon fiber reinforced polymer (CFRP) thin-walled tubular structures have been widely used in lightweight energy absorbing components. In this paper, CFRP tubular braided-textiles, foam-filling technique, and sandwich structure were both applied to make low-cost multi-walled sandwich tubular structures. Through axial compression tests, the compression behaviors, crushing modes and energy absorption performance of the braided-textile reinforced multi-walled sandwich tubes were contrastively analyzed. Experimental results show that the foam-filling technique and the sandwich structure are both effective in modifying the crushing patterns and improving the energy absorption efficiency. Especially for the multi-walled sandwich structure, it can increase the specific energy absorption (SEA) by at least 66% and change the crushing mode from local bucking to progressive diamond folding.
Article
Energy absorption devices are widely used to mitigate damage from collisions and impact loads. Due to the inherent uncertainty of possible impact characteristics, passive energy absorbers with fixed mechanical properties are not capable of serving in versatile application scenarios. Here, we explore a deployable design concept where origami tubes can extend, lock, and are intended to absorb energy through crushing (buckling and plasticity). This system concept is unique because origami deployment can increase the crushing distance between two impacting bodies and can tune the energy absorption characteristics. We show that the stiffness, peak crushing force, and total energy absorption of the origami tubes all increase with the deployed state. We present numerical and experimental studies that investigate these tunable behaviors under both static and dynamic scenarios. The energy-absorbing performance of the deployed origami tubes is slightly better than conventional prismatic tubes in terms of total absorbed energy and peak force. When the origami tubes are only partially deployed, they exhibit a nearly-elastic collapse behavior, however, when they are locked in a more deployed configuration they can experience non-recoverable crushing with higher energy absorption. Parametric studies reveal that the geometric design of the tube can control the nonlinear relationship between energy absorption and deployment. A physical model shows the potential of the self-locking after deployment. This concept for deployable energy-absorbing origami tubes can enable future protective systems with on-demand properties for different impact scenarios.
Article
In this paper, we present a comprehensive fatigue analysis of a foldable origami helical antenna with Finite Element Method (FEM) and Artificial Neural Network (ANN). We study the effect of design parameters such as total height, length ratio (b/a), height of story, thickness, length and thickness ratios of creases, and radius of the circumscribed circle of polygonal on the fatigue life. We employ ANN method to reduce the computational cost of the conventional methods for predicting the fatigue life of the origami antenna. Although ANN is trained with a limited set of data, our results reveal that the proposed approach predicts the fatigue failure of the antenna with high accuracy. This trained ANN determines the life cycle of the origami structure with less than 1% error on the training set and less than 2% error on the test set. The ANN results illustrate that the fatigue life of the structure is improved by increasing the radius of the circumscribed circle and decreasing the thickness of the structure. We discover that some values of the length ratio (b/a) magnify the effect of total height on the life cycle. In addition, we show how the creases parameters of the structure play an important role in the fatigue life of the antenna.
Article
Origami has recently emerged as a platform for building functional engineering systems with versatile characteristics that targeted niche applications. One widely utilized origami-based structure is known as the Kresling origami spring (KOS), which inspired, among many other things, the design of vibration isolators, fluidic muscles, and mechanical bit memory switches. KOSs are traditionally constructed out of foldable materials (e.g. paper, kapton, fabric, polyethylene terephthalate, and acetate sheets) using conventional fabrication processes which include manual folding and creasing. Such materials and fabrication methods are ideal for conceptual illustrations and laboratory testing, but lack many important aspects necessary for real-world implementation. In addition to the very low durability resulting from the high plastic deformations at the folds; lack of repeatability, and high variation of performance among similar samples are typically inevitable. To circumvent these issues, this paper presents a novel approach for the design and 3D printing of a KOS which mimics the qualitative behavior of a paper-based KOS without compromising on durability, repeatability, and functionality. In the new design, each fundamental triangle in the traditional KOS is replaced by an inner central rigid core and an outer flexible rubber-like frame, which are fabricated out of different visco-elastic materials using advanced 3D printing technologies. The quasi-static behavior of the fabricated springs is assessed under both compressive and tensile loads. It is shown that KOSs with linear, softening, hardening, mono- and bi-stable restoring force behavior can be fabricated using the proposed design by simple changes to the geometric design parameters. The durability of the resulting springs is also assessed with no changes observed in the quasi-static behavior even after 5000 loading cycles.
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This work presents an innovative honeycomb cell geometry design with enhanced in-plane energy absorption under quasi-static lateral loads. Numerical and experimental compression tests results under axial and lateral loads are analyzed. The proposed cell geometry was designed to overcome the limitations posed by standard hexagonal honeycombs, which show relatively low stiffness and energy absorption under loads that have a significant lateral component. To achieve this, the new cell geometry was designed with internal diagonal walls to support the external walls, increasing its stiffness and impact energy absorption in comparison with the hexagonal cell. 3D-printed unit-cell specimens made from ABS thermoplastic material were subjected to experimental quasi-static compression tests, in both lateral and axial directions. Energy absorption was compared to that of the standard hexagonal cell, with the same mass and height. Finite element models were developed and validated using experimental data. Results show that the innovative geometry absorbs approximately 15% more energy under lateral compression, while maintaining the same level of energy absorption of the standard hexagonal cell in the axial direction. The present study demonstrates that the proposed cell geometry has the potential to substitute the standard hexagonal honeycomb in applications where significant lateral loads are present.
Article
Textured pipe has been proposed to improve the propagation buckling capacity of subsea pipelines recently. Due to its special geometry, textured pipe may have the potential to mitigate the vortex induced vibration (VIV) by altering the wake vortex street formation. In the present study, the effectiveness of using a full-diamond textured pipe for VIV suppression is numerically investigated in a coupled fluid-structure interaction (FSI) framework. Three-dimensional (3D) Computational Fluid Dynamics (CFD) analyses are performed by using the Reynolds-Averaged Navier-Stokes (RANS) turbulence model equipped with shear stress transport (SST)K−ω model at the subcritical Reynolds numbers (Re) with Re∈[2000,12000]. The results are compared in detail with an equivalent conventional smooth cylinder subjected to the same flow conditions. Numerical results show that the textured cylinder can significantly mitigate the undesired VIV and the associated hydrodynamic forces. It eliminates the upper excitation regime in the conventional smooth cylinder and the width of the synchronization regime is also remarkably reduced.
Article
Thin-walled structures have been widely applied as energy absorption devices due to their lightweight, high energy dissipating capability through large deformation, and low cost. The mechanical behavior of a structure is mainly determined by its deformation mode, which is expected to have a low initial peak force, steady and large deformation progress and most importantly a high energy absorption per unit mass. As a result, thin-walled structures with specifically designed patterns pre-folded on the surfaces have been proposed and extensively studied, by utilizing the patterns to trigger pre-determined deformation modes so as to improve the energy absorption capacity. In this paper, the geometric design, deformation mode and mechanism, and energy absorption of the patterned structures in the form of tubes, foldcores, and metamaterials are reviewed. The main achievements and limitations of the existing works are summarized, followed by suggestions of future research challenges.
Article
Origami-inspired materials, such as the popular Miura-ori design, are gaining popularity as advanced materials. This work expands on the library of origami designs for structural materials. An origami design composed of interlocking triangles was parameterized in a two level, full factorial, design of experiment. Its folding mechanism was analysed and verified through compression testing of 3D printed samples. The peak fold location in the pattern was the most influential parameter affecting the folding mechanism. Varying the top triangle angle affected the origami structures’ radii at given fold angles, and the triangle edge length created small changes in the structures’ shape.
Article
Kirigami-based metamaterials are demonstrated to possess peculiar mechanical behaviors via carefully engineered architectures. This paper reports on the comprehensive investigation of a novel kirigami-based lantern chain. We tailor and fabricate the kirigami lanterns using simple paper sheets yet achieve an exceptional impact mitigation capability (orders of magnitude lower transmission compared to various available metamaterials). Detailed experimental and numerical exploration uncovers that the unique folding-unfolding behavior of kirigami lanterns during stress wave propagation yields energy redistribution and storage in different cells. Accordingly, an expanded waveform with decreasing amplitude and oscillating tails is achieved within the 1D chain, largely mitigating the impact. Meanwhile, the plastic deformation of paper materials also contributes to outstanding performances. Based on a validated finite element (FE) model, the governing laws of critical parameters, including impact energy, cell number, petal number, and hinge number, are systematically explored, where we find that the mitigation effect is also satisfactory even at the increased impact energy scenarios. Furthermore, an adaptable design of kirigami chain length and other geometric parameters is exploited to realize highly efficient and controllable mitigation when subjected to specific impact energy. This paper illustrates a new route to designing superior impact mitigation structures with ultra-lightweight materials, offering insights for innovation of next-generation impact protection strategies in the automotive and aerospace industries.
Article
In this paper, a local surface nanocrystallization technology is used for thin-walled structures with square cross sections, and an energy absorption device of two-staged combined energy absorption structure is proposed. In virtue of the surface nanocrystallization that enables to change the material on local positions, the structural deformation is induced and controlled to maximize the energy absorption capacity. A numerical model of the two-staged combined energy absorption structure is established, and the local surface nanocrystallization layout is optimized. The results show that the specific energy absorption of two-staged combined structure with local surface nanocrystallization can be increased by 34.36% compared with the untreated counterpart of the same material and structural shape. The ratio between the first and second peak crushing forces and the energy absorption allocation ratio between the two stages can be adjusted in the ranges of 0.26–0.55 and 0.31–0.45, respectively, which can be controlled by the local surface nanocrystallization designs. The numerical simulation and experimental results are in good agreement, which shows that the design for energy absorption device with local surface nanocrystallization is feasible and effective.
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Analytical modeling is conducted to examine the quasistatic response of Miura-ori-based metamaterials under compression in two principal directions. For the x3 direction (out-of-plane) compression, the analytical results agree well with experiments and finite-element (FE) simulations. For compression in the x1 direction (in-plane), the analytical model can predict the initial force. Additionally, the strain-hardening effect of the cell wall material of Miura-ori metamaterial is also taken into consideration, and verified by the FE simulations. The ratio of the two forces corresponding to compression in the two respective directions is also obtained, offering a convenient way of assessing material properties. The energy absorption efficiency in different directions is compared. This study demonstrates that the performance of origami metamaterials can be tuned merely by changing the geometric parameters of the origami unit. The work should also provide theoretical guidance for designing metamaterials at small-scale unit cells.
Preprint
Origami-baed metamaterial has shown remarkable mechanical properties rarely found in natural materials, but achieving tailored multistage stiffness is still a challenge. This study proposes a novel zigzag-base stacked-origami (ZBSO) metamaterial with tailored multistage stiffness property based on crease customization and stacking strategies. A high precision finite element (FE) model to identify the stiffness characteristics of the ZBSO metamaterial has been established, and its accuracy is validated by quasi-static compression experiments. Using the verified FE model, we demonstrate that the multistage stiffness of the ZBSO metamaterial can be effectively tailored through two manners, i.e. varying the microstructures (through introducing new creases to the classical Miura origami unit cell) and altering the stacking way. Three strategies are utilized to vary the microstructure, i.e. adding new creases to the right, left, or both sides of the unit cell. We further reveal that the proposed ZBSO metamaterial has several outstanding advantages compared with traditional mechanical metamaterials, e.g. material independent, scale-invariant, lightweight, and excellent energy absorption capacity. The unravelled superior mechanical properties of the ZBSO metamaterials pave the way for the design of the next-generation cellular metamaterials with tailored stiffness properties.
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The bumper systems (beams and face bars) are parts of the car body structure, one of the most important components of an auto vehicle because of its role in absorbing the energy of an impact by deformation. The main objective of this paper is to study, optimize the built shape of the frontal members beams used in the endurance structure of motor vehicles in terms of their ability to absorb internal energy resulting from a frontal impact under the principles of sustainability. The study combines the classical technology used in the construction of vehicles with, the Origami Engineering” technique, which is generally used by NASA, but also by engineers in other fields: aeronautics, nanotechnology or medical technique. Simulation analyses were performed using the finite element on different types of thin-walled metal tubes, but also an origami structure.
Article
Multi-wall profile as one of the most widely approaches can enhance the crashworthiness properties in thin-walled tubular structures. In actual application process as energy absorbers, there may be a variety of circumstances including axial crushing and lateral crushing. However, the crashworthiness in the multi-wall tubular structure considering both axial crushing and lateral crushing circumstances has rarely been evaluated in the existing literature. In the study, a new tailored-property multi-wall thin-walled structure (TMTS) is put forward to increase the ultimate strength of this material in the region of corner to accommodate two conditions including lateral and axial crushing conditions. Finite element models verified from experiments were established in PAM-CRASH to analyse the crashworthiness performance for this structure. Under lateral and axial crushing, it was revealed that TMTSs exhibited obvious superiority to the corresponding traditional structures. It was concluded that wall thickness, tailoring length and other geometry parameters could effectively influence the crushing performance of the TMTSs. In addition, the progressive deformation mode could be exhibited by the well-designed TMTSs under axial impact. Furthermore, the theoretical model of the TMTS was proposed according to the Super-folding Element Theory. Theoretical analysis is consistent with simulation results, which proves that the deformation formula and the analytical model are all correct. Finally, according to the multi-objective optimisation method, the thicknesses of tailored and non-tailored regions of the TMTS were reasonably configured to further enhance crashworthiness. The research results provide good guidance and theoretical support for the development of novel lightweight energy-absorbing structures under various loading circumstances.
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Origami structures have attracted considerable attention from engineering and science fields, and a variety of numerical methods have been proposed for analysis of this kind of structure. Most of the origami-related numerical studies focus on the static or quasi-static analysis of the folding process. However, the dynamic unfolding of origami triggered by the energy stored in the creases could provide us more insight about the origami intrinsic properties. In this study, we propose a dynamic analysis framework in which the particle-bar-spring model and finite particle method are combined. The proposed method can be used in the dynamic analysis of general origami structures, regardless of whether the structure is rigid or non-rigid, and regardless of whether the structure has a single degree of freedom (DOF) or multiple DOFs. The dynamic unfolding process of a simple origami fold, a six-crease waterbomb tube pattern, a Miura pattern, and a quadrangular Resch pattern are simulated and analyzed. The energy analysis of the four patterns helps to verify the correctness of the proposed method and provides the details for how different energies transform into each other during the unfolding process. The dynamic unfolding analysis reveals the global dynamic response and free unfolding trajectories of these origami structures, which have never been presented by previous numerical analysis.
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Auxetic metamaterials are synthetic materials with microstructures engineered to achieve negative Poisson's ratios. Auxetic metamaterials are of great interest because of their unusual properties and various potential applications. However, most of the previous research has been focused on auxetic behaviour of elastomers under elastic deformation. Inspired by our recent finding of the loss of auxetic behaviour in metallic auxetic metamaterials, a systematic experimental and numerical investigation has been carried out to explore the mechanism behind this phenomenon. Using an improved methodology of generating buckling-induced auxetic metamaterials, several samples of metallic auxetic metamaterials have been fabricated using a 3D printing technique. The experiments on those samples have revealed the special features of auxetic behaviour for metallic auxetic metamaterials and proved the effectiveness of our structural modification. Parametric studies have been performed through experimentally validated finite element models to explore the auxetic performance of the designed metallic metamaterials. It is found that the auxetic performance can be tuned by the geometry of microstructures, and the strength and stiffness can be tuned by the plasticity of the base material while maintaining the auxetic performance.
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The specific energy absorbed during uniaxial tension and during axial compression of cylindrical tubes with various wall thicknesses and diameters has been measured for 1015 steel in two heat treatment conditions and for 6061 aluminum alloy in four heat treatment conditions. For axial compression of tubes, the energy absorbed/unit weight, E//s**c, is a function of the thickness to diameter ratio and the present work shows that for 0. 02 less than t/D less than 0. 1, the dependence is well described by a power law of the form E//s**c equals A(t/D)**m where m varies between 0. 5 and 1. 0 for different materials. A salient finding is that the ranking of materials for specific energy absorption depends upon the testing mode. In tension, it is shown that density rho , ultimate tensile strength sigma //u//l//t and the uniform elongation, epsilon //u are significant in the ranking of materials. Specifically, the present and previous results show that the energy absorbed/unit weight, depends upon both the ultimate tensile strength sigma //u//l//t and the corresponding true (tensile) strains epsilon //u, E//4**T equals sigma //u//l//t epsilon //u/ rho (1 plus epsilon //u). In axial compression, however, the measured variations in E//s**c (for a fixed geometry) with the different materials show that E//s**c is simply proportional to the specific ultimate tensile strength ( sigma //u//l//t/ rho ).
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This paper aims to investigate the energy absorption characteristics of tapered circular tubes with graded thickness (TCTGT) under axial loading. TCTGT specimens were fabricated by a tube tapering machine and the forming effects on crush response were investigated. Both the original straight circular tube and the fabricated TCTGT were tested and compared to analyze the relative merits of TCTGT. Numerical simulations of the tests were conducted by using nonlinear finite element code LS-DYNA and a simplified fabrication process was also simulated. The energy absorption efficiency of the fabricated TCTGTs was found to be considerably higher than that of straight tubes and the forming effects showed important influence on the increase of efficiency. In addition, a novel approach was proposed to predict the mean crushing force of circular and tapered tubes with and without forming effects. The outcomes of the present study will facilitate the design of TCTGT structures with better crashworthiness performance.
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Thin-walled tubes are a kind of popular design for the energy absorbing devices. However, when they are subjected to axial loading, there exists a large undesirable initial peak force, followed by fluctuation in the force–displacement curve. In this paper, the origami patterns are introduced to thin-walled tubes to minimize the initial peak and the subsequent fluctuations. Tubes of square, hexagonal and octagonal cross-sections with origami patterns are investigated by finite element analysis. Numerical results show that compared with the conventional tube, the patterned tubes exhibit a lower initial peak force and more uniform crushing load. The critical states are obtained under which the crushing mode follows the initial origami pattern. The parametric study shows the relationship between the pre-folding angle and the initial peak force as well as the mean crushing force for the tubes with different cross-sections. A prototype of the patterned tube is constructed and tested, showing much lower initial peak force and a smooth crushing process which agrees with the numerical results.
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Introducing thickness gradient in cross-section is a quite promising approach to increase the energy absorption efficiency and crashworthiness performance of thin-walled structures. This paper addresses the deformation mode and energy absorption of square tubes with graded thickness during axial loading. Experimental study is firstly carried out for square tubes with two types of thickness distributions and numerical analyses are then conducted to simulate the experiment. Both experimental and numerical results show that the introduction of graded thickness in cross-section can lead to up to 30–35% increase in energy absorption efficiency (specific energy absorption) without the increase of the initial peak force. In addition, structural optimization of the cross-section of a square tube with graded thickness is solved by response surface method and the optimization results validate that increasing the material in the corner regions can indeed increase the energy absorption efficiency of a square tube.
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Multi-cell columns are highly efficient energy absorbing components under axial compression. However, the experimental investigations and theoretical analyses for the deformation modes and mechanisms of them are quite few. In this paper, the axial crushing of circular multi-cell columns are studied experimentally, numerically and theoretically. Circular multi-cell columns with different sections are axially compressed quasi-statically and numerical analyses are carried out by nonlinear finite element code LS-DYNA to simulate the experiments. The deformation modes of the multi-cell columns are described and the energy absorption properties of them are compared with those of simple circular tube. Theoretial models based on the constituent element method are then proposed to predict the crush resistance of circular multi-cell specimens. The theoretical predictions are found to be in a good agreement with the experimental and numerical results.
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Multi-cell metal columns were found to be much more efficient in energy absorption than single-cell columns under axial compression. However, the experimental investigations and theoretical analyses of them are relatively few. In this paper, the quasi-static axial compression tests are carried out for multi-cell columns with different sections. The significant advantage of multi-cell sections over single cell in energy absorption efficiency is investigated and validated. Numerical simulations are also conducted to simulate the compression tests and the numerical results show a very good agreement with experiment. Theoretial analyses based on constitutive element method are proposed to predict the crush resistance of multi-cell columns and the theoretical predictions compare very well with the experimental and numerical results.
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Crushing energy should sufficiently be absorbed in order to secure the protections of passengers in a car accident. There have been a lot of studies on the crushing energy absorption of a basic structure in automobiles. In this paper, the purpose concerns the crashworthiness of the widely used vehicle structure, square thin-walled tubes, which are excellent on the point of the energy absorbing capacity. An experimental investigation was carried out to study the energy absorption characteristics of thin-walled square tubes subjected to quasi-static axial loading to develop the optimum structural members. Notch shapes and structure modification applied to structural design have nowadays been used to keep up the efficiency of energy absorption. Such ideas may result in the reduction of structural stiffness and buckling or collapse can easily be done in collision. The controller is introduced to improve and control the absorbed energy of thin-walled square tubes in this paper. To predict and control the energy absorption, controller is designed in consideration to its influence such as height, thickness, width ratio, in this study. The absorption energy and mean collapse force of square tubes was increased by 15–20% in using the controller and energy absorbing capability of the specimen was slightly changed by change of the high controller's height.
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A series of axial crushing tests on steel circular cylindrical shells loaded either statically or dynamically is reported and compared with various theoretical predictions and empirical relations. A modified version of Alexander's theoretical analysis for axisymmetric, or concertina, deformations gives good agreement with the experimental results when the effective crushing distance is considered and provided that the influence of material strain rate sensitivity is retained in the dynamic crushing case.
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When a very thin metal tube of cylindrical section is compressed between parallel platens, its walls tend to buckle in and out to form a diamond pattern of deformation around the tube. This paper considers the subsequent behaviour of such tubes when the compression is continued to cause large-scale crumpling of the tube walls. The nature and mode of this crumpling is examined in the light of experimental results and, guided by an approximate theory for an idealized case, an empirical expression for the load required to effect the crumpling is obtained.
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An approximate theory for the process is derived, leading to a solution of the type P = Ct1.5√D, where P is the collapse load, t the shell thickness, D the shell diameter, and C a constant for any given material. Good agreement is exhibited between this relationship and experimental results.
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We performed experimental and theoretical analyses that show a thin-walled cylinder with stiff ribs can be used as a structural element to improve or adjust energy absorption characteristics. We conducted impact crushing tests using several different cylinders with ribs. The experimental results showed that the axisymmetric and non-axisymmetric crushing modes were dependent on not only the cross-section size but also on the distances between the ribs. A critical distance between the ribs was found to exist for generating axisymmetric and non-asxisymmetric crushing modes and it was more than double the wavelength of axisymmetric wrinkles regardless of cylinder size. The mean crushing forces of the axisymmetric modes were found to be roughly 1.3 times larger than those of the non-axisymmetric modes. The theoretical results based on plastic hinge behavior showed good agreement with the experimental results. The effects of material and cylinder size on the crushing behavior of a cylinder with ribs were expressed using approximate mathematical equations. The critical distance between ribs for generating axisymmetric or non-axisymmetric crushing mode was also expressed approximately. Stiff ribs appropriately spaced in a cylinder were found to be effective in absorbing a large amount of energy with a short crushing deformation.
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The paper presents the basic guidelines for the design of a landing gear adopting a crash tube as an energy absorbing device in crash conditions. In the considered landing gear lay-out, a light alloy thin walled tube is mounted coaxially to the shock absorber cylinder and, in severe impact condition, collapses in order to enhance the energy absorption performance of the landing system.A novel triggering mechanism, activated in crash impact conditions, has been developed in order to eliminate the initial load peak in the tube collapse process. The device allows to study the possible design solutions for an additional shock absorbing stage that can be integrated in a landing gear structure without requiring the introduction of frangible attachments.The characteristics of the triggering device are presented and the structural lay-out of a crashworthy landing gear adopting the developed additional energy absorbing stage is outlined. Experimental and numerical results relevant to the triggering system development are reported.The potential performances of a landing gear featured with the additional stage are analysed by means of a simplified numerical model, showing that appreciable energy absorbing capabilities and efficiencies can be obtained in crash conditions.
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The onset of densification of cellular solids represents the start of the cell wall interactions, which enhance the compressive resistance of a cellular solid. Currently, there exists ambiguity in the definition and uncertainty in the determination of the compressive strain, from which the densification regime starts. The onset strain of densification and the densification strain are defined and distinguished in the present study. Several commonly used methods to determine the onset strain of densification are examined. It is shown that the method based on the energy absorption efficiency curve gives unique and consistent results. Two types of energy absorption efficiency curves are identified. Further justifications of the use of the energy absorption efficiency method are provided for various types of cellular solids.
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The energy absorption in a foam-filled thin-walled circular AI tube was investigated based on the experimentally determined strengthening coefficient of filling using AI and polystyrene closed-cell foams with three different densities. Foam filling was found to change the deformation mode of tube from diamond (empty tube) into concertina, regardless the foam type and density used. Although foam filling resulted in higher energy absorption than the sum of the energy absorptions of the tube alone and foam alone, it was not effective in increasing the specific energy than simply thickening the tube wall. It was shown that for efficient foam filling an appropriate foam-tube combination Must be selected by taking into account the magnitude of strengthening coefficient of foam filling and the foam filler plateau load. (c) 2004 Elsevier Ltd. All rights reserved.
Article
This paper presents further experimental investigations into axial compression of thin-walled circular tubes, a classical problem studied for several decades. A total of 70 quasi-static tests were conducted on circular 6060 aluminium tubes in the T5, as-received condition. The range of D/t considered was expanded over previous studies to D/t=10–450. Collapse modes were observed for L/D⩽10 and a mode classification chart developed. The average crush force, FAV, was non-dimensionalised and an empirical formula established as FAV/MP=72.3(D/t)0.32. It was found that test results for both axi-symmetric and non-symmetric modes lie on a single curve. Comprehensive comparisons have been made between existing theories and our test results for FAV. This has revealed some shortcomings, suggesting that further theoretical work may be required. It was found that the ratio of FMAX/FAV increased substantially with an increase in the D/t ratio. The effect of filling aluminium tubes with different density polyurethane foam was also briefly examined.
Article
The results of an experimental investigation of the axial crushing modes and energy absorption properties of quasi-statically compressed aluminium alloy tubes are presented. In particular, the influence of tube length on these properties is discussed and quantified and a classification chart presented. This chart together with other experimental data, enables a designer to predict the energy absorbing properties of a given tube as well as its mode of crushing.
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In the present study, crashworthiness characteristics of thin-walled steel tubes containing annular grooves are studied. For this purpose, the grooves are introduced in the tube to force the plastic deformation to occur at predetermined intervals along the tube. The aims are controlling the buckling mode and predicting energy absorption capacity of the tubes. To do so, circumferential grooves are cut alternately inside and outside of the tubes at predetermined intervals. Quasi-static axial crushing tests are performed and the load-displacement curves are studied. Theoretical formulations are presented for predicting the energy absorption and mean crushing load. It is found a good agreement between the theoretical results and experimental findings. The results indicate that the load-displacement curve and energy absorbed by the axial crushing of tubes could be controlled by the introduction of grooves with different distances. Also, grooves can stabilize the deformation behavior and thus, the proposed method could be a good candidate as a controllable energy absorption element.
Article
The energy absorption characteristics of corrugated tubes are experimentally studied. The corrugations are introduced in the tube to force the plastic deformation to occur at predetermined intervals along the tube generator. The aims are to improve the uniformity of the load—displacement behaviour of axially crushed tubes, predict and control the mode of collapse in each corrugation in order to optimize the energy absorption capacity of the tube. Effect of heat treatment and foam filling of these tubes are also considered. Metal tubes are mostly used throughout this study, however, PVC tubes are also considered for comparison purposes. The experimental results of crushing of the corrugated tubes make these tubes a good candidate for a controllable energy absorption element.
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An extensive experimental database has been established for the structural behaviour of aluminium foam and aluminium foam-based components (foam-filled extrusions). The database is divided into three levels, these are: (1) foam material calibration tests, (2) foam material validation tests and finally (3) structural interaction tests where the foam interacts with aluminium extrusions. This division makes it possible to validate constitutive models applicable to aluminium foam for a wide spectrum of loading configurations. Several existing material models for aluminium foam from the literature are discussed and compared. To illustrate the use of the database, four existing material models for foams in the explicit, non-linear finite element code LS-DYNA have been calibrated and evaluated against configurations in the database.
Article
The paper suggests the introduction of patterns to the surface of conventional thin-walled square tubes to improve the energy absorption capacity under axial compressive loads. A quasi-static axial crushing analysis has been conducted numerically by the nonlinear explicit finite element code LS-DYNA. Two types of patterns constructed using the basic pyramid elements were introduced. Type A pattern was aimed at triggering the extensional mode for relatively thin square tubes whereas type B pattern was intended to develop new collapse mode capable of absorbing more energy during collapse. A total of 30 tubes with a length of 120 mm, thickness 1.2 mm and widths of 40 or 60 mm were simulated. Numerical results showed that all tubes with type A patterns developed the extensional collapse mode instead of the symmetric collapse mode and absorbed about 15–32.5% more energy than conventional thin-walled square tubes with a mass increase less than 5%. Meanwhile, a new collapse mode named octagonal collapse mode was observed for tubes with type B pattern and the energy absorption of tubes developing this mode increased by 54–93% compared with the conventional tube. The influence of various configurations of the patterns on the deformation and energy absorption of the tubes was also discussed. The paper opens up a new avenue in design of high energy absorption components.
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