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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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... 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
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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.
... These include deployability (Chen et al., 2015;Liu et al., 2016b), static load-carrying capability Rejab and Cantwell, 2013;Shi et al., 2017), and aesthetics. For example, subway maps (Miura, 2009), ballistic barriers (Seymour et al., 2018), and solar arrays (Zirbel et al., 2013) can all be efficiently compacted into smaller volumes for storage and transportation, as shown in Figure 2.1A-C, respectively; folded corrugations can be used to improve the structural stability and stiffness of timber plate structures (Buri and Weinand, 2008), energy absorption tubes (Yang et al., 2016), and deployable structures (Lee and Gattas, 2016c), as shown in Figure 2.1D-F, respectively; and beautiful sculptures (Demaine et al., 5 2011a,b) and shell components (Tachi and Epps, 2011) can all be folded from a single sheet, as shown in Figure 2.1G-H and Figure 2.1I, respectively. ...
... (D) Folded plate structure (Buri and Weinand, 2008). (E) Energy absorption tube (Yang et al., 2016). (F) Folded accordion shelter (Lee and Gattas, 2016c). ...
... This includes the use of non-uniform wall thickness for a functionallygraded form (Sun et al., 2014;Zhang et al., 2015), or employing cutouts, plastic folds, or dents on the surface to guide the deformation process to a predictable buckling mode (Han et al., 2007;Lee et al., 1999;. Modern thin-walled tubes have also been combined with developable origami-inspired surface textures (Cai et al., 2015;Song et al., 2012;Yang, 2018), where the plastically pre-folded creases can determine the mechanics of the buckling process and act as a mode director (Ma, 2011;Yang et al., 2016). ...
Thesis
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This thesis systematically explored the design and utilisation of elastically-bent curved-crease origami. This was achieved by developing a set of curved-crease patterns with consideration of the interaction between material elastic bending energy behaviours and origami developability constraints. The thesis makes the following contributions. First, an exact analytical surface representation of a curved-crease pattern was developed by introducing the 1D elastica solution for large elastic bending deformation into the mirror reflection curved-crease origami generation process. The new geometry, deemed elastica surface origami, is capable of concisely and accurately capturing the principal surface curvature and developability characteristics of elastically-bent curved-crease origami. A surface error analysis of 3D scanned physical prototypes was used to validate the analytical geometries, which were shown to be highly accurate to within 50% of the 2mm sheet thickness for a range of elastica surface profiles. Limitations of the curved-crease generation method were also explored including the derivation of a maximum compressibility limit; investigation of accuracy of numerical folding motion simulation; and an investigation of a free edge distortion behaviour which occurred in certain origami forms. Second, an elastica-derived bending strain energy formulation was used to generate a customizable force-displacement response in curved-crease compliant mechanisms. This new method was presented by translating the local cross section deployment mechanics to a global frame of reference set according to the design parameters of the curved-crease origami unit geometry. A valid local-global translation and force-displacement response was found when the cross section deformations with and without developability constraints were suitably close to each other. This key feature enabled a range of predictable non-linear force-displacement responses to be realised through the alternation of pattern edge angle, edge length, and tessellated forms. Third, a new application of curved-crease origami was developed for control over the shape of an elastically-buckled thin-walled cylinder, using pre-embedded crease lines. The failure mode was pre-determined as a stabilised high-order elastica surface, which manifests via a diamond buckling mode, similar to imprecise failure modes known to occur in cylinders of this type. A set of prototypes were tested and showed that the buckling process can be guided to a range of designed failure modes. The deformed surface was measured and shown to have a near-exact correspondence to the analytical geometric description. Finally, the investigation into the driving mechanics of the buckling process was closely explored. It was found that the controllable buckling process exhibited a bistable transition from a higher strain energy tubular state to a lower strain energy curved-crease state. Overall, this thesis has made a significant contribution to the research field of origami engineering and large deformation non-linear mechanics. It offers a strong research platform for curved-crease origami ranging from the fundamental geometrical relations to potential engineering applications.
... These include deployability [41,42], static load-carrying capability [43][44][45], and aesthetics. For example, subway maps [46], ballistic barriers [47], and solar arrays [24] can all be efficiently compacted into smaller volumes for storage and transportation, as shown in Fig. 2-1A-C, respectively; folded corrugations can be used to improve the structural stability and stiffness of timber plate structures [48], energy absorption tubes [49], and deployable structures [50], as shown in Fig. 2-1D-F, respectively; and beautiful sculptures [51,52] and shell components [20] can all be folded from a single sheet, as shown in Fig. 2-1G-H and Fig. 2-1I, respectively. ...
... (D) Folded plate structure [48]. (E) Energy absorption tube [49]. (F) Folded accordion shelter [50]. ...
... This includes the use of non-uniform wall thickness for a functionally-graded form [148,149], or employing cutouts, plastic folds, or dents on the surface to guide the deformation process to a predictable buckling mode [150][151][152]. Modern thin-walled tubes have also been combined with developable origami-inspired surface textures [153][154][155], where the plastically pre-folded creases can determine the mechanics of the buckling process and act as a mode director [49,156]. ...
Thesis
Full-text available
This thesis systematically explored the design and utilisation of elastically-bent curved-crease origami. This was achieved by developing a set of curved-crease patterns with consideration of the interaction between material elastic bending energy behaviours and origami developability constraints. The thesis makes the following contributions. First, an exact analytical surface representation of a curved-crease pattern was developed by introducing the 1D elastica solution for large elastic bending deformation into the mirror reflection curved-crease origami generation process. The new geometry, deemed elastica surface origami, is capable of concisely and accurately capturing the principal surface curvature and developability characteristics of elastically-bent curved-crease origami. A surface error analysis of 3D scanned physical prototypes was used to validate the analytical geometries, which were shown to be highly accurate to within 50% of the 2mm sheet thickness for a range of elastica surface profiles. Limitations of the curved-crease generation method were also explored including the derivation of a maximum compressibility limit; investigation of accuracy of numerical folding motion simulation; and an investigation of a free edge distortion behaviour which occurred in certain origami forms. Second, an elastica-derived bending strain energy formulation was used to generate a customizable force-displacement response in curved-crease compliant mechanisms. This new method was presented by translating the local cross section deployment mechanics to a global frame of reference set according to the design parameters of the curved-crease origami unit geometry. A valid local-global translation and force-displacement response was found when the cross section deformations with and without developability constraints were suitably close to each other. This key feature enabled a range of predictable non-linear force-displacement responses to be realised through the alternation of pattern edge angle, edge length, and tessellated forms. Third, a new application of curved-crease origami was developed for control over the shape of an elastically-buckled thin-walled cylinder, using pre-embedded crease lines. The failure mode was pre-determined as a stabilised high-order elastica surface, which manifests via a diamond buckling mode, similar to imprecise failure modes known to occur in cylinders of this type. A set of prototypes were tested and showed that the buckling process can be guided to a range of designed failure modes. The deformed surface was measured and shown to have a near-exact correspondence to the analytical geometric description. Finally, the investigation into the driving mechanics of the buckling process was closely explored. It was found that the controllable buckling process exhibited a bistable transition from a higher strain energy tubular state to a lower strain energy curved-crease state. Overall, this thesis has made a significant contribution to the research field of origami engineering and large deformation non-linear mechanics. It offers a strong research platform for curved-crease origami ranging from the fundamental geometrical relations to potential engineering applications.
... 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
Full-text available
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.
... Inspired by corrugation tubes [27][28][29], columns with prefolded patterns were designed [30][31][32][33][34][35], which inherited such advantages as controllable deformation mode and low peak force to improve their energy-absorbing ability. e reasons are as follows: their modular structure makes the folding process controllable; the prefolded pattern, equivalent to an initial imperfection, reduces the peak force and can induce specific deformation modes with excellent energy-absorption efficiency. ...
... From a perspective of deformation, folding lobes act as the controller of folding waves. Prior research has confirmed that periodic imperfection structures, such as grooves [28], dents [29], and modular prefolded structures [30][31][32][33][34][35], can be used to control the folding wavelengths, thereby influencing the crushing mechanism. Furthermore, the presence of more modules in a tube may activate more plastic hinge lines, thus further improving energy absorption. ...
Article
Full-text available
An improved pyramidal prefolded pattern was designed and applied to thin-walled tubes. This delicately designed pattern modularizes the tube to control the folding process and act as an inducer to trigger deformation modes with outstanding crushing performance. Dynamic crushing tests were conducted numerically; the simulation results reveal that the patterned square tube developed a deformation mode with shorter wavelength, better load consistencies, and higher energy-absorption efficiency (up to 29%) than that of the traditional counterpart. Moreover, geometric analysis was performed and structural improvements were conducted by applying the optimal geometric parameters onto an octagonal profile. The designed patterned octagonal tube collapsed into a highly efficient deformation mode known as diamond mode. Furthermore, the comparative results show that patterned octagonal tubes demonstrated an energy absorption up to 90.1% higher than that of a conventional square column while improving the geometric compliance. These findings enrich research on patterned tubes and provide new explorations for the development of high-performance energy-absorbing structures.
... In the last few years, Origami has received an increasing interest from the scientific community, being used in many applications among which it is possible to highlight its use in the design of energy absorption devices [9][10] and biomedical devices such as heart stents [11]. ...
... where 1 , 1 , 1 , 1 and , , , are the independent parameters which define the Miura-Ori unit cell for the base layer (layer 1) and the unit cells for the rest of the layers ( = 2,3,4). From Eqs. (7) to (9), it can be seen that once the base layer geometry has been defined, the only free parameters are the section angles of each of the remaining layers. Thus, you can define homogeneous structures, where the section angle is the same for all layers; and structures of graded stiffness, where not all the layers have the same section angle (see figure 3). ...
Conference Paper
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Mechanical metamaterials are man-made structures with counter-intuitive mechanical properties that originate from the geometry of their unit cell rather than from the properties of base material. Within this type of metamaterials, origami-inspired structures have gained increasing popularity in the continuous search for materials with exotic properties such as programmable stiffness and negative Poisson's ratio (auxetics). In this work, the dynamic response of multi-layered brass Origami plates subjected to uniaxial compression tests has been numerically analyzed, by quantifying their specific energy absorption (SEA), considering different compression velocities and incorporating a damage criterion. The plates are based on the Miura Ori single cell, which is defined by four independent geometrical parameters: two side lengths and , sector angle and folding angle. Four-layer specimens and two different configurations have been considered: homogeneous or graded stiffness structures, applying the compression load in two directions: the direction in which the structure reproduces an auxetic behavior and the direction in which it shows a variable stiffness. Experimental results, involving quasi-static compression tests published in the scientific literature, have been used to validate the developed numerical model. The results of the present work show the influence of compression velocity and direction on the energy absorption capacity of the structure.
... 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.
... In a different study, inspired by the research of Ma and You [89], Yang et al. [95] introduced two diamond patterns called diamond and full-diamond patterns to circular tubes and investigated their influence on energy absorption capacities (Fig. 18c). They also found that the initial peak force of origami tubes would be significantly reduced, whereas their energy absorption capacity could be improved or Table 4 Energy absorption characteristics of the circumferentially corrugated tube. ...
... General motors company has applied the inverting mechanism to the steering column of cars [6], which plays a good role in protecting the chest of passengers in the event of a collision. The energy absorption appliance of the invertube has the advantages of small size, light weight, easy installation and high energy absorption ratio, so it has been widely used [7][8]. ...
Article
Full-text available
In the external inverting process of thin-walled circular tube, buckling instability often occurs in the straight line section of thin-walled tube due to the size mismatching of forming die. Based on LS-DYNA971, the finite element modeling was built up and a series of simulation calculations were conducted about the external inverting process of thin-walled circular tubes on two circular arc dies under axial compression. The inverting plastic deformation of a Q235 steel thin-walled tube with an outer diameter of 60mm and a wall thickness of 2mm was reproduced on two die types with different fillet radii. The simulation results show that the optimal induced fillet radii of the dies is 10.7±0.1m, and meanwhile the thin-walled tube head has good formability in the early stage, which is convenient for the subsequent shape operation of the invertube. This paper provides a method reference for the die structure design used for inverting the thin-walled tube.
... 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.
... 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. ...
Article
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.
... 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. ...
Article
Full-text available
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.
... 4 buckling analysis in this research. The crushing mechanism of the buckling induced tube (BIT) under quasi-static compression was revealed through finite element analysis (FEA). ...
Article
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To reduce the initial peak force (IPF) and improve the crushing force efficiency (CFE) of tubular energy absorbers, buckling induced tubes (BITs) were designed based on modal analysis of straight-walled triangular tubes. The crushing mechanism of the BIT under quasi-static compression was revealed through finite element analysis (FEA) and theoretical analysis. It is found that the BIT can be folded according to specific mode by cleverly presetting the convex-concave structure form. The larger is the amplitude of the buckling wave, the smaller is the IPF, as well as the mean crushing force (MCF). But the CFE is greatly improved. Compared with straight tubes, high-order mode BITs have lower IPF but greater MCF, CFE and specific energy absorption (SEA). A simplified model based on Shanley model was proposed to predict the IPF of the BIT. The MCF was predicted by improved super folding element (SFE) and simplified super folding element (SSFE) models. End buckling induction mechanism is introduced as an efficient way to reduce the IPF, but keep the MCF and enhance the CFE simultaneously.
... 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. ...
Article
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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.
... 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). ...
Article
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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 study, the effect of the collapse initiators on the energy absorption specifications of square tubes under the inclined quasi-static loads in experimental and numerical conditions has been investigated. Yang et al. [31] used two different origami patterns to investigate the energy absorption capacity and the deformation mechanism of the tubes under the uniaxial loading. ...
Article
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In many industries, it is necessary to use structures that exhibit a proper stability against the design loads and depreciate the energy in a controlled manner. In this study, the energy absorption characteristics of thin-walled structures with rectangular cross sections are investigated under the quasi-static loading. The section of structures has a different aspect ratio, and in all of them, an elliptical cutout with a different diameter ratio exists on the larger side. In all instances, the area of the cross section and cutout is constant. Hence, an experimental design with two design parameters consisting of the shell aspect ratio and the diameter ratio of the cutout was conducted by applying the central composite design method. Energy absorption parameters were modeled using the artificial neural network and the response surface method. A systematic crashworthiness study was carried out with a multi-objective optimization design using the genetic algorithm. The results showed that the optimal amount of the specific energy absorption was 14.48 kJ/kg and the optimal amount of the peak crushing load was 37.77 kN which was obtained in the aspect ratio of 1 and the diameter ratio of 0.7. The validity of the results was confirmed by empirical experiments.
... 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.
... Cai et al. [17] studied the folding and unfolding problems of a Miura origamipatterned cylinder. Yang et al. [18] proposed prefolded circular tubes with a diamond origami pattern, which caused a significantly lowered initial peak force by 10%-35% without compromising the energy absorption efficiency. Ma and You [19] designed a novel device named the origami crash box, which had doubled the number of traveling plastic hinge lines during crushing compared with the conventional counterpart. ...
Article
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A new prefolded tube is proposed by introducing web into a thin-walled tube based on “Miura origami”. The quasi-static compression analysis of this tube shows that the web has an important influence on deformation mode and energy absorption. Compared with a circular tube, the new thin-walled tube not only maintains the superior performance of low initial peak force and induced deformation mode, but also has a better energy absorption capacity. The influences of the number of units, edges, and prefolding angle on the deformation process of the new thin-walled tube are determined through parameter analysis. An optimized structure is designed, and the initial peak force is reduced. The energy absorption of the new structure under quasi-static compression is also theoretically analyzed, and the theoretical results are in good agreement with the numerical simulation results.
... Moreover, the mechanical property of origami increasingly becomes the focus owing to the programmability and functional orientation of the material design [24][25][26][27][28][29]. Families of mechanical metamaterials emerge with an understanding of the force-deformation relationship of origami-based structures, including origami honeycomb [30][31][32], energy dissipation tubes [33][34][35][36][37] and buckling-restrained braces [38]. ...
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Origami structures have received tremendous attention for their excellent kinematic and mechanical performance. Here, the inherent relationship between kinematics and mechanics of origami-based structures is investigated. The coupling phenomena between the axial displacement and the rotational displacement is systematically analyzed. Versatile folding motions of Kresling-inspired spring truss structures (KTS) are analytically calculated to demonstrate the feature of compression bifurcation, snapback behavior, reverse rotation, multipath, and multistability. Popular spring truss models are introduced, and the detailed static analysis of the KTS is performed by total potential energy equations and constraint conditions. The result reveals the relationship between motion paths and bifurcation, snapback and reverse rotation with varied initial geometries. Multipath property significantly broadens the application of origami structures in terms of bearing capacity and energy storage capacity. Moreover, the stable configuration distribution is given with prescribed initial geometries. The principles in this work set forth a significant avenue for designing novel mechanical metamaterials and functional engineering systems.
... Origami is an ancient art such that it transforms a flat sheet of paper into a finished sculpture through folding along predefined creases. Inspired by its compelling and extraordinary features, origami technique has been imitated and utilized to design metamaterials [29,30], self-folding structures [31], sandwich structures [32], mechanisms [33], and energy absorbing structures [34][35], etc. ...
Preprint
Structure/material requires simultaneous consideration of both its design and manufacturing processes to dramatically enhance its manufacturability, assembly and maintainability. In this work, we present a novel design framework for structure/material with requested mechanical performances in virtue of the compelling properties of topological design and origami techniques. The framework comprises four procedures, including topological design, unfold, reduction manufacturing, and fold. Topological design method, i.e. Solid Isotropic Material Penalization (SIMP) method, serves to optimize the structure to achieve preferred mechanical characteristics and origami technique is exploited to make the structure rapidly and easily fabricated. Topological design and unfold procedures can be conveniently completed in a computer; then, reduction manufacturing, i.e. cutting, is performed to remove materials from the unfolded flat plate; the final structure is finally obtained by folding the plate of the previous procedure. A series of cantilevers, consisting of origami with parallel creases and Miura-ori (usually regarded as a metamaterial), made of paperboard are designed with least weight and required stiffness by using the proposed framework. The findings here furnish an alternative design framework for engineering structures which could be better than 3D printing technique, especially for large structures made of thin metal materials.
... In this study, the effect of the collapse initiators on the energy absorption specifications of square tubes under the inclined quasi-static loads in experimental and numerical conditions has been investigated. Yang et al. [31] used two different origami patterns to investigate the energy absorption capacity and the deformation mechanism of the tubes under the uniaxial loading. ...
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In many industries, it is necessary to use structures that exhibit a proper stability against the design loads and depreciate the energy in a controlled manner. In this study, the energy absorption characteristics of thin-walled structures with rectangular cross sections are investigated under the quasi-static loading. The section of structures has a different aspect ratio, and in all of them, an elliptical cutout with a different diameter ratio exists on the larger side. In all instances, the area of the cross section and cutout is constant. Hence, an experimental design with two design parameters consisting of the shell aspect ratio and the diameter ratio of the cutout was conducted by applying the central composite design method. Energy absorption parameters were modeled using the artificial neural network and the response surface method. A systematic crashworthiness study was carried out with a multi-objective optimization design using the genetic algorithm. The results showed that the optimal amount of the specific energy absorption was 14.48 kJ/kg and the optimal amount of the peak crushing load was 37.77 kN which was obtained in the aspect ratio of 1 and the diameter ratio of 0.7. The validity of the results was confirmed by empirical experiments.
... Furthermore, understanding the structural capacity and anisotropic stiffness of curved-crease origami during and after folding requires exploring the mechanics of the sheets beyond bending. The mechanics of straight-crease fold patterns such as the Miura-ori are well understood [17,18], but mechanics literature has not explored curved-crease origami in great detail. ...
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In this paper, we present a method for simulating the structural properties of curved-crease origami through the use of a simplified numerical method called the bar and hinge model. We derive stiffness expressions for three deformation behaviors including stretching of the sheet, bending of the sheet, and folding along the creases. The stiffness expressions are based on system parameters that a user knows before analysis, such as the material properties of the sheet and the geometry of the flat fold pattern. We show that the model is capable of capturing folding behavior of curved-crease origami structures accurately by comparing deformed shapes to other theoretical and experimental approximations of the deformations. The model is used to study the structural behavior of a creased annulus sector and an origami fan. These studies demonstrate the versatile capability of the bar and hinge model for exploring the unique mechanical characteristics of curved-crease origami. The simulation codes for curved-crease origami are provided with this paper.
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A high-efficient energy absorption design in virtue of ultrasonic impact surface nanocrystallization treatment is proposed to enhance the crashworthiness of square thin-walled tubes. Due to significant improvement on mechanical characteristics within the treated areas, structural crashworthiness after surface nanocrystallization is significantly increased without the requirement of modifying configurations or mass. The results reveal that by optimizing local surface nanocrystallization layouts with a nanocrystallization area treatment ratio of approximately 50%, the specific energy absorption is enhanced by 64.29% as compared to the untreated tube. Experimental study validates that this technology is effective in the enhancement of the crashworthiness of square thin-walled tubes.
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A type of tube with corrugated patterns, aiming at inducing extension deformation, was proposed in this paper. Fifteen patterned tubes and one conventional square tube were simulated using the finite element model which was validated by an axial quasi-static compression experiment. The numerical results show that four deformation modes generated, which are closely related to the patterns number and the pattern angle. Tubes deform in D mode has the highest energy absorption. The influence of geometric parameters and wall thickness on energy absorption performance was also investigated. A geometric optimization was carried out as well. Deformation mechanism of two of the four modes, EF mode and E mode, were established and theoretical predictions of mean force were derived. The energy absorptions of different deformation forms were analyzed, and the results show that half of the energy is dissipated by extension deformation in E mode but little in EF mode.
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The work aims to study the large, plastic deformation and energy absorption characteristics of zig-zag folded metamaterials, BCHn, under quasi-static in-plane compression, using an analytical method and numerical analysis. In analytical modelling, the zig-zag folded materials are assumed as rigid origami in the y direction. The BCHn materials are considered as cellular materials with various topologies defined by the characteristic geometric parameters (a,b,h;α,γ0;n) when the strength at large plastic strains and densification strain are defined. The obtained analytical relationships between material topology and material strength provide an easy way to assess the energy absorption of BCHn materials with various geometric parameters. Particular attention is paid to the compression response of BCH2 and BCH3 materials, and comparisons are made with Miura-ori based materials having the same parameters (a,b,h;α,γ0). It is found that the zig-zag folded materials outperform the Miura-ori based material in terms of energy absorption. Besides, tunable geometric parameters of the BCHn zig-zag folded materials allow better tailoring of their mechanical properties. Comparisons of the energy absorption efficiency between zig-zag folded materials and hexagonal honeycomb materials show that the parameters of the BCHn materials can be selected to obtain metamaterials with superior energy absorption characteristics. Finite element models of zig-zag folded materials are built using ABAQUS/Explicit and numerical simulations of quasi-static compression are carried out to verify the analytical results. The observed agreement in terms of force and deformation confirmed that the analytical models are valid, and the analytical predictions are reliable.
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At present, one of the promising solutions to the energy crisis and environmental protection is to widely use pure electric vehicles (PEV). It is noted that lack of range limits the wide use of PEV, in which lightweight can effectively improve the range of PEV. Lightweight and crashworthiness signify two main challenges facing in vehicle industry, which often conflict with each other. The tailor rolled blank (TRB) structure, as a novel configuration, has a great potential to achieve lightweight and improve the crashworthiness. In this study, a series of TRB structures are applied to the front-end components of PEV for the design optimization of vehicle crashworthiness and lightweight. A full-scale finite element (FE) model of PEV is first constructed and validated by physical test. Then the TRB FE models of vehicle front-end components are established to replace the corresponding conventional uniform thickness (UT) structures. Based on the vehicle model with TRB structures, the safety performance of vehicle in full frontal impact is analyzed by FE method. The results show that, compared with the UT design, the front-end components with TRB structures can improve the crashworthiness of vehicle to a certain extent. In order to determine the optimized geometric distribution of TRB structures, a multi-objective design optimization procedure is implemented for the vehicle crashworthiness and lightweight design with UT and TRB structures. On the basis of the Kriging (KRG) model and the multi-objective particle swarm optimization (MOPSO) algorithm, the weight of TRB structures is reduced and the energy absorption is increased relative to the UT design, which indicates the efficient improvement of the vehicle crashworthiness.
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A novel origami-ending tube, which features the origami patterns at the ends, can deform in the diamond mode with an outstanding energy absorption performance. However, many quasi-static axial crushing experimental results showed that the long origami-ending tubes with two modules could deform in the corner symmetric mode and the mixed mode. Thus the SEAs were reduced by up to 38% and 25% compared to the diamond mode. The experimental and numerical results revealed that the local buckling and the initial concave imperfections were the main reasons triggering the corner symmetric mode and the mixed mode, respectively. The imperfection analysis indicated that the opposite local buckling imperfection and opposite concave imperfection had the greatest influence on the collapse mode and the SEA. Therefore, the reinforced metal sheets and slight convex creases were introduced into the tube to reduce the imperfection sensitivity and to improve the stability of deformation. Numerical simulations and quasi-static experiments validated that the performances of the reinforced tubes had been greatly improved in terms of energy absorption and imperfection resistance. Additionally, a simple manufacturing process was proposed, which is hopeful to achieve the mass production of long origami-ending tube.
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Origami structures are commonly constructed by folding a two-dimensional sheet according to a given crease pattern. The existence of abundant crease patterns means that many three-dimensional structures can be fabricated by using a variety of sheet materials, including thin-walled tubes and arcs. Some origami structures can also be used as core structures, sandwich plates, or arcs, whereas other such structures can be stacked to form metamaterials, which are materials designed to possess a property that is not readily available in nature. Because the mechanical performances of these structures are commonly dependent upon their geometry, the properties of these structures can be designed and adjusted through the selection and optimization of the appropriate geometric parameters. This review focuses on the deformation and energy absorption (EA) capability of origami structures subjected to static and dynamic loading. The main characteristics and findings are summarized, and further work in the area is suggested.
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Origami has played an increasingly central role in designing a broad range of novel structures due to its simple concept and its lightweight and extraordinary mechanical properties. Nonetheless, most of the research focuses on mechanical responses by using homogeneous materials and limited studies involving buckling loads. In this study, we have designed a carbon fiber reinforced plastic (CFRP) origami metamaterial based on the classical Miura sheet and composite material. The finite element (FE) modelling process’s accuracy is first proved by utilizing a CFRP plate that has an analytical solution of the buckling load. Based on the validated FE modelling process, we then thoroughly study the buckling resistance ability of the proposed CFRP origami metamaterial numerically by varying the folding angle, layer order, and material properties, finding that the buckling loads can be tuned to as large as approximately 2.5 times for mode 5 by altering the folding angle from 10 ◦ to 130 ◦ . With the identical rate of increase, the shear modulus has a more significant influence on the buckling load than Young’s modulus. Outcomes reported reveal that tunable buckling loads can be achieved in two ways, i.e., origami technique and the CFRP material with fruitful design freedoms. This study provides an easy way of merely adjusting and controlling the buckling load of lightweight structures for practical engineering.
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Natural dermal armor has superior protective performance and flexibility for effectively protecting flexible objects. Limited by the complex microstructure of natural scales, the scales of common bionic armors are mostly solid flat scales, which will have a certain impact on the quality and protective performance of the armor, and it is not suitable for flexible protection object with a curved surface out of consideration for fit and performance. Based on the Miura pattern with single-degree-of-freedom, this paper designs an arc-scale that can fit the curved surface, and proposes an arc-armor inspired by fish scales. Experiments and numerical simulations have proved that the introduction of the origami structure design can induce a stable failure mode of the arc-scale. The origami-based arc-armor has the advantages of low peak load, long effective stroke, and small fluctuation, which greatly improves the protection performance of the armor. And based on the failure mode of the arc-scale, the second-level structure was proposed to further optimize the energy absorption characteristics of the arc-scale, which contributes to reducing the peak load of the scales under medium- and high-velocity impacts. Under high-velocity impact, the denser the distribution of cells inside the scales, the higher the energy absorption efficiency of the arc-scales, which provides certain guidance for the design and application of the arc-armor. We have obtained an arc-armor with excellent energy absorption characteristics that can be reverse-designed according to the target shape. And such structures can find a wide range application in the protection of flexible electronics, human bodies, and other flexible objects that require light weight and flexibility.
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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.
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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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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.
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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.
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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.
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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.
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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.
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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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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.
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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.
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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.
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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.
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.
Conference Paper
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The Radio Frequency Identification (RFID), is a wireless technology system that is used for identifying an individual or objects through the means of radio waves which transfer information from an electronic tag, called Radio Frequency Identification (RFID) tag. Radio Frequency Identification (RFID) consists of two main components the interrogator and the transponder. The Interrogator, which is the Radio Frequency identification reader (RFID Reader), the Interrogator usually transmits and receives the signal while the Transponder (tag) is attached to the object. In the Radio Frequency Identification (RFID) system, an RFID reader interrogates the Radio Frequency Identification (RFID) tags. This tag reader generates a radio frequency interrogation, which communicates with the tags been registered in the system. This reader likewise has a receiver that captures a reply signal generated from the tags and decodes the signal. This reply signal from the tags reflects the tag's information content. Each tag of the students consists of a unique identity, identification card (ID) that is assigned to a single student identification card (ID) which is recorded in the database. The use of the Radio Frequency Identification (RFID) technology enables the institution authorities or management to evade attendance documents from damages such as misplacement, tear, or even got lost. This research review some recent design and implementation of internet of things (IoT) attendance system using the concept of the Radio Frequency Identification (RFID) system articles. The analysis found that the Radio Frequency Identification (RFID) system is a very advanced technology for an automatic attendance system in an institution, organization, or university and it provides a very higher performance and accuracy than the traditional paper-based system that the students normally used to sign. A combination of the model is needed which will confirm higher security, better performance, and consistency of the system.
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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.
Conference Paper
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On March 23, 2006, a full-scale test was conducted on a passenger rail train retrofitted with newly developed cab end and non-cab end crush zone designs. This test was conducted as part of a larger testing program to establish the degree of enhanced performance of alternative design strategies for passenger rail crashworthiness. The alternative design strategy is referred to as crash energy management (CEM), where the collision energy is absorbed in defined unoccupied locations throughout the train in a controlled progressive manner. By controlling the deformations at critical locations the CEM train is able to protect against two dangerous modes of deformation: override and large-scale lateral buckling. The CEM train impacted a standing locomotive-led train of equal mass at 31 mph on tangent track. The interactions at the colliding in Interface and between coupled interfaces performed as expected. Crush was pushed back to subsequent crush zones and the moving passenger train remained in-line and upright on the tracks with minimal vertical and lateral motions. The added complexity associated with this test over previous full-scale tests of the CEM design was the need to control the interactions at the colliding interface. between the two very different engaging geometries. The cab end crush zone performed as intended because the locomotive coupler pushed underneath the cab car buffer beam, and the deformable anti-climber engaged the uneven geometry of the locomotive anti-climber and short hood. Space was preserved for the operator as the cab end crush zone collapsed. The coupled interfaces performed as predicted by the analysis and previous testing. The conventional interlocking anti-climbers engaged after the pushback couplers triggered and absorbed the prescribed amount of energy. Load was transferred through the integrated end frame, and progressive controlled collapsed was contained to the energy absorbers at the roof and floor level. The results of this full-scale test have clearly demonstrated the significant enhancement in safety for passengers and crew members involved in a push mode collision with a standing locomotive train.
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Thin-walled tubes subjected to axial crushing have been extensively employed as energy absorption devices in transport vehicles. Conventionally, they have a square or rectangular section, either straight or tapered. Dents are sometimes added to the surface in order to reduce the initial buckling force. This paper presents a novel thin-walled energy absorption device known as the origami crash box that is made from a thin-walled tube of square cross section whose surface is prefolded according to a developable origami pattern. The prefolded surface serves both as a type of geometric imperfection to lower the initial buckling force and as a mode inducer to trigger a collapse mode that is more efficient in terms of energy absorption. It has been found out from quasi-static numerical simulation that a new collapse mode referred to as the completed diamond mode, which features doubled traveling plastic hinge lines compared with those in conventional square tubes, can be triggered, leading to higher energy absorption and lower peak force than those of conventional ones of identical weight. A parametric study indicates that for a wide range of geometric parameters the origami crash box exhibits predictable and stable collapse behavior, with an energy absorption increase of 92.1% being achieved in the optimum case. The origami crash box can be stamped out of a thin sheet of material like conventional energy absorption devices without incurring in-plane stretching due to the developable surface of the origami pattern. The manufacturing cost is comparable to that of existing thin-walled crash boxes, but it absorbs a great deal more energy during a collision.
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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.
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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.
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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.
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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.
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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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