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Multi-objective optimization of multi-cell tubes with origami patterns for energy absorption
Abstract
Three novel types of multi-cell tubular structures with pre-folded origami patterns were proposed in this paper, aimed at reducing the initial peak force and the crushing force fluctuation while maintaining or increasing the specific energy absorption during uniaxial crush. Experimentally validated finite element modelling was conducted to study the influence of geometric parameters on the mechanical properties. Optimal designs were obtained through multi-objective optimization. The results showed that predesigned origami patterns governed the buckling process of the tubes and quintuple-cell origami tubes could absorb the highest energy in crush with significantly reduced initial peak force and the crushing force fluctuation.
... Nevertheless, there are disadvantages for simple square tubes under axial loading, such as a high initial peak crushing force, low efficiency in energy absorption and high sensitivity to random defects [10,11]. According to the published theoretical works, two-thirds of the plastic energy is dissipated through deformations at stationary and moving plastic hinge lines [7][8][9]. ...
... Recently, the application of origami patterns has attracted much attention [11,25,26]. The origami pattern is not only a geometric imperfection that can reduce the initial peak crushing force, but also a failure mode inducer to make the tube collapse following the premanufactured pattern. ...
... There are four travelling plastic hinge lines in the element shown in Fig. 19(b); thus, the energy dissipated in the rolling of travelling plastic hinges is given by Eq. (11). ...
Thin-walled tubes are widely used as energy absorption devices in transport vehicles. In this paper, with the goal of improving the energy absorption performance of tubes under quasi-static axial loading, origami tubes with polygonal cross-sections are designed. The geometric characteristics of polygonal origami tubes are controlled by three parameters: the number of sides, the number of modules and the dihedral angle. To investigate the effect of the origami pattern and polygonal structure on the crashworthiness of tubes, a full factorial experiment is adopted, and then parametric analysis is conducted based on eighty-five simulations. The numerical results validate that origami tubes collapsing in the complete diamond mode perform better than conventional tubes. However, this special mode can only be triggered in the crushing process of square and hexagonal origami tubes with smaller dihedral angles. The optimal design leads to a maximum reduction in the initial peak crushing force of 56.96% and a maximum increase in the mean crushing force of 45.49%. The parametric study shows that the initial peak crushing force of tubes with an identical number of modules and edges increases with an increasing dihedral angle, while it decreases with an increasing number of modules when the angle remains the same. Additionally, the influence of geometric parameters on the mean crushing force varies with different collapse modes. Furthermore, a deep insight into the in-extensible deformation mechanism of origami tubes deformed in the complete diamond mode is presented. The theoretical model is subsequently proposed to predict the mean crushing force.
... At the beginning, origami was used to stack the solar panel for the convenience of transporting it from the ground to space [10]. Since then, it was mimicked to design advanced materials [11], reconfigurable structures [12], energy absorbing structures [13,14], foldable lithium-ion batteries [15], bioinspired springs [16], robotics [17], sandwich structures [18,19], sound barrier [20] and many others. ...
... displacement responses, axial strains, and bistable behavior, were analytically and numerically investigated. Cylinders comprised by Miura sheets (normally curved ones are needed) also have excellent impact absorption performances [13,14,[28][29][30]. On the basis of the basic Miura sheet, a novel structure with graded stiffness by stacking Miura sheets with different geometry at each layer was presented, which has superior energy absorption capability to that of uniformly tessellating repeated layers [31]. ...
... It should be noted that the origami structure proposed here differs from those of previous works [46][47][48][49][50][51][52][53][54][55][56], where they focused on the constructing of the deployable cylindrical structures, whereas we consider the Miura tube as a structure, meaning that the geometric topology is determined once the tube is fabricated; in other words, it is not rigidly foldable. This treatment is similar with previous studies [13,57]. We emphasize that various Miura tubes can be fabricated from one same metal sheet and exhibit distinctive dynamic properties by altering its geometric topology. ...
... The goal of origami design is to design a specific crease patterns and then transform a sheet-like planar material into an exquisite three-dimensional structure by folding the material along these predefined creases [4]. Owing to the various benefits, including flexible design, simple manufacturing, and light weight, origami structures have demonstrated tremendous application potential in actual engineering for diverse fields, e.g., spacecraft solar panels [5,6], re-configurable structure design [7,8], energy-absorbing structures [9][10][11], biomedical equipment [12,13], foldable lithium-ion batteries [14,15], origami springs [16,17], origami robots [18][19][20], and sound barriers [21][22][23]. ...
... This provides effective methods for designing lightweight structures with high stiffness and the desired natural frequency. The proposed Miura tube in the study has several benefits; for instance, it can be (1) applied to various engineering fields, such as the core layer of a sandwich material, energy-absorbing structures [9][10][11], and so on; (2) fabricated from inexpensive two-dimensional metal materials but possess outstanding dynamic properties [33,34]; and (3) used as the initial design domain of a topology optimization to further enhanced the desired mechanical properties [57][58][59][60][61]. However, we still have some works in progress, for instance, fabricating a carbon fiber/epoxy resin-based origami tube [62][63][64], conducting modal tests [33], and performing a structural optimization to further enhance the dynamic properties of the origami tube [57][58][59][60][61]. ...
Although Miura origami has excellent planar expansion characteristics and good mechanical properties, its congenital flaws, e.g., open sections leading to weak out-of-plane stiffness and constituting the homogenization of the material, and resulting in limited design freedom, should also be taken seriously. Herein, two identical Miura sheets, made of carbon fiber/epoxy resin composite, were bonded to form a tubular structure with closed sections, i.e., an origami tube. Subsequently, the dynamic performances, including the nature frequency and the dynamic displacement response, of the designed origami tubes were extensively investigated through numerical simulations. The outcomes revealed that the natural frequency and corresponding dynamic displacement response of the structure can be adjusted in a larger range by varying the geometric and material parameters, which is realized by combining origami techniques and the composite structures’ characteristics. This work can provide new ideas for the design of light-weight and high-mechanical-performance structures.
... To improve energy absorption characteristics of origami tubes, several configuration modification strategies have been proposed for their structures, such as using multi-cell structures [97], using different folding patterns [98][99][100]. More specifically, Yang et al. [97] proposed a multi-cell origami tube with an aim to reduce the initial peak force and the crushing force fluctuation while maintaining or increasing the specific energy absorption during uniaxial crush (Fig. 18d). ...
... To improve energy absorption characteristics of origami tubes, several configuration modification strategies have been proposed for their structures, such as using multi-cell structures [97], using different folding patterns [98][99][100]. More specifically, Yang et al. [97] proposed a multi-cell origami tube with an aim to reduce the initial peak force and the crushing force fluctuation while maintaining or increasing the specific energy absorption during uniaxial crush (Fig. 18d). Lee et al. [100] used pre-embedded curved-crease origami patterns for the tube (Fig. 18e). ...
... The pre-patterned geometry triggers controlled buckling modes during crushing, which in turn can reduce the peak forces and increase the total amount of energy absorbed (Fig. 2.1B). Origami can also offer a variety of geometric design options and can have the benefit of easy fabrication from a flat developable surface [53,56,57]. For example, a thin-walled tube with pre-folded Yoshimura pattern [32] and a sandwich-like structure with Kresling pattern [58] can both provide favorable energy-absorbing behaviors. ...
Thin-walled origami-inspired tubes can be used as lightweight systems for various functional applications in engineering. Folding motions can allow for deployment, reconfiguration, and compact storage of the systems, while buckling of the thin walls can be used to tune the system properties or achieve secondary functions such as energy absorption. This thesis aims to explore the stability of morphing tubes and harness buckling for functional applications. The dissertation first explores a deployable design where origami tubes extend, lock, and absorb energy through crushing (buckling and plasticity). Numerical and experimental studies investigate the tunable stiffness and energy absorption behaviors of these systems under static and dynamic scenarios. The stiffness, peak crushing force, and total energy absorption of these origami tubes can be changed through reconfiguration. These deployable systems can increase the crushing distance between impacting bodies and can allow for on-demand energy absorption characteristics. Next, the bending stability that allows for morphing in corrugated tubes is explored (bending in drinking straws). Finite element models and a reduced-order elastic simulation package can capture the nonlinear multi-stable behaviors. Modified cross-sections for the corrugated tubes are introduced and explored to identify how geometry affects bending stability, energy barriers, and stable configurations. Results show that thinner shells, steeper cones, and weaker creases are required to achieve bending bi-stability. A bar and hinge simulation model is then used to identify and capture a unique pop-up mechanism in Kresling origami that enables shape-morphing and stiffness tuning. By buckling the valley creases, the conical Kresling will pop into a dome-like shape and the crease network will be distorted. As a result, the flexible twisting motion via crease folding is prohibited, and the cone stiffness can be increased by up-to-four orders of magnitude. Parametric studies revealed that a shallower and more twisted Kresling unit will have more significant stiffness tuning. Experimental tests were used to verify the numerical predictions of tunable stiffness. This thesis explores how buckling in thin-walled origami tubes can be harnessed for functional purposes. The mechanics of three different tubular designs are explored to give insight on how geometry, sheet thickness, and material properties affect the buckling and multi-stable behaviors. These findings can inform future designs of tubular origami for shape-morphing and other functional uses.
... The pre-patterned geometry triggers controlled buckling modes during crushing, which in turn can reduce the peak forces and increase the total amount of energy absorbed (Fig. 1B). Origami can also offer a variety of geometric design options and can have the benefit of easy fabrication from a flat developable surface [3,4]. However, all of these previous origami systems are passive, and the entire energy absorption performance is determined by the design geometry and material properties. ...
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.
... The pre-patterned geometry triggers controlled buckling modes during crushing, which in turn can reduce the peak forces and increase the total amount of energy absorbed (Fig. 1B). Origami can also offer a variety of geometric design options and can have the benefit of easy fabrication from a flat developable surface [3,4]. However, all of these previous origami systems are passive, and the entire energy absorption performance is determined by the design geometry and material properties. ...
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. This concept for deployable energy-absorbing origami tubes can enable future protective systems with on-demand properties for different impact scenarios.
... Additionally, Zhou et al. [28][29][30] verified the excellent performance of the diamond origami crash box. Many scholars also investigate the crashworthiness performance of origami polygonal tubes [27,31] and origami multi-cell tubes [32], etc. However, the origami creases exist on the entire surface of these structures, which leads to a relatively complicated manufacturing process. ...
Thin-walled tube as an energy absorption device is indispensable in vehicles. Recently, the crashworthiness performance of metal/carbon fiber reinforced polymer (metal/CFRP) hybrid tubes has been widely investigated. However, those tubes are mainly straight, which tend to collapse in natural modes with lower energy absorption. Additionally, research has shown that the well-designed origami patterns applied to ends of conventional metal tubes can trigger the diamond mode with excellent performance. Therefore, the similar origami patterns are also applied to the ends of internal and external metal tubes of hybrid tubes. The two metal tubes will deform in diamond mode under the guidance of origami pattern, and then forcing the CFRP tube to deform the same high-performance collapse mode with more materials destroyed. The experimental results show that the hybrid tube indeed collapses in diamond mode with an excellent crashworthiness performance. The SEA can be increased by about 135% and 85.7% compared to conventional metal tube and CFRP tube. The CFE is also higher than other types of hybrid tubes. Besides, this design ensures that the CFRP tube is still straight, which greatly facilitates the manufacturing process.
... 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). ...
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.
... The optimums on Pareto front could be obtained from this optimization process. Yang et al. (15) performed the optimization of the folded-patterns tubes and estimated the design parameters' effect on crashworthiness. Their study showed that the folded patterns control its collapsing behavior. ...
This paper studies the crashworthiness optimization of the multi-cell hexagonal tube under oblique impact. The linear weighted average method (LWAM) performs the optimization design of min PCF and max SEA. A detailed analysis discloses the influence of the tube parameter on crashworthy design. The wall thickness and diameter has an important influence on the crashworthiness performance of these tubes. The collapsing distances and energy absorption of these tubes are approximate if the diameter rises and the wall thickness is constant. This paper proposes a new method for fashioning the tube crashworthiness.
... That is why there are two types of origami structures which are used as energy absorbers: one is four folding lines such as bellows fold and the other one is six folding ones such as spiral folding. Reference [6] introduces mainly four research groups led by Lu and Chen [7], You and coauthors [8][9][10], Wang and coauthors [11,12] and Xie [13,14]. All of them use four folding line types. ...
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.
... Tran and Baroutaji (2018) performed crashworthiness optimization analysis of multi-cell triangular tubes and analyzed their energy absorption characteristics. Yang et al. (2018) carried out design optimization of multi-cell tubes with folded patterns and evaluated the impact of the design parameters on the crashworthiness behavior. Bigdeli and Nouri (2019) combined DoE and multiple objective particle swarm optimization (MOPSO) algorism to perform the optimization of multi-cell tubes and proposed novel cross-section to improve crashworthiness performance. ...
Recently, multi-cell structures have received increased attention for crashworthiness applications due to their superior energy absorption capability. However, such structures were featured with high peak collapsing force (PCL) forming a serious safety concern, and this limited their application for vehicle structures. Accordingly, this paper proposes windowed shaped cuttings as a mechanism to reduce the high PCL of the multi-cell hexagonal tubes and systemically investigates the axial crushing of different windowed multi-cell tubes and also seeks for their optimal crashworthiness design. Three different multi-cell configurations were constructed using wall-to-wall (WTW) and corner-to-corner (CTC) connection webs. Validated finite element models were generated using explicit finite element code, LS-DYNA, and were used to run crush simulations on the studied structures. The crashworthiness responses of the multi-cell standard tubes (STs), i.e., without windows, and multi-cell windowed tubes (WTs) were determined and compared. The WTW connection type was found to be more effective for STs and less favorable for WTs. Design of experiments (DoE), response surface methodology (RSM), and multiple objective particle swarm optimization (MOPSO) tools were employed to find the optimal designs of the different STs and WTs. Furthermore, parametric analysis was conducted to uncover the effects of key geometrical parameters on the main crashworthiness responses of all studied structures. The windowed cuttings were found to be able to slightly reduce the PCL of the multi-cell tubes, but this reduction was associated with a major negative implication on their energy absorption capability. This work provides useful insights on designing effective multi-cell structures suitable for vehicle crashworthiness applications.
... This research also investigated the effect of various loading types such as axial, lateral, and oblique loadings on the energy absorption of these structures [15][16][17][18][19][20][21][22][23][24][25]. The experimental and numerical studies confirmed that the multi-cell sections have a higher energy absorption efficiency than single-cell sections [26][27][28][29]. In a comparative study, Xiong Zhang and Hui Zhang [17,18,20] applied the quasi-static axial loads to multi-cell tubes. ...
In this paper, the energy absorption parameters are investigated for new forms of thin-walled energy absorbers. The effect of adding stiffeners to the outer tube wall, as well as the multi-cell effect of the structure, was investigated both in a separate and simultaneous manner in a tube with the square section. This design has not been investigated in previous studies, and it stimulates innovation in its own right. Such designs can significantly increase the energy absorption of the structure with the least change in the initial geometry and the lowest costs. The nonlinear explicit finite element method was used to simulate the crushing process in the tubes. The numerical simulation results were validated with the results of experimental tests, and a good agreement was observed. Finally, the parameters such as specific energy absorption, crush force efficiency, initial peak force, and mean crush force were calculated and analyzed. The results showed that the proper combination of stiffeners in the middle sides of the tube wall and the creation of a multi-cell column made it possible to improve the specific energy absorption up to 89% and crush force efficiency up to 52% compared with the reference tube, which is a significant improvement. Also, while comparing some of the results, it was analyzed why sometimes inserting stiffeners on the outer wall of tubes is better than the multi-cell method to increase the SEA of structure.
... Ma et al. [37] optimized a thin-walled tube structure and indicated that specific energy absorption increased 29.2% and the initial peak force reduced 56.5% for the optimum case. optimization of energy absorption properties was studied on a wide range of absorbers such as the end-capped conical tubes [38] , honeycomb absorber [39] , a metallic-GFRP impact absorber [40] , foam-filled thin-walled structure [41] , automotive Crashbox [42] , multi-cell tubes with origami patterns [43] , variable wall thickness tube inspired bamboo structures [2] and a steel-aluminum hybrid structure [44,45] . Chahardoli et al. [46] used response surface methodology to optimize parameters using MATLAB software and found specific energy absorption of the capped-end absorbers enhance with increasing both wall thickness and hole heights. ...
Thin-walled tubes are one of the most popular impact absorbers. Recently, some methods have been proposed to improve crush performance parameters of the thin-walled tube such as filling by foam, modifying geometry etc. Each method has its advantages and disadvantages. It is still a challenge for crashworthy designers to design an efficient energy-absorbing system which has all the necessary requirements. Therefore, the present paper aims to introduce a new design technique which is a combination of bar extrusion and thin-walled circular tube. The crushing behavior of the new proposed energy absorber was studied both experimentally and numerically. Finite element models were developed to estimate the force-displacement curve and the folding shapes of the tube. The numerically predicted load-displacement curve and the calculated crush performance parameters were verified using experimental measurements. Moreover, a parametric study was performed to investigate the effects of different parameters on the proposed energy absorber response. According to the results, the percentage increases in energy absorption (Ea) capacity and specific energy absorption (SEA) for the proposed energy absorber were 39.02% and 14.37% respectively compared to the thin-walled tube. In order to determine the optimized geometric parameters of the proposed energy absorber, a multi-objective optimization technique was implemented. Based on the response surface methodology (RSM), Ea and SEA increased 245.5% and 246.3% for the optimum proposed energy absorber. The predictive models for Ea and SEA were obtained by polynomial equations.
... All of the results showed that these tubes performed better in terms of energy absorption with lower F max and higher F m compared to conventional tubes. Yang et al. [34] also introduced an origami pattern into multi-cell tubes and found the F max and crushing force fluctuation could be reduced significantly. Additionally, some scholars studied kirigami structures for energy absorption purposes. ...
An origami crash box (OCB) has a desirable crashworthiness performance because it is inclined to deform in the diamond mode (DM) with a low initial peak force Fmax and high mean crushing force Fm. Theoretically, if an OCB whose shape approaches that of a conventional tube deforms in DM, the energy absorption will be the highest. Whereas, an OCB can deform in an undesirable incomplete diamond mode when its shape approaches that of a conventional tube. Additionally, the manufacture of OCBs is still complicated because it involves welding process. Therefore, a novel origami-ending tube (OET) is proposed in this paper. This OET was designed by introducing some small triangular origami patterns into the ends of the tube module, which greatly simplified the manufacturing process because it did not require welding. The validation experiments showed that the OET could deform in DM with a 46% reduction of Fmax and a 99% increase of Fm, compared to the conventional tube, even though the geometry of the OET was very close to that of a conventional tube. Combined with the results drawn from the validation experiments, parameters and comparison studies, it could be concluded that the OET performed better than the OCB.
... In fact, besides the above methods, there are many other ways to induce the tubes to deform in stable and progressive mode. Such as adding holes [26], grooves [27], tendons [28], corrugations [29][30][31][32] and origami features [33][34][35][36] on the wall, or diaphragms [37] and ribs [13,38] inside the tube. However, while these methods cause progressive deformation, they reduce the energy absorption efficiency. ...
... A large number of studies have investigated the axial compression property of the thin-walled tube . For single thinwalled tube, energy absorption capacity can be further improved by changing the section shape [2][3][4][5][6][7][8][9][10], the structure configuration [11][12][13][14], leading into crack [15], hole and grooved [16] and filling porous materials in thin-walled tube [17][18][19][20][21][22][23]. However, when the thin-walled tube subjected to axial crushing load, relatively high initial crushing force and the force fluctuations will be met [7][8][9]17,18]. ...
... A large number of studies have investigated the axial compression property of the thin-walled tube . For single thinwalled tube, energy absorption capacity can be further improved by changing the section shape [2][3][4][5][6][7][8][9][10], the structure configuration [11][12][13][14], leading into crack [15], hole and grooved [16] and filling porous materials in thin-walled tube [17][18][19][20][21][22][23]. However, when the thin-walled tube subjected to axial crushing load, relatively high initial crushing force and the force fluctuations will be met [7][8][9]17,18]. ...
Thin-walled tubes are widely utilized as energy absorption element. It is necessary to realize the bidirectional self-locked of thin-walled tube system without any constraint under lateral and oblique impact for emergency protection and improving energy absorption. In this study, we designed a novel 3D printed thin-walled tube with variable section achieving rapid assembly of bidirectional self-locked thin-walled system. Comparison among the thin-walled tube with variable section, dumbbell-shaped tube, rectangular-shaped tube and three corresponding systems were conducted with regard to deformation and energy absorption. The typical deformation modes of three kinds of tube and system were obtained by experimental results. Oblique quasi-static compression tests were conducted to validate the bidirectional self-locked effect of system. Geometrical restriction satisfying bidirectional self-locked effect and parametric analysis of presented tube is discussed. It was found that specific energy absorption of the presented thin-walled tube with variable section is superior to these of dumbbell-shaped configuration and rectangular-shaped configuration from both perspectives of tube and system.
... Received 29 January 2019; Received in revised form 29 April 2019; Accepted 11 June 2019 process of the stamping metal sheets and then welding them together. Yang et al. [15,31] used a three-dimensional (3D) printing technique to fabricate brass tubes with equidistant origami patterns, performed the quasi-static compression tests to compress the tubes, and numerically investigated the deformation process. They found that the experimental results of the collapsed mode and plateau force were different from the simulation conclusions of the same tubes, which was because of the imperfections in the additive manufacturing procedure. ...
... However, it is difficult to obtain an optimal configuration for the hybrid tubes with various length, thickness and ply angles of outer CFRP through the three point bending experimental tests. Structural optimization approaches have been considered to be a useful tool to address this issue [40][41][42][43][44][45][46] . While the optimization procedure involving continuous design variables has been extensively implemented through conventional mathematical programming algorithms, it may not be able to address some issues in real life. ...
This study aimed to explore bending collapse behavior and energy absorption capacity of net aluminum (Al), net carbon fiber reinforced plastic (CFRP) and Al/CFRP hybrid tubes, respectively. Based upon the experimental tests, the transverse energy absorption of the Al/CFRP hybrid tubes was found to be even higher than the sum of corresponding net Al tube and net CFRP tube. Specifically, the CF-AL tube (the CFRP tube being placed outside the Al tube) increased the peak force by 6.7% and energy absorption by 20.6%. The AL-CF tube (the CFRP tube being placed inside the Al tube) improved the peak force by 14.1% and energy absorption by 19.1%. The experimental study indicated that overall, the CF-AL tube was of better crashworthiness characteristics. Subsequently, finite element (FE) analyses were carried out by correlating with the experimental results. Based upon this validated FE models, a parametric study and design optimization on the CF-AL tube (with respect to length, thickness and ply angle) were further performed. It was found that the optimization increased specific energy absorption (SEA) by 42.96% and mean crushing force by 37.75%; meanwhile the mass of optimum design decreased by 5.02%, exhibiting significant enhancement of crashworthiness characteristics.
... Typical applications include conical tube [23] and graded thickness tube [24,25]. However, those two approaches usually involve relatively complex manufacture process, such as stamping [20], welding [26], multistage hammering [24], and even additive manufacturing [27,28]. Furthermore, the processing difficulty sharply increases with the physical dimensions, which limits its application in large-scale equipment, such as ship and submarine. ...
The cruciforms are widely employed as energy absorbers in ships and offshore structures, or basic components in sandwich panel and multicell structure. The kirigami approach is adopted in the design of cruciform in this paper for the following reasons. First, the manufacture process is simplified. Second, it can alter the stiffness distribution of a structure to trigger desirable progressive collapse modes (PCMs). Third, the kirigami pattern can be referred as a type of geometric imperfection to lower the initial peak force during impact. Experiments and numerical simulations were carried out to validate the effectiveness of kirigami approach for cruciform designs. Numerical simulations were carried out to perform comparative and parametric analyses. The comparative studies among single plate (SP), single plate with kirigami pattern (SPKP), and kirigami cruciform (KC) show that the normalized mean crushing force of KC is nearly two times higher than those of SP and SPKP, whereas the normalized initial peak force of KC reduces by about 20%. In addition, the parametric analyses suggest that both the parameters controlling the overall size (i.e., the global slenderness and local slenderness) and those related to the kirigami pattern (i.e., the length ratio and the relative position ratio) could significantly affect the collapse behavior of the cruciforms.
... In addition, Wu et al. [7] performed the multi-objective optimal design for a five-cell tube to maximize its specific energy absorption and minimize peak crushing force. Yang et al. [8] optimized the multi-cell tubular structures with pre-folded origami patterns. These results showed that quintuple-cell origami tubes absorbed the highest amount of energy with significantly reduced initial peak force. ...
... The results showed that the LVT multi-cell square tubes could significantly improve the efficiency of material utilization for thin-walled structures. To improve energy absorption and to decrease peak crushing force, optimization designs [6,7] had been applied to identify the best configuration and dimension for multi-cell thin-walled structures, and found that the numerical optimization design was an effective method to improve the crashworthiness of thin-walled structures and obtain optimal parameter configurations. ...
Thin-walled structures are currently used in automotive and aerospace fields due to their excellent lightweight and crashworthiness properties. This paper describes a new crush absorber design based on the Koch fractal (KF) geometry to improve energy absorption performance. The crash performance of three Koch fractal designs, one single-wall and two hybrid (double-wall), with different Koch fractal orders and wall thicknesses are investigated by experimental testing and computational modelling. Computational models of 1st order basic Koch and hybrid Koch structures are developed, with the predictions being compared with the experimental data. The computational simulations reveal a significant synergistic effect in the hybrid Koch structure, stemming from the interaction between the inner Koch wall and the external wall. Among the three designs of Koch structures, the 2nd order hybrid Koch absorbers give the highest specific energy absorption performance. Furthermore, these 2nd order hybrid Koch absorbers outperform a wide range of multi-cell structures of the same mass. The findings of this research open up a new route of designing novel lightweight energy absorbers with improved crash characteristics.
This study involved the design of energy absorbing structures that have precisely tailored performances based on the differences between the bifurcated motions of a Tachi-Miura polyhedron (TMP) with flat-foldable and load-bearing motions. The tailored performance is explored with finite element analysis and experiments using test pieces fabricated via additive manufacturing. Significant differences are observed between the force responses of TMPs with flat-foldable and load-bearing motions. Moreover, no initial peaks of force responses and plateau forces are observed in the long-stroke range by breaking load-bearing motions. In other words, the TMPs exhibit suitable properties for energy absorption. In addition, the force responses against dynamic loading are measured by projecting an impactor with a mass of over 100 kg, where the TMP with load-bearing motion completely absorbs high-impact energy. In conclusion, these findings enable the design of energy absorption structures that can be tailored to handle several types of collision scenarios over a wide energy range.
A cell-based hierarchical strategy was introduced in the preparation of traditional honeycombs to design a novel structure, known as cell-based quadrangular hierarchical honeycombs (CQHHs). The out-of-plane crashworthiness of CQHHs was investigated using experimental, numerical, and analytical methods. The criteria of ideal energy absorption were employed to evaluate the crushing performance. Then, the effects of a hierarchical strategy and geometric parameters, including the cell densities of macrocells and microcells, the relative density, and the thickness coefficient, on the crushing performance of the CQHHs were tested. Consequently, the optimal hierarchical strategy, namely, the completely ordered arrangement (COA) was identified, and a parameter analysis demonstrated that the cell density and thickness coefficient effectively improved the energy absorption efficiency of the CQHHs. Based on the combination of the COA strategy and optimal parameters, an improvement of 74.45% in energy absorption efficiency was observed, compared with a traditional honeycomb with 3 × 3 cells. The mean crushing force (MCF) reached 96.24% of the full plastic strength of the matrix, indicating that the ideal energy absorption could be closely approached by the cell-based hierarchical honeycomb. These achievements provide an effective way for developing lightweight energy absorbers and achieving ideal energy absorption.
Abstract
Origami crash tubes have concerned nowadays due to their superior crashworthiness behavior by controlling the initial buckling force and collapse modes. In this paper, a Multi-layered origami pattern is proposed, and numerical analysis is investigated under quasi-static axial compressive loading and validated by the experimental result of the fabricated origami crash box. To compare the energy absorption efficiency of this proposed origami tube, its mechanical responses are normalized with the conventional octagonal tube. Moreover, for parametric study, the crashworthiness behavior of 64 samples is investigated for the parameters of the dihedral angle 2θ, outer layer height e, and module number M. It is demonstrated that by increasing M with a constant value of e, the critical angle of θ decreases. By increasing the value of e with constant values of M and θ, the mechanical responses of tube increase, and these trends are valid as long as θ is below the critical angle. The number of modules M, angle θ, and outer layer height e have the highest effect on the mechanical responses. Finally, the results show that by maintaining the specific energy absorption of the conventional octagonal tube, the initial peak force can be reduced by 55%. Furthermore, the proposed pattern reduces the initial peak force while maintaining the specific energy absorption, leaving designers free to design.
Keywords: Origami, crash box; energy absorption; FEM; Axial crushing, quasi-static, simulation, experimental.
Thin-walled tubes filled with ultra-light materials have attracted much attention due to excellent energy absorption characteristics. With the development of additive manufacturing technology, it is allowed to manufacture structures with complex geometry shapes as new filled materials. In this study, complex proportional assessment (COPRAS) and discrete optimization algorithm were proposed to design and optimize the topology of thin-walled tubes filled with lattice structures. Firstly, the finite element model verified by experiment was adopted to investigate the influence of cross-sectional configurations and octet truss lattice filling distributions on crashworthiness of hybrid structures. The results show that the cross-sectional configuration has a greater effect on specific energy absorption (SEA) and the lattice filling distribution has a greater effect on peak crushing force (PCF). Then, COPRAS was used to sort the crashworthiness of hybrid structures with different topologies and select the optimal solution. It was found that C3-L4 structure had the best crashworthiness among all design schemes, indicating that the better crashworthiness can be obtained by filling the lattice in the four corner regions of tube or increase the number of cells in corner regions. Finally, the discrete optimization algorithm based on successive orthogonal arrays was adopted to further improve the crashworthiness of hybrid structure. It was found that the thin-walled tubes with different thickness had greater energy absorption capacity than those with the same thickness. Hence, the method proposed in this paper can become an effective way for topology optimization of crashworthiness.
In this paper, a multi-cell design method with built-in stiffeners is proposed to improve the crashworthiness of metal circular tubes. In the study, multi-cell circular tubes with three different stiffeners (Line, Waved, Polyline) were subjected to compression tests under quasi-static load. The finite element model of the metal circular tube was validated by ABAQUS/EXPLICIT, and the geometry of the stiffener was designed on this basis. The results showed that the energy absorption of the multi-cell tube was significantly better than that of the initial tube. Further, ‘Waved’ and ‘Polyline’ are more conducive to improving the crashworthiness of the multi-cell tube from the geometric design of the stiffeners. Through the analysis of load-displacement responses and crashworthiness indexs, it was found that the more the number of ‘Waved’ or ‘Polyline’ (from 2 to 8), the better the energy absorption of the multi-cell tubes and the smaller the load fluctuation. In addition the effect of the number of stiffeners on energy absorption was also revealed.
Energy absorption of traditional tubular energy absorbers is restricted by the low structure efficiency, which makes the mean crushing force of the structure usually much lower than its yield strength. The combination of a multicellular design and a gradient-thickness strategy significantly improves the energy-absorption ability of thin-walled energy absorbers while reducing weight. Gradient-thickness multicellular tubes (GTMT) were studied in this paper to demonstrate this advantage. Mechanical performances of GTMT with two material-distribution principles, sample gradient thickness (SGT) and modified gradient thickness (MGT), were investigated experimentally and numerically, primarily in terms of folding behaviors, energy-absorption ability, and load-carrying capacity undulation. Wire-cut electrical discharge machining technology was used to create a series of aluminum alloy specimens that were then compressed under quasistatic loading conditions.
Following that, finite element method was used to run detailed numerical simulations. The effect of geometric configuration was determined after conducting parametric studies with different cell density and thickness gradient coefficients. The results showed that, compared to a traditional multicellular tube, a gradient-thickness one with MGT material distribution can improve structural efficiency with a stable loading history. Increases in cell density and thickness gradient coefficient have positive effects on energy-absorption ability; however, excessively high parameter values will lead to global bending deformation and weaken the mean crushing force. Therefore, reasonable parameter matching is vital. The result shows that when the cell density reached 9 × 9 and the thickness gradient coefficient reached 1.4, the mean crushing force was 98.16% of the full-plastic strength of the matrix, and there was no irregular deformation, indicating that ideal energy absorption is almost achieved. These achievements pave a way for achieving ideal energy absorption.
Crushing behavior of multi-cell tubes with a novel pattern of design for their cross-section is investigated under axial and oblique loads. The tubes have hexagonal, octagonal and decagonal shapes. According to SAW method, the tubes of H-1, O-1 and D-1 show better crushing performance, and the decagonal tube of D-1 is found as the best energy absorber. Multi-objective optimization design of the D-1 is finally provided using NSGA-II and RBF metamodels. The optimal decagonal tube provides on average of 248% and 61% higher SEA and CFE, respectively, compared to the D-0. However, it offers 11% higher PCF than the D-0.
Lattice structure has become an important energy absorber with its light weight and high strength ratio. In this paper, the stable flat-topped pyramid is used as the structural cell, and square frustum lattice structure (SFLS) with excellent energy absorption performance is designed. The geometry of SFLS is controlled by three factors: cell height, side length ratio and cell number. The quasi-static compression experiment and the finite element (FE) simulation were used to analyse the energy absorption characteristics of SFLS. The results show that the deformation of SFLSs is tightened folding mode, and produce a quasi-rectangular energy absorption curve. The parameterization study found that the better energy absorption performance is the SFLS with arbitrary cell number value, small cell height value and side length ratio close to 1, and the maximum SEA value can reach 72.05 J/g. Finally, by modifying the theoretical prediction model of mean crushing force and comparing with the FE results, it is found that the introduced correction coefficient can reduce the absolute error value from 32.18% to 4.96%, which indicates that the modified theoretical prediction model can be accurately used for prediction.
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.
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.
The paper proposes a design method of the sandwich column with the corrugated sinusoidal core and develops the triangular corrugated sandwich column (TCSC), quadrangular corrugated sandwich column (QCSC) and hexagonal corrugated sandwich column (HCSC). The experimental tests of the TCSC and QCSC with A=8 and N=1 are conducted to estimate the crushing responses and the reliability of the numerical model of the sandwich column. The crushing responses are numerically investigated of the TCSC, QCSC and HCSC with different geometrical characteristics and the same mass under the axial impacting load. The results show that the energy absorption of the sandwich column is significantly affected by the geometric parameters A and N of the sinusoidal core tube, and the sandwich design has the large advantage of the energy absorption over corresponding members. Furthermore, the theoretical model of the mean crushing force is derived using the simplified super folding element theory, and the comparisons on experimental result and the finite element analysis demonstrate high prediction accuracy of the theoretical model. Lastly, a numerical optimization is proposed by combining orthogonal experimental design and discrete optimization to obtain the optimal crashworthiness of the sandwich column. Optimization results show that the discrete optimization method can be fast convergence and obtain the optimal design parameters. The energy absorption of the optimal sandwich column is about 10% higher than the initial design. Furthermore, the HCSC has the highest specific energy absorption under the same mass and design constraints.
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.
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.
In this paper, we evaluate various multi-cell design concepts to optimize the crash performances of thin-walled aluminum tubes. The crash performances of the tubes are evaluated by means of two metrics: the crush force efficiency (CFE) and the specific energy absorption (SEA). The CFE and SEA of the tubes are predicted through the use of the finite element analysis software LS-DYNA. Experiments are also conducted to validate the finite element models. Thirty different multi-cell design concepts are evaluated in terms of CFE and SEA, and the best design concept is selected for further evaluation. Next, we perform surrogate-based optimization of the selected design concept, upon which we find that optimum design for maximum CFE which utilizes smaller wall thickness values (except the wall thickness of the inner tube) and larger tube diameters than those of the corresponding ones for the optimum design for maximum SEA. Additionally, the optimized designs exhibit remarkable CFE and SEA performances.
Origami, the ancient art of paper folding, has inspired the design and functionality of engineering structures for decades. The underlying principles of origami are very general, it takes two-dimensional components that are easy to manufacture (sheets, plates, etc.) into three-dimensional structures. More recently, researchers have become interested in the use of active materials that convert various forms of energy into mechanical work to produce the desired folding behavior in origami structures. Such structures are termed active origami structures and are capable of folding and/or unfolding without the application of external mechanical loads but rather by the stimulus provided by a non-mechanical field (thermal, chemical, electromagnetic). This is advantageous for many areas including aerospace systems, underwater robotics, and small scale devices. In this chapter, we introduce the basic concepts and applications of origami structures in general and then focus on the description and classification of active origami structures. We finalize this chapter by reviewing existing design and simulation efforts applicable to origami structures for engineering applications.
Multi-cell structures have been extensively studied for their outstanding performance as potential energy absorbers. Unlike existing multi-cell tubes with a uniform thickness (UT), this paper introduces a functionally graded thickness (FGT) to multi-cell tubes under dynamic impact, which can be fabricated by an extrusion process. A numerical model is first established using the nonlinear finite element analysis code LS-DYNA and validated with experimental data. Based on a numerical study, the thickness gradient parameters in different regions have considerable effects on the crashworthiness of the FGT multi-cell tubes. Moreover, the FGT multi-cell tubes are able to absorb more energy while yielding a similar level of peak impact force to the UT multi-cell tubes. Finally, multiobjective optimizations of the UT and FGT multi-cell tubes are then performed to determine the optimal gradient parameters that simultaneously improve the specific energy absorption (SEA) and reduce the maximum impact force. In these optimizations, the multiobjective particle optimization (MOPSO) algorithm and response surface (RS) surrogate modeling technique are adopted. The optimization results demonstrate that the FGT multi-cell tubes produce more competent Pareto solutions than the conventional UT counterparts; similar gradients in the outer walls and stronger internal ribs are recommended for the FGT multi-cell tubes because of their improved interactions.
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.
Plastic deformation of structures absorbs substantial kinetic energy when impact occurs. For this reason, energy-absorbing components have been extensively used in the structural design of vehicles to intentionally absorb a large portion of crash energy to reduce the severe injury of occupants. On the other hand, high peak crushing force may to a certain extent indicate the risk of structural integrity and biomechanical damage of occupants. For this reason, it is of great significance to maximize the energy absorption and minimize the peak force by seeking for optimal design of these components. This paper aims to design the multi-cell cross-sectional thin-walled columns with these two crashworthiness criteria. An explicit finite element analysis (FEA) is used to derive higher-order response surfaces for these two objectives. Both the single-objective and multi-objective optimizations are performed for the single, double, triple and quadruple cell sectional columns under longitudinal impact loading. A comparative analysis is consequently given to explore the relationship between these two design criteria with the different optimization formulations.
Thin-walled structures are widely used as energy absorbing devices for their proven advantages on lightweight and crashworthiness. However, conventional thin-walled structures often exhibit unstable collapse modes and excessive initial peak crushing force (IPCF) followed by undesirable fluctuation in force-displacement curves under impact loading. This paper introduces a novel tubal configuration, namely sinusoidal corrugation tube (SCT), to control the collapse mode, and minimize the IPCF and fluctuations. Through validating the finite element (FE) models established, the effects of wavelength, amplitude, thickness and diameter of SCTs on collapse mode and energy absorption were investigated. The results showed that SCTs can make the deformation mode more controllable and predictable, which can be transformed from a mixed mode to a ring mode by simply changing the wavelength and amplitude. Compared with the traditional straight circular tube, the IPCF is reduced appreciably. Furthermore, SCTs have lower fluctuation in the force-displacement curves than traditional straight circular tubes. Finally, a multiobjective optimization is conducted to obtain the optimized SCT configuration for maximizing specific energy absorption (SEA), minimizing IPCF under the constraint of fluctuation criterion. The optimal SCTs are of even more superior crashworthiness and great potential as an energy absorber.
Hierarchy greatly enhances anti-crushing behavior of thin-walled tubular structures. To reveal the energy-absorbing mechanism, hierarchical triangular lattice structures with lattice-core sandwich walls were designed. Crushing experiments were carried out to reveal the progressive collapse modes and folding mechanisms. Compared with single-cell and multi-cell lattice structures, hierarchical structures possess greater mean crushing forces (MCFs), three to four times higher. Three mechanisms, including hierarchical folding, shortening wave length and enlarging plastic bending moment of sandwich wall, help hierarchical structure greatly enhance its anti-crushing behavior. Folding styles turning from single fold, multi-fold, hierarchical fold to single sandwich-fold when increasing micro-cells in the wall were revealed by numerical simulation to propose optimized hierarchical lattice structure possessing the best specific energy absorption (SEA). Based on progressive folding mechanism, global bending mechanism and hybrid folding mechanism, theoretical models were built to predict the MCF. The predictions are reasonable.
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.
This paper presents a novel thin-walled tube design with a pre-folded kite-shape rigid origami pattern as an energy absorption device. Numerical simulation of the quasi-static axial crushing of the new device shows that a smooth and high reaction force curve can be achieved in comparison with those of conventional square tubes, with an increase of 29.2% in specific energy absorption and a reduction of 56.5% in initial peak force being obtained in the optimum case. A theoretical study of the energy absorption of the new device has also been conducted, which matches reasonably well with the numerical results.
This important study focuses on the way in which structures and materials can be best designed to absorb kinetic energy in a controllable and predictable manner. Understanding of energy absorption of structures and materials is important in calculating the damage to structures caused by accidental collision, assessing the residual strength of structures after initial damage and in designing packaging to protect its contents in the event of impact. Whilst a great deal of recent research has taken place into the energy absorption behaviour of structures and materials and significant progress has been made, this knowledge is diffuse and widely scattered. This book offers a synthesis of the most recent developments and forms a detailed and comprehensive view of the area. It is an essential reference for all engineers concerned with materials engineering in relation to the theory of plasticity, structural mechanics and impact dynamics. © 2003 Woodhead Publishing Limited Published by Elsevier Ltd All rights reserved.
Multi-cell structures are highly efficient energy absorber under axial crushing. The present work aimed to resolve some problems concerned with energy absorption of a type of quadruple cells. These problems include influence of geometric compatibility among elements, type of trigger, structural parameter or topology change on crush resistance of the structure. Experimental study was conducted first and numerical simulation was then carried out by using commercial explicit finite element code. Theoretical prediction for the mean crushing force of the quadruple cells was also performed by the existing theoretical models. The results showed that when the structural parameter in the section was varied, the geometric compatibility problem became severe if the discrepancy of folding wavelength among constituent elements was large. However, it generally had limited influence on crush resistance of the multi-cell structure and the existing theoretical models can still predict the crush resistance of the section with good accuracy.
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.
To enhance the energy absorbing ability of thin-walled structures, multi-cell tubes with triangular and Kagome lattices were designed and manufactured. Quasi-static axial compression experiments were carried out to reveal the progressive collapse mode and folding mechanism of thin-walled multi-cell tubes. Combining with the experiments, deformation styles were revealed and classical plastic models were suggested to predict the mean crushing forces of multi-cell tubes. Compared with anti-crushing behaviors of single-cell tubes, multi-cell lattice tubes have comparable peak loads while much greater mean crushing forces, which indicates that multi-cell lattice tubes are more weight efficient in energy absorption.
A type of cylindrical multi-cell column is proposed to improve energy absorption performance, which is inspired by the phenomenon that the circular tube is more efficient than the square tube in energy absorption. This type of structure shows high performance in energy absorption for its considerable number of corners on the cross section and the angles between neighbor flanges are in the optimal range as well as some more efficient cylindrical shells have been adopted. Numerical examples illustrate that cylindrical multi-cell column is more efficient than square column and square multi-cell column in energy absorption. In addition, a parametric study considering the effects of geometrical parameters on the structural crashworthiness has been carried out. And it is found that wall thickness, the number of cells alone the radial and circumferential directions have a distinct effect on the energy absorption.
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.
Due to increasing applications of thin-walled structures, especially as energy absorber, considerable researches have been made about them. In this paper, firstly, behavior of simple and multi-cell square tubes with equal cells is studied analytically, experimentally and numerically. Then, it is shown that for 3×3 square tubes with unequal cells, adding the partitions at corners increases energy absorption capacity of the tubes. Furthermore, the Zhang's formula for prediction of mean crushing load (MCL) is revised to inclusion of unequal cells square tubes; then, analytical and numerical results are validated with experiments. Finally, it is shown that the energy absorption capacity of the proposed new multi-cell square section is about 227% greater than that of simple section.
The out-of-plane crushing behaviour of four types of aluminium hexagonal honeycombs was extensively investigated over a wide range of strain rates where each test was conducted at a constant compressive velocity. The effects of specimen dimensions, relative density, strain rate and honeycomb cell size on the mechanical properties of honeycombs were studied. It was demonstrated that the mean plateau force was linearly related to the specimen dimensions. However, the calculated plateau stress varied with specimen dimensions and a minimum of 9 × 9 cells should be used in order to represent the bulk properties of honeycombs. A large strength enhancement of honeycombs was observed when the relative density and strain rate increased. The tangent modulus also increased towards the end of the crushing process, especially for those honeycombs with small values of wall thickness to edge length ratio (t/l). Semi-empirical relations were obtained to describe the effects of relative density (t/l ratio) and strain rate on the plateau stress. The difference in deformation patterns for honeycombs between quasi-static and dynamic loading conditions was also discussed.
A common multi-objective optimization approach forms the objective function from linearly weighted criteria. It is known that the method can fail to capture Pareto optimal points in a non-convex attainable region. This note considers generalized weighted criteria methods that retain the advantages of the linear method without suffering from this limitation. Compromise programming and a new method with exponentially weighted criteria are evaluated. Demonstration on design problems is included.
A method is developed for predicting crush behavior of multicorner prismatic columns subjected to an axial compressive load. The corner element of an arbitrary angle is analyzed first using rigorous methods of structural plasticity with finite deformations and rotations. On that basis, crush predictions are made for multicorner columns with an even number of corners. Static crush tests on square, hexagonal, and rhomboidal thin-walled columns are also reported here. Good correlation between the theory and experiments was obtained for the magnitude of a mean crushing force and kinematic parameters describing the process of progressive folding.
Assuming a rigid-plastic material and using the condition of kinematic continuity on the boundaries between rigid and deformable zones, a basic folding mechanism is constructed. This mechanism closely reproduces all the main features of folds and wrinkles actually observed on typical crumpled sheet metal structures. Calculations based on the energy balance postulate show that two-thirds of the plastic energy is always dissipated through inextensional deformations at stationary and moving plastic hinge lines. The extensional deformations are confined to relatively small sections of the shell surface but they account for the remaining one-third of the dissipated energy. The theory is illustrated by application to the problem of progressive folding of thin-walled rectangular columns.
The mechanics of the large deformation of a square tube under axial load is discussed. Theoretical results are substantiated by experimental results. The elastic buckling load is predicted by assuming the tube to be comprised of four plates simply supported at their edges. The highest load the tube can sustain is predicted by allowing for the development of plasticity near the corners. The mean crushing load is predicted from an incremental plasticity analysis which allows for travelling plastic hinges. Comparison with circular tube behaviour is considered and an attempt to explain some of the peculiarities is made.
The axial crushing of square multi-cell columns were studied analytically and numerically. Based on the Super Folding Element theory, a theoretical solution for the mean crushing force of multi-cell sections were derived by dividing the profile into 3 parts: corner, crisscross, and T-shape. Numerical simulations of square multi-cell sections subjected to dynamic axial crushing were conducted and an enhancement coefficient was introduced to account for the inertia effects for aluminum alloy AA6060 T4. The analytical solutions show an excellent agreement with the numerical results. It was found that the crisscross part was the most efficient component for energy absorption and the energy absorption efficiency of a single-cell column can be increased by 50% when the section was divided into 3 Â 3 cells. Finally, the proposed method was extended to analyze the plateau stress of square cell honeycomb subjected to out-plane axial crushing and to some extent validate the mechanical insensitivity of honeycomb to cell size.
New types of trigger and multi-cell profiles with four square elements at the corner are developed. In terms of the crash energy absorption and weight efficiency, the new multi-cell structure shows dramatic improvements over the conventional square box column. The optimization process with the target of maximizing the specific energy absorption has been successfully carried out, and the example of design process is provided. In the optimization process, the problem of stable progressive folding is also addressed. The analytical solution for calculating the mean crushing force of new multi-cell profiles is derived showing good agreement with the numerical results. Finally, the advantage of the new design over the conventional single or multi-cell profiles is discussed.
Experimental results are provided for the quasi-static and dynamic axial crushing of thin-walled square and rectangular tubes manufactured from sheet metal. The tubes were tested both empty and filled with polyurethane foam of various densities. Both the stability and the energy absorbing characteristics of the tubes are described and discussed. Simple theoretical models are proposed to explain and quantify the interaction between the foam and the sheet metal tubes.
The axial crushing of hollow multi-cell columns were studied analytically and numerically. A theoretical solution for the mean crushing force of multi-cell sections were derived, and the solution was shown to compare very well with the numerical predictions. Numerical studies were also carried out on foam-filled double-cell and triple-cell columns. Based upon the numerical results, closed-form solutions were derived to calculate the mean crushing strength of these sections. It was found that the interaction effects between the foam core and the column wall contribute to the total crushing resistance by the amounts equal to 140% and 180% of the direct foam resistance for double cell and triple cell respectively. Finally, the relative merits of single-cell, multi-cell and foam-filled sections were discussed.
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.
New functional requirements stimulate a rapid development of novel structural members. This paper presents a crashworthiness design of the regular hexagonal thin-walled columns for different sectional profiles. To formulate the complex crashworthiness design problem, the surrogate model method, more specifically, the response surface method (RSM), is utilized. The design of experiments (DoE) of the factorial design and D-optimal criterion techniques is employed to construct the response surface (RS) for the objective of specific energy absorption (SEA) and the constraint of maximum peak load (Max PL), respectively. In this study, the singly celled and multiply celled hexagonal columns are taken into account with the different sectional configurations. A comparison is made between these different hexagonal profiles, and the crashworthiness merits of multiply connected (MC) sections of the singly celled configuration and the side-connected section of triply celled configuration are quantified.
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.
Proposition of Pseudo-cylindrical Concave Polyhedral Shells, Institute of Space and Aeronautical Science
- K Miura
K. Miura, Proposition of Pseudo-cylindrical Concave Polyhedral Shells, Institute of
Space and Aeronautical Science, 1969, pp. 141-163.
- K Yang
K. Yang et al.
Thin-Walled Structures 123 (2018) 100-113