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Thin-walled tubes have been predominantly utilized in passive vehicle safety systems as crash energy absorbers. With the increasing popularity of additive manufacturing technique, it is feasible to fabricate novel internal reinforcement structures to further reinforce the crashworthy performances of thin-walled tubes. In the present work, a novel nonuniform Lattice-reinforced multi-cell tube based on topology optimization was put forward to explore the crashworthy performances under axial loading and lateral bending. Numeric models validated against the experiments were established to reveal the crashworthy performances of lattice material infilled multi-cell tubes (MCTs). It is observed that the optimized nonuniform lattice structure absorbs more energy than the uniform counterpart. In addition, the hybrid multi-cell filled tubes exhibit remarkable improvements in terms of energy absorption and crushing force efficiency in contrast to the corresponding empty tubes. Furthermore, the specific energy absorption of the three-layer hybrid multi-cell tube is improved by 38.2% and 20.0% under two loading conditions respectively relative to the sum of individual components on account of interplay effect. Collectively, the hybrid nonuniform lattice reinforcement tube provides a promising method for the crashworthy design of MCTs, which can be recommended as an underlying candidate for passive safety protection applications. [ABSTRACT FROM AUTHOR]

• Novel design strategy with cost-efficiency of multi-cell structure for energy absorption. • Shape of node-locked cell can be expanded for NMH. • Various bending shape selected for on-demand design of the node-locked effect. • Irregular localized deformation is beneficial to energy absorption of NMH. Material reconfiguration at node positions is currently a prominent method for enhancing the energy absorption capability of honeycomb structures. However, the complexity of cellar configuration poses challenges in the manufacture with cost-efficiency due to intricate preparation processes, which limits its widespread application. In this work, an innovative approach was proposed to fabricate the multi-cell honeycomb structure by nesting and assembling node-locked components with a specific shape. The stable energy absorption of multi-cell structure with node-locked design strategy was preliminarily validated by the numerical and experimental results. Additionally, the effect of the bent panels number and the cell size ratio were investigated numerically and theoretically to reveal the energy absorption mechanism of node-locked multi-cell honeycomb (NMH). It is demonstrated that the strategy by assembling node-locked components can significantly simplify preparation processes of multi-cell structure while maintaining excellent energy absorption capabilities, this offers a better balance between the cost-efficiency and superb energy absorption for multi-cell structures. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A hierarchical multifunctional chiral metamaterial (HMCM) is proposed for both excellent energy dissipation and low-frequency broadband sound absorption. • The distance ratio and wall thickness distribution of HMCM have vital effects on energy absorption performance. • The quasi-perfect absorption of the HMCM is attributed to the coherent coupling effect and hierarchical scale effect. • The multifunctional performance of the HMCM was investigated systematically through experimental, numerical, and theoretical methods. Traditional materials or advanced artificially engineered metamaterials are incapable of effectively addressing the simultaneous challenges of impact energy hazards and low-frequency noise. There is an urgent need for multifunctional materials that can address this multi-physics field coupling problem. Herein, a hierarchical multifunctional chiral metamaterial (HMCM) is proposed for damage-resistance and low-frequency broadband sound-absorption capabilities fabricated by means of laser powder bed fusion technology. Cavity resonators with internally extended tubes with hierarchical chiral configuration were selected as primary units. The damage-resistance performance of the HMCM was investigated systematically through experimental, numerical, and theoretical methods. Crashworthiness design and optimization on the multifunctional chiral metamaterial were implemented to explore the effect of geometrical parameters including distance ratio and wall thickness distribution on crushing resistance. It was determined that specific configurations in these parameters significantly enhance mechanism for dissipating energy of the HMCM. Furthermore, the designed metamaterial has been experimentally, numerically, and theoretically proven to possess quasi-perfect broadband sound absorption in the target range of 425 Hz to 553 Hz with an average sound absorption coefficient exceeding 0.9. Overall, this work not only offers a promising solution for designing multifunctional metamaterials but also highlights the potential of additive manufacturing techniques in the development of such sophisticated materials. [ABSTRACT FROM AUTHOR]

Lumped parameter modeling (LPM) combined with optimization techniques is an efficient approach for parametric configuration design of energy absorption to improve crashworthiness performance during train collision. This work proposed a simplified model by introducing a bar element to consider the influence of the carbody in a collision process. The optimization method is applied to calibrate the equivalent parameters of the bar element. Bar elements with calibrated parameters are adopted in establishing a one-dimensional (1D) model for the train crash. Subsequently, a novel crash energy management (CEM) mode with functionally graded energy (FGE) configuration is introduced to the train crash model for improving crashworthiness performance. The influence of parameters in graded function on interfacial force and peak acceleration is investigated and optimal design parameters are obtained by Nondominated Sorting Genetic Algorithm (NSGA-II). It is concluded that considering the behavior of the carbody can improve the accuracy of LPM in predicting the longitudinal response, and the gradient CEM is a potential energy configuration mode to improve the crashworthiness of the train in a collision. [ABSTRACT FROM AUTHOR]

The implementation of graded thicknesses in structural designs is an efficient strategy for improving the energy absorption performance of thin-walled columns. In this study, the mechanical responses of square columns with double-surfaced gradients under axial crushing forces were analytically and numerically investigated. A mathematical expression for the mean crushing force on a novel tube design is derived according to the super folding element method by introducing two novel parameters: the average thickness of the efficient energy absorbing region (EEAR) and global average thickness. The analytical predictions show good agreement with the simulation results that were obtained using the nonlinear finite element program ANSYS/LS-DYNA. The results demonstrate that a greater coefficient of average thickness of the EEAR versus global average thickness improves the energy absorption efficiency. However, increasing this coefficient largely depends on the sectional material distribution law. To explore the effects of this law on crushing responses, three different material distribution types were investigated. A significant improvement in specific energy absorption (approximately 30%) was obtained for a double-surfaced column with an optimized material distribution type compared to that of a square column with a uniform thickness. [ABSTRACT FROM AUTHOR]

Higher energy absorption efficiency and better crashworthiness performance are always the key objectives for different energy absorbing structures applied in numerous industries including aerospace, rail equipment transportation, and automotive. In this study, a functionally graded thickness (FGT) design method is introduced in the design of a hexagon honeycomb structure to improve energy absorbing efficiency on the basis of a traditional honeycomb with uniform thickness (UT). The validation of a numerical analysis model for a UT honeycomb under axial loading is implemented by a nonlinear finite element code LS-DYNA (V971). Furthermore, the multiobjective crashworthiness optimization of an FGT honeycomb subjected to axial quasi-static compression is conducted to maximize specific energy absorption (SEA) and minimize peak crashing force (PCF). In addition, three surrogate models, including radial basis function (RBF), response surface method (RSM), and kriging (KRG), are compared in the accuracy of predicting SEA and PCF and capacity for optimization design of FGT honeycomb structure; the Nondominated Sorting Genetic Algorithm (NSGA-II) is applied to obtain the Pareto optimal solutions for the maximum thickness, minimum thickness, and thickness variation gradient exponent of a honeycomb wall. The optimal points obtained by different surrogate models subjected to an SEA value of 18.5 kJ/kg, 20 kJ/kg, 22 kJ/kg, and 24 kJ/kg are validated, and corresponding optimal parameters are compared; RBF and RSM are more suitable in crashworthiness optimization design of the FGT honeycomb structure. It is indicated that the FGT honeycomb with optimal geometrical parameters presents remarkable enhancement and energy absorbing potential compared to the traditional honeycomb structure. [ABSTRACT FROM AUTHOR]

A layered-hybrid metamaterial structure (LHMS) composed of a bio-inspired lattice cell and a dodecagon body-centered lattice cell is proposed, for the purpose of combining the advantages of the bending-dominated and stretching-dominated structures. For the sake of investigating the mechanical performance and deformation evolution of the LHMS, compressive experiments of the specimens fabricated by laser powder bed fusion were performed via electronic universal machine, drop hammer, and Split Hopkinson Pressure Bar system. The deformation modes of the LHMS were captured by a digital camera. The experimental observations reveal that the LHMS exhibits a stable deformation mode under a large range of loading speeds. The outcomes demonstrate that the LHMS exhibits a controllable deformation mode, which has a potential serving as safety protective components. Meanwhile, numerical simulations were carried out to disclose the deformation details. Subsequently, parametric analysis was performed on the basis of the validated finite element results, aiming to discuss the mechanical performance advantage, the effect of component ratio of each sub-cell, and the effect of loading angle on the mechanical properties of the LHMS. The results indicate that the layered-hybrid design possesses superior energy absorption ability and the specific energy absorption is 25.0% and 84.7% higher compared with each individual component with the same mass. Also, the LHMS with component ratio 1.0 possesses the highest specific energy absorption of 10.64 kJ/kg, which is 32.7% and 25.9% higher than that of the LHMS with component ratio 0.7 and 1.5, respectively. • A layered-hybrid metamaterial structure (LHMS) is proposed and tested dynamically. • The layered-hybrid design strategy can effectively control deformation sequence. • The coupling of different cells leads to the superiority of LHMS over single cells. • The component ratio in LHMS has a vital effect on energy absorption performance. [ABSTRACT FROM AUTHOR]

· COPRAS and discrete optimization method are proposed for design and optimization. · COPRAS effectively selects optimal solution from many conflicting design criteria. · Discrete optimization can circularly make mean analysis in optimization process. · The crashworthiness can be improved by filling the lattice in corner regions. 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. [Display omitted] [ABSTRACT FROM AUTHOR]

• A multi-scale collaborative optimization method is proposed for lattice structures. • A proposed parametric interpolation model is superior in terms of computational cost. • The proposed method enables intermediate densities to have actual physical meaning. • Optimized graded lattice structures have higher stiffness under compressive load. In the present work, an effective and efficient design approach is proposed to obtain a three-dimensional multi-scale graded lattice structure by virtue of multiple control parameters via density-based topology optimization. To balance the computational accuracy and cost, a Parameterized Interpolation of Lattice Structure (PILS) model was established, and the math formula combined two novel designing parameters: relative density at macro-scale and aspect ratio at micro-scale. A multinomial function was employed to describe the explicit association between control parameters and equivalent elastic constants with regard to relative density and aspect ratio, which avoided tedious homogenization computation burden in the structural optimization process. Consequently, the multi-scale collaborative design approach could optimize the macro material density distribution and the micro cell topology in an integrated manner. Numerical examples with respect to compliance optimization were offered to validate the benefits of the proposed approach. Finally, the quasi-static and dynamic compression tests were respectively implemented by universal testing machine and Split Hopkinson Pressure Bar (SHPB) system on lattice structures manufactured by laser powder bed fusion (LPBF). The outcomes reveal that graded lattice structures exhibit remarkably improved load-bearing performance than the uniform lattice structures. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, the effect of artificial aging (AA), solution heat treatment (SHT) and solution heat treatment + artificial aging (SHA) at different time and temperature on the microstructures and compression properties of AlSi10Mg lattice structures manufactured by selective laser melting (SLM) were systematically investigated. The microstructure of as-built sample consists of elongate cellular α-Al matrix decorated with eutectic Si network boundaries. After AA, the cellular structure is still maintained and there are a lot of nano-sized Si precipitates of the cellular structure. After SHT and SHA, the unique microstructural characteristic of as-built disappear, whereas the Si-rich cellular boundaries are transformed into Si particles and Si particles become coarse. The Si particles inhibit grain growth in the α-Al matrix, the samples have a strong 〈001〉 orientation. The digital image correlation (DIC) method was adopted to analyze the strain field and strain distribution during the compressive process. The results reveal that the SHA has the best compression properties and stable deformation mode. And the fracture mode changed from the initial brittle fracture to ductile fracture. The correlation between the microstructure evolution and the compression properties and the strengthening mechanism were discussed. Finally, the finite element analysis was carried out to simulate the static response of the lattice structure based on the optimal heat treatment parameters. The results can be used as a reference for control of the microstructure characterization and compression properties of AlSi10Mg lattice structure after heat treatment. • The correlation between the microstructure evolution and the strengthening mechanism are discussed. • With the increase of temperature and time, the Si-rich cellular boundaries are transformed into Si particles. • The precipitate of needle-like AlFeSi have a negative effect on the compression properties of AlSi10Mg lattice. • The Si particles inhibit grain growth in the α-Al matrix, the samples have a strong <001> orientation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel lattice structure inspired from the beetle's front wing and the arrangement pattern of honeycomb cells is proposed. • The deformation mechanisms of the bio-inspired lattice structure under static and dynamic loading are unveiled. • The specific energy absorption of the bio-inspired lattice structure exhibits certain sensitiveness to the strain rate. • Numerical simulations using Johnson-Cook constitutive model of heat-treated AlSi10Mg material are in good agreement with experimental results. The progress of additive manufacturing (AM) technique broadens the conceivement and adoption of new types of lattice structures effectively. A new lattice structure, drawing on inspiration from nature, was developed and manufactured via selective laser melting (SLM) to explore the effects of printing parameters on densification and mechanical performance. Compressive experiments were conducted by universal testing machine and Split Hopkinson Pressure Bar (SHPB) system to assess energy absorption and collapse behaviour of bio-inspired structures subjected to static and dynamic load. Each deformation evolution was captured and the digital image correlation (DIC) method was adopted to analyze the strain distribution in the compressive process. The observations reveal that the bio-inspired structure possesses a steady deformation mode under static and dynamic loading, which exhibits a promising prospect for impact resistant applications. Furthermore, energy absorption of this bio-inspired structure displayed some sensitiveness to the rate of strain. Finally, finite element analysis based on Johnson-Cook constitutive model was performed as well to simulate the static and dynamic response of the bio-inspired structure. The finite element outcomes remarkably coincide with the outcomes of experiments. [ABSTRACT FROM AUTHOR]

Self-similar structures with hierarchy become novel configuration by presenting higher energy absorption efficiency and better crashworthiness performance, however, its performance is hard to increase continually via expanding hierarchy. In this work, a novel multi-cell hierarchical hexagon honeycomb structure (HHHS) was obtained by changing the topological connection, of which structure is ruled by a length coefficient defined as the ratio of 1st and 2nd hexagon honeycomb. The effect of wall thickness and length coefficient on structural energy performance was numerically investigated using finite element model validated by experiments. The optimization problem was established via surrogate model and solved using Non-dominated Sorting Genetic Algorithm (NSGA-II) to increase specific energy absorption (SEA) and decrease peak crushing force (PCF) of the HHHS for seeking superior crashworthiness. It is indicated that there is an optimal ratio between two level sub-structure, which is beneficial to enhance the crashworthy performance due to the interaction effect of adjacent folded element. The HHHS with optimal geometrical parameters presents remarkable enhancement and energy absorbing potential, which can be selected for energy absorption in consideration of a balance between better crashworthiness and preparation cost. • Crashworthy performance was effected by diameters of sub-hexagon honeycomb. • Relation between SEA and equivalent ratio was revealed for hierarchy structure. • Interaction effect of adjacent folded element can enhance crashworthy performance. [ABSTRACT FROM AUTHOR]

The lattice structure manufactured by additive manufacturing has geometric defects, which makes geometric shapes different from initial design. This research aims to incorporate stochastic geometric defects into the strut elements of a lattice structure to enhance predictive capabilities of simulation and analyze the influence of difference defects on mechanical properties. Here, X-ray computed tomography (CT) was used to extract the shape and distribution of process-induced defects. The X-ray CT images showed more geometric defects in horizontal struts than diagonal struts or vertical struts. Then, the geometric defects which are strut thickness variation and strut waviness were statistically quantified and considered into the ideal finite element model (FEM) to create the statistical FEM. Comparing the ideal FEM with the statistical FEM, it turns out that the statistical FEM was closer to experimental results. In addition, influence of different geometric defects in different struts on mechanical properties of the lattices were investigated. It indicated that strut thickness variation had more significant effect than strut waviness and thickness variation of diagonal strut had the greatest influence in difference direction. [ABSTRACT FROM AUTHOR]

The innovative combination of additive manufacturing (AM) and continuous fiber‐reinforced polymer composites (CFRPCs) confers products with the dual advantages of integrated manufacturing and designability of properties, but lack an efficient and reliable method for property prediction. This study presents a materials informatics framework using reduced‐order models and machine learning (ML) to extract the structure–property (SP) linkages between microstructures and macroscopic elastic properties of AM‐CFRPCs. The initial step involves generating microstructural 2D cross‐sections and representative volume elements (RVEs) with random fiber and pore distributions based on the minimum potential method. Then, finite element (FE) calculations are performed on RVEs to obtain nine macroscopic elastic properties. Following that, the quantification and dimensionality reduction of the 2D cross‐sectional dataset are conducted separately using two‐point spatial correlations and principal component analysis (PCA). Finally, a Bayesian optimized composite kernel support vector regression (CK‐SVR) algorithm is used to effectively establish complex mapping relationships between the reduced‐order representations of the microstructures and the mechanical properties. Despite the reduced‐order dataset containing only 3–6 variables, the framework generates an interpretable model exhibiting excellent accuracy with all predicted R2 values surpassing 0.91. Therefore, this framework presents a prospective solution for expediting the design and optimization of AM‐CFRPCs. Highlights: A materials informatics scheme is proposed to predict the 9 elastic properties of AM‐CFRPCs.Microstructures are quantified and dimensionally reduced by two‐point statistics and PCA.SP linkages are established between 2D cross‐sections and 3D macromechanical properties.Modified CK‐SVR exhibits higher prediction accuracy compared to conventional models. [ABSTRACT FROM AUTHOR]

Multi-cell design and graded thickness are two efficient strategies for improving the mechanical behaviors of metallic thin-walled tubes. This paper combines these two strategies to present a novel multi-cell structure with a double surface gradient (DSG) and to address the energy absorption characteristics of the new tube subjected to axial compression. A mathematical formulation for the mean load was derived through theoretical analysis of the multi-cell structure's folding mechanism, and two vital parameters were proposed. Afterwards, comprehensive numerical simulations were conducted to validate the formulation and to investigate effects of the DSG on the mechanical properties. The results demonstrated that the combination of the DSG strategy and the multi-cell structure led to a greater energy absorption capacity. Finally, the key factor of the DSG design in promoting the energy absorption efficiency was analyzed. To achieve a higher promotion, an approach of rationalizing the sectional material distribution of the DSG tube was attempted and proven valid. All these achievements shed a light on the multi-cell and graded thickness effects on mechanical properties. • We theoretically predicted the mean load of a graded thickness multi-cell tube. • Effects of key parameters on the energy absorbing performance are investigated. • Material distribution laws affecting the specific energy absorption are studied. • A material distribution type that is efficient in energy absorption is presented. [ABSTRACT FROM AUTHOR]

• The correlation between defects and thermal behavior is discussed, and the forming causes of defects are analyzed. • A physical model is proposed to simulate the thermal behavior of melt pool under different processing parameters. • Processing parameters have significant influence on macroscopic morphology but have little influence on dendrite spacing. Selective laser melting (SLM) is a kind of material forming technology which involves many processing parameters. The appropriate processing parameters are very important to the forming quality of manufactured samples. In this paper, the influence of laser power and scanning speed on the manufacturing defects, thermal behavior and compression properties of AlSi10Mg lattice structures during SLM were systematically investigated. By observing the macroscopic and microscopic morphology of manufactured samples, it was found that the processing parameters had a significant influence on the strut diameter and internal porosity but had little influence on the dendrite spacing and grain size. A physical model considering thermal loss and thermal conduction in temperature field was proposed to simulate the thermal behavior of melt pool under different processing parameters. The results showed that the thermal behavior was more sensitive to the laser power, and the manufacturing defects were related to the transient temperature and dimension of the melt pool. The digital image correlation (DIC) method was adopted to analyze the strain distribution of manufactured lattice during the compression process. Meanwhile, the relationship between processing parameters, thermal behavior and manufacturing defects was discussed in detail. Finally, based on the optimal processing parameters (250 W-1400 mm/s), the accuracy of manufactured lattice structure was verified by finite element method. The research results can provide a reference for the selection of processing parameters for manufacturing AlSi10Mg lattice structure. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion (LPBF) allows the fabrication of complex parts with high resolution. In the process of manufacturing complex parts, overhanging structures with unique mechanical properties are inevitable. The mechanical properties are relevant to the microstructure that are severely influenced by the support structures and build orientation. In this study, a three-dimensional finite element model was established to numerically investigate the thermal behavior of the melt pool in the overhanging structures, and the effects of different forming conditions on tensile behavior were analyzed through the microstructure of overhanging specimens and fracture surfaces of failed specimens. The simulation results show that the change trend of the melt pool size is the same as that of the maximum temperature. Moreover, the melt pools closer to the down-facing surface of overhanging structures carry higher temperature and larger size. The application of the support structures effectively reduces the temperature of the melt pool in the starting layer by 5.3%. With the increase of inclination angle, the melt pool temperature in the starting layer decreases slightly. The experimental results indicate that the mechanical properties of 45° specimens fabricated above the entity are stronger than those of 45° specimens with support structures, and the mechanical properties of 45° specimens with support structures are stronger than those of 45° specimens without support structures. Moreover, the mechanical properties of the specimens deteriorate when the build orientation of the overhanging structures varies from 0° to 45°. The mechanical properties of different specimens with 45° build orientation are mainly affected by the thickness of defect area, and the mechanical properties of the specimens with different build orientations are mainly affected by fracture path. The results will facilitate the understanding and application of the LPBF manufacturing technique for overhanging structures in complex parts. [ABSTRACT FROM AUTHOR]

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. • Cell-based hierarchical strategy was proposed to achieve ideal energy absorption (IEA). • Cell-based quadrangular hierarchical honeycombs (CQHHs) were studied under out-of-plane compression. • CQHHs' high crushing performance was verified by experiment, simulation, and theory. • CQHH's energy absorption potential was further explored through parameter analysis. • The purpose of IEA was almost achieved by an optimal CQHH. [ABSTRACT FROM AUTHOR]

• Multicellular structure and gradient thickness design were combined to achieve ideal energy absorption (IEA). • Multicellular tubes with different cell densities and material distribution principles were tested under axial compression. • High energy absorption performance of multicellular tubes with modified gradient thickness (MGT) was confirmed by experiment and simulation. • Its performance potential was further explored through parameter allocation. • Comparison of the structural efficiency of various energy absorbers revealed the MGT multicellular structure to be feasible to approach IEA with controllable cost. 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. [Display omitted]. [ABSTRACT FROM AUTHOR]