Traditional Honeycomb Research Articles

Static and global buckling analysis of sandwich panels with improved star-shaped honeycomb using VAM-based downscaling model

Enhancing the stiffness of high-porosity honeycomb sandwich panels is a critical research field. To address this issue, a novel improved star-shaped honeycomb sandwich panel (SP-ISH) is designed by replacing the sharp corners with cubic struts and elongating the inclined ribs of the traditional star honeycomb. To fill the gap between global behaviors and local field distribution, an asymptotic analysis of the energy functional stored in periodic unit cells is performed. Based on the obtained effective plate properties, a two-dimensional equivalent downscaling model (2D-EDM) is developed and validated through comprehensive comparisons with results from 3D-printed experiments and 3D FE models, including assessments of static displacement, global buckling, and local field distribution. Furthermore, the effects of material and structural parameters on the effective plate properties and static performance are systematically investigated. The results reveal that the slenderness ratio of the rib and the core height-width ratio have the strongest influence on the equivalent tensile stiffness and bending stiffness, respectively. Notably, the SP-ISH outperforms other star-shaped honeycomb panels in specific stiffness, deformation resistance, and buckling load capacity due to the extended ribs and added struts. The study’s findings provide valuable insights for future designs and applications of this honeycomb structure.

Impact response analysis of stiffened sandwich functionally graded porous materials doubly-curved shell with re-entrant honeycomb auxetic core

Owing to unique deformation behavior and high capacity of energy absorption, auxetic structures have garnered significant research attention. To reveal the energy-absorbing properties of the auxetic structure, the impact response of stiffened sandwich functionally graded porous materials (FGPM) doubly-curved shell with re-entrant honeycomb auxetic core is studied by the established analytical model in the present work. The material properties in the thickness direction of FGPM face sheets are adjusted according to the volume fraction of constituents by power law and exponential law, while the core layer is made of the re-entrant honeycomb auxetic core with negative Poisson's ratio. On the basis of the Hertz theory for elastic impacts and the first-order shear deformation theory (FSDT), an analytical model is developed to study its impact phenomenon. Equations of motion are derived using Hamilton's principle, which are further solved analytically using Navier's technique of assuming unknown variables in the double trigonometric series. The time-dependent contact force is obtained by applying the spring-mass (SM) model consisting two-degrees-of freedom. Afterward, the transverse central displacements of the stiffened sandwich FGPM doubly-curved shell are calculated by adopting the Duhamel integration. The impact force and transverse displacements are compared with the previously published results, indicating that the theoretical results agree with the previously published results.Parametric analyses have been carried out to investigate the effect of variation of various parameters such as volume fraction exponents, radii of principal curvatures, porosity volume fraction, core layer inclined angle on the impact response of the sandwich shell. Additionally, the results show that compared with the traditional hexagonal honeycomb core type, the stiffened sandwich FGPM doubly-curved shell with re-entrant honeycomb core type has significant advantages in impact energy absorption. This work may provide an extensive reference and valuable guidance in the impact design and application of auxetic sandwich shell structures.

In-plane equivalent modulus of a novel zero Poisson’s ratio honeycomb structure

This paper proposed a new zero-Possion’s ratio (ZPR) honeycomb structure. The proposed ZPR honeycomb structure improves the traditional semi-reentrant honeycomb structure by introducing vertical cell walls and changing the topological structure between cells to achieve better in-plane deformation capability. The in-plane modulus of the structure was constructed during this research by a mathematical framework and a FEM model. The test specimen of the construction was created using the Stereolithography Apparatus (SLA) technology, and an axial compression experiment was utilized to confirm the model’s accuracy and the zero-ratio Poisson’s property. Geometrical parameters are also investigated to ascertain the relationship between the new zero-Poisson ratio honeycomb structure’s geometrical characteristics and the structure’s flexibility.

Dynamic characteristics of sandwich panels with novel improved star-shaped honeycomb

This study proposes a novel sandwich panel with an improved star-shaped honeycomb (SP-ISH) by replacing sharp corners with cubic struts and lengthening inclined ribs of traditional honeycomb. To more effectively analyze its special dynamic characteristics, the bending Poisson’s ratio was derived and effective engineering constants were obtained through asymptotic analysis of the energy functional stored in periodic unit cells. Based on this analysis, a two-dimensional equivalent downscaling model (2D-EDM) was developed to investigate the free vibration of SP-ISH under various boundary conditions, and the influence of initial deformation on free vibration was also discussed. The frequency-domain and time-domain analyses were employed to identify the resonance characteristics of the SP-ISH under harmonic loading. Our findings demonstrate that 2D-EDM can accurately predict the free and forced vibration of SP-ISH and improve computational efficiency by reducing DOFs. The results indicate that the maximum resonance response was obtained by applying excitation at the center of the sandwich panel. Additionally, under cyclic loading, a sharp change in local stress amplitude was observed in the facesheet-core interface region. Compared with traditional star-shaped honeycomb, the incorporation of extended ribs and added struts could significantly reduce the maximum resonance amplitude by 3.8%. Notably, the natural frequencies of SP-ISH were affected by initial compression (up to a 40.6% reduction) and tensile deformation (up to a 26.4% increase).

Dynamic response of the hybrid honeycomb sandwich panel with zero Poisson’s ratio under low-speed impact

The dynamic response of the hybrid honeycomb sandwich panel under low-speed impact is studied. According to Hamilton’s principle and first-order shear deformation theory, the motion equation of the hybrid honeycomb sandwich panel is deduced. Then the Navier method and Duhamel’s integral are used to solve the vibration displacement of panels. Besides, the mass-spring (MS) model is used to calculate the contact force between the honeycomb sandwich panel and the impactor. The results of this model are compared with those of Abaqus and published studies, which verifies the feasibility of the theoretical model in this paper. Based on the developed theoretical model, the influences of the unit cell angle, cell wall length, cell wall thickness, core layer height and impact speed on the dynamic response of sandwich panels have been studied. The results show that under the same low-speed impact, the maximum lateral displacement of hybrid sandwich panels was 11.65% smaller than that of conventional sandwich panels when honeycomb parameter θ = 60°, and was 15.45% when honeycomb parameter The energy absorption character of the hybrid honeycomb sandwich panel are better than those of the traditional hexagonal honeycomb sandwich panel and the concave hexagonal honeycomb sandwich panel.

Energy absorption characteristics of a super hexagonal honeycomb under out-of-plane crushing

Designing innovative honeycomb materials with improved energy absorption capacity is a long-term pursuit to provide adequate impact protection for crucial structural components. The edge-based design has been regarded as an effective strategy to enhance the mechanical properties and energy absorption of honeycomb materials. This paper proposes a novel super hexagonal honeycomb (SHH) structure to pursue better energy absorption capacities. Its geometry is derived from the outline of a hexagonal honeycomb. The crushing performance of the SHH is investigated based on the out-of-plane compression experiments, and an explicit finite element model is established to explore the crashworthiness characteristics of the structure. Furthermore, a theoretical model based on the simplified super folding element (SSFE) method is established to predict the mean crushing force during the crushing process. The comparison with the experimental and numerical results verifies its accuracy. Besides, the crushing mechanisms and collapse modes of the constitutive Y and V elements in the SHH are discussed. The parametric analysis of the crashworthiness of the SHH is conducted in terms of the cell-wall length ratio, sub-corner angle and hierarchy. The results reveal that the crashworthiness of SHH is much superior to traditional hexagonal honeycomb and presents 106%, 62%, 104% and 162% improvement in the mean crushing force, crushing force efficiency, specific energy absorption and volumetric energy absorption, respectively. This work can inspire future research on lightweight edge-based honeycombs with excellent energy absorption capacity.

Study on Concave Direction Impact Performance of Similar Concave Hexagon Honeycomb Structure.

Based on the traditional concave hexagonal honeycomb structure, three kinds of concave hexagonal honeycomb structures were compared. The relative densities of traditional concave hexagonal honeycomb structures and three other classes of concave hexagonal honeycomb structures were derived using the geometric structure. The impact critical velocity of the structures was derived by using the 1-D impact theory. The in-plane impact characteristics and deformation modes of three kinds of similar concave hexagonal honeycomb structures in the concave direction at low, medium, and high velocity were analyzed using the finite element software ABAQUS. The results showed that the honeycomb structure of the cells of the three types undergoes two stages: concave hexagons and parallel quadrilaterals, at low velocity. For this reason, there are two stress platforms in the process of strain. With the increase in the velocity, the joints and middle of some cells form a glue-linked structure due to inertia. No excessive parallelogram structure appears, resulting in the blurring or even disappearance of the second stress platform. Finally, effects of different structural parameters on the plateau stress and energy absorption of structures similar to concave hexagons were obtained during low impact. The results provide a powerful reference for the negative Poisson's ratio honeycomb structure under multi-directional impact.

Effect of truss core on sound radiation behavior of sandwich plate structures under structure borne excitation

Compared with traditional honeycomb and stiffened sandwich structures, lattice-based structures are considered an ideal substitute for traditional core structures due to their high stiffness and other potential multifunctional application characteristics. Based on that, the sound radiation characteristics of the sandwich plate with different truss cores under structure borne excitation were investigated in the current paper, wherein three truss cores, including pyramidal, tetrahedral and 3D-kagome cores types, are considered. The governing equations for the vibration and sound radiation analysis of the sandwich plate structure are carried out using the static equilibrium method, and then solved via the Navier approach and Rayleigh integral. By comparing the experimental results, the validity of the proposed theoretical model is verified. The theoretical model is subsequently used to investigate the influences of truss core geometric parameters and types, face sheet-core face sheet thickness ratio and aspect ratio on sandwich plate sound radiation characteristics. The results indicate that, in the range [ 5 ∘ ≤ θ ≤ 52 ∘ ] and [ 52 ∘ < θ ≤ 85 ∘ ] , the tetrahedral and 3D-Kagome core types have the maximum natural frequency values, respectively, while the resonance peaks of sound pressure level curves move to lower frequency region with the increase in truss core radius and face sheet-core face sheet thickness ratio, and the sandwich plate with the 3D-kagome core shows better sound radiation characteristics in the wide frequency range.

Out-of-plane energy absorption and crashing behavior of arc-curved hexagonal honeycomb structure

To enhance the out-of-plane mechanical performance, a novel honeycomb with arc-curved edge is proposed. The numerical model is built based on the elastoplastic failure criterion. The impact performance of proposed honeycomb is investigated and revealed. The influence of central angle and thickness on the crashworthiness is researched. The results show that the numerical result is in agreement with that of experimental test. The central angle has great influence on the deformation mode. The global buckling of edge tube is exhibited for the small central angle, and the consistent deformation mode is demonstrated for the central area. With the increasing of central angle, the energy absorption ability is enhanced for the plastic hinge could absorb more impact energy. The more stable deformation mode is exhibited for the larger central angle. The honeycomb with relatively large central angle has the best crashworthiness performance for the balance of energy absorption and structural mass. Compared with traditional honeycomb, the proposed honeycomb could improve the out-of-plane energy absorption characteristics.

Low-Velocity Impact Resistance of 3D Re-Entrant Honeycomb Sandwich Structures with CFRP Face Sheets

Lightweight sandwich structures have been receiving significant attention. By studying and imitating the structure of biomaterials, its application in the design of sandwich structures has also been found to be feasible. With inspiration from the arrangement of fish scales, a 3D re-entrant honeycomb was designed. In addition, a honeycomb stacking method is proposed. The resultant novel re-entrant honeycomb was utilized as the core of the sandwich structure in order to increase the impact resistance of the sandwich structure under impact loads. The honeycomb core is created using 3D printing. By using low-velocity impact experiments, the mechanical properties of the sandwich structure with Carbon-Fiber-Reinforced Polymer (CFRP) face sheets under different impact energies were studied. To further investigate the effect of the structural parameters on the structural, mechanical properties, a simulation model was developed. Simulation methods examined the effect of structural variables on peak contact force, contact time, and energy absorption. Compared to traditional re-entrant honeycomb, the impact resistance of the improved structure is more significant. Under the same impact energy, the upper face sheet of the re-entrant honeycomb sandwich structure sustains less damage and deformation. The improved structure reduces the upper face sheet damage depth by an average of 12% compared to the traditional structure. In addition, increasing the thickness of the face sheet will enhance the impact resistance of the sandwich panel, but an excessively thick face sheet may decrease the structure's energy absorption properties. Increasing the concave angle can effectively increase the energy absorption properties of the sandwich structure while preserving its original impact resistance. The research results show the advantages of the re-entrant honeycomb sandwich structure, which has certain significance for the study of the sandwich structure.

Broadband Flexible Microstrip Antenna Array with Conformal Load-Bearing Structure.

To enhance the load-bearing mechanical properties and broadband electromagnetic characteristics of the conformal antenna, a broadband microstrip antenna array with a conformal load-bearing structure is proposed in this paper, which consists of three flexible substrate layers and two honeycomb core layers stacked on each other. By combining the antenna and honeycomb core layer in a structural perspective, the antenna array is implemented in the composition function of surface conformability and load-bearing. Additionally, the sidelobe level of the antenna is suppressed based on the reflection surface loaded. Meanwhile, an equivalent model of a honeycomb core layer has been established and applied in the design of a conformal antenna with a load-bearing structure. The presented model increases the accuracy of simulated results and reduces the memory consumption and time of the simulation. The overall size of the proposed antenna array is 32.84 × 36.65 × 4.9 mm (1.36 λ0 × 1.52 λ0 × 0.2 λ0, λ0 is the wavelength at 12.5 GHz). The proposed antenna element and array have been fabricated and measured in the flat state and under other various bending states. Experiment results show the operating relative bandwidth of the antenna array is 20.68% (11.67-13.76 GHz and 14.33-14,83 GHz) in the flat state. Under different bending conditions, the proposed antenna array covers 24.16% (11.08-14.1 GHz), 23.82% (10.63-13.5 GHz), and 23.12% with 30°, 60°, and 90° in the xoz plane (11.55-14.33 GHz). In terms of mechanical load bearing, the structure has better performance than the traditional single-layer honeycomb core load-bearing structure antenna.

Effective performance analysis of stiffened honeycomb sandwich panels using VAM-based equivalent model

The stiffened honeycomb sandwich panel (stiffened HSP) is an improved honeycomb structure by adding the stiffeners into the traditional honeycomb core to enhance the structural performance. The novelty of this work is that the constitutive parameters of the panel are obtained by asymptotical analysis of the strain energy stored in the periodic unit cell, and a 2D dimensional reduced model (2D-DRM) is constructed on this basis. The efficiency and accuracy of 2D-DRM are verified by comparing with the results of 3D direct numerical simulations (3D-DNS) under different working conditions (including static displacement, local field distribution, free vibration and global buckling). In addition, the effects of the structural parameters of the stiffened HSP and the layup configuration of the facesheet on the equivalent stiffness, specific stiffness as well as static and dynamic performance are systematically studied. The results reveal that the facesheet thickness-to-core height ratio had the greatest influence on the buckling load, while the side length-to-height ratio of core cell had the greatest influence on the fundamental frequency. Compare with the traditional and vertical stiffened HSPs, the horizontal stiffened HSP has larger buckling load and lower natural frequency.

FEA of in-plane compression of aluminum alloy honeycomb panels

In this study, we investigated the aluminum alloy honeycomb panel and conducted a quantitative analysis. First, three kinds of honeycomb panels with different configurations were fabricated using resin materials using 3D printing technology. These honeycomb panels included the traditional honeycomb panel (Type 1), the wall middle column honeycomb panel (Type 2), and the wall end column honeycomb panel (Type 3). The results of the experiment showed that the maximum bearing capacity of the Type 3 panel increased from 28 to 34.7 kN, and the compressive performance of the Type 3 panel was better than the Type 1 panel. Finally, the numerical model was established and compared with the results of the experiment. The average error between the simulated and empirical results was only 3.366 %, which showed that the numerical model was valid. Three types of numerical models for the honeycomb panels were constructed based on the performances of aluminum alloy, and then, numerical analyses were performed to determine the lateral compression and eccentric compression. The results showed that the lateral compression of the wall end column honeycomb panel outperformed that of the traditional honeycomb plate. The thickness of the upper and lower panels of the beetle plate had the greatest influence on the lateral pressure-bearing capacity of the system. The panel thickness increased from 1 to 2.5 mm, the yield-bearing capacity increased by 2.44 times, and the maximum bearing capacity increased by 2.36 times. The results showed that the eccentric lateral compression performance of the wall end column honeycomb board improved significantly and was greater than that of a traditional honeycomb board. When the eccentric distance was 7 mm, the ultimate bearing capacity increased by 23 %. In this study, the mechanical characteristics of the honeycomb panel under lateral and eccentric compression were determined, which provided a theoretical basis for the application of this kind of aluminum alloy honeycomb panel in the field of engineering.

A novel star-shaped honeycomb with enhanced energy absorption

To obtain a structure with excellent energy-absorbing ability, based on the traditional star-shaped honeycomb (SSH), a crossed star-shaped honeycomb (CSSH) was designed via evolving the horizontal and vertical walls of the honeycomb into crossed inclined walls. In this paper, the Poisson's ratio and Young's modulus of honeycomb under axial load are theoretically deduced, and a method is proposed to evaluate the deformation stability of honeycomb with the maximum deviation of unilateral horizontal strain (MDUHS). Numerical simulation is employed to verify the theoretical solution, and the in-plane mechanical properties and deformation behavior of CSSH are investigated in detail. The numerical simulation method in Abaqus software was verified by using quasi-static crush test data of 3D printed CSSH specimens. It is found that by changing the inclined angle θ2, CSSH can evolve into a positive Poisson's ratio(PPR), zero Poisson's ratio(ZPR), or negative Poisson's ratio structure(NPR), and Young's modulus is very sensitive to the difference between the opened angle θ1 and the inclined angle θ2; increasing θ1 or decreasing θ2 not only significantly improves the energy absorption capacity of the honeycomb but also facilitates the generation of a more pronounced double plateau region on the stress-strain curve; by changing the length of the crossed inclined wall, three improved CSSHs(ICSSH) can be obtained. Among them, by adjusting the length of the crossed inclined wall in the horizontal direction, the structure with the superior energy absorption capacity can be obtained. The structure with excellent deformation stability can be obtained through adjusting the length of the crossed inclined wall in the vertical direction. Results show that the performance of CSSH is better than that of SSH, with a specific energy absorption (SEA) of 245% higher than that of SSH. This work is expected to guide the design of new auxetic honeycombs with better energy absorption properties, and can also provide a reference for the optimization of honeycombs.

Research on the energy absorption properties of origami-based honeycombs

It has been demonstrated that origami structures can be successfully used for honeycomb structures. And the excellent energy absorption properties of origami structures make them a promising candidate for use in cushioning when paired with honeycomb structures. Consequently, the honeycomb structure was recreated using origami structures to generate new specimens, aiming to reduce the initial peak force under out-of-plane crushing while maintaining the energy absorption properties. The specimens were created using 3D printing technology, and experiments with quasi-static flat pressing were carried out. The properties of the origami-based honeycomb were investigated during out-of-plane crushing, with an emphasis on its energy absorption properties. Additionally, the compressive properties of the origami-based honeycomb are compared with those of traditional re-entrant honeycomb in z-axial directions. To further investigate the properties of the origami-based honeycomb, a validated model was developed in Abaqus, and the accuracy of the finite element model’s forecast was confirmed. The results show excellent lateral material shrinkage under axial compression, which is an obvious negative Poisson’s ratio (NPR) effect, and a distinct hardening process with stiffness increases when the origami-based honeycomb structure experiences densification. Moreover, compared to the traditional re-entrant honeycomb structure, the origami-based honeycomb has a lower peak crushing force and a smoother plateau stress curve, making it an ideal material for protective structural applications. Increasing the height H or decreasing the forward length V are effective methods for increasing the structure’s specific energy absorption (SEA). Additionally, different configurations will have distinct consequences for the structure. Compared to ordinary origami-based honeycombs, the honeycomb with different configurations has superior energy absorption properties and can also achieve stiffness jumps and segmental self-locking.

Buckling Analysis of Re-Entrant Honeycomb Structures Under General Macroscopic Stress States

Based on the negative Poisson’s ratio effect of the re-entrant honeycomb, the finite element simulation of its buckling mechanical properties was carried out, and 2 buckling modes other than those of the traditional hexagonal honeycomb structures were obtained. The beam-column theory was applied to analyze the buckling strength and mechanism of the 2 buckling modes, where the equilibrium equations including the beam end bending moments and rotation angles were established. The stability equation was built through application of the buckling critical condition, and then the analytical expression of the buckling strength was obtained. The re-entrant honeycomb specimen was printed with the additive manufacturing technology, and its buckling performance was verified by experiments. The results show that, the buckling modes vary significantly under different biaxial loading conditions; the re-entrant honeycomb would buckle under biaxial tension due to the auxetic effect, being quite different from the traditional honeycomb structure; the typical buckling bifurcation phenomenon emerges in the analysis of the buckling failure surfaces under biaxial stress states. This research provides a significant guide for the study on the failure of re-entrant honeycomb structures due to instability, and the active application of this instability to achieve special mechanical properties.

Quasi-static and dynamic out-of-plane crashworthiness of 3D curved-walled mixed-phase honeycombs

Honeycombs are widely used in engineering protections due to desirable crashworthiness. However, the gap between peak and mean stresses remains to be narrowed, and effect of interaction between the cells should be enhanced. To break these limits, novel three-dimensional curved-walled mixed-phase honeycombs are proposed in this paper. The specimens manufactured by three-dimensional printing method using 316L stainless steel are used to conduct out-of-plane crushing experiments, and finite element method simulations are carried out by ABAQUS/Explicit. According to experimental and simulation results, theoretical model is established based on the Simplified Super Folding Element theory to estimate the out-of-plane effective mean stress. From the results, the proposed honeycombs display efficient progressive folding mode and desirable mechanical properties, and the gap between peak and mean stresses is effectively narrowed. Compared with traditional straight-walled honeycomb, total energy absorption, specific energy absorption, energy absorption efficiency and force efficiency can be enhanced respectively by 57.8%, 33.8%, 3.4% and 55.3% after implementing 3D curved-walled mixed-phase design, which can be further improved by parameter optimization and thickness gradient design. The work represents an effective approach for designing and optimizing high-performance honeycombs through curved-walled design and mixed-phase mechanism.

Out-of-plane crushing performances of cell-based hierarchical honeycombs based on the evaluation criteria for ideal energy absorption

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.

Mechanical behaviors of a novel auxetic honeycomb characterized by re-entrant combined-wall hierarchical substructures

The current focus of the metamaterials is to further improve their performance by the unit cell innovation, while for the auxetic metamaterials, the compromise between the mechanical properties and auxetic effect still needs more efforts. Given this issue, here we developed a novel auxetic honeycomb, named re-entrant combined-wall (RCW) honeycomb, by introducing four hierarchical substructures to the RE cell. Analytical expressions were derived and used to study the in-plane elastic constants of the RCW honeycomb, which were well confirmed by the established finite element model. Further, we investigated its crushing behaviors under large deformation by the explicit numerical method, and the quasi-static crushing experiments were also carried out by the 3D-printed specimens. Results show that the properties of the proposed RCW honeycomb have a high degree of orthogonality and tunability. Compared with the traditional RE honeycomb, the Young’s modulus of the RCW honeycomb in the y direction increases by more than 120%, and the Poisson’s ratio decreases by about 43%. Besides, behaviors of the cell wall contact induced by the adding substructure can lead to an interesting stress enhancement phenomenon under large deformation, which significantly increases its crushing strength, up to 140%, compared with the RE honeycomb. Therefore, the results in this work effectively demonstrate the improved mechanical properties and auxetic performance of the proposed RCW honeycomb. Besides, the adopted design strategy of hierarchical substructure also exhibits great potential for developing novel and excellent auxetic mechanical metamaterials.

Modular technique to construct lightweight CFRP lattice structures

Carbon fiber reinforced polymer (CFRP) lattice structures are ultralight but stiff and strong. A modular technique based on tubular textiles was proposed to design and made CFRP lattice structures with different unit cell topologies. Foam-filling technique was applied to strength the modular lattice structure (MLS). The out-of-plane compression behavior and energy absorption performance of these MLSs were investigated by axial compression experiments. Modular and foam filling techniques remarkably improve the energy absorption performance through changing the crushing mode from local bucking to progressive folding and can increase the specific energy absorption (SEA) at a level of 66%. Meanwhile, MLSs have much greater compression strength than traditional foams and honeycombs.