Design Of Honeycomb Structures Research Articles

Stiffener and staggered-square honeycomb structure design for lobster eye x ray micro pore optics.

Lobster eye x ray micro pore optics (MPO) is a novel bionic optical technology with a unique microchannel structure. All square microchannels point to the same spherical center position, providing a wide field of view and high focusing and imaging capabilities. Enhancing the optical performance of MPO has been a significant challenge. This study introduces what we believe is a novel approach using a stiffener and staggered-square honeycomb structure design to enhance the optical properties of the MPO devices. The x ray test results show that the multifiber stiffener design enhances optical quality by approximately 20% during the melt pressing stage. The staggered-square honeycomb structure design reduces channel errors by nearly 67% in the thermal forming and coating stage. Consequently, the angular resolution of the MPO has been significantly enhanced, reducing from 4.25 to 2.68 arc min. This innovative structure design shows promise for enhancing lobster eye optics performance and has potential applications in the related field.

Structural optimization of PVDF cellular resonators for energy-harvesting enhancement based on backpropagation neural network and NSGA-II algorithm

Metamaterials with honeycomb structures have garnered significant attention in energy-harvesting applications. In this study, we present three conventional cantilever resonators with honeycomb substrates featuring positive, zero, and negative Poisson’s ratios (PPR, ZPR, and NPR). Polyvinylidene fluoride consisting electrode layers is attached to the substrate surfaces. A process parameter optimization method of honeycomb structure design was proposed, in which finite element simulation for data generation, backpropagation neural network for data prediction, and nondominated sorting genetic algorithm II (NSGA-II) for data optimization. This method aims to determine the optimum geometric parameters of the honeycomb structures, which addresses general cantilever resonators, where the first structural vibration modes are typically of interest and have to match specific target eigenfrequencies for engineering applications. Finite element simulations show that the peak voltage of PPR, ZPR, and NPR resonators at 75 Hz is increased by 12 %, 22 %, and 32 %, respectively, due to optimization. The optimized structures are fabricated and measured to validate the numerical model. The performance of the resonators with cellular materials featuring a full characteristic range of Poisson’s ratios is then compared systematically to explore their energy-harvesting potential. The results revealed that the NPR structure exhibits superior performance for energy-harvesting. Moreover, stress distribution and displacement have also been highlighted in this paper.

Honeycomb structure design of automotive crash box

The crash box can protect the safety of passengers when a car collides. Due to its excellent mechanical properties, honeycomb structure can be applied to automotive crash boxes. Two kinds of crash boxes made of regular hexagonal honeycomb structure and re-entrant hexagonal honeycomb are designed. The research results indicate that, compared to the crash box made of hexagonal honeycombs, the crash boxes made of re-entrant hexagonal honeycombs have superior energy absorption ability. Furthermore, the influence of different structural parameters on the energy absorption performance (EAP) of the crash box made of re-entrant hexagonal honeycombs is analyzed. It is found that the total energy absorption and peak force increase with the increase of thickness and concave angle. The research in this article provides certain reference significance for the design of honeycomb structure crash boxes.

Design methodology for functional gradient star-shaped honeycomb with enhanced impact resistance and energy absorption

To enhance the impact resistance and energy absorption capacity of the honeycomb, a "gradient" design approach has been developed, incorporating the angle gradient, thickness gradient, and dual gradient star-shaped honeycomb (SSH). Subsequently, the impact mechanical properties of these gradient SSHs at various impact velocities are examined using numerical analysis. The results indicate that enhancing the initial stress peak and plateau stress of SSH, thereby improving its impact resistance and energy absorption rate, can be achieved through two modifications. Firstly, by configuring a layer with a smaller cell angle gradient at the impact end while utilizing a layer with a larger cell angle gradient at the bottom. Alternatively, by employing a layer with a larger wall thickness gradient at both the impact and fixed ends and a layer with a smaller wall thickness gradient in the middle. Furthermore, it has been observed that the deformation of dual gradient SSHs under dynamic loads is primarily governed by a thickness gradient. The results offer valuable insights that can be utilized in optimizing honeycomb structure design and investigating the mechanical properties influenced by the non-uniform distribution of honeycomb.

A novel elliptical annular re-entrant auxetic honeycomb with enhanced stiffness

Auxetic structures have sparked a lot of interest due to their excellent mechanical characteristics and unusual negative Poisson's ratio influence. However, the large porosity property results in low stiffness, which limits their application scope. Current approaches to augment stiffness often result in diminished auxetic performance. Therefore, it is challenging to simultaneously enhance the auxetic, stiffness and energy absorption capacity of auxetic structures. To address this issue, this paper proposes a novel elliptical annular re-entrant honeycomb (EARE) by introducing an elliptical annular structure into a conventional re-entrant honeycomb (RE) cell, which can provide extra longitudinal support without hindering lateral deformation. The plateau stress, Poisson's ratio and energy absorption properties of the EARE are investigated by quasi-static compressive tests and finite element modeling. The results show that the EARE honeycomb has two plateau stages due to the supporting effect of the elliptical annular structure. Compared with the conventional RE honeycomb with the same wall thickness, the EARE honeycomb not only exhibits a stronger auxetic effect embodied in the Poisson's ratio reduced by 5.19%, but also has a higher average plateau stress and a higher specific energy absorption of 171.63% and 28.03%, respectively, which significantly improves the stiffness and energy absorption performance. The parameterized analysis reveals that by appropriately adjusting the geometric parameters, the stiffness, energy absorption, and auxetic effect of the EARE honeycomb can be enhanced. The research findings address the conflict between auxetic performance and honeycomb stiffness, providing new insights into the optimization of honeycomb structure design.

A numerical study to improve honey-comb topography designed for antifouling applications

Biofouling is a common issue faced by marine industry as having biofouling on the ship hulls increase unnecessary drag and friction which results in the increases of fuel consumption and decreases of cruising speed. Therefore, there are several antifouling approaches developed to mitigate the development of settlement of microorganism. The most environmentally friendly approach is surface modification by using foul-resistance topographies. The objective of this study is to investigate the antifouling performance based on the characteristics of the hydrodynamic variables which are the fluid velocity, wall shear stress, and shear strain rate at the surrounding of various designs of honeycomb topography surface. Three models were generated for this study which were Model 1 with an indented honeycomb structure surface, Model 2 with a protruded honeycomb structure surface, and Model 3 with a protruded honeycomb structure surface with different spacing and depth. The dimensions for Model 1 and Model 2 are the same whereas one is indenting while another one is protruding. In addition, Model 3 with different spacing and depth of protruded honeycomb structure was constructed to indicate the optimum design of honeycomb topography. The computer-aided design (CAD) model of the designs of honeycomb topography will be modelled using SolidWorks 2021. The CAD model will then be exported to ANSYS CFX simulator to determine the hydrodynamic variables of different designs of honeycomb topography. By analyzing the results of the simulation, the justification of the overall antifouling performance can be made and validated. The expected outcomes of this study would show a better antifouling performance of a protruding honeycomb topography design as compared to an indented honeycomb topography design. Other than that, the fluctuations in the hydrodynamic variables were higher for the protruded honeycomb structure model as the fluid is flow in the gaps between honeycomb structure instead of inside the honeycomb structure. Furthermore, the probability of fouling organisms being entrapped inside the honeycomb structure is eliminated by using the protruding honeycomb structure design. However, further research needs to be carried out as this study only focuses on the numerical method. The results obtained from this study can be used for future development on honeycomb topography design in antifouling applications, also helped to identify the optimum design of honeycomb topography that will improve the antifouling performance.

Multifunctional Hierarchical Metamaterial for Thermal Insulation and Electromagnetic Interference Shielding at Elevated Temperatures.

The custom design of lightweight cellular materials is widely concerned due to effectively improved mechanical properties and functional applications. However, the strength attenuation and brittleness behavior hinder honeycomb structure design for the ceramic monolith. Herein, the ceramic matrix composite metamaterial (CCM) with a negative Poisson's ratio and high specific strength, exhibiting superelasticity, stability, and high compressive strength, is customized by combining centripetal freeze-casting and hierarchical structures. CCM maintains a negative Poisson's ratio response under compression with the lowest value reaching -0.16, and the relationship between CCM's specific modulus and density is E ∼ ρ1.3, which indicates the mechanical metamaterial characteristic of high specific strength. In addition to the extraordinary mechanical performance endowed by hierarchical structures, the CCM exhibits excellent thermal insulation and electromagnetic interference shielding properties, in which the thermal conductivity is 30.62 mW·m-1·K-1 and the electromagnetic interference (EMI) shielding efficiency (SE) reaches 40 dB at room temperature. The specific EMI shielding efficiency divided by thickness (SSE/t) of CCM can reach 9416 dB·cm2·g-1 at 700 °C due to its stability at elevated temperatures, which is 100 times higher than that of traditional ceramic matrix composites. Moreover, the designed hierarchical structure and metamaterial properties provide a potential scheme to implement cellular materials with collaborative optimization in structure and function.

Crushing responses and energy absorption of bionic inspired corrugated honeycombs

To improve the energy absorption of traditional structures, impact resistant natural materials are usually mimicked to develop novel structures with desirable energy absorption. In this work, inspired by the unique 3D corrugated microstructure of vascular bundles in pomelo peel, a new design of honeycomb structure with corrugated characteristics is proposed. Further, motivated by special nodal bulkhead architecture of bamboo, layered honeycombs with diaphragms are designed and fabrication by metal 3D printing technology. The quasi-static and dynamic crushing responses and energy absorption characteristics of six types of bio-inspirational honeycombs (ISWH, LSWH, ISCH, LSCH, IPCH and LPCH) are studied using quasi-static testing machine and dynamic drop-weight impact experimental systems. To investigate the effect of impact speed on the crashworthiness performance of the honeycombs, the tests of the honeycombs impacted by the drop-weight with two different mass (106.07 and 59.60 Kg) and three impact velocity (V1=6.23, V2=8.82 and V3=11.77 m/s), respectively, are performed. The experimental results indicate that the crush failure mode of the layered honeycombs is more regular than that of the integrated honeycombs. Failure of all layered honeycombs occurs first at the junction of the honeycomb and diaphragms. Under impact loading, the layered corrugated wall honeycombs exhibit a greater final crushing distance than their corresponding integrated honeycombs. The design of corrugated wall can effectively reduce the initial peak force of the integrated honeycombs, while the layered honeycomb design also facilitates the reduction of the initial peak force, thus avoiding damage to personnel or equipment from excessive peak collision forces. The layered design will reduce the specific energy absorption of the integrated honeycombs in most cases, but a reasonable combination of layered and corrugated wall design can also effectively increase the specific energy absorption of the honeycombs under a specific loading speed. And, the layered design can also effectively improve the crush force efficiency of the corresponding integrated honeycombs.

Boosting high-rate lithium storage in Li3VO4via a honeycomb structure design and electrochemical reconstruction

A concise electrospraying approach was developed to synthesize novel Li3VO4/C honeycombs comprised of Li3VO4@C nanoparticles, which show an unprecedented high-rate lifespan, demonstrating great potential toward high-power applications.

Design and evaluation of new honeycomb configurations with high in-plane/out-of-plane loading-carrying capacity under impact

An aluminum honeycomb is widely used in the field of impact cushioning because of its excellent performance. In order to solve the problem of large difference between the in-plane and out-of-plane load-carrying capacities of traditional honeycombs, three new configurations of honeycombs were proposed as follows: bow-shaped, staggered and folded configurations. The finite element models for these new honeycombs were established, and their deformation modes and load-carrying capacities were analyzed. The results show that under the same relative density, compared with the traditional hexagonal honeycombs, the three new configurations can reduce the difference of load-carrying capacity in in-plane and out of plane directions. The average in-plane/out of plane (I/O) ratio of loading-carrying capacity of the bow-shaped honeycombs in two coplanar directions increased by 21.3 times. For the staggered honeycomb, the load-carrying capacity of each in-plane direction is of great difference, in which the I/O ratio of the excellent direction is increased by 42 times due to its special structure. For the folded honeycomb, the I/O ratio is increased by 21.3 times on average. The research results can provide a new idea and reference for the design of honeycomb structure under multi-directional impact load.

Achieving broad absorption bandwidth of the Co/carbon absorbers through the high-frequency structure simulator electromagnetic simulation

Confronting with increasing electromagnetic pollution, traditional microwave absorbing materials have their limitations, such as low yield and long preparation periods. At the same time, it is well established that electromagnetic simulation is an effective technology to enhance work efficiency, which can quickly explore the impedance matching conditions and electromagnetic characteristics to improve absorbing performance. Honeycomb structure has been widely used in the field of microwave absorption due to its light weight, high strength and heat resistance. This structure also possesses the advantages of multiple scattering, which is beneficial to microwave attenuation. In this work, Co/carbon (Co/C) particles with effective absorption bandwidth (EAB) (the band corresponding to the reflection loss value less than −10 dB) of 5.8 GHz were synthesized by a simple hydrothermal method. Whereupon through the high-frequency structure simulator (HFSS) electromagnetic simulation, Co/C absorbers with honeycomb structure were macroscopically designed, achieving an ultra-broad effective absorption bandwidth of 11.6 GHz. Herein, the effective combination of electromagnetic simulation and honeycomb structure design greatly improves the absorption bandwidth of Co/C. This work paves the way for designing microwave absorption materials with broad effective absorption bandwidth.

Gradient 3D-printed honeycomb structure polymer coated with a composite consisting of Fe3O4 multi-granular nanoclusters and multi-walled carbon nanotubes for electromagnetic wave absorption

Electromagnetic wave radiation has adverse health effects on humans and can hamper nearby electronic devices’ regular operations. Therefore, the need to develop new materials with a substantial wave absorption property, a broad absorption bandwidth in a wide incident angle, and lightweight is of enormous technological interest worldwide. Here we report the experimental frequency-dependent permittivity and permeability behaviors of the composite consisting of Fe3O4 multi-granular nanoclusters (MGNCs) and multi-walled carbon nanotubes (MWCNTs). We also apply the results for the starting point for the gradient honeycomb structure design and optimization. We study the effect of the tilted angle on the reflection loss (RL) by finite element analysis (FEM). We obtain a flat RL over the X-band for the regular honeycomb structure with a 0° tilted angle. An increase in the tilted angle from 0° to 4° increases the RL, and a peak is formed at the maximum tilted angle of 4°. Coating the regular honeycomb structure with a thin layer of MGNC/MWCNT enhances the electromagnetic shielding (EMI). Furthermore, as tilted angle increases for the coated honeycomb structure from 0° to 4°, SE increases dramatically over the frequency range from 8.2 to 12.4 GHz at incident wave angles of 0° and 90°.

The enhanced microwave broadband absorbing ability of carbon microspheres via electromagnetic simulating honeycomb design

The electromagnetic simulation can be used to design the macroscopic absorbing structure of the microwave absorbing material. Research indicates that the macrostructure can adjust the impedance matching and electromagnetic properties of the materials, thereby improving the absorption performance. Among them, the honeycomb structure is often used in actual products due to its good absorption characteristics and mechanical properties. Therefore, in this work, the absorption performance of the carbon microsphere material was improved through the honeycomb structure design. The carbon microsphere material is firstly prepared by sintering phenolic resin, which has the advantages of convenient synthesis, high yield, and a narrow absorption bandwidth of 4.4 GHz. Then, through the high frequency structure simulator (HFSS) electromagnetic simulation, the honeycomb structure based on the carbon microspheres was macroscopically designed, achieving a larger 8.3 GHz absorption frequency bandwidth. This research completed the combination of electromagnetic simulation and honeycomb structure, improved the absorption bandwidth of carbon microspheres, and opened up a new way for the further improvement and practical application for traditional absorption materials.

Nonlinear constitutive relations of thin-walled honeycomb structure

An analytical model is developed to investigate the in-plane mechanical properties of a thin-walled honeycomb structure. Nonlinear constitutive relations of honeycombs are presented based on in-plane large deformation analysis of a beam; elastic and plastic behaviors are both considered. These relations reflect the dependence of the equivalent stress, equivalent Young's modulus, and equivalent Poisson's ratio on deformation. Numerical simulation results indicate the effectiveness of the proposed method. Paramatric study is then conducted to investigate the effects of structural and material parameters on the honeycomb structure which is valuable for honeycomb structure design.

3D-Printing Piezoelectric Composite with Honeycomb Structure for Ultrasonic Devices.

Piezoelectric composites are considered excellent core materials for fabricating various ultrasonic devices. For the traditional fabrication process, piezoelectric composite structures are mainly prepared by mold forming, mixing, and dicing-filing techniques. However, these techniques are limited on fabricating shapes with complex structures. With the rapid development of additive manufacturing (AM), many research fields have applied AM technology to produce functional materials with various geometric shapes. In this study, the Mask-Image-Projection-based Stereolithography (MIP-SL) process, one of the AM (3D-printing) methods, was used to build BaTiO3-based piezoelectric composite ceramics with honeycomb structure design. A sintered sample with denser body and higher density was achieved (i.e., density obtained 5.96 g/cm3), and the 3D-printed ceramic displayed the expected piezoelectric and ferroelectric properties using the complex structure (i.e., piezoelectric constant achieved 60 pC/N). After being integrated into an ultrasonic device, the 3D-printed component also presents promising material performance and output power properties for ultrasound sensing (i.e., output voltage reached 180 mVpp). Our study demonstrated the effectiveness of AM technology in fabricating piezoelectric composites with complex structures that cannot be fabricated by dicing-filling. The approach may bring more possibilities to the fabrication of micro-electromechanical system (MEMS)-based ultrasonic devices via 3D-printing methods in the future.

Design of honeycomb structures with tunable acoustic properties

ABSTRACTHoneycomb structures, owing to their microstructural periodicity, exhibit unique and complex acoustic properties. Tuning their acoustic properties typically involves either changing their topology or porosity. The former route can lead to topologies that may not be readily amenable for large-scale production, while the latter could negatively affect the honeycombs’ weight. An ideal approach for tailoring the acoustic behavior of honeycombs should neither affect their porosity nor should they require customized and expensive fabrication methods. In this work, a novel honeycomb design that alters the microstructural topological features in a relatively simple way, while preserving the porosity of the honeycombs, to tune the acoustic properties of the honeycombs is proposed. The proposed honeycomb can be fabricated using the traditional approach employed to mass produce honeycomb structures; that is by bonding identical corrugated sheets with two periodic thicknesses. The acoustic behavior of the proposed honeycomb in terms of dispersion and phase velocities is analyzed using the finite element method. Simulation results demonstrate the potential of the designed honeycomb to exhibit tailored acoustic behavior at a constant porosity or mass. For example, it is demonstrated that the phase velocities of asymmetric and symmetric waves traversing the proposed honeycomb of aluminum with 90% porosity can be tuned by 30% and 17%, respectively.

Design of Honeycomb Structures Produced by Investment Casting

Design of Honeycomb Structures Produced by Investment Casting

Enhanced tunable fracture properties of the high stiffness hierarchical honeycombs with stochastic Voronoi substructures

Abstract For multifunctional optimization design of honeycomb structures, the high stiffness hierarchical honeycombs with stochastic Voronoi substructures (HHSVS) are proposed by substituting cell walls of the regular hexagonal honeycombs (ORHH) with Voronoi honeycomb lattices of equal mass. In this study, the tunable linear elastic fracture properties of the HHSVS are investigated by finite element analysis. Results demonstrate that size effect on fracture toughness of the HHSVS is noticeable and a brittleness number is suggested to determine it. At the same time, compared with the ORHH and conventional Voronoi honeycombs of equal mass/density, the in-plane fracture toughness of the HHSVS could be more than 2 times larger and regardless of the cell regularity and hierarchical parameters, fracture toughness of the HHSVS exhibits a weaker quadratic dependence on the relative density and is the highest. As a whole, the HHSVS exhibit the combined properties of tunable Poisson’s ratio, higher stiffness, enhanced tunable fracture toughness, lower imperfection sensitivity and better structural-acoustic performance etc. The research provides a novel strategy for the multifunctional optimization design of the honeycombs structures widely used in the engineering fields.

Equivalent Modeling Method and Experimental Verification of Honeycomb Sandwich Panels

In this paper, the sandwich panel theory of honeycomb sandwich panel is applied to the finite element model of solar wing veneer. The equivalent mechanical parameters are extracted by its equivalent calculation equation, and then the model of solar wing veneer is completed by applying specific boundary conditions. The dynamic analysis of the solar wing veneer structure is carried out, and the first 5 order modal frequencies and their vibration nephogram are obtained. The modal frequency and mode shape of the test are obtained by modal test of the solar wing veneer. Comparing the simulation results with the experimental results, it is found that the first five-order modal frequency error is less than 11 %, and the simulation results are in good agreement with the experimental results. The results show that the equivalent accuracy of sandwich panel theory is very high, and the design and analysis time can be saved in the allowable calculation error range, which provides important support and reference for the honeycomb structure design of solar wing.

Graded negative Poisson’s ratio honeycomb structure design and application

A sub-domain size optimization method is conducted to design degraded negative Poisson’s ratio honeycomb structures, which could fully utilize the material behavior, such as minimum weight, maximum...