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In order to further study the cushioning performance of concave hexagonal cores (CHCs) and expand their application range, the in-plane finite element model of CHCs is established in this paper. A dynamic cushioning coefficient method was proposed to characterize the cushioning performance of CHCs. The dynamic cushioning coefficient curve and minimum dynamic cushioning coefficient (MDCC) of CHCs with different impact velocities and structural parameters are obtained. The influence rules of structural parameters and impact velocities on the MDCC are analyzed; the deformation mode and transformation empirical formula are also obtained. The results show that when other parameters are constant, the MDCC of CHCs decreases with the increase of impact velocity, increases with the increase of wall thickness and side length ratio, and decreases with the increase of expansion angle. The theoretical analysis is consistent with the finite element results, which further verifies the reliability of the model. This paper provides a solid theoretical basis for the industrial application of the cushioning performance of CHCs and forms a key technical support. [ABSTRACT FROM AUTHOR]

This paper investigates the metric dimensions of the polygonal networks, particularly, the subdivided honeycomb network, Aztec diamond as well as the subdivided Aztec diamond network. A polygon is any two-dimensional shape formed by straight lines. Triangles, quadrilaterals, pentagons, and hexagons are all representations of polygons. For instance, hexagons help us in many models to construct honeycomb network, where n is the number of hexagons from a central point to the borderline of the network. A subdivided honeycomb network SHCN n is obtained by adding additional vertices on each edge of HCN n . An Aztec diamond network AZN n of order n is a lattice comprises of unit squares with center a , b satisfying a + b ≤ n. The subdivided Aztec diamond network SAZN n is obtained by adding additional vertices to each edge of AZN n . In this work, our main aim is to establish the results to show that the metric dimensions of SHCN n and AZN n are 2 and 3 for n = 1 and n ≥ 2 , respectively. In the end, some open problems are listed with regard to metric dimensions for k -subdivisions of HCN n and AZN n . [ABSTRACT FROM AUTHOR]

Graphene, a 2D sp2 hybridized carbon sheet consisting of a honeycomb network, is the building block of graphite. Since its discovery in 2004, graphene's exceptional electronic and mechanical properties have peaked interest in various applications. However, the inability to mass produce high-quality graphene affordably currently limits the practical application of the material. Researchers are continuously working on advancing graphene synthesis methods to alleviate these limitations. Therefore, this review looks at the overview of established graphene synthesis methods and characterization techniques, and then highlights an in-depth review of graphene production through flash joule heating. The environmental concerns related to graphene synthesis are also presented in this review paper. [ABSTRACT FROM AUTHOR]

In order to impprove the protective effect of the automotive energy absorption (EA) box, the design of the reentrant bioinspired EA box is proposed, that is, novel bioinspired structures are inserted into the original EA box to improve the EA effect of the box. The improved bionic structures with curvature are designed according to the spider web: honeycomb structure (HS), arc-honeycomb structure (AHS), negative Poisson structure (PS), and arc negative Poisson structure (APS). A new bionic automobile energy absorbing box is constructed by combining with automobile energy absorbing box. Experiments and simulations further verify excellent mechanical properties of bionic structures. The results show that EA of AHS and APS is 117.2% and 105.8% of HS and PS. Their specific energy absorption is 112.2% and 102.7% of HS and PS. HS EA box structure, AHS energy absorption box structure, PS energy absorption box structure, and APS energy absorption box structure are 114.2%, 117%, 109.2%, and 116.2% higher than traditional EA box structures, respectively. The excellent characteristics of biological structures can provide ideas for structural design objectives of engineering applications and greatly simplify the process of optimal design. [ABSTRACT FROM AUTHOR]

The reed structure is the key component in the foldable space deployment mechanism. In the aerospace industry, weight loss occupies a pivotal position. The use of lightweight structure can achieve significant savings in launch costs and improve load efficiency. Aiming at the lightweight requirements of the space deployment mechanism, this paper discusses the substitution effect of the honeycomb topology on the reed structure in the space deployment structure. Firstly, the column structure of the honeycomb is equivalent to an orthotropic cylindrical block-shell structure. According to the bending theory of an orthotropic cylinder, the expanded honeycomb structure equivalent to an orthotropic cylindrical block-shell structure is deduced. Then, the exact expression of the reverse bending moment was obtained, and the bending moment-curvature curve during the folding process was drawn. The bending moment-curvature characteristics during the folding process are simulated by finite element numerical simulation. By proposing the index of unit mass for analysis and comparison, the results show that compared with the common spring steel structure, the honeycomb structure has better mechanical properties per unit mass and has a certain substitution effect on the reed structure. [ABSTRACT FROM AUTHOR]

This paper presents an in-depth study and analysis of the mathematical control of space-based kinetic energy weapons and the evaluation of the damaging effect by partial differential equations. The spectral element discrete format of the optimal control problem is constructed, the a priori error estimate of the control problem solution is proved theoretically, the posteriori error estimator is constructed, and the adaptive solution algorithm is designed. The posteriori error estimator is used as the encryption criterion to guide the local encryption of the grid so that the distribution of the dissection nodes is denser where the function regularity is poor. In the case of a compartment subjected to a shell attack, the effect of different factors on the structural damage of a single compartment under two explosions is investigated by varying the explosive mass, the location of the blast point, and the interval between the two explosions. In this paper, the problem of implosion in the cabin is studied, and the main factors affecting the response of the implosion structure are analyzed using dimensionality. The data of various simulation conditions are counted, and the dimensionless damage number is fitted with the deformation results of the bulkhead under each damage mode. It is still difficult to obtain the acceleration information of the target. Experimental studies were conducted on the composite honeycomb sandwich structure penetrated by fragmentation at different velocities and angles, and the accuracy of the theoretical model and the fragmentation residual formula was verified based on the test results. The analysis found that the antidamage performance of the composite honeycomb sandwich structure is better than the existing honeycomb sandwich body structure, and the energy absorption per unit volume of the structure is 27.2%–84.2% higher than that of the existing structure in the range of different penetration velocities. The average error between the theoretical calculation results and experimental results of the remaining velocity of the broken piece is within 6%, the error with the numerical simulation is about 8%, and the composite honeycomb sandwich structure with the best energy absorption characteristics and structural parameters is obtained. [ABSTRACT FROM AUTHOR]

In order to improve the adsorption performance of molecular sieve honeycomb ceramics for VOCs, the author proposes a research method for the adsorption performance of VOCs based on the honeycomb ceramics loaded with molecular sieves. The method prepared cordierite honeycomb ceramic-supported HY, Na Y, USY, ZSM-5-300, and ZSM-5-360 monolithic adsorption materials by the coating method. Using toluene, ethyl acetate, isopropanol, and acetone as adsorbates, the adsorption properties of single-component and mixed-component organic compounds on the supported molecular sieve honeycomb ceramics were investigated. The result shows ZSM-5-300 has the largest adsorption capacity for the four adsorbates, which are toluene 68.0 mg/g, ethyl acetate 118.7 mg/g, isopropanol 70.9 mg/g, and acetone 72.5 mg/g. The test results show that ZSM-5-300 molecular sieve has high saturated adsorption capacity and is an ideal VOCs adsorption material. [ABSTRACT FROM AUTHOR]

To enhance the mechanical performances of traditional honeycombs, a novel combined honeycomb (HKH) was proposed based on the regular hexagonal honeycomb (RHH) and Kagome honeycomb (KH). A systematic investigation of the in-plane dynamic crushing behaviors of the honeycombs was conducted via the finite element method, and the crashworthiness characteristics of the three honeycombs were examined. Using one-dimensional shock wave theory and least squares fitting, a fitting formula of the plateau stress was obtained, and the deformation mechanism of the HKH was determined based on the elastic buckling of the cell wall. The results showed that the HKH exhibited a higher plateau stress than the RHH for any velocity impact, while the negative Poisson's ratio effect was more significant than that of the KH for low-velocity impacts (the peak Poisson's ratios of the HKH and KH were −0.312 and −0.286, respectively). Furthermore, the effects of the impact velocity and relative density on the energy absorption and auxetic performances were explored. In this study, a novel design was proposed by combining various cell elements to obtain better crashworthiness, providing a new concept to promote the development of lightweight materials. [ABSTRACT FROM AUTHOR]

The physical properties of solidified mud will deteriorate under the combined action of freezing-thawing cycle and chlorine salt, which will affect the safety and stability of solidified mud engineering. In order to study the damage characteristics of solidified mud under the action of freeze-thaw cycle and chloride salt, the solidified mud samples were soaked in different concentrations of sodium chloride solution and treated with freeze-thaw cycle. Besides, the unconfined compressive strength test was carried out to study the damage characteristics of the samples caused by different concentrations of sodium chloride solution and freeze-thaw cycles. The test results show the following. (1) Under the action of freeze-thaw cycle and sodium chloride solution, the surface of the sample deteriorated in varying degrees. With the increase in freeze-thaw cycle times and sodium chloride solution concentration, the mass loss of the sample was greater. (2) Under the action of chlorine salt and freeze-thaw cycle, the strength of the sample decreases with the increase in freeze-thaw cycle times. With the increase in the concentration of sodium chloride solution, the strength of the sample decreases and the damage degree increases gradually. (3) Under the action of freeze-thaw cycle, the internal pores of the samples gradually expand and more honeycomb holes appear, and the content of hydration products is higher. As the concentration of sodium chloride solution increases, the particle connection inside the sample gradually weakens, and the sample is more likely to be damaged. [ABSTRACT FROM AUTHOR]

Composite honeycomb sandwich plates have been widely used in aerospace, ships, construction bridges, machinery, stationery, and other industries. In order to improve the performance and configuration, taking the structural dynamic characteristics of periodic honeycomb plate as the research object, a structural optimization design method based on natural frequency and stiffness was proposed with the goal of weight reduction. The geometric parameters of the structure system were trained by the multiobjective optimization genetic algorithm (MOGA), and the Pareto optimal solution of variable combination was obtained. This paper presented a decoupling method for complex system optimization design based on dynamic performance from the perspective of basic unit, which could solve the coordination problem of vibration stability and weight reduction in periodic honeycomb plate structure optimization design. It has reference significance for the similar composite material frame base structure design. [ABSTRACT FROM AUTHOR]

In order to promote the development of honeycomb composite reinforcements, the mechanical properties and optimization methods of honeycomb beams are studied. A structural optimization design method is proposed based on natural frequency and stiffness and the lightest weight. According to the vibration frequencies and mechanical analysis, the equivalent density and equivalent stiffness of the section in the unit length are deduced, which is considered a typical example. The geometric parameters of the structure system are trained by multiobjective optimization minimax algorithm (MOMA), and the Pareto optimal solution of variable combination is obtained. The results show that optimized objects are significantly better than that previously. Therefore, the optimized scheduling algorithm has some reference value and prospects for practical application. [ABSTRACT FROM AUTHOR]

High hydrostatic pressure (HHP) can enhance the physicochemical properties of soluble dietary fiber (SDF) from fruit and vegetable residues including hydration properties, emulsibility, and rheological properties, while the pretreatment methods such as solid-water suspension status are ignored all along. Here, three groups of lotus root residue (LRR) for HHP treatment (400 MPa, 15 min) were prepared: the fresh lotus root residue (FLRR), FLRR mixed with water (FLRR + W), and dried FLRR suspended in water at the same solid/water level with FLRR + W (DLRR + W). As a control, non-HHP-treated FLRR was tested. Results showed that FLRR + W obtained the highest SDF yield and presented a honeycomb structure which was not observed in other LRR samples. In addition, properties of SDF extract from FLRR + W changed most significantly, including not only the enhancement of SDF yield, the improvement of hydration properties, and the reduction of molecular weight but also the increase of thermal and rheological stability. Principal component analysis (PCA) profile illustrated that the difference of LRR-water system contributed 27.6% to the SDF physicochemical changes, and SDF from DLRR + W distinguished it from the other samples with mannose, ribose, and glucuronic acid, indicating that the drying procedure also played a role in the HHP treatment focusing on the sugar constitution. Therefore, the solid-water suspension status is a noteworthy issue before HHP treatment aiming at SDF modification. [ABSTRACT FROM AUTHOR]

The introduction of hierarchical structures into conventional honeycomb structure materials can increase the mechanical properties of honeycomb materials. This paper studies the in-plane collapse response of a new second-order diamond-shaped hierarchical honeycomb (DHH) (the cell walls are composed of equilateral triangles) and systematically studies the quasi-static collapse response and dynamic collapse response of the DHH in two directions through the finite element method. The quasi-static collapse response of the DHH is analyzed by a two-scale research method, and combined with momentum conservation law, the study is extended to dynamic collapse response. This paper also studies the collapse response of the DHH with different number of substructures, different relative densities, and different impact speeds, and the results are verified by theoretical analysis and numerical simulation. The results show that adding hierarchical structure can greatly increase the collapse stress of the diamond honeycomb structure and make the structure have better energy absorption effect. [ABSTRACT FROM AUTHOR]

This study aims to investigate the hysteretic behavior of H-shaped honeycombed steel web composite columns with rectangular concrete-filled steel tube flanges (STHCCs). Taking the shear span ratio (λs), axial compression ratio (n), steel ratio of section (α), aspect ratio of section (D/B), yield strength of steel tube (fyfk), and compressive strength of concrete (fck) as the main parameters, we designed 22 full-scale STHCCs. By comparing the load-displacement curves between test and simulation, the rationality of finite element modeling method was verified. The quasi-static analysis of 22 specimens was carried out, and the influence regularity of different variables on the hysteretic behavior, skeleton curves, ductility, energy dissipation, resistance degradation, and stiffness degradation of STHCCs was obtained. The results show that the hysteresis curves of all the specimens show full shuttle shape and strong energy dissipation capacity. λs, α, and fyfk have great influence on the bearing capacity of skeleton curves. With the increase of α and fyfk, the initial stiffness of the specimens gradually increases. The stiffness degradation rate of the specimens gradually slows down, and the energy dissipation coefficient gradually decreases by increasing λs, α, and fyfk, but energy dissipation capacity is still at a high level. The resistance degradation of specimens increases gradually by increasing λs, α, fyfk, and D/B. The ductility of specimens gradually increases by increasing n, α, and fck. The maximum bulging deformation and maximum stress of specimens appear at the column foot. The trilinear skeleton curve model and restoring force model of STHCCs are established by statistical regression. [ABSTRACT FROM AUTHOR]

Cartilage regeneration is still a challenge for clinicians because of avascularity, denervation, load-bearing, synovial movement, and the paucity of endogenous repair cells. We constructed a multilayered osteochondral bionic scaffold and examined its repair capacity using a rabbit osteochondral defect model. The cartilage phase and interface layer of the scaffold were prepared by freeze-drying, whereas the bone phase of the scaffold was prepared by high-temperature sintering. The three-phase osteochondral bionic scaffold was formed by joining the hydroxyapatite (HAp) and silk fibroin (SF) scaffolds using the repeated freeze-thaw method. Different groups of scaffolds were implanted into the rabbit osteochondral defect model, and their repair capacities were assessed using imaging and histological analyses. The cartilage phase and the interface layer of the scaffold had a pore size of 110.13 ± 29.38 and 96.53 ± 33.72 μ m , respectively. All generated scaffolds exhibited a honeycomb porous structure. The polydopamine- (PDA-) modified scaffold released platelet-derived growth factor (PDGF) for 4 weeks continuously, reaching a cumulative release of 71.74 ± 5.38 %. Synovial mesenchymal stem cells (SMSCs) adhered well to all scaffolds, but demonstrated the strongest proliferation ability in the HSPP (HAp-Silk-PDA-PDGF) group. Following scaffold-induced chondrogenic differentiation, SMSCs produced much chondrocyte extracellular matrix (ECM). In in vivo experiments, the HSPP group exhibited a significantly higher gross tissue morphology score and achieved cartilage regeneration at an earlier stage and a significantly better repair process compared with the other groups (P < 0.05). Histological analysis revealed that the new cartilage tissue in the experimental group had a better shape and almost filled the defect area, whereas the scaffold was nearly completely degraded. The new cartilage was effectively fused with the surrounding normal cartilage, and a substantial amount of chondrocyte ECM was formed. The SF/HAp three-layer osteochondral bionic scaffold exhibited favorable pore size, porosity, and drug sustained-release properties. It demonstrated good biocompatibility in vitro and encouraging repair effect at osteochondral defect site in vivo, thereby expected to enabling the repair and regeneration of osteochondral damage. [ABSTRACT FROM AUTHOR]

A topological index is a numeric quantity related with the chemical composition claiming to correlate the chemical structure with different chemical properties. Topological indices serve to predict physicochemical properties of chemical substance. Among different topological indices, degree-based topological indices would be helpful in investigating the anti-inflammatory activities of certain chemical networks. In the current study, we determine the neighborhood second Zagreb index and the first extended first-order connectivity index for oxide network O X n , silicate network S L n , chain silicate network C S n , and hexagonal network H X n . Also, we determine the neighborhood second Zagreb index and the first extended first-order connectivity index for honeycomb network H C n . [ABSTRACT FROM AUTHOR]

The functionally graded honeycomb has the characteristic of light weight, low density, high impact resistance, noise reduction, and energy absorption as a kind of new composite inhomogeneous materials. It has the advantages of both functionally graded materials and honeycombs. In this paper, a functionally graded honeycomb sandwich plate with functionally graded distributed along the thickness of the plate is constructed. The equivalent elastic parameters of the functionally graded honeycomb core are given. Based on Reddy's higher-order shear deformation theory (HSDT) and Hamilton's principle, the governing partial differential equation of motion is derived under four simply supported boundary conditions. The natural frequencies of the graded honeycomb sandwich plate are obtained by both the Navier method from the governing equation and the finite element model. The results obtained by the two methods are consistent. Based on this, the effects of parameters and graded on the natural frequencies of the functionally graded honeycomb sandwich plate are studied. Finally, the dynamic responses of the functionally graded honeycomb sandwich plate under low-speed impacts are studied. The results obtained in this paper will provide a theoretical basis for further study of the complex dynamics of functionally graded honeycomb structures. [ABSTRACT FROM AUTHOR]

To obtain the resources of the moon, humans have launched a series of exploration activities on the moon, and the landing buffer device is an indispensable device on the lander required to perform lunar surface exploration missions. It can effectively protect the lander during landing scientific payloads such as instruments on the lander. Based on the mechanical properties and deformation mechanism of the aluminum honeycomb as buffer material, this paper compares and analyzes different simulation schemes and finally establishes the bonding model of the honeycomb by using the discrete element method; the parameters of the honeycomb material are matched through compression experiments to verify the discrete element honeycomb simulation and the feasibility of the scheme and its parameters. To meet the buffering requirements of large landers, a spider web honeycomb structure is proposed, its modeling method is studied by using the discrete element secondary development program, and the model is compressed as a whole to verify the energy consumption characteristics of the spider web honeycomb structure. Aiming at the honeycomb buffer device during the landing process, the cobweb honeycomb buffer structure and its corresponding landing coupling model were established using the discrete element method, the landing process was simulated and analyzed, and the landing results were predicted to verify the feasibility of the device, providing a reference for the design of the lander and its buffer device. [ABSTRACT FROM AUTHOR]

In this paper, an equivalent method based on sandwich plate is deduced, and the equivalent parameters of the honeycomb plate are obtained. With these equivalent parameters, the honeycomb plate equivalent FEM simulation model and actual model are established, and three-point bending simulations of the equivalent model and the actual model three-point are completed. Then, a three-point bending test of a real honeycomb sandwich panel was performed for comparison with the simulation result, which agrees well with the test result and shows the effectiveness of the equivalent model. The equivalent model of honeycomb sandwich plate win ribs is established for structural topology optimization and wing static simulation analysis, and a prototype of the solar UAV is made for flight testing according to the topology optimization results. The simulation and prototype test results indicated that the sandwich equivalent theory is suitable for the lightweight design of solar UAV wing structures with honeycomb sandwich plate materials, and this method can provide a reference for the same type of wing structure design. [ABSTRACT FROM AUTHOR]

To reduce the loss of life and property caused by the collision of a ship against a bridge pier, this study proposes a new type of anticollision facility. The facility uses corrugated steel plates and corrugated steel pipes (CSPs), or ordinary steel plates and corrugated steel pipes (OSPs), as structural elements to form a honeycomb structure, which can greatly improve the impact resistance of bridge piers and reduce any damage to ships. To evaluate the anticollision performance of the proposed anticollision facility, this work uses the CSPs and OSPs as study objects in the impact test research. A pendulum impact test system was utilized to compare and analyze the column with CSP and OSP specimens and the column without any anticollision facilities. Test results show that the CSP and OSP specimens have a relatively high energy dissipation effect. When the impact energy is small, the energy dissipation effect of the OSPs with the same plate thickness is stronger than that of the CSPs. When the impact energy is large, the energy dissipation effect of the CSPs with the same plate thickness is stronger than that of the OSPs. In addition, the extreme value analysis method is used to analyze the relationship curve between the peak value of the D1 lateral displacement and the specimen's plate thickness, weight, and natural frequency; the optimal thickness, weight, and natural frequency values of the CSP and OSP specimens are also deduced. Taking the optimal value of the specimen's natural frequency as a target, the structure of the CSP and OSP specimens is optimized. When the optimized plate thickness is 2.50 mm, the ratios of the optimal value of the specimen plate thickness, weight, and natural frequency to the optimal calculation value are all in the range of [0.80, 1.12]. OSP and CSP specimens are found to have the best energy dissipation effect. The peak value of the D1 lateral displacement of the top of the column equipped with the CSPs is at least 88.37% lower than that of the column without any anticollision facilities. For the top of the column equipped with the OSPs, the peak value of the D1 lateral displacement is at least 80.37% lower than that of the column without any anticollision facilities. Optimization results show that the extreme value analysis method is suitable for the optimal design of anticollision facilities for piers. [ABSTRACT FROM AUTHOR]

This article has been retracted by Hindawi following an investigation undertaken by the publisher [[1]]. We wish to credit our own Research Integrity and Research Publishing teams and anonymous and named external researchers and research integrity experts for contributing to this investigation. [Extracted from the article]

This article has been retracted by Hindawi following an investigation undertaken by the publisher [[1]]. We wish to credit our own Research Integrity and Research Publishing teams and anonymous and named external researchers and research integrity experts for contributing to this investigation. [Extracted from the article]