Papers by Keyword: Honeycomb Structure

Abstract: The structure of the two-dimensional BN containing 9941 atoms has been studied by classical molecular dynamics simulation with Tersoff potential. The periodic boundary condition is applied to the two x and y directions, while the z direction is free. The analysis results of the function of total energy per atom and heat capacity, mean squared displacement, diffusion coefficient, radial distribution function, distribution of coordination number, angle distribution, and ring statistics show that the melting point of the material is about 4600 K. This value is higher than the experimental value as well as the previous simulation results. The observations also show that the melting process begins at the corners and edges and then spreads across the face of the model. The breakage of the B-N bond leads to the formation of clusters of N₂ molecules and B with different sizes.

Abstract: Textile industry is commonly use dyes in colouring process which become the major dye wastewater source that leads to serious pollution in the environment. The disposed dyes can lead to serious harm to the water users and life in the aquatic because of the dye properties. Hence, the dye adsorption by activated carbon prepared from foxtail palm fruit was studied. The objectives of this study were: 1) to prepare activated carbon from foxtail fruit palm and 2) to study the effect of contact time, adsorbent dosage and initial concentration of dye usage toward the efficiency of the prepared activated carbon. Nitric acid was used as activating agent in this experiment, with impregnation time of overnight and 500 °C of 2.5 hours carbonization. The adsorption capability of foxtail fruit palm activated carbon as activated carbon was determined with the use of a dye called methylene blue. The results showed that 5 g of activated carbon was used to reduce 97.1% of 2 mg/L methylene blue with 150 minutes contact time. This result aligns with the SEM result which indicated that the produce activated carbon is rich with well-developed and irregular size of pores ranging between 1.585 μm to 7.556 μm. This study indicates that activated carbon from foxtail palm fruits could be utilized as an alternative activated carbon to treat dye wastewater.

Abstract: The purpose of this paper focuses on adhesive layer strength while having a thermal cycling of honeycomb composite sandwich structure by using the uniform design of experiments method improving the von Mises stress of honeycomb structure. Three system parameters of the honeycomb structure are selected as the control factors to be improved. Uniform design of experiment is applied to create a set of simulation experiments. Applying ANSYS/Workbench software, the finite element modelling is investigated and the von Mises stress of the honeycomb structure is calculated under metal-honeycomb core flatwise tensile test. From the numerical results, the best honeycomb structure dimension of all the experiments which causes the smaller von Mises stress is selected as the improved version of design. Finally, the best model of the experiments which causes the minimum equivalent stress is regarded as the improved version of design. Compared with the original design, the result of ASTM C297 improved version is 17.386 MPa, which mean improved 36.28%, ASTM C364 improved version is 19.015 MPa, which mean improved 25.26%, ASTM C365 improved version is 16.86 MPa, which mean improved 12.35%.

Abstract: The problem of medical implants honeycomb structures loading has been stated. The problem was solved using simulation by the finite element method. Simulation revealed that it is possible to change the elastic modulus of the material more than three times with respect to the bulk titanium alloy. The quality of the simulation was estimated based on the convergence of the simulation data.

Abstract: Hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂) can be obtained from calcium carbonates through dissolution-precipitation reaction in a phosphate solution under a hydrothermal condition, with keeping its external shape. In this study, we assumed preparation of hydroxyapatite honeycombs from a calcite (CaCO₃) honeycomb. Calcite honeycomb was hydrothermally treated in a phosphate solution. After hydrothermal processing for 24 h, calcite transformed partially to hydroxyapatite phase and its external shape was kept. Moreover, specific surface areas of the specimens were increased after the hydrothermal processing. Consequently, this processing is useful to prepare honeycomb structure of hydroxyapatite from calcium carbonates.

Abstract: In this work, room temperature polarized infrared attenuated total reflection (ATR) spectroscopy was employed to characterize a nanoporous GaN thin film with honeycomb structure. Prominent ATR dips due to the surface phonon polariton (SPP) and guided waves of nanoporous GaN thin film were observed. Both SPP resonance and guided waves were detected in the p-polarized ATR spectrum while only guided waves were detected in the s-polarized ATR spectrum. The ATR results were compared with the theoretical spectra generated by means of effective medium model. Good agreement was achieved between the measured and theoretical spectra. Finally, the thickness and porosity of porous layer were determined unambiguously.

Abstract: The element model of a honeycomb structure is established by using ANSYS software. Then theinfluence of design parameters such as inscribed circle diameter and thicknessof honeycomb on the strength and stiffness of honeycomb structure is explored.Under a given external load condition, the honeycomb structure which satisfies the equivalent stress criteria is got by changing inscribed circle diameter,wall thickness and skin thickness of a standard structure respectively. Comparethe weight of honeycomb structure get from these three methods and generalize a method of honeycomb structure lightweight design which satisfies different requirements.

Abstract: Composite material is becoming the key material of aviation industry, in this paper we get the optimal detection parameters of aircraft honeycomb structure by digital ray detection technology after many trials and testing image contrast, using gray linear transformation and reliefs enhancement technology to improve image contraction and sensitivity.

Abstract: Vacuum insulation panels (VIPs) are regarded as one of the most promising high-performance thermal insulation solutions on the market today. In this paper, a novel structure, i.e., honeycomb glassfiber mat was proposed as the core material of VIP. The honeycomb glassfiber mat was composed of glass wool mat and glassfiber chopped strand mat. Among them, 70% centrifugal glass wool and 30% flame attenuated glass wool were mixed together to form the 0.5mm-thickness glass wool mat, while thirteen holes with diameter of 10mm were opened uniformly on the surface of glassfiber chopped strand mat. Glassfiber VIPs possessed honeycomb core material have superior thermal conductivity of 1.52mW/(m•K). In order to obtain better thermal insulation performance, ultrafine and stiff fibers with three-dimensional overlapping structure is preferable. Meanwhile, hollow fibers with bifurcated structure are the guarantee of high-strength core material.

Abstract: The influence of structure parameters on mechanical properties of honeycomb sandwich mirror was investigated. Gibson hexagon equivalent theory, sandwich plate theory and Hoff theory were modified based on the theoretical analysis. The results were shown that structure parameters had non-linear influence on dimensionless structure tensile specific stiffness, shearing specific stiffness and bending stiffness in different direction while the honeycomb core was equivalent as solid material with modified material properties. The honeycomb mirror and equivalent model was modeled by using finite element method. The root mean square (RMS) and peak-to-valley (PV) values of mirror surface were determined under gravity with the optical axis pointed to the zenith. Compared with the actual modeling data, the relative error of equivalent results was less than 5%. And the optimal structure parameter range was obtained by these analyses.