Hexagonal Angle Research Articles

Crushing Behaviour of Plain Weave Composite Hexagonal Cellular Structure

The tradition of fibre composite materials in energy absorbing tube applications has gained interest in structural collisions in the composite materials industry. Thus, the subject of this work is the experimental investigation to understand the effects of the failure initiator at the specimen’s edge, causing the increase in the specific absorbed energy (SEA), as well as the influence of the cellular structure composed of cells with small hexagonal angle exhibited high energy absorption capability. An extensive experimental investigation of an in plane crashing behavior of the composite hexagonal cellular structure between platen has been carried out. The cellular structure composed of hexagonal cells with angles varying between 45 and 60°. The materials used to accomplish the study are the plain weave E-glass fabric as a reinforcement and the epoxy resin system as a matrix. Furthermore, the specific energy absorption increases as the hexagonal angle increases.

Crashworthiness Characteristics and Failure Mode of Composite Tubes

The woven plain weave/epoxy hexagonal tubes’ capacity for energy absorption is investigated in present work. The experimental work was performed on composite hexagons with different hexagonal angles between 35° and 55° in aspect ratios L/t = 70 and 10° angular increments. Observation was made on how the configuration impacts the crash-worthiness behavior of the reinforced hexagonal tubes. Moreover, the impact on absorbed energy was also investigated. The highest energy absorption capability and average crashing load was demonstrated by the woven plain weave/epoxy hexagonal tube with β = 45°. Failure of the woven plain weave/epoxy hexagonal tube was found to be in progressive mode. Furthermore, apart from the influence of geometry, the energy absorption capabilities of the hexagonal tubes were also affected by the type of material.

Modeling and optimization of the crushing behavior and energy absorption of plain weave composite hexagonal quadruple ring systems using artificial neural network

Composite structures are being increasingly utilized in the automotive industry for their lightweight and specific energy absorption capabilities. Recently, the Composite Hexagonal Quadruple Ring System (CHQRS) has been proposed as a passive energy absorber device, due to its performance quality. Experiments show that the energy absorption capacity of this system significantly varies dependent on the interior hexagonal ring angle value. Thus, there is a need to develop an accurate model, which can be evaluated based on its performance, to then be used for predictions of its nonlinear loading capacity at various angle configurations and to optimize the interior hexagonal angle for a maximum system energy absorption capability.Within this paper, Artificial Neural Network (ANN) based models have been developed, optimized and compared using the Mean Squared Error (MSE) performance function, with the objective to precisely predict the high non-linear crushing behavior of the CHQRS at different angle configurations, as well as to optimize its internal hexagonal angle for a maximum energy absorption capability. The predicted results and the experimental results have also been compared in terms of their load carrying capacity and energy absorption capability. The developed ANN-based models accurately predict the load carrying capacity and the energy absorption capability at different angles, with an MSE of as low as 0.39 N and 1 J, respectively. The best ANN model has been identified and then utilized to optimize the internal angle of the CHQRS, in order to maximize its energy absorption capabilities; this was found to be 47°, with an energy absorption value of 69 J. For an angle of 35°, the energy absorption was 62 J.

Crystalline structure and optical properties of thin film LiTaO3

The coatings of LiTaO3 material on p-type Si (100) substrates were fabricated by using Chemical Solution Deposition (CSD) technique. In the fabrication process, the spin coater is used to flatten the LiTaO3 solution on the p-type Si (100) substrates surface, which was set at 4000 rpm for 30 seconds. Furthermore, the coating on those substrates was annealed in the furnace (Nabertherm type B410) for 15 hours at 750°C, 800°C, and 850°C temperature. The study of crystalline structure was obtained through the X-Ray Diffraction (Shimadzu XRD-7000) measuring with the interval of angular diffraction 2θ from 10° to 80° in the increment of 0.02°. Moreover, the study of optical properties was observed using the spectrometer (Ocean Optics USB4000-UV-VIS). Based on the results of the study, obtained a hexagonal angle diffraction peak for the crystal structure, when viewed from the refractive index, the optical properties are sensitive to visible and ultraviolet light. The results of the crystalline structure and optical properties that are sensitive to visible and ultraviolet light can be used to improve the performance of satellite systems in the term of the optical remote sensing.

Comparative Investigation on the Failure Modes of Natural Kenaf/Epoxy Reinforced Composite Hexagonal Tubes

This study aims to investigate failure mode response of woven natural kenaf/epoxy composite hexagonal tubes subjected to an axial and lateral quasi-static crushing test. The hexagonal composite tubes were prepared by the hand lay-up technique using a variety of hexagonal angles 40ο, 50 ο, and 60 ο. The result showed that hexagonal composite tubes under an axial compression test exhibited few failure modes such as, the transverse crack failure mode . Splaying failure mode and local buckling failure mode respectively, whereas the tubes under lateral test only exhibited longitudinal fracture.

Lateral crushing properties of non-woven kenaf (mat)-reinforced epoxy composite hexagonal tubes

The current study investigated the energy absorption capability and load carrying capacity of non-woven natural kenaf fiber (mat)/epoxy–hexagonal composite tubes subjected to a lateral quasi-static crushing test. The hexagonal composite tubes were manufactured by the hand lay-up technique. Natural non-woven kenaf (mat) was chosen as reinforcement due to low cost, low specific weight, easy processing, no need for tooling when dealing with the raw material, and no skin irritation and epoxy resin was used as the matrix to manufacture three configurations of β=40°, β=50° and β=60° of natural non-woven kenaf (mat)/epoxy laminate. The effects of hexagonal angles, supporting plate inside the tubes, and failure modes were studied by a lateral compression test. The crashworthiness of the tubes was evaluated by analysis of the specific energy absorption in quasi-static lateral compression. Specific energy absorption (SEA) was obtained from the load–displacement curve during testing. The failure mode of the tubes was analyzed from high-resolution photographs. Overall, the tube with β=40° had the best crashworthiness among the tubes. Furthermore, the results showed that the tubes with supporting plates have better specific energy absorption for all tested specimens and exhibited approximately 69% better crashworthiness than the non-supporting ones. The results also demonstrated that all specimens failed by the longitudinal failure mode.

Quasi-Static Lateral Crushing of Non-Woven Kenaf Fibre Reinforced Composite Hexagonal Tubes

This investigation presents the lateral quasi-static compression crushing testing and load carrying capacity of three different hexagonal angles ranging from 40ο to 60ο. The objective of this study is to understand the effect of hexagonal shape on the progressive deformation, crashworthiness and failure modes. A hand lay-up technique was used to fabricate a hexagonal composite. Quasi-static tests have been carried out on all the specimens tested. From the experimental study, it was found that the tubes crushed with four longitudinal cracks on all sides of the tubes. Furthermore, the energy absorption capability, decreased with the increase of the hexagonal side angles from 40ο to 60ο.

Experimental Quasi-Static Axial Crushing of Non-Woven Kenaf Fibre/Epoxy Hexagonal Composite Tubes

An experimental study was carried out to study the crashworthiness parameters of non-woven kenaffibre/epoxy composite hexagonal tubes. The static crushing behavior of composite hexagonal tubes under constant axial load was investigated experimentally. Three lengths of hexagonal composite tubes were tested 50, 100, and 150 mm with the same hexagonal angle 45°. Load-Displacement curves and deformation histories of typical specimens are presented and discussed. Results exhibited that tube with length 150 mm exhibits high specific energy absorption.

Preparation and Structure of a Solid-State Hypervalent-Iodine Polymer Containing Iodine and Oxygen Atoms in Fused 12-Atom Hexagonal Rings

The treatment of dilute aqueous solutions of [hydroxy(tosyloxy)iodo]benzene with aqueous Mg(ClO4)2 produced thin elongated-hexagonal plates exhibiting a supramolecular structure in which tetra-mu-oxopentaiodanyl dication repeat units are joined to each other by significantly ionic bonds and each unit is associated with two perchlorate ions. The linearly extended cationic structure is formed from the 12-atom hexagonal rings of alternating iodine and oxygen atoms, a novel structure. Each 12-membered ring forms a nearly planar hexagonal shape with sides defined by almost linear O-I-O segments (175.7+/-1.6) degrees. The apexes are occupied by bridging oxide ligands where the I-O-I angles deviate only slightly from an ideal 120 degrees hexagonal angle (116.8+/-1.2) degrees, consistent with sp2 hybridization of the bridging oxygen atoms that participate in three-center four-electron bonds with iodine. These 12-atom hexagons are slightly "chair" distorted at the oxygen atoms. The planes of the rings are separated by layers containing the phenyl rings. The perchlorate ions reside in void spaces created by the three-up, three-down arrangement of the phenyl rings around each 12-membered I-O ring and are positioned directly above and below the I-O rings.

The role of plasticizer on the exfoliation and dispersion and fracture behavior of clay particles in PVC matrix: a comprehensive morphological study

The clay nanoparticles are readily dispersed and exfoliated in the PVC matrix with the help of Dioctyl phthalate (DOP) plasticizer. X-ray, TEM and AFM analysis of the nanocomposites indicate that there is an optimum concentration of DOP for the process. If used in high concentrations, the ability to transfer forces to the clay particles through the polymer matrix decreases due to substantial decrease in viscosity. The individual platy montmorillonite particles dispersed in PVC matrix were directly observed by AFM and found to lie preferentially on their basal surfaces, especially when the compounded batch is compression molded. The edges of the particles were in some cases straight forming hexagonal angles and in other cases irregular.

Theoretical model for the hcp-bcc transition in Mg.

Using a first-principles total-energy pseudopotential method, we investigate the transition mechanism for a pressure-induced martensitic transformation hcp..-->..bcc which occurs in Mg at pressures around 50 GPa. Two internal structural degrees of freedom are selected and one lattice is transformed into the other by relaxing these two parameters continuously. One of the parameters characterizes the relative displacement of the hexagonal layers and corresponds to a transverse phonon at the Brillouin-zone edge A in the hexagonal structure. The other characterizes the distortion of the internal hexagonal angles and corresponds to uniform strain along one of the (0010)/sub hcp/ directions. The interaction between these two distortion modes causes important anharmonic effects in the zone-edge phonon and provides a low-energy path for the structural transition. The small activation barrier at the transition indicates that quantum fluctuations between the two structures could be taking place.

Zeeman Effect of Nuclear Quadrupole Resonance Spectrum in 1, 3, 5-Trichlorobenzene

A study of the Cl 35 resonance spectrum was carried out at the room temperature on a single crystal of 1, 3, 5-trichlorobenzene. Spatial orientation of the C–Cl bonds was determined to the accuracy of 1° . An orthorhombic structure was concluded, with the unit cell containing at least four equivalent molecules oriented with the symmetry of D 2 h . The angles between the C–Cl bonds in each molecule were close to the hexagonal angle, but one of the C–Cl bonds was deformed by ca. 1.6° from the plane of the other two. The asymmetry parameters were observed to be 0.09 3 , 0.11 1 , and 0.12 9 for three absorption lines, 35.020 Mc, 35.296 Mc, and 35.545 Mc, respectively. The results were discussed from the viewpoint of intermolecular interaction.