Metal Cylinder Research Articles

A framework for formulating and implementing non-associative plasticity models for shell buckling computations

In modelling the behavior of thick-walled metal shells under compressive loads, the use of J2 flow theory can lead to unrealistic buckling estimates, while alternative ‘corner’ models, despite offering good predictions, have not been widely adopted for structural computations due to their complexity. The present work develops a new and efficient plasticity model for predicting the structural response of compressed metal shells. It combines the simplicity of the Von Mises yield surface, with a non-associative flow rule, mimicking the effect of a yield surface corner. This allows for tracing the equilibrium path of the loaded shell and identifying consistently structural instability, employing a single constitutive model. A robust backward-Euler integration scheme, suitable for both three-dimensional (solid) and shell elements is developed, along with the corresponding consistent algorithmic moduli for nonlinear isotropic hardening materials, accounting rigorously for the nonlinear dependence of plastic straining on the direction of strain increments. The model is implemented in ABAQUS as a user material subroutine. Simulations of thick-walled metal cylinders under compression predict structural instability in good agreement with experimental data.

Double Approach in the Investigation of Light Scattering by a Nickel Metal Cylinder

In the present work, we have investigated the light scattering from a Nickel metal cylinder under normal incidence. A double approach using the Fresnel reflectance model and Lorenz-Mie approach shows that the Fresnel model cannot follow the changes in the scattering regime when the size parameter changes. Experiments show that, even for large cylinders, the Fresnel model overestimates the effects of reflection in the forward direction. The simulation using the Lorenz-Mie formalism shows that as the size parameter changes the scattering regime changes and for size parameter lower than one the distribution of light intensity tends to become uniform and, for size parameter equal or lower than 0.1 the distribution is uniform and independent on the scattering angle, with a strong polarization around 70%.

Improvement of nano-polycrystalline diamond anvil cells with Zr-based bulk metallic glass cylinder for higher pressures: application to Laue-TOF diffractometer

ABSTRACT Single-crystal neutron diffraction provides direct information about crystal structures such as hydrogen positions and magnetic structures. However, in-situ experiments conducted under high pressure entail technical difficulties such as attenuation correction, masking of parasitic diffraction, and limitations of sample volumes and accessible directions. For this study, we improved diamond anvil cells with a tubular frame made of Zr-based bulk metallic glass and nano-polycrystalline diamond anvils for single-crystal neutron diffraction. The thicker tubular frame was confirmed through experimentation as stably generating 4.5 GPa. Its feasibility for neutron diffraction was assessed at the Laue-TOF diffractometer at the BL18 (SENJU) beamline in the MLF J-PARC using time-resolved two-dimensional detectors covering wide solid angles. In addition to ambient-pressure measurements of NH4Cl, diffraction patterns of a high-pressure phase of ice were also collected in-situ. The obtained intensities are of refinable quality sufficient for structure analysis.

Experimental investigation of chaotic induced-charge electro-osmosis

Near-surface chaotic induced-charge electro-osmosis (ICEO) was numerically predicted on a metallic cylinder some years ago [Davidson et al., “Chaotic induced-charge electro-osmosis,” Phys. Rev. Lett. 112, 128302 (2014)]. However, no systematic experimental investigation has yet been conducted on this problem. In this paper, we experimentally observed that ICEO is stable in weak electric fields and becomes chaotic in strong electric fields. Unlike the numerical prediction, the observed chaotic ICEO is irregular and unstable across the whole velocity field. The chaotic ICEO flow pattern varies significantly with time. The chaos degree grows upon increasing the electric field. Moreover, the critical electric field at which the ICEO transits from the stable to chaotic state shows a dependence on the sodium chloride concentration and electric field frequency. The new findings can contribute to the understanding of ICEO and facilitate the development of ICEO-based micro- and nano-fluidic applications.

Нестаціонарний теплообмін у вертикальному циліндричному об’ємі, заповненому рідиною

The paper analyzes the conditions of convective heat transfer in the "limited volume" and in the "large volume". It is established that the process of heat exchange in the elements of the basic experimental setup in the system of experimental calculation method corresponds to heat exchange in a "large volume" under conditions of free convection. An experimental stand for the study of nonstationary heat exchange in the system "environment I ― body II", the main elements of which are two working cavities — the outer filled with water, volume V1, and the inner filled with the studied liquid medium volume V2, and V1 is larger V2 3 times. The results of experimental determination of heat transfer between the inner surface of a thin metal cylinder and the investigated liquid medium in a limited space for the system “environment I — body II” under the conditions of laminar regime of both the environment and the investigated liquid medium are presented. The heat transfer coefficient was investigated using the calculation-experimental method during heating and cooling of refined sunflower oil, distilled glycerin, sugar solution with a concentration of 50 %, 60 % under conditions of free convection. The experimental results are compared with the results of studies by well-known authors for "large volume" conditions. The conditions of the heat exchange process during the experiment at different directions of heat exchange in a "limited volume" (inside a thin-walled metal cylinder with the liquid under study) are described. It is substantiated that at the surface of a cylindrical metal wall in the process of heat exchange a thermal boundary layer is formed, within which the coolant temperature changes and heat transfer within the boundary layer occurs due to thermal conductivity. The criterion equations for determining the heat transfer coefficient during heating and cooling of the investigated liquid medium under free convection conditions are obtained.

Optical Interactions in Subwavelength Metallic Materials Array

When light is incident on the interface of different media, refraction and reflection occur. Also, while light propagates through a medium, scattering by particles constituting the medium is a well-known basic property. Recently, the non-classical phenomenon is expected to be the core of many technologies such as resonantly transfer energy, nanosized quantum optical energy amplifiers, and nano-sensing technique. This technique uses a surface plasmon induced by the reconfiguration of the distribution of electrons in a metallic material by stimulation of an external field. This is because, in the nanoscale structure of the medium, the light intensity distribution in the medium is changed by the interaction of the fields in the medium including the surface plasmon. In this study, the light transmission characteristics of the metal material array medium with a size smaller than the skin-depth were investigated by 3D simulation of the FDTD method. The light intensity distribution and light transmittance of the light passing through the medium of the metal (Au) cylinder and sphere array structure were analyzed. The synergistic effect of light transmittance appeared as the light spread was reduced due to the interaction between metal materials. In addition, when light is incident on the interface in an oblique direction, the beam peak is split into several parts.

Calculation technique of intrinsic and mutual admittance of longitudinal slot radiators on a circular metal cylinder based on their radiation patterns

Calculation technique of intrinsic and mutual admittance of longitudinal slot radiators on a circular metal cylinder based on their radiation patterns

STRUCTURAL DESIGN OF A ROTATING COMPOSITE CYLINDRICAL SHELL OF HIGH-PERFORMANCE CARDING MACHINE

The cylinder is the heart of a carding machine. The composite structure of the cylinder consists of a composite cylindrical shell fixed at both ends that rotates at a constant speed around its axis. A simplified mechanical model of the filament winding composite forming and ribbing a metal cylinder is given, the differential equation of the boundary value problem of the laminated composite cylindrical shell is established, and the method for solving the static and dynamic characteristics is discussed. The PTC Creo5.0/ANSYS Workbench 2020R1 software program was employed to obtain the results used in the design and calculation models of the cylinder rotor structure system of a high-performance carding machine based on different established structural parameters and material combinations. The deformation and the critical speed of the cylinder rotor system under the combined action of the metallic clothing wrapping tension and centrifugal inertia force were calculated. The analysis and calculation results showed that the working speed of the cylinder rotor structure system was far less than its first critical speed, and the system was operating in a rigid or quasi-rigid rotor state. Under the actions of the wrapping tension of the metallic card wire and centrifugal inertia force, the maximum radial deformation of the cylinder was less than 0.06 mm. Both the aluminum alloy and filament winding cylinders were found to be light weight and highly efficient, which provided an important basis and reference in the structural design, processing and manufacturing, assembly, working gap adjustment, and operation maintenance of the cylinder. These characteristics ensured the high-precision operation and efficient carding of the cylinder system. The research results obtained in this study can be used as a reference in the development of high-efficiency carding machines.

A Compact, Band-Notched Ultra-Wideband Fully-Recessed Antenna With Pattern Diversity for V2X Communications

In this paper, a compact, band-notched ultra-wideband (UWB) fully-recessed antenna with pattern diversity is proposed and demonstrated for vehicle-to-X communications. The antenna is composed of a multi-port central radiator fully embedded inside a bowl-shaped ground structure with a flush top. The multi-port central radiator consists of a top circular plate, four split-quarter conical monopoles, four vertically-and horizontally-orientated strips, a central metallic cylinder, and a bottom cylinder. Moreover, four F-shaped monopoles are loaded to the multi-port central radiator for producing two narrow notched bands. The integrated antenna achieves a form factor of 0.23λL3, where λL is the free space wavelength at the lowest working frequency. The proposed antenna was fabricated and characterized, achieving a measured S11 < -10 dB band ranging from 1.7 to 6 GHz with two stopbands at around 2.5 and 5.15 GHz for all four ports. Moreover, the measured mutual coupling is smaller than -15 dB, while the envelope correlation coefficients (ECCs) are below 0.1 between different input ports. A vertically-polarized (VP) omni-directional pattern can be supported when all four ports are excited simultaneously, whereas four directional patterns pointing towards different directions in the azimuthal plane can be realized when the four ports are excited individually. The demonstrated antenna is a promising candidate in multiple-input multiple-output communication systems for a wide variety of platforms.

Heat Exchange of the Cylindrical Liquid Body of a Limited Height with the Environment

The experimental investigations of the intensity of the heat exchange between the internal surface of the thin-wall metal cylinder and the studied liquid medium were carried out in conditions of its cooling (heating), i.e. under nonstationary heat exchange conditions. The existence of the regular thermal mode in the liquid medium surrounded by the thin-wall metal cylinder has been established. Local in time heat loss coefficients were derived using appropriate dimensionless equations for the stationary mode conditions of heat-exchange in a large volume. Heat loss coefficients were determined using regular thermal mode methods and computational-&amp;-experimental heat loss coefficients. The changes in the relative values of the heat loss coefficients were analyzed using the method of regular thermal mode and computational-&amp;-experimental heat loss coefficients. The deviations in the values of given coefficients in time are mainly within ± 10 %. Relative values of the heat loss coefficients deviate within ± 40 % using appropriate dimensionless equations for the conditions of the stationary mode of heat exchange in a large volume. This conclusion is natural because the cooling (heating) process is nonstationary.

Numerical study of the effect of geometric parameters on compressive mechanical properties of metallic lattice cylinders

In the current research, the numerical simulations were done on 15 cylindrical lattice specimens under compressive stress at a constant strain rate using Abaqus software. The lattice cylinders have different strut thicknesses of 3, 4, and 5 mm, and with the fillets in the radiuses of 0.3, 0.6, 0.9, and 1.2 mm, respectively. The mechanical properties of the AlSi11Cu2 (Fe) aluminum alloy were used. The Mises stress distribution was evaluated to determine the effect of fillet radius on the lattice structure for the strut thickness of 3 mm. Also, the effective strain distribution of the lattice structure was investigated after different stages of deformation. After comparing the simulation results, it was shown that by applying fillets with a radius of 0.3 mm in lattice cylinders, the maximum energy absorption and maximum force can be achieved at the ultimate tensile strength (UTS) point. Also, the optimal strain can be obtained at the UTS point.

Effects of B on the Structure and Properties of Lead-Tin Bronze Alloy and the Mechanism of Strengthening and Toughening.

High lead–tin bronze is widely used in the selection of wear-resistant parts such as bearings, bearing bushes, aerospace pump rotors, turbines, and guide plates because of its excellent wear resistance, thermal conductivity, fatigue resistance, and strong load-bearing capacity. At present, high lead–tin bronze is used as a material for bimetal cylinders, which cannot meet the requirements of high-strength, anti-wear in actual working conditions under high temperature, high speed, and heavy load conditions, and is prone to de-cylinder, cylinder holding, copper sticking, etc. The reason for the failure of cylinder body parts is that the strength of copper alloy materials is insufficient, the proportion of lead in the structure is serious, and the wear resistance of the material is reduced. Therefore, it has important theoretical significance and application value to carry out research on the comprehensive properties of high-performance lead–tin bronze materials and reveal the strengthening and toughening mechanism. In this paper, The ZCuPb20Sn5 alloy is taken as the main research object, and the particle size, microstructure, mechanical properties, and friction of lead particles in ZCuPb20Sn5 alloy are systematically studied after single addition of B in ZCuPb20Sn5 alloy liquid. This paper takes ZCuPb20Sn5 alloy as the research object to study the effect of adding B on the morphology, microstructure, mechanical properties, and friction and wear properties of ZCuPb20Sn5 alloy lead particles, and discusses the strengthening and toughening mechanism of ZCuPb20Sn5 alloy under the action of B, and prepares a double high-performance lead–tin bronze alloy for metal cylinders. The main research results are as follows: The addition of B elements has an obvious refining effect on the α (Cu) equiaxed grains and lead particles in ZCuPb20Sn5 alloy. The average size of lead particles decreases from 30.0 µm to 24.8 µm as the B content increases from 0 wt.% to 0.1 wt.%. The reason for grain refinement is that B is easily concentrated at the grain boundary during the ZCuPb20Sn5 alloy solidification process, which affects the diffusion of solute atoms at the solidification interface, inhibits the grain growth, refines the grain, and hinders the sinking and homogenizes distribution between dendrites of lead; the tensile strength of the ZCuPb20Sn5 alloy improves. Relatively without B, when the addition of P is 0.1 wt.%, the tensile strength is the largest at 244.04 MPa, which enhances 13%; the maximum hardness gets 75.0 HB, which enhances 13.6%, as well as elongation get the maximum value at 17.2%. The main mechanism is that the addition of B forms a high melting point submicron Ni4B3 phase in the lead–tin bronze alloy. The Ni4B3 phase is dispersed in the matrix and strengthens the matrix. With the increase in B content (more than 0.1 wt.%), the Ni4B3 phase changes from sub-micron degree granular to micron degree block-like, and some defects such as shrinkage and porosity appear in the structure, resulting in a decrease in mechanical properties.

Nonlinear Cylindrical Markers Using Metamaterials

In this paper, the research of nonlinear cylindrical metastructure was obtained. An algorithm for finding the total field of a nonlinearly loaded perfectly conducting cylinder covered with a metamaterial (MM) layer based on Maxwell’s equations with nonlinear boundary conditions on the surface of nonlinear loads (NL) was developed. A software package implementing this algorithm was created. Based on the results of numerical calculations of the program, the scattering diagrams of a metal cylinder with NL, covered with a layer of MM at the fundamental, second, and third harmonics were obtained. The dependences of the harmonics of the scattered field on the parameters of nonlinear loads were also studied. With the help of numerical simulation using Ansys HFSS, the extract procedure of the effective parameters of cylindrical MM was realized. Based on the results of calculation and numerical simulation, a model of a nonlinear cylindrical structure of two radii was made and an experimental study was carried out. As a result of the experiment, the frequency characteristics of the metastructure were obtained at various angles of incidence of the wave. The results of numerical simulation were confirmed by the results of the experiment. It is shown that the use of the provided nonlinear cylindrical marker with metamaterial makes it possible to obtain the levels of the first and second harmonics in a scattered field of the same order. This structure can be used as a nonlinear marker in both military and civilian areas.

Study on the traveling magnetic field water purifier

The article discusses a new technology for Uzbekistan of purifying drinking water from mechanical particles. This is achieved due to the generated traveling magnetic field of the electric winding wound on the metal cylinder. An analysis of the resulting mechanical attraction forces in the space of a cylindrical purifier is given. Mathematical expressions are given to calculate these forces. The analysis of the obtained graphs of temporal and spatial characteristics is presented. The values of currents allow effectively implementing the process of water purification from mechanical impurities is determined.

Deformation of cylindrical parts mated with an axis during induction heating

In the paper, we consider separation of a metal cylinder hot or cold-pressed to the axis, when the separation is assisted with induction heating of details. The equations of thermal conduction and deformation were solved numerically, assuming all material properties are temperature depended, and magnetic susceptibility depends on the magnetic field as well. We compare the computed results with our experimental data. Keywords: deformation, thermal conductance, induction heating, computer modelling, thermal contact resistance, numerical solution. vladimir.dudin@gmail.com

The effects of fetal neural cell conditioned medium on cell proliferation in the rat brain after traumatic brain injury

Traumatic brain injury (TBI) is accompanied by an increase in the number of proliferating cells. However, the question of the nature, conditions of production and mechanisms of action of humoral factors secreted by fetal neural cells (FNCs) on reparative processes and neurogenesis in the brain after trauma and FNCs transplantation remains open. The purpose of the study was to establish the possibility of the influence of the conditioned medium of fetal neural cell cultures on the proliferative activity of Ki-67-positive cells in the cortex and subcortical structures of the rat brain after TBI. Materials and methods. TBI was simulated by dropping a metal cylinder on the rat’s head. Rats (E17-18) were used to obtain cultures of neural stem/progenitor cells. Conditioned media from cell cultures with high adhesive properties (HA-CM) and low adhesive properties (LA-CM) were used to treat the effects of experimental TBI in rats by intramuscular injection. The effect of conditioned media on the proliferative activity of Ki-67-positive cells in the cortex and subcortical structures of the brain after TBI was determined by immunohistochemical analysis using antibodies against Ki-67 protein. Results. Immunohistochemical analysis of the brain sections showed that on the 5th day after traumatic brain injury in rats there was a probable increase in the number of Ki-67-positive cells in the cortex, hippocampus and thalamus. It was found that the injection of HA-CM or LA-CM in animals with TBI increased the number of Ki-67-positive cells in the hippocampus compared with the TBI group and their value for the TBI+LA-CM group reached 59.6 ± 6.1, and for the TBI+HA-CM group – 47.2 ± 3.1 cells (p &lt;0.05 compared with the TBI group). In the cortex and thalamus, the number of Ki-67-positive cells in contrast decreased compared with the group of animals with TBI and for the group TBI+LA-CM was 20.2 ± 1.6 and 12.0 ± 1.7, respectively, and for the group TBI+HA-CM – 25.3 ± 2.1 and 13.3 ± 1.3, respectively. Conclusions. The administration of LA-CM or HA-CM to animals with traumatic brain injury increases the number of Ki-67-positive cells in the hippocampus, possibly associated with increased neurogenesis, and decreases in the cortex and thalamus, which may be due to a weakening of reactive gliosis.

3D prism shaped circularly polarised MIMO diversity antenna with 360o angular coverage

ABSTRACT This paper presents the 3D prism-shaped circularly polarised MIMO Diversity Antenna with 360° angular coverage. The proposed antenna has six elements, and it covers the X-band with impedance matching from 8.0 to 11.8 GHz (38.4%), 3 dB axial ratio from 8.05 to 10.6 GHz (27.34%). A metallic copper cylinder is placed inside the prism to improve the isolation and axial ratio. All the antennas are highly isolated, with isolation is more diminutive than −20.5 dB, except the adjacent element to the edge of the prism, for which it is −14.7 dB. The Envelope Correlation Coefficient (ECC) is less than 0.035. The proposed antenna structure shows the pattern or angle diversity in the whole 360° angle with polarisation diversity.

Electrodynamic analysis method of a photon crystal consisting of perfectly conducting hollow 3d cylinders

A strict, effective electrodynamic method for analysing three-dimensional periodic lattices made of hollow metal cylinders with walls of finite thickness has been developed. The software developed has high accuracy and short computing time. It is used to find the dependences of the delays of eigenwaves on dimensions of the lattices and cylinders (length, diameter, wall thickness) for different directions of propagation and polarization of the wave. Analysis of rectangular and hexagonal lattices is performed.

Design of Broadband and Wide-Angle Hexagonal Metamaterial Absorber Based on Optimal Tiling of Rhombus Carbon Pixels and Implantation of Copper Cylinders

A design method for a broadband and wide-angle metamaterial absorber is proposed based on optimal tiling of rhombus carbon pixels on and implantation of metal cylinders inside an acrylic substrate for which the backside is blocked by the perfect conductor. First, an intermediate carbon metapattern is achieved via optimal tiling of rhombus carbon pixels based on the genetic algorithm (GA), which can minimize the reflectances of both of the transverse electric (TE) and transverse magnetic (TM) polarized electromagnetic (EM) waves for the incident angles 0∘ and 60∘ simultaneously. Then, copper cylinders are implanted inside the substrate to boost the absorptions of both of the TE and TM polarizations for the 60∘ oblique incidences. To extend the absorption bandwidth, the design is finalized by evolving the intermediate metapattern using the GA. Based on the finalized carbon metapattern, the 90% absorption bandwidth is confirmed in the frequency range 8.8 to 11.6 GHz, for which the fractional bandwidth is 27.5% for both of the two polarizations with the incident angles from 0∘ to 60∘. The proposed method could open a way to design a broadband and wide-angle EM metamaterial absorber that can be applied to the edges of three-dimensional structures such as a regular tetrahedron or square pyramid that have interior angles of 60∘ that cannot be covered by conventional square or rectangular metamaterial absorbers.

Forced convective heat tranfer in a metallic foam cylinder cooled by a slot jet flow and comparison with a smooth cylinder and a full flow

The aim of the present paper is to study experimentally the enhancement of heat transfer, due to the presence of a layer of aluminum foam covering a smooth circular cylinder. The measurements are carried on with the impingement of a rectangular jet of air, which has a transversal dimension equal or smaller than the cylinder diameter, or jet flow, and full flow (or uniform flow, which has a greater dimension than the cylinder diameter). Literature does not report any paper dealing with this multiple problem. Experimental heat transfer and fluid dynamics measurements are carried out at Reynolds number ranging from ReD=2200 to ReD=24,750. The layer of the aluminum foam, 8 mm thick, is glued onto the smooth cylinder, with an external diameter of D = 10 mm. The height of the slot jet is H = 10 mm, with a width of W = 135 mm. Jet flow visualizations are performed for the smooth and the foam-covered cylinder to explain the heat transfer results from the fluid dynamics point of view. The flow visualizations show that the jet flow always penetrates into the foam, wetting it completely, while the reattachment never occurs downstream. In the smooth cylinder, the jet completely envelops the cylinder, at greater Reynolds numbers and a distance of x/H = 7, with a small recirculation zone, showing that the rear surface also participates in the heat transfer. The heat transfer on the foam-covered cylinder increases, mainly, because of the large increase in the exchange surface, while it is somewhat penalized, at the higher Reynolds values and at the greater distance from the slot exit, because the rear surface is little involved in the heat transfer.