Layers Of Composite Material Research Articles

ОЦЕНКА НЕСУЩЕЙ СПОСОБНОСТИ СОСТАВНОЙ КОНСТРУКЦИИ САМОЛЕТА, СОСТОЯЩЕЙ ИЗ МЕТАЛЛОПОЛИМЕРНОГО КОМПОЗИЦИОННОГО МАТЕРИАЛА И КЛАССИЧЕСКОГО МЕТАЛЛА

The requirements for modern models of aviation equipment are constantly increasing, as a result of which it is necessary to look for new ways to solve the assigned engineering tasks through the use of new materials, new principles of manufacturing and assembly, as well as through an extraordinary approach to the design of the design of modern aircraft products. In this paper, the engineering methodology of power calculation and design of composite aircraft structures combining metal-polymer composite materials and metal materials is considered. As a composite structure under study, a fragment of an aircraft wing panel is considered, including a stringer made of a traditional structural material (metal) and a metal-polymer composite material skin attached to it. Metal- polymer composite material is a layered material consisting of metal sheets and layers of polymer composite material. Previously, in [1], the characteristics of the stress-strain state (SSS) of a single metal-polymer composite material and each layer in its package were investigated. In this paper, analytical and graphical dependences of the stress state of the elements of a composite structure on their ultimate deformations are obtained. The parameters of the composite panel of the wing, working on tension, and their effect on the stress-strain state, safety margin and load-bearing capacity are investigated. The obtained graphical dependences can be used for a preliminary assessment of the strength of an element of a composite structure at the stage of working out the design concept of an aircraft airframe assembly using a metal-polymer material.

Исследования устойчивости монолитных и слоистых пластин при сжатии

The results of calculations of the stability of monolithic and layered plates, obtained by analytical and numerical methods, are presented, which are compared with experimental data. The obtained results of stability calculations are within the limits of the permissible error. The results of numerical calculations of stability by the finite element method in the ANSYS program turned out to be higher than the values ​​determined by the Euler formula and lower than the results obtained by the formula for calculating the stability of plates. To study the bearing capacity of layered samples under compression, an assessment of their stability was carried out with different numbers and arrangement of layers of alloy and composite material. The optimal layouts of layers in the material for designing a composite panel have been determined. The results were used to design a composite wing panel based on sheets and profiles made of high-strength aluminum-lithium alloy and laminated aluminum-fiberglass. Stability of the composite panel under compression were 7% higher than the experimental values due to the local loss of stability of its elements, which precedes the general loss of stability and reduces the value of the critical load.

ОЦЕНКА ВОЗМОЖНОСТИ ПРИМЕНЕНИЯ ВИБРОПОГЛОЩАЮЩЕГО МАТЕРИАЛА НА ОСНОВЕ ПОЛИУРЕТАНА В КАЧЕСТВЕ УПЛОТНИТЕЛЕЙ

The article presents the results of a study of the operational properties of the VTP-1V grade material, including cold flow. It was found that the material of the VTP-1V grade hasn’t cold flow and, according to the complex of properties studied in the work, can be recommended as an alternative to layered polymeric composite materials used in the bolted joints of the aircraft wing rib. The possibility of operating VTP-1V in an environment of aggressive liquids was assessed and it was shown that the material is resistant to the effects of TC-1 fuel, including retaining low deformability under prolonged loading.

Cervical margin relocation - basic principles and influence on the periodontal tissues

INTRODUCTION: Cervical margin relocation (CMR) involves the placement of a base layer of direct resin composite material in order to elevate the cavity margins located below the gingiva. CMR is applied prior to the cementation of bonded restorations. AIM: The aim of this review is to briefly present the basic principles of the CMR technique and to assess whether the execution of this method before the cementation of bonded restorations is beneficial to the long-term outcome of the treatment and to the periodontal tissues according to the literature. MATERIALS AND METHODS: This review includes articles searched without date restriction in the Medline/PubMed database along with bibliographic data. A variety of keywords and their combinations were used: margin relocation, proximal box elevation, indirect restorations, adhesion, marginal adaptation, marginal sealing, deep margin elevation. RESULTS: The review is based upon 41 references. The literature data provided information on the basic principles of cervical margin relocation and its relation to periodontal health. CONCLUSION: Further research, scientific evidence and longer follow-up results are needed in order to conclude that CMR is entirely beneficial to the long-term outcome of the treatment and to the periodontal tissues.

Investigation of nonlinearity of longitudinal displacement function from mechanical and geometric characteristics of the plate

Layered composite materials are characterized by a high transverse anisotropy and low values of relations between the transverse shear modulus and the modulus of longitudinal elasticity. As a result, the behavior of longitudinal displacements and longitudinal normal stresses differs from the linear law, and the behavior of transverse tangential stresses differs from the parabolic law. The paper presents the analysis of the degree of the plate displacement nonlinearity functions depending on its elastic properties and geometric shape. The article considers a 2D square plate deformation problem. In non-dimensional terms, the authors could received a complete and demonstrative solution. A similar 3D problem is more bulky but it has no principle differences. The study of the degree of the longitudinal displacement nonlinearity functions due to elastic properties and the geometric shape of the deformable plate is based on the finite element method. The potential energy of the deformable plate is expressed through a square form of the variables with coefficients that are polynomials of dimensionless parameters such as plate size, ratio of the elasticity and shear moduli, Poisson's modulus. It is shown that the variational principle reduces the problem to the solution of the system of linear equations. As a result, the subareas of linearity and nonlinearity of the plate longitudinal displacements are constructed with an accuracy acceptable for engineering calculations of 5 %. It is necessary to consider the plate nonlinear longitudinal deformations for a length of the composite plate on order more than its thicknesses. As for steel, nonlinearity is characteristic for quite thick plates. The constructed areas of linearity and nonlinearity of the longitudinal displacements make it possible to construct the strain-stress state models with a smaller number of variables.

Effect of Modified Li2MnO3 on Electrochemical Properties of Li-Rich Composite Layered Cathode

xLi2MnO3-(1-x)LiMO2(M = Mn, Ni, Co, etc.) is a general formula representing composite layered cathode materials. Interestingly, this cathode exhibits surprisingly high reversible capacity and receives great attention for practical applications. Li2MnO3 is known to play an important role of providing extra Li source for stabilizing the layered structure. For single phase Li2MnO3, it shows limited capacity during charging/discharging reaction. Furthermore a characteristic 1st charging plateau corresponding to the extended capacity contribution from oxygen release in Li2MnO3. Accordingly, such oxygen release also causes the formation of oxygen defects (vacancies) and may cause the instability of Li2MnO3. Thus, the performance of Li-rich composite oxides cathode with layered structure is highly influenced by the electrochemical properties of Li2MnO3 Therefore, the main objective of this study is (i) to modify the electronic defects of Li2MnO3 through changing pO2, (ii) to add dopants to introduce more electrons to Li2MnO3 for better conduction, (iii) to assemble and test cells using Li2MnO3 as the cathode and Li metal as the anode, (iv) to characterize and understand the electrochemical properties of Li2MnO3. In this study, Li2MnO3 are prepared using sol gel/solid state reaction processes and treated by dopant addition and reducing atmospheres. Impedance of Li2MnO3 is measured using Electrochemical Impedance Spectroscopy (EIS). XRD analysis and SEM observation are performed for synthesized Li2MnO3 particles. A full cell based on Li/ Li2MnO3 and Li/ 0.5Li2MnO3-0.5LiMO2 using treated Li2MnO3 will be assembled and tested.

Long-term low friction maintenance and wear reduction on the ventral scales in snakes

Snake skins evolved to withstand permanent friction and wear during sliding. Here, the microstructure of ventral scales of the snake Lampropeltis getula californiae was analyzed using scanning electron microscopy, and the long-term dynamic friction behavior was investigated by reciprocating sliding friction tests. A smooth epoxy resin with similar elasticity modulus and hardness was used for comparison purposes. Strong differences in frictional and wear mechanisms between the two materials were revealed in spite of similar mechanical properties. Snake skin showed a considerably lower frictional coefficient that kept stable over several thousands of sliding cycles. A reduction of the stick-slip behavior was also denoted by analyzing the variation of the friction coefficient in the forward and reverse motion influencing the wear mechanism. This frictional behavior can be explained by three different but complementary mechanisms: fibrous layered composite material of the skin with a gradient of material properties, surface microstructure, and the presence of ordered layers of lipid molecules at the skin surface.

Study of the stressed state in the layers of the composite material of the construction element

Numerical analysis was used to estimate influence of orientation of composite material layers on strain changes in a constructive element. A finite element method was used to conduct a strain-stress state analysis. A cylindric shell with a radius of 300 mm, a height of 600 mm and a wall thickness of 1,56 mm was examined. The shell consisted of eight differently oriented carbon fiber layers, that were impregnated with epoxy resin. Plate Laminate type elements were used to imitate composite layers orientation and to create a model of cylindric shell walls. Lower base of the cylinder had rigid fasteners and the upper base was under external loading. During strain-stress state analysis of composite layers were examined following loading types: axial tension, bend, torsion, internal pressure. Numerical analysis revealed that tension distribution in layers of composites depends on layer orientation and the cylindric shell loading type. Moreover, this paper defines estimated fatigue life of the shell under pulsatory load. It was determined that characteristics of fatigue strength of the constructive element depend on loading type.

Sandwich-like GO@Co(OH)2/PANI derived from MOFs as high-performance electrode for supercapacitors

Sandwich-like layered composite materials possess a high contact area and can expose many reactive active sites, which exhibit great potential in the application of supercapacitors. In this paper, a sandwich-like composite material was synthesized based on polyaniline (PANI), graphene oxide (GO) and ZIF-67 (denoted as GO@ZIF-67/PANI). Among them, GO is designed as a deposition substrate of ZIF-67 and transfer scaffold of electrons and PANI works as a wire to connect graphene layers and nanoparticles, which increases the conductivity of the material and makes the electron transfer easier. At the current density of 1 A g−1, the specific capacitance of the ZIF-67 composite is up to 5 times that of the ZIF-67. After alkali treatment, ZIF-67 is converted into Co(OH)2 nanosheet (denoted as GO@Co(OH)2/PANI), which remarkably promotes the transfer of electrolyte ions and electrons. At the current density of 1 A g−1, the resulting specific capacitance is 15 times more than ZIF-67. The excellent energy storage performance indicates that the prepared novel composite material has important development prospects in energy storage.

Smart control of cylindrical shells incorporating Murakami Zig-Zag function

The work is devoted towards incorporating the Murakami zig-zag function (MZZF) for modelling the active constraining layer damping (ACLD) treatment of ‘N’ layered laminate cylindrical shells. The ACLD treatment in the patch form comprises of two material layers with the viscoelastic material layer constrained between the host shell and the smart 1–3 piezoelectric composite (PZC) material layer. The kinematics of deformation are derived successfully implementing the MZZF in the displacement fields. Virtual work principle has been employed for the finite element (FE) model to deduce governing equations of shell ACLD system in complete form. A feed-back control system has been considered to arrive at closed loop governing equations of motion. Considering the above, a MATLAB code for the same is generated to emphasise on dynamics of the cylindrical shell ACLD system. Cylindrical shells with various lamination schemes have been considered to assess the validity and implementation of MZZF for ACLD treatment of shells. Also, the oblique orientation of the 1–3 PZC material layer and its effect on the damping behavior of the cylindrical shell has been thoroughly explored.

Layered Self-Healing Composite Material with an Internal Functional Layer Based on Borosiloxane

Layered Self-Healing Composite Material with an Internal Functional Layer Based on Borosiloxane

Publisher’s note

This article refers to:Hot cracking susceptibility of commercial filler metals for Alloy 617 by Varestraint test. Study of hot cracking of Alloy 617 in multipass weldsTomographic measurement of current density and heat input density for tilting TIG arcIn-situ measurement of weld quality during MAG welding using laser ultrasonicPrevention of cold cracking by the welding process for reducing diffusible hydrogen in high-tensile thick plate weldingFundamental plasma diagnostic study for guiding TIG arc phenomenon by laser beam irradiationEffect of weld line shape on laser welded joint strength of automotive high-strength steel sheetsCharacteristics of material flow in friction stir spot welding tools in consideration of cutting toolsInvestigation of relationship between resistance spot welding condition and nugget shape by utilizing machine learning based techniqueHot cracking susceptibility and solidification segregation analysis by computer simulation in duplex stainless steelsStudy on welding phenomena observation method based on arc and molten pool light emission characteristics in visible and infrared wavelength region – development of image sensing technology for in-process welding monitoring technologyInfluence of thickness reduction in base plate on elastic stress state of patch plate joint by combination of welding and bondingProposal and applicability of a method to evaluate surface tension of liquid using large volume sessile drop in gravityInfluence on factors of cold crack formation factors of a steel 10G2FBYu welded joint by regulating linear energyTechnological features of the porous functional ceramic coatings formation on aluminium by the method of microarc oxidation in silicate electrolytesImproving friction stir welding toolFeatures of pulsed laser welding with deep fusion penetrationFormation of undetachable mechanical joints by cold plastic deformationFixed joints of dispersion-hardened composite materials based on aluminium, made by friction stir weldingHigh-temperature brazing of structural elements for the first wall of the DEMO reactor with rapidly hardened tungsten and steel alloys-soldersThe influence of the welding circuit magnetic field on the formation of the joint at unsupported weldingFeatures of the heat generation process at ultrasonic welding of polycarbonate under independent pressureInduction brazing of carbide cutters for a mining tool. The choice of composition and solder formEvaluation of residual stresses and structural-phase composition in longitudinal welds of high pressure pipesFinite element modelling of the stress-strain state in specimens from dissimilar Ni-based alloys during pressure welding with displacementFor creating layered composite materials based on monocrystalline silicone for gradient heat measurement based by diffusion welding methodStudy of joints for heat-resistant alloy XN55MVTs obtained by diffusion weldingMechanical properties of aluminium alloy AMg6 obtained by wire electron beam additive formingCalculation of the transverse magnetic field parameters, allows the mixing of the melt in the bath during electric arc deposition and welding

The microstructure and tensile property of the cuticle ofturtle shells

<p indent="0mm">Turtle shell is a composite layered structural material consisting of cuticle and bone layers. It possesses superior mechanical properties, such as lightweight, high specific strength and toughness. In the present paper, the cuticle of turtle shell is experimentally studied, whose multi-scale microstructures and tensile properties are mainly focused on, including the characteristics of microstructures, constructing modes of inner interfaces and the influencing factors of the tensile properties. It is shown that the cuticle is constructed by many micro protein platelets, stacking tightly and randomly. In the thickness direction, the upper and lower platelets are connected by discrete protein bridges, while in the in-plane direction, neighboring micro platelets with rough surfaces overlap each other with a certain length. The cuticle has obvious anisotropic tensile properties. The effect of water content on the material properties of cuticle, the tensile strength and fracture toughness is significant. Under tension, it breaks through the fracture of some inner platelets and pull-out of some platelets. Simple finite element simulations are further carried out to analyze the micro-mode of fracture of such layered structural materials, the result of which is consistent with the experimental observation qualitatively. The study of this paper should be useful for further investigation of the multi-scale mechanical property and physical mechanism of turtle shells, and the design of lightweight structural materials with high strength and toughness.

Design and measurement of broadband magnetic composite metamaterial absorber with C-band absorption

We present the design and measurement of broadband magnetic composite metamaterial absorber with C-Band absorbing effect. The absorber embeds the periodic array of concentric semicircular copper sheet in the FeSiAlp/epoxy composite material layer. The wave-absorbing properties of the FeSiAlp/epoxy resin composite is greatly improved compared with the simple FR4 matrix material, bandwidth with reflectance less than −10 dB increases from 0 GHz to 8.13 GHz. Simultaneously, due to the introduction of the frequency selective surface (FSS) structure, the absorber performance of the absorber is also improved in C-band. The peak of the absorber appears at 7.46 GHz, and the reflectivity reaches −12.78 dB, and the absorption reaches 94.72%. After optimizing the dimensions of FSS, The FeSiAlp/epoxy resin composite absorber with a thickness of 2.6 mm reached peak simultaneously at 7.46 GHz and 16.64 GHz, and peak reflectance reach −12.78 dB and −18.21 dB, respectively, and corresponding absorption reached 95.68% and 99.70%, respectively. Bandwidths with reflectivity less than −10 dB reaches 8.13 GHz, the absorber has obvious absorption effect in C-band. The experiment basically verified the simulation results. Hence, the absorber with special structure design not only overcomes the problem of narrow absorption band of metamaterials, but also solves the shortcoming of weak C-band absorption effect of magnetic material absorber.

Complete transverse stress recovery model for linear shell elements in arbitrarily curved laminates

Out-of-plane failure is common in composite layered materials. Its detection in numerical simulations usually involves a high-level of spatial refinement which may lead to an excessive computational time for large structures. This paper presents a formulation for the recovery of the transverse stresses in conventional linear shell elements based on First-Order Shear Deformation Theory. Starting from the equilibrium equations, the proposed formulation allows the calculations to be made for arbitrary curvatures including variable ones. Compared to the Extended-2D method, it has the advantage of including all the contributions from the force and moment derivatives making it reliable in complex load cases. Several examples with different laminates, curvatures and loads are presented. The numerical results confirm the potential of the proposed method to be used both as post-processing tool for conventional models and as an enrichment criterion for adaptive modelling.

Deformation of Explosion-Welded Titanium-Aluminum Composite in Conditions of Transient Rolling Process

Explosion-welded titanium-aluminum layered composite materials (LCM) can subsequently be subjected to pressure treatment, which leads to a change in the ratio of layer thicknesses, structure, and properties. The deformation of the composite leads to uneven longitudinal and vertical deformation of the layers, which depends on the temperature of the process, the shrinkage, and the nature of the boundaries between the layers. It was found that, at a temperature of 450°C, there is a sharp increase in the deformation ability of the composite, which is associated with an increase in the plastic properties of aluminum layers.

ПРИМЕНЕНИЕ КОМПОЗИТНЫХ МАТЕРИАЛОВ ПРИ РЕКОНСТРУКЦИИ ПОЛОВ ПРОМЫШЛЕННЫХ ЗДАНИЙ

the article discusses the relevance of the use of composite materials in the reconstruction of exposed to heavy loads of concrete and reinforced concrete floors of industrial buildings. It is noted that at the present stage of development of the construction industry special attention is paid to the use of steel fibreconcrete, as this material allows with minimal material and labor costs to carry out work on the reconstruction of industrial floors. The novelty of this study is the use as an adhesive between the existing floor, which is to be restored and strengthened, and the newly laid steel-fiber concrete layer of polymer-bitumen composite material with the addition of cement and graphite powder, previously obtained by the authors experimentally. This material with the required thickness is also a structural layer for leveling the surface of the lower layer, reducing friction under the sole of the upper steel-fiber concrete layer and the existing floor. The paper presents the technology of work in the reconstruction. The composition of the steel-fiber concrete layer is adopted on the basis of studies by other authors. Despite the fact that the experiments proved the solidity and strength of the reconstruction of the floor by the developed technology, the article notes that the final characteristics of the proposed floor design and technology can be identified only during operation, which can be the basis for further research on optimizing the thickness of the layers proposed for use of composite materials. For the evaluation of economic efficiency of application of these composite materials in the reconstruction of the concrete floors in the course of the experiment, there are revealed some figures for labor and material costs.

Manufacturing, modeling and analysis of ankle disarticulation prosthetic for transmalleolar amputation

Three groups of composite material layers are used in this work to measure the mechanical properties of ankle disarticulation prosthetic socket. The polymer matrix acrylic (Lamination 80:20) and reinforced with different materials, the first type is (4Perlon) layers, second type (2 Perlon and 4 Glass fiber and 2 Perlon) layers and third type is including (2 Perlon, 4 Carbon fiber and 2 Perlon) layers used in this study. Tests Results showed that the mechanical properties of all groups, ultimate strength, yield stress and Young modulus for the first group; were 10.12MPa, 38.8MPa and 1.16GPa respectively, for second group were73.8MPa, 146MPa and 1.45GPa respectively and for the third group were 106.6MPa, 209.4MPa and 1.9GPa respectively. The results of the bacteria test growth show inability of bacteria (Staphylococcus aureus) to analyze of the surfaces of materials available and suggested for feeding it therefore bacteria can grow on them. By using (F-socket) the pressure between stump and socket measured and the values are (236kPa) and (275kPa) for the lateral and posterior reign. From fatigue test for all groups and ANSYS 14.5 software, the safety factors for composite material (2Perlon, 4carbon fiber,2perlon) layers is about (1.57) which are safe and acceptable in design applications.

Двухслойный композит, армированный базальтовыми волокнами различной длины

The article considers the issues of creating composites using long, continuous structures along the entire length of the structure, and short basalt fibers, and, based on them, multilayer composite materials as reinforcement. A mathematical description of the strength properties of multilayer composite materials based on layers of composites using long, continuous along the entire length of the structure, and short basalt fibers as reinforcement is considered. The results of theoretical studies showed that the multilayer composite material has improved properties. The first layer of material, which is a layer of reinforcement made of continuous fibers, provides tensile and bending strength. The second layer of composite material provides thermal insulation properties and compressive and deformation strength. This layer consists of a composite whose reinforcement is short fibers. It is shown that a multilayer composite material, which is a combination of composites created on the basis of long continuous and short fibers, works as a single system. The first layer of the composite, created on the basis of continuous fibers, works in tension and bending, the second layer, created on the basis of short fibers, determines the strength characteristics during compression and deformation. In order to confirm the theoretical results, work was carried out to create composites based on long and short basalt fibers. When creating a layered composite, a heat-insulating plate was used as the first component, which was reinforced with pieces of basalt fiber. For the production of such plates, a plant was developed to obtain pieces of basalt fiber and further uniform distribution of these pieces in a composite plate. A multilayer composite material with improved properties based on long and short basalt fibers is obtained. The composite slab was reinforced with a mesh assembled from continuous basalt fibers.

Fabrication of Polyamide-Ag2Se composite films with controllable properties by an adsorption–diffusion method

A study of the formation of polyamide (PA)-Ag2Se composites on PA-6 polymer surface through an adsorption–diffusion method and the resulting surface properties is presented. The two-stage process used to deposit these thin layers involved (a) treatment of PA with a precursor K2SeS2O6 solution as a selenium source, and (b) treatment with a solution of AgNO3 as a silver source. The chemical and physical properties of the obtained PA-Ag2Se composites have been investigated by means of AAS, XRD, SEM/EDX, AFM, and sheet resistivity measurements. This study shows that increasing the number of cycles can produce layers with the desired morphology, chemical properties, and phase composition. AAS and EDX analyses have shown that the concentrations of Ag and Se in Ag2Se-PA composite increase with increasing number of cycles. XRD data show crystalline polyamide as a single phase, naumannite Ag2Se as a crystalline phase, and two phases due to monoclinic and rhombohedral Se. The thickness of the composite material layers ranged from several μm to about 10.2 μm, and depended on the number of adsorption–diffusion cycles. It was found that, after five cycles, the sheet resistance of the layers decreased from >20000 to 32 Ω/and then remained constant. SEM and AFM further revealed that Ag2Se does not grow as a uniform film on the polyamide surface, but rather through a nucleation mechanism followed by particle growth, gradually covering the entire polymer surface.