Composite Rods Research Articles

A Continuous Extrusion‐Shear (ES) Composite Process for Significantly Improving the Metallurgical Bonding and Textures Regulations and Grain Refinements of Al/Mg Bimetallic Composite Rods

To improve metallurgical bonding and texture regulations and grain refinements of Al/Mg bimetallic composite rods, Al/Mg bimetallic composite rods have been prepared by direct extrusion (DE) and extrusion‐shear (ES) processes. The bonding layers of the composite rods prepared by DE and ES processes with different preheating temperatures are investigated. Research results demonstrated that good metallurgical bonding layers with no voids and cracks are formed by the ES process with 390 °C, there are relatively poor bonding layers during the DE process and ES process with 330 and 360 °C. The microstructures and textures and dynamic recrystallization (DRX) evolution of Al/Mg bimetallic composite rods fabricated by the ES process are analyzed. Simultaneously, the microhardness and the shearing strength of bonding layers in the Al/Mg composite rods are investigated. The research results show that the grains are refined significantly due to DRX during the ES process. The texture intensities of basal planes <0001> and non‐basal textures <11‐20>,<10‐10> weakens as the preheating temperatures increased during the ES process. The DRX volume fraction is enhanced. The texture strength of the Al alloy weakens during the ES process, and the texture characteristics of the Al alloy changes obviously after the ES process. The ES process can improve metallurgical bonds in Al/Mg composite rods by applying shear forces and has great potential in improving the comprehensive properties of bimetallic materials.

Microstructural and mechanical investigations of powder reinforced interface layer of hot extruded Al/Cu bimetallic composite rods

In this study, the Aluminum/Copper (Al/Cu) bimetallic composite rods were fabricated using a new method consisting of the hot extrusion process with different extrusion temperatures, volume fractions of participating metals, and types of reinforcement powders in the interface layer. Microstructural and mechanical properties of extruded bimetal composite rods and their interface layers were entirely investigated using optical microscopy (OM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS), and also compression, shear strength, and microhardness tests. Three types of Al/Cu composites with volume percentages of 30, 42, and 51% Al were fabricated at two extrusion temperatures of 400 °C (IET4) and 500 °C (IET5). In the next step, the interface layers were reinforced with four types of Cu, Al, a combination of Al and Cu (Al-Cu), and Al2O3 powders. The OM metallography results showed that the copper sleeve has a more twining and elongated grain perpendicular to the extrusion direction (ED), which indicates dynamic recovery (DRV) is the dominant mechanism at 400 °C. In contrast, hot extruded samples at 500 °C showed fine recrystallized grains forming around the prior grain boundaries. It was found that volume fractions significantly affect the flow behavior of composite samples as the extrusion force decreases with increasing the volume fraction of Al. During compression tests at the high value of strain, fracture occurred in the interface layer of composite samples with volume percents of 42 and 51% Al. However, there is good bonding and diffusion at the interface layer reinforced, especially with Cu and Al-Cu as reinforcement powders. Also, EDS analysis showed that the CuAl3 intermetallic phase appeared at the interface layer of the Al/Cu composite.

Fabrication and amplified spontaneous emission behavior of FAPbBr3 perovskite quantum dots in solid polymer rods

Abstract Formamidinium lead tribromide (FAPbBr3) perovskite quantum dot (PQ-Dot) solution was incorporated in a polymer sol, which was used to fabricate solid nanocomposite rods and disks. The solid nanocomposite samples were studied by different characterization techniques. The absorption, emission, and excitation spectra of the PQ-Dot in the solid rods/disks were quite significant as compared to the spectra of the PQ-Dot solution. Scanning electron microscopy (SEM) was used to inspect the structural morphology of the PQ-Dot in the solid environment. The PQ-Dot particles were evidently present in the solid matrix and were confirmed by the SEM images and energy dispersive X-ray spectroscopy (EDX) spectra. The size of the PQ-Dots was examined by transmission electron microscopy (TEM). The majority of the particles were about 3–8 nm in size. The spontaneous and stimulated emission profiles of the solid composite rods/disks were studied using pumping energy ranging from 2 μJ to 18 μJ from a high-power picosecond neodymium-doped yttrium aluminum garnet (Nd:YAG) tunable laser system. The observed emission signal was quite significant. The emission peak of the PQ-Dot solution had a slight change when it was included in the solid matrix. Amplified spontaneous emission (ASE) behavior was obtained from the PQ-Dot composite rod. The ASE peaks were quite steady at different levels of excitation energy. ASE was achieved at low threshold energy. The composite rod with ASE behavior indicates that it is a promising composite material that can be used to achieve lasing in the future. The ASE obtained from the composite rods/disks may improve to achieve lasing if a high concentration of PQ-Dot solution is used in the matrix.

Thermally Conductive Cellulose/Coper Composite Rods for Tailoring the Characteristics of Cigarettes

A new style of low temperature combustion cigarettes was prepared by implanting a thermally conductive cellulose/coper composite rod (TCCR) in the cut tobacco section, so as to explore the application feasibility at the low temperature environment. The burning temperature of the cigarettes was investigated by thermocouple to study the influence of the implanted TCCRs. The emission of conventional components and seven harmful components in mainstream smoke were also carried out to study the effect of TCCRs. The results show that implantation of TCCRs could reduce the burning temperature of cigarettes effectively, which decreased over 100 °C. In compared with conventional cigarettes, the amount of nicotine and nicotine-freed dry particulate matter (NFDPM) in mainstream smoke of TCCRs implanted cigarettes changed little, while the release of harmful components such as CO, HCN, NNK and phenol decreased over 20%. Moreover, the TCCRs, which made of copper paper with 2 g / 18 g weight ratio of pulp and copper, and 5 mm interval perforating, could reduce the burning temperature of cigarettes by 145 °C and the hazard index by 2.01.

Effect of acid corrosion on properties of composite insulator core rod

In recent years, there have been a number of composite insulator decay-like fracture faults characterized by resin degradation and irregular fracture morphology, which seriously threaten the safety and stability of power system. At present, the research of composite insulator’s decay-like fracture is still in the initial stage at home and abroad, and there is no clear conclusion on the causes of its fracture, influencing factors and other important scientific and technical issues, and there is no unified understanding of the mechanism of decay-like fracture. In view of the above problems, this paper carries out acid corrosion test on core rod samples to explore the corrosion law of nitric acid on core rod and its influence on properties. The results show that acid corrosion is one of the factors causing the degradation of epoxy resin. With the increase of nitric acid concentration and soaking time, the degradation rate of epoxy resin accelerates, and the core rod sample gradually changes from emerald green to yellowish brown, then to light yellow, and finally to white hair like glass fibre. The effect of the sample under the long-time action of low concentration nitric acid is the same as that under the short-time action of high concentration nitric acid. Nitric acid will continuously erode into the core rod, resulting in the decrease of hardness and performance on the core rod surface.

Dynamic analysis of composite rod fastening rotor system considering multiple parameter influence

Dynamic performances of composite rod fastening rotor system are analyzed considering the integration of multiple parameters. A dynamic modeling method of multi-disk rod fastening rotor system is proposed based on the composite rotor structure and the influences of multiple parameters. The interaction of system parameters and fault features are revealed in the composite rod fastening rotor system. The dynamic analysis discloses the influence of fault degree and multiple parameters on the nonlinear behaviors. The results show that the dynamic characteristics of the rod fastening rotor system alter under the crack fault. The evolution of nonlinear performances is displayed in the analysis of multiple parameters. The analysis results contribute to the identification of dynamic characteristics for rod fastening rotor system and fault detection of gas turbine rotor system.

Penetration Failure Mechanism of Multi-Diameter Tungsten Fiber Reinforced Zr-Based Bulk Metallic Glasses Matrix Composite Rod

In order to increase the penetration ability of tungsten fiber-reinforced Zr-based bulk metallic glasses matrix composite rod, two multi-diameter tungsten fiber-reinforced Zr-based bulk metallic glasses matrix composites (MD-WF/Zr-MG) are designed. In MD-WF/Zr-MG-I, the diameters of tungsten fiber (WF) increase gradually from the inside to outside, which is the opposite in MD-WF/Zr-MG-II. Penetration experiment of two kinds of MD-WF/Zr-MG rods into rolled homogeneous armor (RHA) steel target from 1470 m/s to 1630 m/s is conducted. The average penetration depth of the MD-WF/Zr-MG-II rod is higher than that of the MD-WF/Zr-MG-I rod. Penetration failure modes of MD-WF/Zr-MG-I and MD-WF/Zr-MG-II rods are bending, backflow of WFs and shear failure respectively. The failure mode of MD-WF/Zr-MG is affected by the bend spaces and the ultimate bending diameters of WFs. If the bend spaces of all WFs are equal or larger than their ultimate bending diameters, the penetration failure mode is the bending and backflow of WFs, oppositely the penetration failure mode is the shear failure. The MD-WF/Zr-MG rod with shear failure exhibits high penetration ability because of low penetration resistance and little residual material in the crater. When designing MD-WF/Zr-MG, bend spaces of a part of WFs should be smaller than their ultimate bending diameter to cause shear failure.

Effect of Water Absorption on Flexural Properties of Kenaf/Glass Fibres Reinforced Unsaturated Polyester Hybrid Composites Rod

This study investigates the effect of water absorption on the flexural strength of kenaf/ glass/unsaturated polyester (UPE) hybrid composite solid round rods used for insulating material applications. Three volume fractions of kenaf/glass fibre 20:80 (KGPE20), 30:70 (KGPE30), and 40:60 (KGPE40) with three different fibre arrangement profiles of kenaf fibres were fabricated by using the pultrusion technique and were aimed at studying the effect of kenaf fibres arrangement profile and its content in hybrid composites. The fibre/ resin volume fraction was maintained constant at 60:40. The dispersion morphologies of tested specimens were observed using the scanning electron microscope (SEM). The findings were compared with pure glass fibre-reinforced UPE (control) composite. The water absorption results showed a clear indication of how it influenced the flexural strength of the hybrid and non-hybrid composites. The least affected sample was observed in the 30KGPE composite type, wherein the kenaf fibre was concentrated at the centre of a cross-section of the composite rod. The water absorption reduced the flexural strength by 7%, 40%, 24%, and 38% of glass/UPE (control), 20KGPE, 30KGPE, and 40KGPE composites, respectively. In randomly distributed composite types, the water absorption is directly proportional to the volume fraction of kenaf fibre. At the same time, flexural properties were inversely proportional to the volume fraction of kenaf fibres. Although the influence of water absorption on flexural strength is low, the flexural strength of pultruded hybrid composites was more influenced by the arrangement of kenaf fibre in each composite type than its fibre loading.

Continuous swaging of composite wire bundles through controlled material flow

Due to their enhanced mechanical and magnetic properties, composite wire bundles play a central role in many industrial areas. For the production of these parts, continuous metal forming processes with stationary conditions are economically advantageous and enable large-scale production. However, the different mechanical properties of the materials used in the composite rods often make a continuous process execution a technological challenge. The paper at hand investigates the process limits of swaging operations of wire bundles via analytical, numerical and experimental methods. The knowledge gained about the effect of process parameters on the material flow enables a favourable process design.

Microstructure and mechanical properties of the AZ31/GW103K bimetal composite rods fabricated by co-extrusion

The AZ31/GW103K bimetal composite rods consisting of a soft AZ31 sleeve and a hard GW103K core were fabricated by the co-extrusion at 350 °C, 400 °C and 450 °C, and their microstructure and mechanical properties were investigated. The results show that the AZ31/GW103K bimetal composite rods have favorable bonding interfaces at above three extrusion temperatures, and the interfacial layer thickness thickens with the increase of the extrusion temperature. Compared with the monolithic extrusion, the co-extrusion promotes the growth of grains in the AZ31 sleeve but makes grains in the GW103K core to be refined. The AZ31/GW103K bimetal composite rod has higher compressive yield strength and compressive strength than the monolithic AZ31 rod, and the plasticity is similar to that of the monolithic AZ31 rod. Compared with the monolithic GW103K rod, the AZ31/GW103K bimetal composite rod has better plasticity. As the volume fraction of GW103K in the AZ31/GW103K bimetal composite rod increases, its strength gradually increases. Compared with the monolithic AZ31 and GW103K rods, the co-extrusion enhances the texture intensity of the AZ31 sleeve and the GW103K core, but their texture types are hardly changed. The AZ31/GW103K bimetallic composite rod extruded at 350 °C has the thinnest interfacial layer and its yield strength is nearest to the rule of mixture (ROM) predicted value when co-extruding at this extrusion temperature.

Pecularities of fatigue cracks growth in steel and composite sucker rods

To predict the fatigue life of sucker rods, it is important to take into account the effect of technological environments under various loading schemes on the conditional fatigue limit of steels used for their manufacture (in particular, such as steel 20N2M), and compare these properties with modern materials for the manufacture of fiberglass and hybrid sucker rods (with metal heads and polymer rod) as prototypes of steel elements of oil-producing equipment.Specimens of sucker rods with technological or operational defects were tested for fatigue life-time in aggressive technological environments. It has been established that the fatigue life-time and fatigue endurance of sucker rods decrease with an increase in their diameter. So, with a test base of 107 loading cycles, the endurance limits of rods with a diameter of 19, 22, and 25 mm were 95, 85, and 80 MPa, respectively. It was shown that technological defects practically did not affect the life-time of the rods. Minor differences were associated with the scatter of the fatigue characteristics of the metal. Defects formed in rods during their operation in wells have a more noticeable effect on their life-time under variable loads. It was found that the resource of sucker rods with a diameter of 19 mm decreased faster compared to rods with a diameter of 22 mm in the presence of operational defects of the same depth in both rods. This is due to the greater sensitivity of smaller diameter rods to defects.According to the curves of the crack growth rate in specimens made of sucker rods with a diameter of 22 mm, it was found that the critical state (according to the jump in the crack growth rate) is reached if the crack length along the perimeter of the rods is within 15...16 mm, and its depth is 4.5 ... 5.6 mm. Such cracks were fixed at a stress range of 100 MPa, which is commensurate with the operating loads of the rods. For rods of other standard sizes, the critical crack depth, which preceded the almost spontaneous destruction of the specimens, was 3...4, 4...5 and 5...6 mm for rods with a diameter of 16, 19 and 25 mm, respectively. In article we also evaluated fatigue life on samples of fiberglass sucker rods under cyclic loading by circular cantilever bending and obtained the corresponding fatigue curves. According to the results of these tests, probabilistic curves of fatigue endurance of samples with steel and fiberglass sucker rods in the technological environment of reservoir water were constructed with different probability of their non-destruction P(N). Fatigue endurance of samples with steel, fiberglass and hybrid sucker rods was compared.

Работа тонкостенных стальных стержней, предварительно напряженных вытяжкой стенки, при случайных динамических воздействиях

A method for prestressing thin-walled beams with an asymmetric cross section is described. The parameters of the stressed and strained state of the rods are established. By comparing the kinetic and potential energies of composite rods, the circular frequency and angular velocity of conventional and pre-stressed beams when loaded with a single load are determined using the energy method. Stressed and deformed state of ordinary and pre-stressed steel beams under sudden single rotation of the section of the support node has been investigated. It has been established that pre-stressing does not affect the stressed and strained state of the support nodes. The maximum influence of the pre-stressing is set in the area of the maximum moment from the external load. The bearing capacity of the beams changes insignificantly with a sudden single rotation of the support nodes.

Влияние жесткой и пластичной матриц на предельную прочность и механизмы разрушения полимерных композиционных материалов при ударе и в статике

An universal method “Break upon Impact and Static” (RUS) has been developed for the experimental determination of the ultimate strength properties of polymer composite materials based on multifilament nanocrystalline ultra-high molecular weight polyethylene (UHMWPE) fibers, which differs in the method of fixing the sample in a testing machine.The method is carried out using a uniform BIS-sample with an intermediate matrix at the ends and equipment for its attachment to the platforms of testing machines. The sample is a round composite rod composed of the fibers and matrices under investigation, which is held in the tooling by an additional matrix that fixtures it under various loading rates. The RUS method was used to study the properties and mechanisms of destruction upon impact and in a static situation of anisotropic polymer and hybrid composite materials (PCM and HCM) based on flexible and rigid matrices reinforced with hybrid fibers of carbon, aramid, and UHMWPE-fibers activated by non-equilibrium low-temperature plasma. The breaking loads under low-velocity impact and static bending conditions, relative deformation, specific absorbed-in-fracture energy, work of adhesion, shear strength, and other properties are determined. It was found out that the plasticity of the matrix and the hybrid fiber composition affect the properties and fracture mode of PCM and HCM. For the destruction of HCM with a flexible matrix upon impact, a load twice as large as for composites with a rigid matrix is required. HCMs have the highest strength, in which at all stages of loading up to failure, joint deformation of the matrix and the reinforcing fiber occurs. The mechanism of deformation and destruction of anisotropic HCM upon impact is stepwise, while the nature of the deformation curve is zigzag. In statics, the deformation proceeds smoothly. By changing the ratio of carbon and UHMWPE-fibers during hybridization, it is possible to control the properties of HCM and improve its specific properties. The combination of carbon and UHMWPE-fibers in a hybrid fiber for reinforcing a flexible matrix makes it possible to create a material with a delayed fracture. It has been established that for HCM based on a flexible matrix reinforced with a hybrid fiber combining 20 % carbon and 80 % UHMWPE fiber, the fracture load increases by factor 2, the specific fracture work by 42 %, relative deformation by 68 %.

Research of carbon fiber plastic rod connections with steel heads at the action of bending loads

To increase the efficiency of the use of a sucker rod pumping unit (SRPU) today the columns of sucker rods of fiberglass and carbon fiber are used. Such polymer composites have a number of advantages over steel, but they have a significant drawback in the design of a sucker rod - a high concentration of stresses at the point where theyare connected to a steel head containing a thread. Many constructive solutions to this problem have been developed, but maintaining the connection of a fiberglass or carbon-plastic barrel with a metal head remains quite a challenge. As practice shows, the bending of the pump rods in the well are also subjected to bending loads, torque, friction to the column of tubing (tubing) and the like. Therefore, a comparative analysis of the parts of the pump rod structures: traditional steel and combined (metal tip with composite rod) should be carried out. In this work, such joints were subjected only to bending loads, which are particularly dangerous when passing through a rod of bent sections of a well and when running down the bar. It is established that at the time of bending the maximum normal stresses are distributed along the length of the pump rod unevenly and are concentrated in the transition between the head and the rod. The maximum normal stresses occurring in the transition between the steel tip and the carbon-plastic core, which are jointed without structural features (galtels, different transitions, etc.), have been determined to be greater than 1600 MPa. Such value of stress is undesirable when cycling the connection in well. For example, the design of a metal head was proposed, which allows reducing the stresses arising from bending and distribute them on the connection more evenly, compared to the traditional sucker rod.

Effect of fiber hybrid mode on the tension–tension fatigue performance for the pultruded carbon/glass fiber reinforced polymer composite rod

In order to promote the application of fiber reinforced polymer (FRP) rod in bridge engineering, the carbon/glass fiber uniformly dispersed hybrid (UDH) rod with a diameter of 22 mm was developed as the bridge cable through the pultrusion technology. In the present paper, the tension–tension fatigue performances of hybrid rod were investigated with three stress levels of 0.33, 0.44, 0.60 and the fixed stress ratio of 0.4. The fatigue life, stiffness degradation and stress redistribution during the fatigue loading were obtained by linear variable differential transformer (LVDT) and digital image correlation (DIC) method. Furthermore, the fatigue failure mechanism was revealed by microstructure damage analysis. Through the fiber uniformly hybrid technology, the fatigue failure mode of hybrid rod transferred from shell-core debonding to uniformly carbon and glass fiber/resin interface splitting. The positive hybrid effect of fatigue performance was realized to obtain higher fatigue life, stiffness retention and residual mechanical properties. The reliable fatigue life prediction model was developed, and the recommended fatigue limit of present hybrid rod applied for bridge cable was 0.45 at the stress ratio of 0.4 to obtain more than two million fatigue cycles.

UV durability assessment of a thermoplastic epoxy-based hybrid composite rod for structural reinforcement and retrofitting

Recently, a hybrid composite cable has been developed for external strengthening of structures in seismically active zones, containing a novel thermoplastic epoxy matrix. While this resin has advantageous properties such as processability, the UV resistance for outdoor service conditions has not been studied. This paper examines the accelerated UV degradation behavior by using a xenon arc source, and reporting the changes in chemical structure and mechanical properties of both the resin and FRP rods. While the neat resin is susceptible to photo-oxidation and a sharp decline in strength, the hybrid FRP shows no significant changes in tensile properties even after nearly 2000 MJ/m2 of UV radiation (equivalent to seven years in Florida, USA). This was attributed to the fiber-dominant nature of unidirectional composites, further supported by a Curtin-type analytical model.

Effects of temperature and water absorption on the interfacial mechanical properties of carbon/glass-reinforced thermoplastic epoxy hybrid composite rods

The effects of temperature and water absorption on the mechanical properties at the interface of a two-phase hybrid carbon/glass fiber reinforced thermoplastic epoxy composite rods were investigated. The push-out tests were performed on three types of these hybrid composite rods, with different carbon/glass ratios, at various temperatures and water immersion times to investigate their interfacial shear strength and fracture mechanism. Debonding occurred at the interface between glass fiber bundles and thermoplastic epoxy, followed by sinusoidal behavior during sliding, as revealed by the load–displacement curve. The interfacial debonding and sliding strengths decreased with increasing the temperature. The interfacial strengths also decreased with increasing water immersion time, but they were both restored after drying, for all the samples tested. In addition, the effects of temperature and water absorption on the thermoplastic epoxy matrix were also evaluated and the interfacial shear properties of hybrid composite rods were estimated.

Pultrusion of large thermoplastic composite profiles up to Ø 40 mm from glass-fibre/PET commingled yarns

Pultrusion is a rapid and cost-effective manufacturing technology for continuous fibre reinforced thermoplastic composite profiles. As the cross-sections of pultruded profiles grow to meet increasing performance requirements, manufacturing challenges concerning heat transfer are encountered. In this study, a two-dimensional finite element model was used to simulate the heat transfer and fluid flow physics of the pultrusion process for increasing diameters from Ø 5–Ø 40 mm. To facilitate the experimental validation, a novel batch-wise pultrusion concept is introduced in which the impregnation process is observed in-situ using a transparent die. The pultrusion studies, conducted on glass-fibre/amorphous polyethylene terephthalate (GF/PET) commingled yarns, show that – with proper design – pultrusion is able to deliver consistent, high quality (void content < 2%) profiles up to at least Ø 40 mm. • Pultrusion of solid thermoplastic composite rods from commingled yarns with diameters up to Ø 40 mm. • Multi-physics FE model simulating the temperature distribution and evolution during pultrusion. • In-situ observation of novel batch-pultrusion process via a transparent die.

ANALYSIS OF THE STRAIN-STRESS STATE OF THE BENDING CONTINUOUS RC-BEAMS WITH HYBRID REINFORCEMENT IN THE TENSILE ZONE UNDER INTERMEDIATE SUPPORT

The article considers the proposed model describing the stress-strain state of bent statically indeterminate reinforced concrete beams with combined reinforcement (the joint arrangement of metal and composite rods) of the stretched zone of the central support section, based on the positions of the general deformation model of cross-sections with normal separation cracks between concrete subelements formed by two adjacent cracks and the block model of the resistance of the bent element. The prerequisites and assumptions for applying the proposed model are presented. The stress-strain state of the central reference section of the considered elements is analyzed according to the proposed model. The criterion of destruction of statically indeterminate reinforced concrete beams with hybrid reinforcement of the stretched zone of the central support section is revealed, which fully allows taking into account the redistribution of internal forces between the support and span sections of the element.

Determination of the variable density of the rod from natural frequencies of longitudinal vibrations

Rods of various configurations are elements of many structures and machines. Therefore, the acoustic and vibration diagnostics of such parts has been widely developed. The paper considers the problem of determining the variable density of the rod from the natural frequencies of longitudinal vibrations. It is assumed that the density changes along the axis and is described by a polynomial function. This approach allows one to determine the law of density variation from a finite set of eigenvalues. The results of the study can find applications for finding hidden defects in steel and composite rods, which arise during the production process or due to corrosion.