Nonmetallic Composites Research Articles

Benefits and risks of application of non-metallic composites as an alternative to steel reinforcement in concrete elements

The paper presents an overview of possible alternative reinforcement solutions to the most popular steel reinforcement currently used for concrete elements. Particular emphasis was placed on the use of composite reinforcement, taking into account the types of components concerned, possible applications and presenting an analysis of the risks and opportunities facing the construction industry related to the use of this type of reinforcement. In addition, an analysis of the material parameters taking into account the division of composite reinforcement due to the different types of fibers used in their production is presented. The paper also presents a comparative analysis of the parameters of steel and composite reinforcement, among others: tensile strength, susceptibility to corrosion, compressive and bending strength, fire resistance. It also analysed the needs of the construction market in the search for alternative concrete reinforcement in reinforced concrete structures, particularly in the context of recent events such as the Covid-19 pandemic and armed conflicts, which disrupt the supply chain and force the search for alternative materials that can replace reinforced steel. The availability of standards and instructions for the design of concrete elements and the related responsibilities of structural designers were analysed, identifying the research directions necessary to popularize and ensure the safety of the design of concrete elements with the use of alternative material solutions – in particular composite reinforcement in concrete slabs.

Defects Detection Method Based on Programmable Spoof Surface Plasmon Polaritons in Non-Metallic Composites

Microwave nondestructive testing (NDT) offers promising application prospects due to its advantages of non-contact inspection in detecting defects in non-metallic composites. However, the detection sensitivity of this technology is generally affected by the lift-off effect. To reduce this effect and highly concentrate electromagnetic fields on defects, a defect detection method using scanning instead of moving sensors in the microwave frequency range was proposed. Additionally, a novel sensor based on the programmable spoof surface plasmon polaritons (SSPPs) was designed for non-destructive detection in non-metallic composites. The unit structure of the sensor was made up of a metallic strip and a split ring resonator (SRR). A varactor diode was loaded between the inner and outer rings of the SRR, and by changing the capacitance of this diode using electronic scanning, the field concentration phenomenon of the SSPPs sensor can be moved along a specific direction for defect detection. By using this proposed method and sensor, the location of a defect can be analyzed without moving the sensor. The experimental results demonstrated that the proposed method and designed SSPPs sensor can be effectively applied in detecting defects in non-metallic materials.

Highly selective conversion of tetrabromobisphenol A epoxy resin waste to high-purity phenolic chemicals by subcritical water-CuO process

Tetrabromobisphenol A epoxy resin (TBBPA-ER) is the most important nonmetallic composition of waste printed circuit boards (PCBs). Currently, the TBBPA-ER waste is mainly sent to incineration or landfills. The great obstacle of the recovery of the TBBPA-ER waste is the low value-added products obtained by existing technologies. In this study, a novel resource conversion strategy was developed to produce high-purity phenolic chemicals from the TBBPA-ER waste by subcritical water-CuO (SubCW-CuO) process. The high selectivity of the SubCW-CuO process for the recovered products from the TBBPA-ER waste could be attributed to the regulating effect of CuO. The CuO could preferentially trigger the rupture of C-O and C-Ph bonds in the TBBPA-ER chain, resulting in the producing of high-purity phenol (91.47 %) at 300 °C. The reaction between phenol and methyl radical (derived from β-scission of ternary carbon chain groups in the TBBPA-ER waste) resulted in the recovery of high-purity p-cresol (90.30 %) at 350 °C. The optimal conditions of the SubCW-CuO process were solid-liquid ratio of 1:30 g/mL, M(TBBPA-ER):M(CuO) ratio of 10:1 g/g, and 60 min. The conversion ratio of the TBBPA-ER waste could reach 70 % under the optimal conditions. Approximately 3 % of the bromine was transferred into the oil phase products after the SubCW-CuO process at 250 °C, while no organic bromine could be found in the oil phase products at 300 and 350 °C. More than 70 % of the bromine was fixed in the solid residue after the SubCW-CuO process at 300 and 350 °C. The bromine contained in the solid residue mainly existed in the form of CuBr and the Cu species had efficient capture ability for the bromine released from the molecular chain of the TBBPA-ER. It is believed that the SubCW-CuO process developed in this study is a promising alternative technology for the high-efficiency resource conversion of the TBBPA-ER waste.

A hemispherical near‐field focusing antenna for non‐metallic delamination detection

This paper proposes a novel hemispherical near-field focusing radial line slot array (RLSA) antenna to detect delamination within non-metallic composites. By adjusting the positions and dimensions of the antenna slots, the near-field focusing antenna produced a radiation pattern with a narrow beamwidth and a low side lobe level of the normal component of the electric field. Since the electromagnetic (EM) field of the near-field focusing antenna can be focused on the material under test (MUT), delamination within it will significantly affect the reflected information of the antenna. Simulation and measurement have shown the good focusing characteristics of the novel RLSA antenna, a low side lobe level (−19 dB) and a narrow beamwidth (6 mm) were attained. Taking glass fiber reinforced polymer (GFRP) sheets as MUTs, delamination with different thicknesses are detected using a set of mechanical scanning experimental devices. The results show that delamination as thin as 30 μm can be detected. The proposed near-field focusing antenna can detect thinner delamination inside non-metallic composites at a lower cost and in a simpler way than other microwave non-destructive testing (NDT) methods.

CT STUDY OF PRODUCTS FROM NON-METALLIC COMPOSITES REINFORCED BY CARBON FIBERS

Computerized tomography is used to study products from non-metallic composites reinforced by carbon fibers. It is demonstrated that samples do not rotate during the analysis process and can have diameter not exceeding the gantry hole (75 cm) of the unit. The weight of samples can be up to 200 kg, and the length during one-time testing does not exceed 150 cm. The results of spatial calibration of the technology are shown using a set of copper wires with diameters from 0.56 to 0.05 mm. The paper presents the results of defects detecting in products in the form of gas pores and metal inclusions.

Detection and Location of Defects in Non-Metallic Composites Pipeline Based on Multi-Resonant Spoof Surface Plasmon Polaritons

Detection and Location of Defects in Non-Metallic Composites Pipeline Based on Multi-Resonant Spoof Surface Plasmon Polaritons

Advanced Non-Metallic Coatings and Composite Materials for O & G Industry

Materials used in the oil and gas industry are required to possess resilient properties to sustain operational challenges. These include high pressures and temperatures of the working fluids created by both reservoir depths and compressors combined with the inherent aggressive and corrosive components. Multiple solutions have been introduced to the industry to minimize corrosion probability in recent years. Utilizing external and internal tubular non-metallic coating as well as switching to the products entirely made of the non-metallic composites are the most commonly used and best performing solutions. This paper presents a comprehensive overview of the advances of the most promising research and development activities in the area of protective coatings as well as non-metallic composite material products with real case studies in downhole applications. Special emphases are put on the most promising technological breakthroughs such as 3D printing with non-metallic composites containing nano-sized short fibers and continuous nanofibers, which could be potentially used in the fabrication of future downhole composite products. The breakthrough solutions in composite technologies such as self-healing systems, including capsule-based, fiber-based and vascular healing network, which are perfectly aligned with the 4th Industrial Revolution are also described.

Effect of Eccentricity in Microwave Imaging of Multiple Composite Pipes

The use of non-metallic composites that are durable, low cost, and lightweight is growing fast in various industries. A commonly used form of these materials is in the shape of pipes that can be used, for instance, in oil and gas industry. Such pipes can be damaged due to material loss (defects and holes), erosions, and more which may cause major production failures or environmental mishaps. To prevent these issues, non-destructive testing (NDT) methods need to be employed for regular inspections of such components. Since traditional NDT methods are mainly used for metallic pipes, recently microwave imaging has been proposed as a promising approach for examination of non-metallic pipes. While microwave imaging can be employed for inspection of multiple layers of pipes, the effect of undesired eccentricity of the pipes can impose additional imaging errors. In this paper, for the first time, we study the effect of eccentricity of the pipes on the images reconstructed using near-field holographic microwave imaging when imaging double pipes.

Method of Defects Detection in Non-Metallic Composites Based on Liquid Flow Controlled Spoof Surface Plasmon Polaritons

This paper proposes a new microwave non-destructive testing (NDT) method based on liquid flow controlled spoof surface plasmon polaritons (SSPPs) to detect defects in non-metallic composites. The sensor based on this method is composed of SSPPs structure and liquid flow controller. The liquid flow controller can be used to control the sensing area of the sensor. The detection is based on the change of the transmission coefficient at the cut-off frequency of SSPPs sensor, which is caused by defects. Since liquid movement has continuity, the sensor's field distribution is also continuous change. So in a certain detection range, the liquid flow scanning method can avoid the problem of defect missing detection. Taking FR4 as an example, both the simulation and experiment results reveal that this liquid flow controlled SSPPs sensor can effectively realize defects detection with a radius of 1mm in non-metallic composites. The sensor has the advantages of simple structure, easy operation, fast detection speed and convenient detection of curved MUT.

Wafer-scale growth of two-dimensional graphitic carbon nitride films

<h2>Summary</h2> The extension of graphitic carbon nitride (g-CN) materials into optoelectronic applications beyond photocatalysis has long been anticipated due to their non-metallic composition, moderate electronic band gap, and excellent stability. However, large-scale synthesis of uniform two-dimensional (2D) g-CN films with high crystallinity and tunable thickness remains the bottleneck for their future applications in optoelectronic devices. Here, a vapor-phase transport-assisted condensation method has been developed for the wafer-scale synthesis of uniform 2D g-CN films with tunable thickness. First-principle calculations indicate the direct condensation from melem to heptazine-based carbon nitride enables the formation of high-quality g-CN films. A facile water-assisted transfer strategy is developed for subsequent fabrication on arbitrary substrate. A free-standing flexible photodetector array with strain-insensitive responsibility is demonstrated with the g-CN films as imaging pixels. This study provides a convenient route to wafer-scale growth of high-quality 2D g-CN films and paves the way to the g-CN-based electronic and optoelectronic devices.

The effect of structural factors on tribological behaviour of copper-zinc gas-dynamic coatings

The paper studies the effect of the structure of copper and brass coatings, obtained by gas-dynamic spattering, on their tribological behaviour. Using durometrical, chemical and X-ray analyses, as well as the wear tests, the authors have determined that the copper coating structure hardness is 102.7 HV, it has pores up to 2 urn in diameter, brass coating consists of 106.5 HV copper, 49.7 HV zinc and 168.7 HV non-metallic compositions (y - and e - phases), distributed by mass as 62:7.9:24.2 % correspondingly. The both coatings have presented good results in sliding friction couple tests.

ОЦЕНКА СКЛОННОСТИ ПОКРЫТИЙ К ОБРАЗОВАНИЮ ПОР И НЕМЕТАЛЛИЧЕСКИХ ВКЛЮЧЕНИЙ В СВАРНОМ ШВЕ

The task of welding steel elements painted with various coatings is found in a number of industries at the stages of factory assembly and installation of large-sized structures, as well as during repair and restoration work. The porosity of the welded metal is the most common defect in electric arc welding without removing the coating, and the tendency to pore formation is a normalized parameter in the certification of interoperable primers (EN ISO 17652-2: 2003). The studies carried out cover wide-spread polyacrylate, alkyd, epoxy, polyvinyl butyral primers in an extended working thicknesses range. In addition, the evaluation technique is used for zinc-filled and organosilicate protective coat-ings. Based on the study of the nonmetallic inclusions composition in a weld by energy dispersive X-ray spectroscopy and using a scanning electron microscope, the behavior features of the coatings de-struction products and their derivatives during physical and chemical transformations under welding are described. The technological features of welding without coating removing are noted: stability of the mode parameters, resistance to metal spraying and coating burnout activity in the areas adjacent to a weld.

Detection of Defects in Non-Metallic Composite Material Based on Electronically Controlled Spoof Surface Plasmon Polaritons

A novel sensor based on electronically controlled spoof surface plasmon polaritons (SSPPs) is proposed to detect internal defects in non-metallic composites. The designed sensor is flexible and can be wrapped around the materials under test (MUT), therefore, compared with non-flexible sensors, it has a great advantage in detecting curved MUT. Moreover, traditional microwave sensors have to scan the MUT by the way of mechanical moving which consumes much time. For improving the detection speed, the electronic control scheme is adopted to control the sensing area of designed sensor, so as to replace mechanical moving. The detection is based on monitoring change in resonance frequency of the designed sensor which is caused by the defects. The sensor has the advantages of high sensitivity, fast detection speed and it is very convenient to detect curved MUT.

Study of non-metallic inclusions composition in rail joints welded seams, obtained at their contact arc welding

The quality of welded rail joints depends on various factors, in particular, on the type and quantity of non-metallic inclusions, formed at their contact arc welding. To check a hypothesis of the cause-effect of welded joint mechanical properties decrease and composition of non-metallic inclusions in the welded seams, their chemical and metallographic analysis accomplished. To study the non-metallic inclusions, samples of 90×30×10 mm dimensions used, cut of Э76ХФ steel rail head. After contact butt welding at MC-2008 machine, the samples were cut by electro-erosion method perpendicularly to the welding seam into two parts. One part of the sample was used for tensile test, the other – for metallographic analysis for non-metallic inclusions and structure of the welded joint. The microstructure of the welded butts studied after milling and intensive etching in the 50% water solution of hydrochloric acid. The microstructure was studied at the optical microscope OLYMPUS GX71 in the light field at magnification 100–1000 folds after etching in an alcohol solution of nitric acid. The chemical composition of all the revealed inclusions were determined at the scanning electron microscope MIRA 3. It was established, that silicon and manganese oxides were the basic components of inclusions, revealed in the welded seam, as well as oxides of aluminum, iron, titanium, chrome – to a less amount. In the samples seam microstructure the ferrite net, typical for rail butts, was not discovered, which is probably stipulated by their accelerated heating due to the small section of the samples.

Special Issue on Fatigue and Fracture of Non-Metallic Materials and Structures

This Special Issue covers the broad topic of structural integrity of non-metallic materials, and it is concerned with the modelling, assessment and reliability of structural elements of any scale. In particular, the articles being contained in this issue concentrate on the mechanics of fracture and fatigue in relation to applications to a variety of non-metallic materials, including concrete and cementitious composites, rocks, glass, ceramics, bituminous mixtures, composites, polymers, rubber and soft matters, bones and biological materials, advanced and multifunctional materials.

Evaluation of a conducting elastomeric composite material for intramuscular electrode application

Electrical stimulation of the muscle has been proven efficacious in preventing atrophy and/or reanimating paralyzed muscles. Intramuscular electrodes made from metals have significantly higher Young's Moduli than the muscle tissues, which has the potential to cause chronic inflammation and decrease device performance. Here, we present an intramuscular electrode made from an elastomeric conducting polymer composite consisting of PEDOT-PEG copolymer, silicone and carbon nanotubes (CNT) with fluorosilicone insulation. The electrode wire has a Young's modulus of 804 (±99) kPa, which better mimics the muscle tissue modulus than conventional stainless steel (SS) electrodes. Additionally, the non-metallic composition enables metal-artifact free CT and MR imaging. These soft wire (SW) electrodes present comparable electrical impedance to SS electrodes of similar geometric surface area, activate muscle at a lower threshold, and maintain stable electrical properties in vivo up to 4 weeks. Histologically, the SW electrodes elicited significantly less fibrotic encapsulation and less IBA-1 positive macrophage accumulation than the SS electrodes at one and three months. Further phenotyping the macrophages with the iNOS (pro-inflammatory) and ARG-1 (pro-healing) markers revealed significantly less presence of pro-inflammatory macrophage around SW implants at one month. By three months, there was a significant increase in pro-healing macrophages (ARG-1) around the SW implants but not around the SS implants. Furthermore, a larger number of AchR clusters closer to SW implants were found at both time points compared to SS implants. These results suggest that a softer implant encourages a more intimate and healthier electrode-tissue interface. Statement of significanceIntramuscular electrodes made from metals have significantly higher Young's Moduli than the muscle tissues, which has the potential to cause chronic inflammation and decrease device performance. Here, we present an intramuscular electrode made from an elastomeric conducting polymer composite consisting of PEDOT-PEG copolymer, silicone and carbon nanotubes with fluorosilicone insulation. This elastomeric composite results in an electrode wire with a Young's modulus mimicking that of the muscle tissue, which elicits significantly less foreign body response compared to stainless steel wires. The lack of metal in this composite also enables metal-artifact free MRI and CT imaging.

Research status of artificial bone materials

The many types of material currently used to treat bone injuries (caused by various reasons) have undergone changes over time. From the initial metal implants of stainless steel or titanium to those made of ceramics and polymers (which are now widely used), each material has its own advantages, disadvantages, and suitable uses. Artificial bone material needs to be selected according to the different stress conditions of the body part in which it will be used, and the characteristics of the different materials need to be studied before a reasonable selection of the material can be made. This article reviews the artificial bone materials that have been studied so far, including metals, inorganic nonmetallic materials, polymers, and composites. Their advantages, disadvantages, and development status undergo comprehensive analysis, and the basis for future material selection is provided. An examination of publications shows that the future trend in developing bone materials for treating bone defects is to combine the above-mentioned materials with growth factors and bioactive proteins. This article may be helpful for choosing the right materials.

Пути решения проблем формообразования режущего инструмента для обработки неметаллических композитов

Пути решения проблем формообразования режущего инструмента для обработки неметаллических композитов

Study of High-Strength Austenitic Nitrogen-Containing Steel Ingot Phase Formation and Structure

Thermodynamic modeling is performed for phase formation of nitrogen-containing steel 04Kh20N6G11M2AFB during crystallization, solidification, and cooling that shows crystallization proceeds through δ-ferrite. In this case depending on alloying element content within the limits of the grade composition δ-ferrite may exist both at temperatures corresponding to the cuidus — solidus interval, and also be retained below the solidus temperature. Ingot metal is examined comprehensively in different ingot zones in order to study structure formation throughout the ingot volume, alloying element liquation, and nonmetallic inclusion and secondary phase composition and distribution.

Effect of Temperature Exposure on the Flexural Mechanical Behavior of Two Pultruded Composites

The use of non-metallic composites at floor gratings in offshore platforms is driven by the need for increased component life in corrosive environments. As a result, these floor gratings contribute to a lower demand for maintenance and greater operational continuity. However, these composite materials have limitations when are exposed to high temperatures. The application of these floor gratings, on ships and floating offshore platforms have the requirement to retain a significant level of mechanical integrity during and after exposure to a fire. In this work, the mechanical behavior of two composites materials after being subject to a temperature rise was evaluated. One composite has an isophthalic polyester resin as matrix and the other used a phenolic resin. Before the mechanical characterization, thermogravimetric analysis was performed to determine the temperatures of beginning of the thermal degradation, and the microstructure of the composites was evaluated by digital image analysis. From the results of the thermal analysis a temperature of 250°C was chosen as the maximum one to be used, in order to evaluate the behavior of these composites in regions close to fire but not directly exposed to fire. Flexural properties of the two composites were performed by three-point bending test with 25 specimens of each composite. For the phenolic resin composite, the test specimens were manufactured with the average dimensions of 90.5 mm long, 19.5 mm large and 4.2 mm thick. The average dimensions of isophthalic composite specimens were 135.0 mm long, 25.0 mm large and 6.9 mm thick. The results show that the isophthalic resin matrix composite lost its mechanical integrity with the time of exposure to temperature, while the phenolic matrix composite maintained their properties. For example, regarding the maximum flexural stress a decrease of almost 50% was measured for the isophthalic matrix composite in comparison to only 3% for the phenolic matrix composite. However, the mechanical behavior of this composite was impaired by the presence of a high content of voids (5.7%) and of touching fibers arising from the manufacturing process.