High-performance Reinforcement Research Articles

Research of stress-strain state of the reinforcement profile during the stretching–bending–rebending (cold stretching)

The Cold Stretching method (SBR: stretching, bending with rebending), widely used abroad, makes it possible to implement low strain degrees in high-performance reinforcement production lines, increasing the level of reinforcement mechanical proprieties till A500. The process consists of a combination of stretching the reinforcement at a controlled degree of cold plastic deformation with the addition of alternating bending elements in special roller systems. The paper presents the results of computer finite element modeling in SIMULIA Abaqus complex of stress-strain state of periodic profile reinforcement in the process of SBR. The simulation results showed that during the SBR process the reinforcement receives an equivalent degree of compressive and tensile strain when passing through each subsequent roller, that is, during the transition between groups of rollers and individual rollers in a pair, each section of the profile receives a tensile load commensurate in modulus with the subsequent compression load. To verify this observation in the industrial conditions of OJSC MMK-Metiz, samples of the studied A400 reinforcement were selected in the hot-rolled state and after the SBR process. The study showed that the geometric parameters of the profile remained within normalized limits and no protrusion integrity violations were observed, which confirms the modeling results.

Current and Future Trends in Textiles for Concrete Construction Applications

Textile-reinforced concrete (TRC) is a composite material consisting of a concrete matrix with a high-performance reinforcement made of technical textiles. TRC offers unique mechanical properties for the construction industry, enabling the construction of lightweight, material-minimized structures with high load-bearing potential. In addition, compared with traditional concrete design, TRC offers unique possibilities to realize free-form, double-curved structures. After more than 20 years of research, TRC is increasingly entering the market, with several demonstrator elements and buildings completed and initial commercialization successfully finished. Nevertheless, research into this highly topical area is still ongoing. In this paper, the authors give an overview of the current and future trends in the research and application of textiles in concrete construction applications. These trends include topics such as maximizing the textile utilization rate by improving the mechanical load-bearing performance (e.g., by adapting bond behavior), increasing design freedom by utilizing novel manufacturing methods (e.g., based on robotics), adding further value to textile reinforcements by the integration of additional functions in smart textile solutions (e.g., in textile sensors), and research into increasing the sustainability of TRC (e.g., using recycled fibers).

Covalently functionalized cellulose nanocrystal-reinforced photocurable thermosetting elastomer for 3D printing application

Due to distinct advantages of 3D printing (3DP), multifunctional materials are swiftly finding their applications into diverse industries nowadays. Among the existing 3DP materials, polymers present vast and exciting opportunities but simultaneously face new challenges to satisfy certain specifications. Among the existing polymer classes, elastomers play an important role because of its wide range of applications in nearly every industry such as automotive, marine, aerospace, electronics, medical, and consumer. However, 3D printing of elastomers remains an exigent task because of the resulting weak mechanical properties that impede its proliferation to different industrial applications. In improving material properties, the use of nanofiller has been a widely accepted approach. In pursuit of global environmental sustainability, the trend nowadays is to identify a material from a biobased source. As a biobased filler with inherently high stiffness, high strength, and high aspect ratio, cellulose nanocrystal has the potential to impart high-performance reinforcement to 3D-printed elastomers and consequently satisfy end-use requirements. Notwithstanding its inherent characteristics, the inhomogeneous dispersion of CNC in an elastomeric matrix would cause detrimental effects on the structural integrity of the nanocomposite material. Earlier attempts of reinforcing stereolithography resins using CNC, pristine and modified, yield to a moderate increase in strength but greatly compromise the elongation at break of the composite material. Hence, this study first reports high toughness improvement of the 3D-printed photocurable elastomer via stereolithography using a covalently functionalized CNC. More so, it is interesting to note that percolation threshold of < 1 wt% has significant effects on the different mechanical properties of the new nanocomposite material. The morphological, thermal, and mechanical properties of the new nanocomposite material are delineated. The approach prescribed in this study presents an effective route to expand the utility of CNC to nonpolar matrices such as the thermosetting elastomer and to increase the biobased content of a 3DP material in achieving the global need for sustainable materials.

Erratum to: Self-sacrificial templating synthesis of flower-like nickel phyllosilicates and its application as high-performance reinforcements in epoxy nanocomposites

Erratum to: Self-sacrificial templating synthesis of flower-like nickel phyllosilicates and its application as high-performance reinforcements in epoxy nanocomposites

Effect of Nanosilica and Multiwalled Carbon Nanotubes on the Mechanical and Impact Performance of Unidirectional Kevlar/Epoxy Based Composites

The introduction of numerous nanoparticles into nanotechnology in recent years has opened the door for the incorporation of nanoparticles into polymeric-based composite materials for mechanical improvement. Composite materials are becoming a promising substitute material in the fabrication of numerous components due to their high weight-to-strength ratio and mechanical characteristics such as tensile Strength, flexural Strength, interlaminar shear strength, and impact strength. This research aims to determine the effect of a combined mixture of silica and multiwalled carbon nanotube particles (MWCNT) on the mechanical and impact properties of unidirectional Kevlar (UD)/epoxy composites for use in defence and aerospace applications. The addition of these Nanofillers results in high-performance reinforcement and the formation of hybrid composites with improved properties due to their use. The addition of specific nanomaterials can further enhance these characteristics, dependent on the concentration at which they are introduced into the solution. The most challenging aspects of incorporating nanomaterials into matrix materials are ensuring uniform mixing of the nanomaterials with the matrix material and increasing the viscosity of the matrix material when the nanomaterials are introduced into the matrix. Using different weight percentages, it is possible to determine the optimal ratio of nanofiller for predicting the enhanced mechanical properties of nano-composites. Preparation of the composite with different weight percentages (1 percent and 3 percent) of Nano SiO2 particles mixed with 0.25 percent MWCNT and 6 layers of the UD Kevlar fibre was accomplished using an ultrasonic vibration-assisted hand layup process. Tensile tests, Charpy impact tests, and interlaminar shear strength tests evaluated the material's mechanical properties. Experimental results revealed that tensile strength and impact strength increased by up to 80 percent and 50 percent, respectively, compared to the neat specimens. The ILSS test demonstrates a 271 percent improvement in shear strength at 3 percent and 0.25 MWCNT. The overall results determined that the combination of 3 percent SiO2 and 0.25 percent MWCNT provided the most enhanced mechanical properties while also being the most optimized. This study's findings indicate that applying a nano-silica and MWCNT mixture of Nanofillers to Kevlar fabrics is a promising method for improving a Kevlar-based hybrid composite's mechanical and impact energy absorption laminate.

Hierarchical toughening of laminated nanocomposites with three-dimensional graphene/carbon nanotube/SiC nanowire

High-performance reinforcement together with advanced innovative structure design has been attracting much attention as a means of circumventing the conflict between toughness and hardness or strength of ceramic matrix. Herein, we developed the laminated tungsten carbide (WC) matrix composite reinforced by hybrid one-dimensional (1D) carbon nanotubes (CNTs) and SiC nanowire (SiCnw) as well as two-dimensional (2D) graphene (G), with a striking combination of high hardness (25.3 GPa), high fracture toughness (13.7 MPa m1/2), and high strength (1,501.7 MPa), exhibiting superiority in mechanical properties compared with most WC-based materials, such as WC-metal, WC-intermetallic, WC-carbide, WC-oxide, WC-nitride, WC-whisker, WC-CNT, and WC-graphene. The optimum structure was determined as laminate of five symmetrical layers with thickness ratio of golden ratio squared. In addition, the three-dimensional (3D) hybrid G/CNT/SiCnw demonstrated a strong hierarchical lamellar interconnected structure, in which CNT and SiCnw were well sandwiched between G sheets, synergistically facilitating the enhancement in the mechanical properties of the host matrix. This present investigation shows promising future in achieving state-of-the-art multiscale ceramic composites for safety-critical applications as in the transportation and aerospace.

Structure and properties of bast fiber of Alchornea Davidii Franch based on chemical alkali degumming and biological enzyme degumming

In this work, the effects of degumming treatment on the structure and properties of OS-BADF were discussed. Alkali degumming and biological enzyme degumming were used to obtain AD-BADF and BED-BADF respectively. Spinnability index, thermal property, macromolecular structure, bending property and antibacterial property of OS-BADF (Original Sample of Bast Fiber of Alchornea Davidii Franch), AD-BADF (Alkali Degummed Bast Fiber of Alchornea Davidii Franch), and BED-BADF (Biological Enzyme degummed Bast Fiber of Alchornea Davidii Franch) were tested. The surface morphology of the above three kinds of fiber was analyzed by SEM. The results showed that the main component of degummed OS-BADF was cellulose, and the fiber had stripes in longitudinal direction, and kidney ellipsoid, irregular polygon in the cross section. After degumming treatment, the fineness of fiber decreased obviously and reached the spinnability index. Non-cellulose substances in OS-BADF can be removed by degumming. SEM observation showed that AD-BADF and BED-BADF became smoother after degumming. Compared with AD-BADF, BED-BADF had finer linear density, better thermal stability and higher antibacterial property. The equivalent flexural modulus and flexural rigidity of AD-BADF and BED-BADF were decreased compared with OS-BADF. In particular, the equivalent flexural modulus and the flexural rigidity of BED-BADF were mostly reduced, which indicated that BED-BADF became thinner and softer. The initial thermal decomposition temperature and the highest thermal decomposition temperature of AD-BADF and BED-BADF had been significantly increased. And -OH (free group) decreased significantly after degumming treatment. The testing results of the antibacterial properties of the three blended fabrics showed that the antibacterial properties of AD-BADF and BED-BADF were improved. Compared with AD-BADF, the antibacterial properties of BED-BADF were improved significantly. On the one hand, this research can provide a basis for technological research for the development of ADF (Alchornea Davidii Franch) bast fiber blended yarn and its textile product development. On the other hand, because of the high mechanical properties of ADF bast fiber, it also provides new development idea for the development of natural high-performance fiber reinforcement composites.

Investigations on Dynamic Mechanical Analysis and Crystalline Effect of Neem/Banyan Fiber–Reinforced Hybrid Polymer Composite

Abstract Natural fiber is often considered to be deficient for high-performance reinforcement of polymer matrix composites. However, the environmental aspects of natural fiber are attractive to many researchers in the area of natural composites because of the specific strength and eco-friendly properties of natural fibers. In this research, alkali-treated natural fibers are chopped neem fibers, and bidirectional woven mat was used as reinforcement and blended with epoxy matrix. Also, sawdust cellulose was used as a filler material to fabricate composite laminates by the conservative hand layup method. The composite laminates are varied by different weight fractions of reinforcement (25 %), epoxy matrix (70 %), and filler (5 %). Then, to quantify the effect of storage modulus, loss modulus and the damping factor of the hybrid composites are taken by conducting dynamic mechanical analysis. Maximum storage modulus is 1,343 MPa. The results show that increasing the bidirectional woven fiber loading will give 61 % more stiffness in the elastomeric region when compared to chopped neem fiber loading in the hybrid composites, and analyses of the crystallinity effects by x-ray diffraction also identify the adhesion quality between the fibers, fillers, and matrix by using the surface morphology test scanning electron microscopy of the hybrid composites.

Batch production and fused filament fabrication of highly aligned discontinuous fibre thermoplastic filaments

Fused filament fabrication (FFF), which is a thermoplastic layer-by-layer additive manufacturing technique, called as 3D printing, can quickly build complex geometries, reducing design limitations and production costs of conventional manufacturing methods. Using a fibrous reinforcement strengthens the thermoplastic matrix, allowing FFF to be used in more structural complex-shape small-size applications in engineering. Aligned discontinuous fibre composites (ADFRC) incorporate a high-performance reinforcement architecture that, owing to a sufficient fibre length and high level of alignment, results in mechanical performance comparable to those of continuous fibre composites. Moreover, it can offer higher formability and, fewer manufacturing defects. In this paper, ADFRC preforms, produced with the High Performance Discontinuous Fibre (HiPerDiF) technology, were impregnated with poly(L-lactic acid) (PLA) and then reshaped to a circular-shaped 3D printing filament using a customised manual moulding and pultrusion method. Two different mould types were compared to maximise the filament quality and reduce the amount of trapped voids. The printability of the circular filaments was investigated by varying three parameters: deposition speed, processing temperature, and layer thickness. Finally, the tensile properties of samples from each manufacturing step: moulded, filament, single raster printed, and full height rectangular part, were investigated. Overall, the HiPerDiF-PLA filament can be printed using an 3D printer. Although the tensile properties of filament in each stage reduced as the result of the shape transformation process, the deposited layer of HiPerDiF-PLA part has greater stiffness and strength than other PLA composite materials. At this stage of technology development, the material has lower mechanical performance yet than the nylon continuous fibre composites printed with commercially available machines. However, there are clear routes forward for the improved performance of the HiPerDiF FFF printed filaments.

Dynamic mechanical behavior of natural fibers reinforced polymer matrix composites – A review

The environmental awareness and rapid development in the area of material science attracted the researchers into natural based materials on account of their chemical resistance, ease of fabrication, low density, specific strength, inexpensiveness and favourable mechanical properties. However, some cellulose fibres extracted from natural sources have somewhat high mechanical properties nearer to those of synthetic fibres. Composites using natural fibres as reinforcement have shown favourable results. These natural fiber reinforced composites often considered as high performance reinforcements in polymer composites. DMA had become important for both industry and academia. DMA is an effective thermal analysis tool for the determination of elastic nature of a composite material with respect to of time, frequency, temperature and combination of these. A dynamic mechanical analysis utilizes applied force and deformation data to evaluate the stiffness changes in a material under varied temperatures. DMA measures elastic nature with reference to storage modulus (E’), loss modulus (E”), damping factor (Tan delta) and glass transition temperature (Tg). These properties will be very helpful to measure the performance characteristics of polymer composite materials including both thermosets and thermoplastics. Now a days, most effective and flexible DMA instruments under different modes are available. Dynamic Mechanical Analysis (DMA) is currently used by rubber manufacturers to study the performance of their materials. For the purposes of industrial testing as well as for research and development, DMA is recognized as a highly informative characterisation technique. DMA curves depicts variation of dynamic moduli and damping in glassy or rubbery regions. The current review studies the effect of natural fibres on dynamic mechanical properties of polymer composites. Many results exhibited that inclusion of natural fibres with polymers tends to increase the elastic nature of the polymer matrix.

Self-sacrificial templating synthesis of flower-like nickel phyllosilicates and its application as high-performance reinforcements in epoxy nanocomposites

Self-sacrificial templating synthesis of flower-like nickel phyllosilicates and its application as high-performance reinforcements in epoxy nanocomposites

Fabrication of degradable and high glass-transition temperature thermosets from palm oil and isosorbide for fiber-reinforced composites

Inexpensive, abundant, and low iodine value palm oil (PO) from oil palm (Elaeis guineensis Jacq.) was utilized to formulate biobased polymer matrices for fiber-reinforced composites. A reactive PO fatty acid-ethyl acrylamide (POFA-EA) was synthesized from PO and N-(2-hydroxyethyl)acrylamide (HEAA) via a benign transesterification. Another glucose-derived monomer, i.e., isosorbide was used to react with methacrylate anhydride to synthesize a comonomer, isosorbide-methacrylate (IM). Then, a new class of renewable, property-tunable, and degradable PO-based thermosets were prepared from flexible POFA-EA and rigid IM. The cross-linked POFA-EA/IM resins had suitable processability for composites, high glass transition temperatures (Tgs) (150−204 °C), and superior mechanical strengths and moduli, while maintaining high biobased contents (∼60 %). The PO-based thermoset composites reinforced by kenaf, bamboo, glass, and carbon fibers, respectively, exhibited higher Tgs (136–193 °C) than their petroleum-based counterparts. Meanwhile, the PO-based matrices can be decomposed in a mild alkali solution, which provides a feasible way to recycle high performance reinforcements such as carbon fibers.

Realising the Potential of Pineapple Leaf Fiber as Green and High-performance Reinforcement for Natural Rubber Composite with Liquid Functionalized Rubber

Realising the Potential of Pineapple Leaf Fiber as Green and High-performance Reinforcement for Natural Rubber Composite with Liquid Functionalized Rubber

Flexural behavior of concrete beams cast with high-performance materials

The use of ultra-high strength concrete (UHSC) is advantageous in construction. In fact, a combination of UHSC with regular reinforcement steel still has problems with corrosion after years in service, typically in exposed structures. This effect is more profound by climate changes (i.e., extensive heat waves or unexpected long and cold winter). This research investigates the flexural performance of concrete beams, cast with UHSC and high-performance reinforcement (HPR) steel; which is characterized by its high-strength and high-corrosion resistance. The testing matrix consisted of 8 concrete beams, cast with UHSC and high-strength concrete (HSC), in combination with ASTM A1035 Grade 830 steel and ASTM A615 Grade 420 steel. For each flexural test, along with measuring the applied loading and deflection, the variation in concrete compressive strain and steel tensile strain were monitored through a number of strain gauges. Experimental results revealed that Grade 830 can enhance the flexural capacity by 33% as compared to Grade 420 steel. On the other hand, UHSC can enhance the flexural capacity by 11% and decrease the concrete strains by up to 26% as compared to HSC.

Structural performance of concrete bridge decks reinforced with Grade-830 steel bars

High-performance reinforcement, which is known by its high-corrosion resistance and high-strength, is advantageous in the design and construction of concrete bridge decks. This research investigates the structural behavior of concrete bridge decks reinforced with either high-performance A1035M (Grade 830) or ASTM A615M (Grade 420) reinforcing steel at both the service and strength limit states. The tensile strain of the reinforcing steel, the compressive strain of the concrete, and the deflection of the specimens were monitored continuously during testing. A crack width microscope was used to measure the maximum crack width and the number of cracks. The results indicated an increased serviceability and flexural strength for the decks containing Grade 830 reinforcing steel.

Effects of hybrid carbon-aramid fiber on performance of non-asbestos organic brake friction composites

The present investigation aims to explore the influence of simultaneous loading of aramid/carbon fibers, as high-performance reinforcements, on thermal, mechanical, and frictional behaviors of phenolic-resin-based non-asbestos organic (NAO) friction materials. The hybrid composite specimens were made at different ratios of carbon and aramid fibers but at a total fixed fiber loading of 8 vol%. The influence of carbon fiber on the improvement of impact strength and thermal conductivity was found to be more prominent than aramid fiber. The thermal stability of friction composites under nitrogen and real condition was investigated. The frictional data drawn from a Chase type friction tester revealed that the coefficient of friction and fade behavior were improved by incorporating aramid fiber. However, carbon fiber improved the wear resistance significantly in comparison with aramid fiber. The surface morphology of the composites was investigated precisely using scanning electron microscopy. Taking all the characterizations (physical, thermal, and tribological) into account, it was revealed that the sample holding 6 vol% aramid fiber and 2 vol% carbon fiber presented the best performance in terms of coefficient of friction, wear rate and fade behavior.

Processing and evaluation of thermal-sprayed high-performance polymer fiber reinforced Zn metal matrix composites

This novel research work reports the possibility of using a high-performance polymer fiber as a potential reinforcement in a suitable metal matrix for the development of composites. The manufacturing route is an additive process using High-Velocity Oxy-Fuel Thermal-Spray technique. Continuous strands of Poly-benzobisoxazole and para-aramid were used as high-performance polymer reinforcement in a uni-directional configuration, and Zinc metal was used as matrix material. The developed Thermal-Spray composites were subjected to mechanical tensile test and characterized by Scanning Electron Microscopy and Optical Microscopy. The results of the tensile tests revealed a substantial increase in the tensile properties and the investigation of Scanning Electron Microscopy and optical images showed a good deposition of matrix material on the reinforcing polymer fibers. The testing and characterization results were conclusive of the fact that Poly-benzobisoxazole and para-aramid can be used as an effective reinforcement even at low volume content for high strength structural applications.

Comparative study of pineapple leaf microfiber and aramid fiber reinforced natural rubbers using dynamic mechanical analysis

Natural fiber is often considered inadequate for high performance reinforcement of polymer matrix composites. However, some natural fibers have relatively high mechanical properties with modulus close to that of high-performance synthetic fibers. Since the reinforcing efficiency of a short fiber is determined not only by the fiber modulus, but also by other physical properties such as the length to diameter ratio. Here it is shown, for the first time, that pineapple leaf fiber, whose modulus is somewhat lower than that of aramid fiber, can be used to reinforce natural rubber more effectively than aramid fiber. The situation was achieved by breaking down the fiber bundles into the constituent microfibers to gain very high aspect ratio. Comparisons were made at fiber contents of 2, 5 and 10 parts (by weight) per hundred of rubber (phr) using dynamic mechanical analysis over a range of temperature. The results reveals that at temperature below the glass transition of the matrix rubber and low fiber contents of 2 and 5 phrs, aramid fiber displays slightly better reinforcement efficiency. At high temperatures of 25 and 60 °C and high fiber content of 10 phr, pineapple leaf microfiber clearly displays higher reinforcement efficiency than does aramid fiber. Surface modification of the fiber by silane treatment provides a slight improvement in reinforcing efficiency.

Optimization of a mono-composite leaf spring using a hybrid fiber-layup approach

Conventional leaf springs are simple in design, utilizing multiple metallic bars (leaves) with low geometrical moment of inertia to generate an economical and linear spring rate. In its early form, the leaf-spring was manufactured using metals like steel, but, in modern applications, there exist composite leaves reinforced by advance glass and carbon fibers. Benefits of composite spring designs include: high specific strength, ability to form complex profiles, and possibility of subcomponent consolidation to reduce assembly. Due to the bending characteristics of the leaf spring, the axial load decreases through the beam thickness, reaching a minimum at the neutral surface. Given this fact, a design optimization approach for mono-composite leaf springs is developed considering a hybrid fiber-layup. Initially, a detailed topology optimization is conducted to optimize the geometry of the leaf spring based on the Tsai-Wu failure model. This process yielded a unique spring design which reduced the mass of the spring by 29% compared to the initial non-optimized spring and 80–90% compared to a steel spring. Subsequently, the design is further optimized by replacing low stress, high modulus reinforcement with lower modulus and cost-effective materials to improve overall vehicle mass, efficiency, and operation. The second stage of the optimization based on the hybrid fiber-layup approach resulted in an additional 7% mass reduction. As there is a connection between fuel efficiency and vehicle mass, the significant reduction of spring mass has a positive impact on vehicle fuel consumption and leads to suspension responsiveness gains. Moreover, the possibility of swapping up to 20% of the middle plies reinforcement with commodity plastics demonstrates the cost benefits of the hybrid fiber-layup design approach considering the high cost of carbon and other high-performance reinforcements.

Environmentally Friendly and Controllable Pyrolysis Method to Synthesize Ni-Modified Graphene Nanosheets as Reinforcement of Lead-Free Solder

A tactic for the synthesis of Ni-modified graphene nanosheets (Ni-GNSs) as a high-performance reinforcement of a lead-free solder is proposed and achieved via an environmentally friendly and controllable pyrolysis method. The segmented pyrolysis processes of an Ni(CH3COO)2∙4H2O@GNSs hybrid are discussed. The morphology, microstructure, phase transition, and adsorption strength of nanoparticles on the surface of GNSs with various theoretical Ni loadings are characterized. The adsorption mechanism of a single Ni atom on the surface of perfect graphene and defective graphene was studied based on density functional theory. The corresponding underlying formation mechanisms of Ni-GNSs are analyzed. The results show that the grain size, distribution and phase composition of the nanoparticles on GNSs could be controlled by changing the theoretical Ni loading level. The morphology and dispersity of Ni nanoparticles on GNSs did not significantly change after long-time or high-power ultrasonic treatment, suggesting that the adsorption strength between Ni nanoparticles and GNSs was relatively large and belonged to chemical adsorption based on first-principle calculation. Ni atoms tend to adsorb in the center of the carbon six-membered ring. The obtained Ni-GNSs nanohybrid exhibited a small size, fewer defects, and higher crystallinity and adsorption strength when the theoretical Ni loading was 17 mol %. The results have potential applications in the design of the reinforced phase of composites.