Reinforcement Material Research Articles

Property investigation of functionally graded materials leaf spring plate fabricated through stir casting process by using new gradient evaluation method

AbstractAutomobile and aviation industries require lightweight solutions in the suspension system to improve overall performance and payload capacity. This can be achieved by materials having high strength to weight ratio. Fiber composites, known for their lightweight and high strength, face a major issue of delamination, which shortens the lifespan of fiber‐reinforced polymer leaf springs. Current researchers are emphasizing the use of functionally graded materials as a promising alternative to tackle this problem. In the present work, a functionally graded leaf spring plate was fabricated using stir casting technique with five layered gradations in the mid portion. The amount of molten material required for each gradation was ensured using a novel experimental technique. On the other hand, the matrix and reinforcement have been adopted from the output of the analysis conducted using CES EduPack 2019 software. Low density and high fatigue strength were primary focal point for the consideration of matrix and reinforcement materials. Aluminium 7075 and boron carbide were considered as matrix and reinforcement materials respectively. Stir casting technique, used in the present work, is simple, suitable and cost effective technique which creates a gradation at central part of the leaf.

Structural Health Monitoring of Partially Replaced Carbon Fabric-Reinforced Concrete Beam

Textile-reinforced concrete (TRC) is a composite concrete material that utilizes textile reinforcement in place of steel reinforcement. In this paper, the efficacy of the partial replacement of steel reinforcement with textile reinforcement as a technique to boost the flexural strength of reinforced concrete (RC) beams was experimentally investigated. To increase the tensile strength of concrete, epoxy-coated carbon textile fabric was used as a reinforcing material alongside steel reinforcement. Beams were cast by partially replacing the steel reinforcement with carbon fabric. Partially replaced carbon fabric-reinforced concrete beams of size 1000 × 100 × 150 mm3 were cast by placing the fabrics in different layers. A four-point bending test was used to test cast beams as simply supported until failure. Then, 120 ohm strain gauges were used to study the stress–strain behavior of the control and TRC beams. Based on this experimental study, it was observed that 50% and 25% of the steel replaced with carbon fabric beams performed better than the conventional beam. ABAQUS software was used for numerical investigation. For the load deflection characteristics, a good agreement was found between the experimental and numerical results. Based on the experimental analysis carried out, a prediction model to determine the ultimate load-carrying capacity of TRC beams was created using an Artificial Neural Network (ANN).

Lignocellulose sustainable composites from agro-waste Asparagus bean stem fiber for polymer casting applications: Effect of fiber treatment

In the past decades, lignocellulose fibers have attracted significant attention due to their low density, environmental friendliness, and biodegradability. Consequently, researchers are intensifying their efforts to explore the potential of lignocellulosic fibers as sustainable alternatives to synthetic fibers in polymer composites. Among various natural fibers identified as potential reinforcements, agro-waste from the Asparagus Bean stem (ABS) which has been discarded as landfill after harvest has emerged as a promising source of lignocellulose fibers for promoting sustainability. This study investigates the reinforcement suitability of ABSF in polymer matrices. A water-retting process was used for extraction, followed by treatment with a 5 % alkali solution. Cellulose content was enhanced to 65 wt%, and fiber density increased to 1.13 g/cm3 after chemical treatment. Thermogravimetric analysis indicated improved thermal stability of the treated fibers up to 247 °C. Morphological analysis showed increased surface roughness and impurity removal. To evaluate the reinforcing effect of the chemical treatment, epoxy composites with 10 wt% reinforcement were developed. The mechanical properties of these composites improved significantly, with more than 1.1 times when used alkali-treated ABSF as reinforcement. Flexural properties were substantially enhanced, with flexural strength increasing from 90.53 MPa to 122.71 MPa and flexural modulus from 2.41 GPa to 2.95 GPa due to better fiber-matrix interaction and removal of weak, amorphous constituents. The primary objective of this study is to demonstrate that ABSF is a viable alternative raw material for composite reinforcement, suitable for developing lightweight structural applications.

Synergetic control of multi‐level interface structure of basalt fibers by plasma and chemical functionalization to enhance the mechanical, thermal and interfacial performances of PBZ composites

AbstractThe composites of polybenzoxazine (PBZ) containing functionalized plasma treatment basalt fibers (fP‐BFs) were fabricated through in‐situ polymerization‐mixing technique. fP‐BFs is an effective reinforcement material that can improve the mechanical, thermal, and interfacial properties of composites. Surface activation of fP‐BFs can be enhanced through plasma modification, which improves the interaction between fP‐BFs and 3‐aminopropyltriethoxysilane. A systematic study on fP‐BFs/PBZ composite showed that a processing power of 300 W, a processing time of 5 min, and a fiber content of 9% can achieve good comprehensive mechanical properties. Thermogravimetric analysis results showed that fP‐BFs‐7/PBZ has the highest thermal stability, and its carbon residue rate, decomposition temperature and thermal decomposition activation energy are 36.80%, 452.2 °C and 133.56 kJ/mol, respectively. The dynamic mechanical analysis experiment showed that the addition of fP‐BFs improved the Tg of the composites. Among them, fP‐BFs‐5/PBZ showed the highest Tg, reaching 233.2 °C.Highlights Plasma treatment produced multi‐level structure of basalt fibers (fP‐BFs). Polybenzoxazine (PBZ)/fP‐BFs composites showed excellent performance. Interfacial bonding mechanism between fP‐BFs and PBZ was elucidated. Interfacial interactions between BFs and PBZ contributed to property enhancement. This work provided a green fabrication strategy of PBZ composites.

Development of sustainable and high-performance polymer composite rebar using vegetable waste biochar and areca fiber as reinforcement materials for green construction

Development of sustainable and high-performance polymer composite rebar using vegetable waste biochar and areca fiber as reinforcement materials for green construction

Synthesis and characteristics of natural fiber reinforced nano hybrid composite – an experimental study

Abstract Recently, research on natural hybrid composites has occupied a significant role in the materials science sector. Due to the low density, high specific strength, dimensional stability, and biodegradability, natural fiber composite has become a predominant research area. The present study deals with the fabrication of a jute–banana fiber hybrid composite using the hand layup method with compression molding. A fixed concentration of 5 % carbon nanotubes (CNT) is included over the fiber surfaces as an additional reinforcement material to improve their thermal and electrical conduction properties. The prepared composite material is subjected to different fiber loading (0, 10, 20, and 30 wt.%) with jute and banana weight ratios of 1:1, 1:3, and 3:1. The investigation is conducted for testing the physical, mechanical, and thermal properties of the prepared composites along with morphological studies. Final results revealed a maximum longitudinal tensile strength of 68.8 MPa, 67.0 MPa, and 86.7 MPa and the maximum transverse tensile strength of 41.2 MPa, 40.5 MPa, and 48.0 MPa at 30 wt.% with respective fiber ratio of 1:1, 1:3, and 3:1. The maximum longitudinal flexural strength of this hybrid composite is noticed as 94 MPa, 90 MPa, and 103 MPa for the weight ratio of 1:1, 1:3, and 3:1. Higher impact energy is obtained for the composition ratio of 1:3 (JBC 1:3) which has more banana fiber than the other two. A new attempt at adding carbon nanotubes has improved their thermal conductivity compared to regular composites of jute–banana.

Shear performance of FRP panel-reinforced rc columns attached using corner angles and bolts without epoxy resin

As the frequency of earthquakes has risen globally, the importance of seismic design in building construction has intensified. Fiber-reinforced polymers (FRP) are increasingly utilized as seismic reinforcement materials for reinforced concrete (RC) columns because of their lighter weight and superior strength compared to concrete and steel. However, the epoxy resin commonly used for FRP reinforcement is susceptible to fire, as it exhibits a glass transition temperature below 100 °C, and its performance can vary depending on the skill of the applicator. A method was therefore proposed to involve the non-adhesive application of FRP panels using corner angles and angle connections, eliminating the need for epoxy resin. Experimental and analytical studies were conducted to assess the shear performance of FRP-reinforced RC columns without adhesive attachment. The findings revealed that the maximum shear force capacity increased by more than 1.5 times compared to traditional RC columns. By securing the corner angle and FRP panel with angle connection materials, the attachment effect can be maximized to the extent of the corner angle area, suggesting its potential for enhancing shear performance.

Effect of MWCNTs-OH on the mechanical properties of cement composites: From macro to micro perspective

This study is focused on elucidating the role and mechanism of hydroxyl-functionalized multi-walled carbon nanotubes (MWCNTs-OH) as a reinforcement material in cement-based composites. The dispersion of MWCNTs-OH within the cement composites was first assessed using Raman spectroscopy. Subsequently, SEM, FT-IR, TGA, XRD, and nano-indentation techniques were employed to investigate the structural transformation and phase changes occurring in the cement matrix upon incorporating MWCNTs-OH. The results reveal that MWCNTs-OH can significantly improve the macro-mechanical properties of cement composites by their capacity for pulling out, pore-filling, inducing multi-cracking, and promoting hydration. From a micro-perspective, observations of the micro-morphology demonstrate that MWCNTs-OH reinforces cement composites through crack-bridging and pull-out effects. Regarding the hydrated calcium silicate (C-S-H), the addition of MWCNTs-OH has a negligible impact on the ratio of low-density C-S-H (LD-CSH) to high-density C-S-H (HD-CSH). Moreover, the results obtained from FT-IR and XRD tests provide evidence that the bonding between MWCNTs-OH and the cement matrix is predominantly governed by physical interactions.

Multifunctional composite electrolytes for mechanically-robust and high energy density carbon fiber structural batteries

Mechanically robust electrolytes with high ionic conductivity play an essential role in carbon fiber (CF) structural batteries that simultaneously store energy and bear mechanical loads. However, multifunctional composite electrolytes are rarely developed, especially for air-stable and safe structural Zn-ion batteries. Herein, a composite electrolyte GF-SPE is designed and fabricated by integrating ionic conductive poly(ethylene glycol) diacrylate (PEGDA)-based solid-state polymer electrolyte (SPE) matrix and glass fiber fabric (GF) reinforcement, which simultaneously exhibits mechanical robustness and high ionic conductivity, facilitating homogeneous Zn electrodeposition without obvious side reaction, such as dendrite growth, corrosion et al. Therefore, the symmetric cells Zn//GF-SPE//Zn cell can cycle stably for more than 800 h at 1 mA cm−2. The carbon fiber structural battery fabricated with composite structural electrolyte GF-SPE delivers a high energy density of 19.35 Wh kg−1 based on the total mass of the whole device and cycling stability over 1,000 cycles in extreme environments. Furthermore, the high capacity of structural Zn-ions batteries can be maintained when they withstand flexural stress of over 120 MPa. The in-situ mechanical-electrochemical testing further confirms the priority of structural Zn-ion batteries.

Bond stress-slip models and behavior of externally bonded aluminum alloy (AA) plates to concrete surface

This paper aims to assess the feasibility of employing high strength aluminum alloys (AA) with a rough (R) surface as externally bonded reinforcement (EBR) material. A comprehensive experimental investigation was carried out to evaluate the bond strength and behavior through single shear tests. The variables considered were concrete strength and bonded length, while the remaining parameters were kept constant. The study measured the ultimate load, extension, and strain values, and subsequently calculated the bond stress and slip. It was observed that the ultimate load, bond stress, and failure modes exhibited variations depending on the concrete strength and bond length. For a concrete strength of 60 MPa and a bonded length of 80 % of the concrete prism length, the ultimate load and maximum bond stress increased by 54.0 % and 66.0 % respectively, compared to those with a concrete strength of 20 MPa and the same bonded length. Additionally, when comparing a bonded length of 80 % (200 mm) of the concrete prism length to a bonded length of 20 % (50 mm), the ultimate load and maximum bond stress increased by 20.0 % and 99.0 % respectively for a concrete strength of 60 MPa. The study also developed bond stress-slip models for the AA-concrete interface, as well as models for predicting the ultimate load based on concrete strength and bonded length. These models displayed high accuracy in their predictions. In conclusion, the results indicate that AA plates are effective and suitable as EBR materials for the reinforcement of RC members.

Alternatives for Enhancing Mechanical Properties of Recycled Rubber Seismic Isolators.

Base isolators, traditionally made from natural rubber reinforced with steel sheets (SERIs), mitigate energy during seismic events, but their use in developing countries has been limited due to high cost and weight. To make them more accessible, lighter, cost-effective reinforcement fibers have been utilized. Additionally, the increasing use of natural rubber has caused waste storage and disposal issues, contributing to environmental pollution and disease spread. Exploring recycled rubber matrices as alternatives, this study improves seismic isolators' mechanical properties through modified reinforcements and layer adhesion. Eight reinforcement materials and eight adhesives, which may be activated with or without heat application, are systematically evaluated. Employing the chosen reinforcements and adhesives, prototypes are tested mechanically to examine their vertical and horizontal performance through cyclic compression and cyclic shear testing. Two innovative devices using recycled rubber matrices were developed, one using a layering technique and another through a monolithic approach shaped with heat and pressure. Both integrate a fiberglass mesh reinforced with epoxy resin; one employs a heat-activated hybrid adhesive, while the other uses a cold bonding adhesive. These prototypes exhibit potential in advancing seismic isolation technology for low-rise buildings in developing countries, highlighting the viability of recycled materials in critical structural applications.

Evaluating concrete material models for blast analysis using 3D finite element analysis

Blast loads are extremely detrimental to structural elements of a building and can result in minor damage to complete failure of a building. Finite element analysis (FEA) is an effective tool to study the behavior of structural elements exposed to blast loading. The focus of this study was to evaluate the performance of three concrete material models available in LS-DYNA and compare the results to experimental results from blast loaded reinforced concrete (RC) panel supported on four sides (two-way bending). Concrete material models chosen for this study were Winfrith (MAT_84-85), Karagozian & Case (MAT_072R3), and Continuous Surface Cap Model (MAT_159). These are widely used in finite element modeling related to civil structures and can account for strain rate dependent properties. Each concrete material model was implemented with and without strain rate effects. The finite element model had concrete material as solid elements and steel reinforcement material as beam elements with simply supported boundary conditions. Results from two different blast loading methods are presented: (1) blast pulse load curve from experimental data (2) blast input by defining type, location, and amount of explosive in terms of TNT. The finite element models were evaluated by comparing fundamental period, peak displacement, and residual displacement to experimental results. In this study, the model using MAT_072R3 most closely matched experimental behavior in comparison to MAT_84-85 and MAT_159. Additional discussion is presented about: (1) single degree of freedom (SDOF) analysis, (2) comparison of numerical and experimental crack patterns, and (3) behavior of concrete material models accounting for compressive and tensile dynamic increase factors (DIFs).

Waste ramie fiber/EVA composites with wideband sound-absorbing performance with mixing and foaming process

Increasing noise pollution and ramie fibers waste resource problems need to be solved urgently. In order to resolve the problems, the porous sound-absorbing composites with high sound-absorbing performance were prepared by using waste ramie fibers as reinforcement materials, vinyl acetate copolymer (EVA) as matrix materials, azodicarbonamide(AC) as foaming agent, ZnO as auxiliary foaming agent, and dicumyl peroxide (DCP) as cross-linking agent, which were mixed in a two-stick mixer according to a certain ratio and then hot-pressing process. The process conditions were optimized using single factor analysis. Under the optimal process conditions, the sound-absorbing composites had a maximum sound absorption coefficient (SAC) of 0.72, an average SAC of 0.37, and a noise reduction coefficient (NRC) of 0.41. The sound absorption performance grade reached level III, and the sound absorption performance was excellent in the frequency range of 600 ∼ 6300 Hz. The introduction of foaming agents made the composites with more pores, and the average SAC of foamed composites increased by 346 %(compared with the unfoamed composites). Then, the sound-absorbing mechanism was analyzed. This study presents a novel approach to the recycling and reusing of the waste ramie fibers. It also provides a theoretical and experimental basis for the development of sound-absorbing composites with wider sound absorption band, larger (sound absorption coefficient) SAC and wider application, which is of great significance for sound absorption in the building fields.

Surgical Outcomes, Ocular Safety and Tolerability of Bio-Interventional Cyclodialysis with Allograft Scleral Reinforcement: Clinical Experience of More than 240 Cases.

Background: To report the surgical safety of reinforced bio-interventional cyclodialysis with scleral allograft reinforcement. Methods: This was a consecutive case series of 243 eyes with open-angle glaucoma who underwent a bio-scaffolded cyclodialysis (BSC) procedure for uveoscleral outflow enhancement using allogeneic bio-spacers to maintain patency of the internal filtration conduit. Results: 79% of the eyes underwent concomitant phacoemulsification cataract surgery prior to BSC intervention, while the remaining eyes underwent stand-alone BSC surgery. All patients had a postoperative surgical safety period of at least 30 days. There were no sight-threatening or serious ocular adverse events. There was one case of prolonged iritis beyond 30 days, which resolved with topical treatment. Two cases (0.8%) of intraoperative and five (2%) of postoperative non-sight-threatening hyphema were without clinical sequelae, which resolved with conservative management. There were 11 cases of IOP elevation and one case of numeric hypotony without maculopathy, which resolved within the study period. The rate of secondary surgical intervention for IOP control was low, and overall, IOP for the cohort improved in the postoperative period, with 78.6% of eyes achieving IOP ≤ 18 mmHg without an increase in medications. Conclusions: Allogeneic biotissue for cyclodialysis intervention demonstrates a biocompatible ocular profile as an implantable material for internal scleral reinforcement during uveoscleral outflow enhancement surgery.

Material extrusion fabrication of continuous metal wire-reinforced polymer–matrix composites

3D printing via material extrusion is capable of using polymeric materials for a large range of applications. They are generally used, however, for prototyping as opposed to creating functional parts due to their lower mechanical properties in comparison to other materials, such as metals or epoxies, and processing methods, such as compression molding or injection molding. Carbon fiber, glass fiber, and kevlar have been used as reinforcement materials with very positive results in terms of creating functional parts. However, little focus has been placed on metallic wire reinforcement. In this investigation, a novel strategy to manufacture continuous metallic wire-reinforced polymer–matrix composites with increased mechanical properties by material extrusion is presented. A customized multimaterial 3D printer was built and used to fabricate coupons of unidirectionally reinforced Al wire/PLA matrix composites with either 15% or 25% wire volume fraction. The microstructure of the composites was analyzed to understand the formation of porosity during processing. These results also showed the potential of the manufacturing technique to precisely control the wire location and orientation. Incorporation of a volume fraction 25% of Al wires led to a 600% increase in elastic modulus and a 63% increase in tensile strength compared to pure PLA. These results indicate an efficient load transfer between the polymer matrix and the incorporated wires, despite exhibiting a relatively low interface strength. Overall, the novel strategy opens the possibility to manufacture high volume fraction composite laminates of thermoplastic polymers reinforced with metallic wires by material extrusion.

Mechanical properties of Kenaf textile-reinforced concrete

This study aims to evaluate the mechanical characteristics of Kenaf Textile Reinforced Concrete (KTRC) specimens to address the growing interest in sustainable construction materials. The research investigated various parameters, including modulus of rupture, total toughness, and toughness indices, while also exploring the impact of polypropylene (PP) chopped – fibre, the number of textile layers (3 and 5), and their arrangement (symmetric and asymmetric) on the mechanical properties of KTRC. The results demonstrated that Kenaf meshes could be used as natural and cost-effective reinforcement in TRC. Increasing the number of reinforcement layers significantly enhanced total energy absorption, and the combination of chopped fibre and Kenaf meshes contributed to maintaining the crack strength of the composites. The results of the three-layer specimens demonstrate that as the percentage of PP fibres increases from 0% to 0.5% and 1%, there is a noticeable increase in toughness compared to the reference samples. Specifically, the toughness of the samples increased by 978.6, 1381.1, and 1520.7, respectively. Eventually, the behavior of the specimens until the moment of complete rupture mostly depends on the number of layers in the thickness of the specimen.

Damage analysis caused by 60Co ions in functionally graded materials

Functionally graded composite/hybrid materials (FGCM/FGHCM) were produced by adding B4C, TiO2, and B4C+TiO2 ceramic materials at various ratios (0–50%) into the AA6082 matrix. The analysis of the damage caused by 60Co ions' (1.173–1.1332 MeV) on the material was examined using the SRIM/TRIM Monte Carlo simulation software. In the simulation, the following data regarding the atoms of the target materials were obtained: ion distribution, target ionization, total displacements, surface binding energy, lattice binding energy, and displacement energy. Among the studied four materials, the one with the highest ion range value was found to be AA6082 with 8550 Å. TiO2 was found to be the reinforcement material that reduced the ion range the most in the material. Due to its high binding energy, B4C reinforced AA6082+(0–50%) B4C FGCM was found to have the least vacancy with 4782/ion.

Degradation kinetics of PLA/hemp biocomposites: Tradeoff between nucleating action and pro-hydrolytic effect of natural fibers

Natural fibers are not only a sustainable alternative to synthetic reinforcement materials, but can also be used to produce truly sustainable biocomposites with fast degradation kinetics. Indeed, due to their hygroscopicity, lignocellulosic fibers allow water and/or degrading organisms from the external environment to penetrate inside the host matrix and trigger its hydrolysis. The latter is the rate-limiting step for the degradation of bio-polyesters, which exhibit unacceptably slow degradation kinetics at ambient temperature and humidity. However, fibers also promote crystallization of the host matrix and thus slow down its degradation kinetics. To better understand and potentially control the degradation kinetics of biocomposites, here we investigate the ability of hemp shives, a hygroscopic by-product of hemp fiber production, to accelerate the hydrolysis of poly (lactic acid) (PLA). The degradation kinetics and degree of crystallinity of PLA are monitored in water and mature compost as a function of fiber content, which was varied across the percolation threshold (Φc) to study the effect of fiber interconnectivity. Above Φc, the fibers accelerate PLA hydrolysis in water despite their nucleating effect. Conversely, in compost the shielding effect of fiber-induced crystallinity prevails, and the fibers eventually slow down the degradation kinetics of PLA.

Non-linear critical speed in high-speed ballasted railways with ground reinforcement

When constructing or upgrading high-speed railway lines on soft soils, reinforcing the soil foundation becomes crucial. This not only involves small track displacements but also increases the critical speed, thereby ensuring safe and efficient regular operations. Nevertheless, existing studies on the critical speed phenomenon in high-speed railway tracks with ground reinforcement are limited, and they all assume a linear elastic behavior for both the soils and reinforcement materials. The main novelty of this research is that it presents the first study on the effect of non-linear soil behavior on the critical speed of high-speed railway ballasted tracks with soil reinforcement and introduces a novel simplified approach based on an equivalent homogeneous soil layer by replacing the soil layer containing inclusions/columns. To accomplish this, a full 3D non-linear numerical model was developed and experimentally validated. The findings from a detailed and comprehensive parametric analysis demonstrate a significant influence of non-linear behavior on the critical speed, resulting in reductions of up to 30% compared to the linear elastic scenario. Furthermore, it is found that the soil-reinforcement stiffness contrast, the area replacement ratio, and the plasticity index of the soil foundation play a crucial role in the critical speed. Other aspects such as the installation pattern and the thickness of soft soil have a relatively lower impact on the critical speed.

Non-conformance aspects of moulded composite materials and “corresponding” simulation models with 3D textile reinforcement

Composite materials with 3-dimensional (3D) reinforcement were manufactured and corresponding simulation models were created in parallel. The used simulation approach has earlier been shown to produce close to authentic geometrical representation of the yarn architecture in 3D reinforcement. It is shown that although the as-woven reinforcement pattern can be modelled quite reliably, significant distortion from the nominal fibre arrangement might take place later in manufacturing, primarily related to compression during moulding. Such effects have earlier received significant attention for composites with 2-dimensional reinforcement but not as much for their 3D counterparts. The yarns in the real and the simulated materials are studied and compared, and some of the discrepancies and the mechanisms behind are discussed. The distortions are partly attributed to the relatively sparse weave that allows yarns oriented in the through-thickness direction, in particular, to deviate from their original positions.