Glass Fiber Research Articles

Investigation of the hybridization effect of glass fibers and diboron trioxide epoxy composites on some mechanical properties

Abstract The mechanical behavior was most important in industry, and one way to enhance the mechanical properties involves preparing hybridized epoxy composites. Different additives (glass fiber and B2O3 powder) have various concentrations (0, 5, 10, 20, and 30% wt.) for B2O3, while glass fibers have a fixed concentration (10% wt.). Hybrid epoxy composites have been manufactured by the hand lay-up method. Mechanical investigations involve tensile tests, impact tests, and hardness tests. According to the results, increasing the boric oxide concentration increased the examined mechanical characteristics (strength, stiffness, strain-at-break, hardness, toughness, and fracture toughness). Hybrid materials with a weight percentage of 20% B2O3 and 10% glass fibers had the best mechanical properties. These findings are most likely due to the reinforcing elements being evenly distributed and scattered, which enhances mechanical characteristics. A slight decrease in the mechanical properties of the composite at 30% weight percentage of B2O3 and 10% glass fibers, which is related to the presence of voids and agglomerations, is thought to be a sign that the material has reached the saturation level of reinforcement and that the mechanical properties of the structure will collapse if more reinforcing materials are added.

Constructing ZSM-5 loaded with 2-mercaptobenzimidazole on glass fiber for enhancing the anti-corrosion and erosion resistance properties of epoxy coating

Glass fiber reinforced polymer coatings (GFRPC) are used to protect steel structures in harsh Marine environments due to high mechanical strength and chemical stability. The composite coating not only suffers from impact damage by seawater and sediment but also experiences corrosion damage in the splash zone. However, the GF has weak interfacial adhesion with polymer resins due to the chemical inertia and smooth surface, which limits the service lifespan of GFPRC. Hence, ZSM-5 zeolites were in situ prepared on the surface of glass fibers by hydrothermal synthesis, and 2-mercaptobenzimidazole (MBI) was further adsorbed to obtain difunctional hybrid glass fibers (ZGFM) to enhance the interfacial adhesion strength of glass fiber/resin and also the erosion resistance and anti-corrosion ability of composite coatings. Compared to GF/EP, the interfacial shear strength of ZGFM/EP was increased by 104.39 %. After immersion under an alternating hydrostatic pressure of 20 MPa for 12 days, the impedance value of the ZGFM/EP composite coating remained at 6.40 × 109 Ω•cm2, demonstrating outstanding deep-sea anti-corrosion performance. Following the erosion test, the ZGFM/EP exhibited a reduction in mass loss and volume loss by 10.65 % and 12.55 %, respectively, in comparison to the pure EP coating. The excellent interfacial strength between ZGFM and EP ensured effective stress transfer, which prevented crack propagation, thus enhancing the mechanical properties and erosion resistance of the composite coating. Meanwhile, electrochemical experiment proves glass fiber with MBI loaded obviously inhibited the corrosion reaction.

Novel Retrofitting Technique for Beam by External Wrapped with Glass Fiber and Internally Embedded Damper System for Sustainable Construction

Abstract Reinforced concrete structures are often exposed to extreme loads, such as those from sudden and accidental impacts. This has led to an increasing interest in strengthening these structures, improving their fatigue performance, and extending their service life, particularly for components like beams. A more sustainable approach to maintaining their functionality involves strengthening and repairing damaged components. Therefore, glass fiber polymers are ideal reinforcements for retrofitting due to their high tensile strength and low cost compared to other polymer substitutes This paper presents the performance of plain concrete beams reinforced externally with glass fiber sheets (GFS) and dampers embedded internally. A unique methodology has been adopted to improve the adhesion between the fiber glass sheets (GFS) and the concrete surface. Two adhesive components utilized are epoxy resin (ER) and epoxy hardener (EH), mixed in a ratio of 9:1. Internally embedded dampers are devices used to resist lateral forces on structures, particularly during impact or sudden loading. The adopted damper technique involves incorporating chopped Glass Fiber during the casting process of the dampers. These dampers are subsequently embedded into beams at point of failure. After the curing of 28 days, all the cast beam compositions undergo flexural test, and dampers are tested for compressive strength. After the dampers have undergone compression testing, a microstructural analysis is conducted using SEM (Scanning Electron Microscope). For further details on stress formation in beams, finite element analysis of Ansys is used to model beams for all beam compositions. Also, sustainability goals are addressed by reducing cement usage in construction by introducing retrofitting in older buildings and using this system to improve the design of newer buildings by reducing overall section sizes

Effect of Vinyl Acetate, Glass Fibers Contents, and Buffer Space on EVA's Mechanical Property and Shock Absorption Ability.

The aim of the study was to evaluate the mechanical properties and impact absorption capacity of prototype materials comprising ethylene vinyl acetate (EVA) of different hardness reinforced using different amounts of glass fibers (GFs), considering a buffer space. Six prototype materials were made by adding E-GFs (5 and 10 wt%) to EVA with vinyl acetate (VA) contents of 9.4 wt% ("hard" or HA) and 27.5 wt% ("soft" or SO). Durometer hardness and tensile strength tests were performed to evaluate the mechanical properties of the materials. Moreover, an impact test was conducted using a customized pendulum impact tester to assess the impact absorption capacity (with or without a buffer space) of the specimens. The mechanical properties of the prototypes, namely, durometer hardness, Young's modulus, and tensile strength, were significantly higher in the HA group than in the SO group, regardless of the presence or added amount of GFs. The addition of GFs, particularly in a large amount (10 wt%), significantly increased these values. In terms of the impact absorption capacity, the original hardness of the EVA material, that is, its VA content, had a more substantial effect than the presence or absence of GFs and the added amount of GFs. Interestingly, the HA specimens with the buffer space exhibited significantly higher impact absorption capacities than the SO specimens. Meanwhile, the SO specimens without the buffer space exhibited significantly higher impact absorption capacities than the HA specimens. Moreover, regardless of the sample material and impact distance, the buffer space significantly improved impact absorption. In particular, with the buffer space, the impact absorption capacity increased with the added amount of GFs. The basic mechanical properties, including durometer hardness, Young's modulus, and tensile strength, of the EVA prototype were significantly increased by reducing the amount of VA regardless of the presence or added amount of GFs. Adding GFs, particularly in large amounts, significantly increased the values of aforementioned mechanical properties. Impact absorption was significantly affected by the hardness of the original EVA material and enhanced by the addition of the buffer space. The HA specimen had a high shock absorption capacity with the buffer space, and the SO specimen had a high shock absorption capacity without the buffer space. With the buffer space, impact absorption improved with the amount of added GFs.

Fibre waviness reduction in thermoplastic pultrusion by using DREF yarns

Non-reactive thermoplastic pultrusion impregnation issues are mitigated by using hybrid input materials. Co-wound (CW) and commingled yarns are an assembly of continuous polymer and reinforcement fibres. Continuous thermoplastic fibres have shown to induce waviness in the reinforcement fibres during pultrusion due to their shrinkage at high temperature. DREF yarns are composed of a core of continuous reinforcement fibres onto which discontinuous polymer fibres are applied using the friction spinning process. This study, based on the application of 3N and 0N tension on CW and DREF yarns, aimed to highlight the contribution of discontinuous polymer fibres on reducing reinforcement waviness in pultruded rods. CW yarns’ reaction to heating showed continuous polyethylene terephthalate (PET) fibres shrinkage resulting in wavy glass fibres (GF). Conversely, the GF in DREF yarns remained straight. Pultrusion experiments with yarn tension of 3N were done to alleviate the GF waviness. However, the porosity was rather high at 4.2% for CW rods and 2.3% for DREF rods. Pultrusion experiments without tension showed lower porosity of level of 2.9% for CW yarns and as low as 1.1% for DREF yarns. However, CT-scan image indicated GF waviness in CW rods. GF in DREF rods remained straight. The in-plane shear strength reached 119 MPa. Thermoplastic pultrusion using DREF yarns resulted in composites without reinforcement fibre waviness, lower porosity level and superior shear strength.

Fiber Alignment's Effect on the Properties of Hybrid Glass/Flax Fiber‐Reinforced Epoxy Composite Laminates

ABSTRACTIn this study, glass fiber and flax fiber reinforced with epoxy and ZnO nanofiller were used to create composites utilizing the hand layup method. The purpose of this study is to develop a novel hybrid polymer‐matrix composite that can be employed in various application areas such as aerospace, sports, medical equipment, railways, etc. The fabricated composite was made with epoxy as a matrix material reinforced with nano‐ZnO, glass fiber, and flax fiber. Six fiber layers with varying fiber orientations were inserted into the matrix in a specific stacking order. The results show the maximum tensile, flexural, impact, and ILSS as the values of 264.74 MPa, 492.12 MPa, 595.72 J/m, and 50.05, respectively. Along with the mechanical properties, Physical characterization such as density, void content, thickness swelling, moisture content, and water absorption tests were conducted. FE‐SEM test was conducted to check the uniformity of nanoparticles in the matrix material and the breakdown of fibers.

Experimental Research on the effect of Structural glass fibre in the Tensile Strength Ratio and Retained Stability of VG40 Bituminous mix

Abstract The tensile characteristics of bituminous mix are a major concern for pavement engineers due to the cracking issues. The cracking infuses moisture into the pavement layers which affects the stability of the pavement. The measures to reduce the fatigue tensile cracks have to be taken in the design stage rather than the maintenance stage. The tensile properties and the stability are evaluated using the indirect tensile strength and retained stability tests. While fibers improve the tensile properties of pavement, the S-glass fiber possessing superior mechanical strength has been found to have less scope in past studies. Thus, the current study primarily focuses on examining how Structural Glass fiber reinforced in VG-40 bituminous concrete mix improves the tensile and moisture susceptibility characteristics. The Marshall technique of bituminous mix design was used to establish the ideal bitumen content for casting the bituminous concrete specimens. At the ideal bitumen content, the attributes of bituminous mixes were established. Tensile strength ratio (TSR), Indirect Tensile Strength (ITS), and Retained Stability of modified bituminous concrete mix were assessed. It is observed that the bituminous mix prepared by adding the S-Glass fibre of 8mm length by 3% weight of aggregates exhibited higher ITS, TSR, and Retained stability. The bituminous mix with glass fiber incorporated had higher retained stability (95.36%) than the conventional mix (91.17%). The results of the Indirect Tensile Strength Test revealed that the mix with glass fiber added had a higher Tensile Strength Ratio (92%) compared to the mix with conventional fiber (87%). A noteworthy outcome that creates opportunities for more study in this field is the rise of 5% TSR and 4.66% maintained the stability of the glass fiber-modified bituminous mix.

Design and test of a module of a breathable Electrostatic Shield for the MITICA 1 MV negative ion Beam Source

The electrical insulation of the MITICA Beam Source at 1 MV is a challenging issue, which has not been fully addressed so far on the basis of experimental results and of theoretical models available in literature. Being MITICA the full-size prototype of the Heating Neutral Beam Injector for the ITER fusion experiment, its electrical insulation is constituted just by vacuum gaps and alumina insulators, since other insulating materials such as SF6 gas or fibreglass-reinforced plastic (FRP) would be quickly degraded by the expected neutron flux produced by fusion reaction. Extrapolations based on HV tests on reduced-scale models have recently indicated the risk of electrical breakdowns in the vacuum gap between electrodes nominally operating at -1 MV and the vacuum vessel (at ground potential). The risk of electrical breakdown can be mitigated by introducing an intermediate Electrostatic Shield (ES), which essentially is an equipotential (metallic) enclosure surrounding the HV electrode, so as to divide the vacuum gap in two independent insulating gaps of 400 kV and 600 kV respectively. However, for optimal negative ion production, the ion source shall operate in H2 or D2 at a pressure of ∼ 0.3 Pa and unavoidably produces a flow of gas leaking out in the surrounding vacuum. Thus, the presence of an intermediate shield can substantially increase the background gas pressure in the vacuum gaps, and, due to the large gap length (0.6 m), exacerbate the risk of breakdown when the pressure approaches the conditions of Paschen-type discharges. In addition to this, RF-induced breakdowns were found on the rear side of the ion source during the operation of the prototype source SPIDER, which were somewhat correlated to a relatively high hydrogen pressure in that area. For these reasons, a structure capable of constituting a full equipotential barrier all around the BS and, at the same time, having sufficient gas conductivity (breathability) to allow efficient pumping of background gas, has been designed. In the first part of the paper, the requirements and design optimization of a breathable module of the intermediate ES are described. Then, an experimental campaign for the validation of the electrode implementation the test configurations and the experimental procedure is discussed.

Influence of Sustainable Materials and Glass Fibers on Properties of Lightweight Perlite Concrete

Influence of Sustainable Materials and Glass Fibers on Properties of Lightweight Perlite Concrete

Experimental study of natural fiber Jute reinforced by metal wires and its using as patch on semi-elliptical defected of the API X52 pipelines corroded according to ratio a/t

The aim of this study is to evaluate the efficiency of a hybrid patch of Jute with/without Glass fiber reinforced with Steel wire for repairing defective API X52 pipeline. Five specimens were tested using Jute fiber, Glass fiber and Steel wire to enhance the mechanical properties according to ASTM 3039 and D790 standards. The experimental results showed that the effects of hybrid materials (synthetic and natural) for repairing API X52 pipeline defect depend on the nature of the patch and the properties of the adhesive (polyester resin) by increasing the tensile strength and bending load. In the first step, specimen S5 was selected due to its distinctive mechanical properties, which revealed maximum values of tensile strength, toughness and bending load respectively 47.42014 MPa, 2357.42 kJ/m3 and 488.3 N. In the second step, the selected sample (S5) was used as a patch to repair API X52 pipeline, which has semi-elliptical defects where the bending load is 31.4246 kN. According to the obtained results, the patch efficiency is 103% for defects with a/t < 0.3, which can be, restored 100% of the mechanical properties. There fore, repairing API X52 pipeline using hybrid patch (Jute reinforced with Steel wires) with shallower defects can be a successful technique.

Evaluation of the relationship between the number of surface and internal defects and stress in inorganic fibers

To better utilize the mechanical properties of ceramics fibers, it is very important to understand the ceramics fiber distribution. The strength distribution of ceramics fibers is strongly dependent on defects that are present in or on the surface of the material. When the defects are large, the location of the defects is identified by observing the fracture surface, and the strength of the material is analyzed based on the results. However, in recent years, defects in high-strength ceramics such as carbon fibers have become so small that it is very difficult to analyze the location of such defects. To overcome this problem, a defect analysis method has been developed based on the observation that the tensile strength of fibers decreases when tensile tests are performed in liquids. In this study, a new model that considers both surface and internal defects of fibers was introduced into this analysis method, and the newly developed method was applied to quantitatively separate surface and internal defects of polyacrylonitrile-based fibers, pitch-based carbon fibers, SiC fibers, and glass fibers in air, water, and organic solvents. The number of internal and external defects was expressed as a function of stress. Based on the number of defects, the influence of surface defects was significant for glass fibers, polyacrylonitrile-based carbon fibers, silicon carbide fibers, and pitch-based carbon fibers, in that order. This method is useful for analyses of surface defects in fibers.

Behavior of laminated timber portal frames reinforced with fiber-reinforced plastic laminates under cyclic lateral load

This study aimed to enhance the structural performance of a drift joint with a slotted-in steel plate using laminated timber made from small- to medium-diameter timbers. An analysis was conducted to compare and evaluate the structural performance and seismic behavior of laminated timber portal frames reinforced with fiber-reinforced plastic (FRP) laminates, such as glass fiber cloth (GFC), glass fiber reinforced plastic sheet (GS), and carbon-reinforced plastic sheet (CS), under low amplitude cyclic lateral loads, in comparison to unreinforced portal frames (UR). The reinforced portal frame, strengthened by FRP laminates, exhibited higher resistance to strength and stiffness strength degradation due to cyclic loading-induced degradation at low drift angles compared to the unreinforced frame affected by heterogeneous timber. The reinforced portal frame, particularly the GFC and GS, exhibited energy dissipation rates 32% and 17% higher than UR, respectively, making them the most effective in vibration damping. FRP laminates mitigated fiber direction cleavage from drift pin holes. The average maximum moment and average yield moment of the reinforced portal frame increased by 18% and 21%, respectively, due to the alleviation of joint failure. Finally, CS significantly affected the maximum moment, while GFC significantly influenced the yield moment.

Synthesis and characterization of new continuous phosphate glass fibers intended for structural engineering applications: Structure/property relationships

Nowadays, phosphate glass fibers (PGF) are considered quite competitive respective to conventional glass fibers. This work focus on the development of PGF fibers intended for structural engineering applications such as composite reinforcement for building and automotive fields. For this purpose, two series of phosphate glasses based on 52P2O5-24CaO-13MgO-(11-(X+Y+Z)) K2O-XAL2O3-YF2O3-ZTiO2; (X=1; 3; 5, Y=0; 5, Z=0; 1 mol %) were processed and transformed into phosphate glass fibers by melt spinning. The resulting fibers were characterized. XRD analysis confirmed the non-crystalline nature of phosphate glasses. In addition, the substitution of K2O by Al2O3 and by the combination of Al2O3, Fe2O3 and TiO2 in the composition of phosphate glass could lead to a significant increase in fiber density from 2,16 g/cm3 to 2,80 g/cm3. The stability of the produced phosphate glass fibers was examined using two methods: weight loss at 37°C and dissolution kinetics under different pH levels (4, 7, and 12). The results showed that the chemical resistance of the PGF fibers was improved with up to 99% increase respective to the original formulation. In addition, the mechanical properties of the spinnable phosphate glass manufactured by replacing K2O oxide by Al2O3 oxide were improved, such a substitution led to a maximum tensile strength and modulus of 2668 MPa and 140 GPa, respectively. Therefore, the tensile proprieties were improved by 75% compared to the original formulation. This comparative study between phosphate glass fibers (PGF) and traditional fibers highlight similar tensile strength but combined to notable enhancements in chemical stability through cation addition, expanding their potential use in composite and biomedical materials. Finally, a correlation analysis of mechanical performances was carried out. It was observed that the results obtained using the statistical methods were consistent with the experimental data.

An experimental analysis of mechanical properties for a dissimilar pattern structure in the 3-D printing of a PLA5F filament using the Taguchi method

Abstract Many automobile components and machine parts can be fabricated using the Fused Deposition Modeling (FDM) process with materials such as Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), Polyethylene Terephthalate Glycol (PET-G), and polymeric composite materials (e.g., PLA with carbon fiber, PLA with glass fiber). In this study, a new polymeric composite material was fabricated using Polylactic Acid and natural flax fiber was analysed for tensile stress, elongation, and impact load resistance using Taguchi Analysis. This analysis optimized the printing parameters, including layer thickness (0.15, 0.25, 0.35 mm), nozzle movement speed (80, 100, 120 mm s−1), filling structure (Lines - a, Triangular - b, and Octet - c), and occupancy rate (20%, 40%, 60%). The American Society for Testing and Materials (ASTM) standards for tensile strength (ASTM D638) and impact strength (ASTM D256) were used for evaluation. As a result, layer thickness was found to be the most effective variable for improving tensile characteristics, compared to extruder temperature, occupancy rate, or filling structure pattern. Mechanical properties including a layer thickness of 0.25 mm, an occupancy ratio of 20% for the bottom of the 2nd layer and 40% for the top of the 4th layer, triangular and octet filling structures, a nozzle speed of 100 mm s−1, and an extruder temperature of 200 °C are considered the most appropriate parameters for producing automotive parts in Three Dimensional (3D) Printing. Due to its tensile properties and impact strength resistance, these settings can be utilized in potential application in a wide variety of machine parts and vehicle components.

Assessment of recycling and repair methods for discontinuous glass fiber reinforced vitrimer composites with reclaimed parts

In the context of fiber-reinforced polymer composites, the pursuit of sustainability is of paramount importance to promote environmentally responsible practices. Vitrimer materials have recently gained significant attention for their potential to enable repair and recycling, rendering them an attractive choice for manufacturing eco-friendly composites while maintaining mechanical strength akin to a thermoset resin like epoxy. This study specifically focuses on glass fibers, and delves into the examination of mechanical properties using both chemical and mechanical recycling methods for quasi-isotropic, randomly dispersed discontinuous glass fiber-reinforced vitrimer composites. It places specific emphasis on the optimization of factors to promote sustainable production. The findings indicate that chemical recycling methods are remarkably effective, resulting in the almost complete restoration of mechanical properties when appropriately selected process parameters are applied. Additionally, this study investigates diverse repair techniques, with the overlap repair method exhibiting the highest degree of recovery. These findings underscore the remarkable potential of glass fiber reinforced vitrimer composites, characterized by their high mechanical properties, for applications in various industries, particularly in structural contexts. Overall, this study highlights the significant reduction in composite waste achievable through recycling and repair strategies, aligning with the broader goal of advancing sustainability within the domain of engineering and manufacturing.

Effects of aggregates and fibers on the strength and permeability of concrete exposed to low vacuum environment

The performance and regulation of concrete in low vacuum environments are receiving increasing attention. This study investigates the effects of aggregates and fibers on the strength and permeability of concrete in a low vacuum environment, using varying gradients of sand ratios (37.5 %, 40 %, and 42 %) and aggregate-to-binder ratios (3.27, 3.92, and 4.14). Three types of non-metallic fibers are utilized: polyethylene (PE), polyvinyl alcohol (PVA), and glass fibers. Evaluations focus on concrete strength, mass loss, gas permeability, capillary water absorption, and porosity. Results indicate that higher sand and aggregate-to-binder ratios enhance both flexural and compressive strength. Fiber incorporation improves flexural and compressive toughness, with PE fibers showing the most significant toughening effect. The low vacuum environment increases the strength of the concrete but reduces its axial compression toughness ratio and increases brittleness, while fiber incorporation helps improve the compression toughness of the concrete. Higher sand and aggregate-to-binder ratios reduce mass loss and accelerate drying equilibrium, while fibers increase mass loss and prolong drying equilibrium, with PVA fibers causing greater mass loss. The pattern of concrete mass loss can be explained by the tortuosity of the moisture diffusion path. Additionally, low vacuum significantly increases the gas permeability of concrete. Enhancing the sand and aggregate-to-binder ratios reduces permeability both before and after low vacuum treatment. Although fibers increase the gas permeability, they help mitigate this increase under low vacuum condition. Capillary water absorption tests reveal that concrete under low vacuum condition has a significantly higher water absorption rate compared to air-drying condition. Increasing sand and aggregate-to-binder ratios reduces water absorption and capillary water content, whereas fibers have the opposite effect. Porosity tests show that moisture migration in a low vacuum environment is mainly related to permeable porosity, while total porosity is more closely related to compressive strength.

A seaweed-inspired separator for high performance Zn metal batteries: Boosting kinetics and confining side-reactions

Uncontrolled dendrite growth, sluggish reaction kinetics, and drastic side reactions on the anode-electrolyte interface are the main obstacles that restrict the application prospect of aqueous zinc-ion batteries. Traditional glass fiber (GF) separator with chemical inertness is almost ineffective in restricting these challenges. Herein, inspired by the ionic enrichment behavior of seaweed plants, a facile biomass species, anionic sodium alginate (SA), is purposely decorated on the commercial GF separator to tackle these issues towards Zn anode. Benefiting from the abundant zincophilic functional groups and superior mechanical strength properties, the as-obtained SA@GF separator could act as ion pump to boost the Zn2+ transference number (0.68), reduce the de-solvation energy barrier of hydrated Zn2+, and eliminate the undesired concentration polarization effect, which are verified by experimental tests, theoretical calculations, and finite element simulation, respectively. Based on these efficient modulation mechanisms, the SA@GF separator can synchronously achieve well-aligned Zn deposition and the suppression of parasitic side-reactions. Therefore, the Zn||Zn coin cell integrated with SA@GF separator could yield a prolonged calendar lifespan over 1230 h (1 mA cm−2 and 1 mAh cm−2), exhibiting favorable competitiveness with previously reported separator modification strategies. Impressively, the Zn-MnO2 full and pouch cell assembled with the SA@GF separator also delivered superior cycling stability and rate performance, further verifying its practical application effect. This work provides a new design philosophy to stabilize the Zn anode from the aspect of separator.

Assessing PET composite prosthetic solutions: A step towards inclusive healthcare

The demand for affordable prostheses is particularly high in Low Middle-Income Countries (LMICs). Currently, sockets are predominantly manufactured using monolithic thermoplastic polymers, which lack durability and strength, or consumptive thermoset resin reinforcing with expensive composite fillers like carbon, glass, or Kevlar fibers. However, there exist unmet and demanding needs among amputees for procuring low-cost, high-strength, and faster socket manufacturing methods. We evaluate a socket made from a novel manufacturing technique utilizing an affordable and sustainable composite material called commingled PET (polyethylene terephthalate) yarn, along with a reusable vacuum bag, to produce custom-made sockets in a purpose-built curing oven. Our innovative fabrication methodology enables the production of complex-shaped patient sockets in under 4 h. To evaluate the efficacy and performance of the PET sockets, we conducted trials with both unilateral and bilateral amputees over a six-month period, in collaboration with Bhagwan Mahaveer Viklang Sahayata Samiti (BMVSS) in India. Utilizing a 6-min walking test, we measured various gait parameters, including ground reaction forces and flexion angle, for both unilateral and bilateral amputees.The gait analysis conducted on amputees using our PET-based sockets demonstrated their ability to engage in daily activities without interruptions, reaffirming the functional efficacy of our approach. By combining self-reinforced PET with our novel fabrication technique, we offer a unique and accessible solution that benefits clinicians and patients alike. This study represents significant progress towards achieving affordable and personalized prostheses that cater to the needs of LMICs.

Waste Paint as Admixture for Glass Fiber–Reinforced Concrete Building Façades

Waste Paint as Admixture for Glass Fiber–Reinforced Concrete Building Façades

Crushing behavior of GFRP composite-reinforced PVC tubes: Experimental testing and numerical simulation

This paper introduces glass fiber reinforced polymer (GFRP)-reinforced Polyvinyl Chloride (PVC) tubes, both corrugated and non-corrugated, designed as energy absorber devices. The PVC tubes were externally and internally reinforced with GFRP composite oriented at ±45∘ and subjected to quasi-static axial compression tests. Results indicated that all reinforced tubes exhibited significantly higher load-bearing capacity, energy absorption capability, and crushing force efficiency compared to standard PVC tubes. Among the tested specimens, externally reinforced corrugated tubes demonstrated the highest specific energy absorption (SEA), surpassing other configurations by 17.5 kJ/kg when considering both pre- and post-crushing stages combined. However, these corrugated specimens showed instability during crushing, reflected in poor instantaneous crush force efficiency (iCFE) and the lowest iCFE among the composite tubes, with an average decrease of 43.59%.The corrugation notably increased the initial peak load, enhancing energy absorption in the pre-crushing stage without compromising the stability of crush force efficiency (CFE). Additionally, the combination of external and internal reinforcement significantly improved CFE and iCFE. Consequently, the PVC tubes combining corrugation with both external and internal reinforcement emerged as the best-performing configuration among all tested tubes.Furthermore, a 3D Finite Element (FE) model was developed using ABAQUS FE code with user-defined subroutines to simulate the crushing process. The constitutive models and numerical procedures employed are detailed. The FE model’s predictions showed a satisfactory correlation with experimental results, providing valuable insights into the crushing mechanics and offering a predictive tool for future design optimizations.