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Highlights The goal of this project was to recycle the waste forming in the production of a flexible, multilayer food packaging film. The film consists of five layers, two polyamides containing three different polymers, a polyethylene and two adhesive layers of maleated polyethylene. The type of the components and the exact composition are not disclosed because they represent proprietary information. The key to recycling is the selection of an appropriate strategy and target product. In this case, glass fiber reinforced PA composites were produced with an acceptable property profile. The properties of the recycled product are comparable to those of commercial composites available on the market. The crucial question was the selection of the glass fiber grade with the appropriate sizing. The selection was further complicated by the possible interaction of the functionalized polymer with the sizing of the fiber. The implementation of the solution is feasible technologically, the properties of the product are comparable to those available on the market, and its price is very advantageous. An engineering material can be produced from flexible multilayer packaging waste. The properties of the recycled product are comparable with those on the market. The selection of the glass fiber is crucial for mechanical properties. The solution is feasible technologically and the final price is competitive. [ABSTRACT FROM AUTHOR]

Highlights Interfacial adhesion properties are a key factor affecting the mechanical properties of composites. It is a very effective way to improve the low‐velocity impact resistance of composites by improving the interfacial adhesion properties. To improve the fiber/matrix interfacial adhesion properties of GF/PA6 (glass‐fiber/polyamide 6) composites, polyethyleneimine (PEI) and γ‐aminopropyltriethoxysilane (KH550) were used to co‐modify GF together in this study. The GF/PA6 composites with different modifications of glass‐fiber (GF) were also prepared using a hot pressing process, and then their flexural strength, shear strength, pendulum impact strength, and low‐speed impact resistance were investigated. Next, the relationship between fiber/matrix interfacial adhesion and mechanical properties of GF/PA6 composites was investigated by combining x‐ray photoelectron spectroscopy, scanning electron microscopy, and x‐ray computed tomography test results. The results showed that the GF‐reinforced PA6 matrix composite with co‐modified GF by PEI and KH550 (PEI‐KH550‐GF/PA6) had the best mechanical properties, with flexural, shear, and pendulum impact strengths of 660.7 MPa, 53.1 MPa, and 261.6 kJ/m2, respectively. Furthermore, the low‐velocity impact resistance was measured in terms of stress peak, absorbed energy, residual stress, and damage extension, and the results showed that the low‐speed impact resistance of PEI‐KH550‐GF/PA6 composites was also substantially improved that the Fmax increased from 7402.1 to 10414.0 N. Due to the poor surface activity of GF, in this experiment, GF was co‐modified with PEI and KH550 to achieve better fiber/matrix interfacial adhesion and successfully improve the mechanical properties of the composites; Different modification methods are used to improve the interfacial adhesion of the fiber/matrix interface. The relationship between the interface and impact strength of composites has been studied; The relationship between fiber/matrix interfacial adhesion and internal cracking in composites was investigated using X‐CT and SEM and other test results. [ABSTRACT FROM AUTHOR]

This paper presents the experimental results of six full‐scale one‐way reinforced concrete slabs with variations in reinforcement detailing. Test specimens consisted of two reference concrete slabs reinforced fully with glass fiber reinforced polymer (GFRP) rebars or with steel rebars and four hybrid‐reinforced slabs. The variables included the arrangement of rebars, mechanical reinforcing ratio, and the ratio of steel rebar area to GFRP rebar area. The fabricated specimens were subjected to four‐point loading until failure in the strong floor laboratory. Experimental results indicated that hybrid reinforcement enhances stiffness compared to FRP reinforcement and provides a higher load‐bearing capacity than steel reinforcement. Also, it was observed that FRP bars placed as tensile reinforcement, similar in number and diameter size to steel bars placed as compressive reinforcement in a slab result in the highest ultimate capacity. Moreover, it was observed that while the mechanical reinforcing ratio contributes to the overall behavior of hybrid‐reinforced concrete slabs, the ratio of steel rebar area to GFRP rebar area is not considerably effective. Furthermore, image processing was employed to determine the exact crack widths of specimens after failure. Finally, finite element modeling results showed good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Aqueous zinc–iodine batteries show immense potential in the electrochemical energy storage field due to their intrinsic safety and cost‐effectiveness. However, the rampant dendritic growth and continuous side reactions on the zinc anode, coupled with the shuttling phenomenon of polyiodides, severely affect their cyclic life. In response, this study utilizes a carboxyl‐functionalized metal‐organic framework UiO‐66‐(COOH)2 (UC) to modify commercial glass fiber (GF) to develop a novel ionic selective separator (UC/GF). This separator exhibits cation exchange ability for Zn2+ and polyiodides, thereby simultaneously stabilizing the zinc anode and inhibiting the shuttle effect of polyiodides. Enhanced by the abundant polar carboxyl groups, the UC/GF separator can effectively facilitate Zn2+ ion transport and accelerate the desolvation of hydrated zinc ions by its zincophilicity and hydrophilicity, while significantly hindering the transfer of polyiodides via electrostatic repulsion. Consequently, the Zn|UC/GF|Zn symmetric battery enables a long lifespan of over 3400 h at a current density of 5.0 mA cm−2, while the Zn|UC/GF|I2 exhibits an exceptional discharge capacity of 103.8 mAh g−1 after 35 000 cycles at 10 C with a capacity decay rate of only 0.0013% per cycle. This separator modification strategy that synergistically optimizes anode and cathode performance provides unique insights into the commercialization of zinc–iodine batteries. [ABSTRACT FROM AUTHOR]

Glass fiber reinforced polymer (GFRP) composites with chopped strand mat (CSM) and woven roving mat (WRM) reinforcements are widely used in high‐pressure piping due to their favorable strength‐to‐weight ratio. However, cyclic loading from vibrations and pulsating forces can induce internal microstructural damage, ultimately leading to performance degradation. A thorough understanding of this damage mechanism is imperative for its mitigation, necessitating a detailed examination. The present study aims to investigate the fatigue response and damage mechanisms in CSM and WRM composites subjected to tension‐tension cyclic loading. Scanning electron microscopy analysis of edge sections revealed the development of perpendicular microcracks in both composites. CSM composites exhibited fatigue cracks parallel to the loading direction and higher levels of parallel interface debonding compared to perpendicular matrix cracks. Finite element analysis of the representative volume element revealed the role of shear stress in the matrix in initiating parallel cracks, thereby explaining the damage initiation mechanism in CSM. These findings highlight the distinct damage mechanisms arising from the differing fiber arrangements in CSM and WRM composites, providing valuable insights for optimizing their performance under cyclic loading conditions. Highlights: Fatigue response of CSM and WRM was influenced by fiber orientation and weaving pattern.Perpendicular fibers were the most probable fibers to have their interface form a crack.Fatigue cracks parallel to the direction of loading were observed in CSM composites.Quantified the true 3D internal microstructural damages for the first time. [ABSTRACT FROM AUTHOR]

The main objective of this study is to investigate the effect of combining natural and synthetic fibers on the mechanical characteristics of hybrid and novel functionally graded hybrid composites by considering hemp as natural fiber and carbon and glass as synthetic fibers. Before manufacturing, the natural fibers were treated with sodium hydroxide (NaOH) solution to remove the impurities on the fiber surface. The fibers were reinforced in an epoxy‐based matrix using a hand‐layup technique. The volumetric fraction of the hybrid composites was 40% fibers and 60% matrix. Different types of composites, such as plain fiber reinforced polymer (FRP), sandwich hybrid (SH), alternative hybrid (AH), and functionally graded hybrid (FH), were manufactured from hybridizations of hemp/carbon and hemp/glass. In accordance with ASTM standards, the tensile, compression, flexural, short beam shear, water absorption, and wettability properties of composites were determined. FH composites with hemp fiber at the top surface had the highest improvement in tensile strength, stiffness and compressive strength compared with pure hemp FRP (HFRP) composites. Hemp SH composites had the highest improvement in flexural and short beam properties in both hybridizations compared with HFRP composites due to the stacking of synthetic fiber at the outer layers. Scanning electronic microscopic (SEM) studies identified the failure mechanism of the tensile failure specimens and also the effect of mercerization on fiber surfaces. In conclusion, this work identified the structural capacity of hybrid composites and emphasizes that FH and hemp SH composites can replace glass FRP composites in structural applications. Highlights: Treating hemp fiber with 2 g/L of NaOH for an hour had a better impact.Functionally graded composites had better in‐plane strength and stiffness.Composites made with synthetic fiber on the outer layers were good at bending.In structural applications, hemp/carbon hybrid composites can replace GFRP. [ABSTRACT FROM AUTHOR]

Due to the requirements of high stiffness and impact strength of HDPE pipes, in this article, long fiber reinforced HDPE were developed and the effects of fiber length, volume fraction, types, and matrix/fiber interface on the mechanical properties were investigated. Tensile properties, notched impact strength, as well as microstructures were tested. The results showed that fibers increased the tensile strength, modulus, and impact strength, but decreased their plastic deformation. Larger fiber fraction indicates more fibers are involved in load bearing, but easy agglomeration. With ascending fiber length, tensile, and impact strength first increased and then decreased, whereas tensile modulus first increased and then maintained an almost constant value. Carbon fibers showed no advantages over glass fibers and basalt fibers in reinforcing HDPE due to the relatively poor interface bonding strength. Interface modification with KH550 improved the mechanical performance of composites, but the enhancement was limited. More effective methods should be developed for better performance. Highlights: Fiber increases strength and modulus, but decreases plastic deformation.Critical fiber length for basalt LFT is 2.6 mm obtained from SEM.Larger fiber volume and length lead to agglomerations.Difference in BF, CF, and GF reinforced HDPE is determined by interface.Interface modification enhances mechanical properties of LFT but limited. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable solutions, this study investigates the potential of bio‐based polyamide 5.6 (PA56) as a promising alternative to petroleum‐derived polyamide 6.6 (PA66). Novel composites of PA56 and PA66 were prepared with the incorporation of glass fibers and flame retardant additives by twin screw extruder. Subsequently, these composites were subjected to comprehensive characterization to determine their performance. The physical, mechanical, rheological, thermal, and flammability properties of PA56 composites were investigated and compared with those of PA66 composites with the same formulations. This article aims to unveil the remarkable potential of bio‐based PA56 composites in industrial applications. The results showed that bio‐based PA56 exhibits comparable, and in some cases superior, performance to PA66 while offering the added advantage of environmental sustainability. The findings suggest that bio‐based polyamide 5.6 can serve as a sustainable alternative to petroleum‐derived polyamide 6.6, contributing to a greener future in industrial applications. Highlights: Bio‐based PA56 exhibits comparable properties to petroleum‐derived PA66.Incorporation of glass fibers and flame retardants enhances the properties of PA56.Findings propose PA56 as a sustainable alternative to PA66 in various applications. [ABSTRACT FROM AUTHOR]

This study investigates the mechanical properties of continuous carbon/glass hybrid fiber‐reinforced polylactic acid (PLA) composites (HFRC) produced through the three dimensions (3D) printing process, comparing them with single carbon fiber‐reinforced PLA composites (CFRC). Initially, composite prepreg filaments are prepared using an impregnation device, followed by fabrication using a 3D printer. The mechanical performance results reveal a 13% increase in tensile strength for HFRC compared with CFRC. Due to differing elongation rates of carbon and glass fibers, HFRC exhibits two strength peaks, while CFRC demonstrates a 37% higher bending strength than HFRC. Scanning electron microscope images indicate that the tensile failure mechanism involves fiber brittle fracture and fiber‐matrix interface debonding, while the bending failure mechanism includes fiber pullout, fiber debonding, fiber cluster buckling, and interlayer interface failure. Highlights: To realize the moldless rapid manufacturing of continuous hybrid fiber‐reinforced PLA composites.The stress–strain curves of single fiber‐reinforced composites and hybrid fiber‐reinforced composites are obviously different.Elucidating the effect of single fiber/hybrid fiber in composites on mechanical properties and failure mechanism according to micro‐morphology. [ABSTRACT FROM AUTHOR]

The rapid advancement of the electronics industry has continuously increased demands for the E‐glass yarn's quality and production capacity. The twisting and winding process stands out as a crucial step in E‐glass yarn production. Twisted bobbin yarns are produced separately using constant spindle speed technology and constant tension technology in order to address issues such as high yarn breakage rates and excessive yarn hairiness during twisting. By comparing the twisting tension, yarn breakage rates, and yarn hairiness between these two technologies, this study delves into the impact of twisting technology on E‐glass yarn quality and production capacity. The results indicate that, in comparison with constant spindle speed technology, constant tension technology reduces the unevenness ratio of twisting tension from 8.94% to 0.55%, decreases yarn breakage rates from 3.05% to 2.03%, reduces long hairiness by 20.3%, and reduces short hairiness by 25.1%. By reducing the spindle speed when the bobbin yarn's diameter increases, constant tension twisting technology reduces the unevenness ratio of twisting tension, yarn breakage rate, and yarn hairiness. These research findings lay the foundation for the development of high‐end E‐glass yarn products and carry significant practical value in improving yarn quality, enhancing production capacity, and reducing E‐glass yarn losses. Highlights: The twisting and winding principle of E‐glass yarn is revealed.The relationship among four tensions in the twisting and winding process is clarified.The parameters for the constant tension twisting technology are developed.The measurement method for the twisting tension is improved. [ABSTRACT FROM AUTHOR]

The present study investigates the mode‐II fracture resistance and interlaminar shear strength (ILSS) in glass epoxy laminates with the aid of glass‐carbon veils hybrid interleaving technique. Hybrid interleaves were prepared using various areal densities of non‐woven carbon and glass veils. Two methods, specifically inter‐ply and inter‐weaved ply interleaved glass epoxy composite laminates were manufactured by hand layup technique. End notch flexural and short beam test specimens were tested to estimate the mode‐II fracture resistance and ILSS. Test results indicated that the interleaved with inter‐weaved veil composite exhibited ~58% to ~82% and ~13% to ~61% enhancement for inter‐ply veil composite laminates when compared to plain samples. In context with the short beam test, a significant enhancement of approximately 23% in ILSS was noticed for the plain inter‐weaved veil constructed with a lower areal density of the carbon veil. Finally, the plain inter‐weaved interleaving technique has a prominent role in enhancing the resistance to fracture and shear strength in Glass epoxy laminates. Further, the fracture mechanisms of non‐interleaved and hybrid ply interleaved composite laminates were observed by scanning electron microscopic images. Highlights: Interleaving non‐woven microfiber veil is the most promising and cost‐effective strategy to enhance the Interlayer toughness and strength.Interleaving techniques used in this investigation have a significant effect on interlaminar fracture toughness (IFT) and interlaminar shear strength (ILSS).The areal density of high‐modulus carbon veil showed a different phenomenal influence on IFT and ILSS. [ABSTRACT FROM AUTHOR]

Highlights Highly transparent and mechanically robust thermoplastic composites have been developed by hot‐pressing PETG with E‐glass fabrics. The tow‐spreading technique facilitates the reduction of internal defects and fiber crimp angle in the composites, thereby significantly improving their optical and mechanical properties. The optimized composite containing 55.1 vol% glass fibers and 0.4 mm thickness has a high transmittance of 86.1%@616 nm and a low overall haze of 7.2%. Moreover, the 1 mm thick composites exhibit tensile strength of up to 340 MPa and impact strength of up to 86.3 kJ/m2. After 28 days of hygrothermal or UV aging, the composites show minimal changes in their glass transition temperature and thermal degradation temperature. The chemical structure also remains unchanged, with no observed crystallization. In comparison to UV aging, the composites demonstrate better resistance against hygrothermal aging. Specifically, the hygrothermal aged sample displayed a light transmittance retention rate of 93.5% and a bending strength retention rate of 94.3%, while these values were reduced to 73.3% and 90.5%, respectively, in the UV aged sample. The opto‐mechanical properties enhanced mechanism and aging degradation mechanism have been identified by microscopic morphological observation. This work provides an innovative and straightforward approach to fabricate transparent, recyclable, high‐strength thermoplastic composites. Highly transparent, mechanically robust, recyclable glass‐fabric reinforced thermoplastic composites are fabricated. Composites with spread‐tow fabrics exhibits improved transparency. The fabrication route is scalable and cost‐effective. The mechanism for opto‐mechanical properties enhancement are proposed. [ABSTRACT FROM AUTHOR]

Highlights In this paper, the mechanical properties, damage modes, and bolt load distribution of the bonded‐bolted hybrid three‐bolt joint were investigated by a combination of experiments and numerical simulations. Acoustic emission (AE) was used to monitor the tensile process of the connection in real time, and the K‐means clustering algorithm was used to realize the cluster analysis of the damage modes. A numerical simulation model of the tensile process of the joint was established using ABAQUS simulation software. The progressive damage evolution of composite laminates, and adhesive layer was characterized by using the VUMAT subroutine, the B‐K failure criterion, and cohesive element with zero thickness, respectively. The results show that four main damage modes occur in composite laminates during tension: matrix cracking, delamination, fiber pull‐out, and fiber breakage, with corresponding peak frequency ranges of (0–80 kHz), (80–210 kHz), (210–330 kHz), and (330–375 kHz), respectively. The adhesive layer between the laminates mainly exhibits peeling failure because of the secondary bending effect. In the load‐bearing process, the adhesive layer was loaded first and failed, and the bolt loading was delayed. Meanwhile, the results of bolt load distribution showed that the bolts and the adhesive layer at both ends carried greater loads. Damage modes and damage evolution of the bonded‐bolted hybrid joint in tension were analyzed by combining acoustic emission technology and numerical simulation. The simulation of delamination damage in composite laminates was carried out by inserting zero‐thickness cohesive elements into the laminates, and the delamination damage between the carbon fiber layup and the adjacent glass fiber layup was analyzed. The effect of the inclusion of the adhesive layer on the mechanical properties of the joint and the distribution of the bolt load was analyzed. [ABSTRACT FROM AUTHOR]

The increasing awareness of safety standards for personal protective equipment in various industries and everyday life has significantly increased the demand for effective cut‐resistance clothing to prevent injuries. Ultra‐high molecular weight polyethylene (UHMWPE), renowned for its strength, is predominantly used to produce cut‐protective clothing for sectors such as automotive, manufacturing, glass, and metal. These cut‐resistance clothing are often exposed to harsh workplace conditions, including elevated temperatures, which can compromise their structural integrity and diminish their cut‐protection efficacy. The present work investigates the effect of temperature on the cut‐resistance performance of core‐spun UHMWPE yarns integrated with stainless‐steel and glass filament‐based knitted fabrics. Cut‐performance was assessed across industrial work handling temperatures ranging from 30 to 75°C. Furthermore, thermal cut performance was analyzed by structural characterization and surface morphology of the samples. The results revealed a general decline in cut performance with increasing temperature for all samples, with stainless steel‐reinforced UHMWPE fabrics experiencing the most pronounced reduction % compared with their glass fiber‐reinforced and 100% UHMWPE counterparts. These results are substantiated by analyses of surface temperature distribution profiles and x‐ray diffraction outcomes. This study benefits industry workers, guiding them in selecting effective protective clothing for varied thermal conditions. [ABSTRACT FROM AUTHOR]

The adhesive bonding approach is widely used in assembling of spars, stringers, ailerons, flaps, and rudders in aircraft. The present research investigated the impact of silicon carbide (SiC) nanoparticle inclusion on the shear and free vibrational behaviour of adhesively bonded single lap joints (SLJ). The shear test results showed that the inclusion of 1.5 wt.% SiC in the epoxy resin enhanced the shear behaviour of adhesively bonded SLJ. Furthermore, the failure surfaces of adhesively bonded SiC-reinforced SLJ were examined using a field emission scanning electron microscope (FESEM). The microstructural investigation of the failure surface demonstrated that the development of rougher surfaces, plastic void enlargement, and formation of shear bands in the joint region had improved adhesion among GFRP adherends. Thus, the SiC-incorporated adhesively bonded SLJ had predominant cohesive failures. Meanwhile, the SiC-free lap joint had an adhesive failure due to lower adhesion. The vibrational results avowed that 1.5 wt.% SiC-incorporated adhesively bonded SLJ has higher natural frequencies. Results also affirmed that higher wt.% SiC-incorporated joint had better modal damping values due to nanoparticle accumulation, which increased the interaction between glass fiber reinforced polymer (GFRP) adherends. [ABSTRACT FROM AUTHOR]

In order to address the 'capacity crisis' caused by the narrow bandwidth of the current C band and the demand for wide-spectrum sensing sources and tunable fiber lasers, a broadband luminescence covering the C + L bands using Er3+/Yb3+ co-doped fluorotellurite glass fiber is investigated in this paper. The optimal doping concentrations in the glass host were determined based on the intensity, lifetime, and full width at half maximum (FWHM) of the fluorescence centered at 1.5 µm, which were found to be 1.5 mol% Er2O3 and 3 mol% Yb2O3. We also systematically investigated this in terms of optical absorption spectra, absorption and emission cross-sections, gain coefficients, Judd–Ofelt parameters, and up-conversion fluorescence. The energy transfer (ET) mechanism between the high concentrations of Er3+ and Yb3+ was summarized. In addition, a step-indexed fiber was prepared based on these fluorotellurite glasses, and a wide bandwidth of ~112.5 nm (covering the C + L bands from 1505.1 to 1617.6 nm) at 3 dB for the amplified spontaneous emission (ASE) spectra has been observed at a fiber length of 0.57 m, which is the widest bandwidth among all the reports based on tellurite glass. Therefore, this kind of Er3+/Yb3+ co-doped fluorotellurite glass fiber has great potential for developing broadband C + L band amplifiers, ultra-wide fiber sources for sensing, and tunable fiber lasers. [ABSTRACT FROM AUTHOR]

The detection of impact and depth defects in Glass Fiber Reinforced Polymer (GFRP) composites has been extensively studied to develop effective, reliable, and cost-efficient assessment methods through various Non-Destructive Testing (NDT) techniques. Challenges in detecting these defects arise from varying responses based on the geometrical shape, thickness, and defect types. Long Pulse Thermography (LPT), utilizing an uncooled microbolometer and a low-resolution infrared (IR) camera, presents a promising solution for detecting both depth and impact defects in GFRP materials with a single setup and minimal tools at an economical cost. Despite its potential, the application of LPT has been limited due to susceptibility to noise from environmental radiation and reflections, leading to blurry images. This study focuses on optimizing LPT parameters to achieve accurate defect detection. Specifically, we investigated 11 flat-bottom hole (FBH) depth defects and impact defects ranging from 8 J to 15 J in GFRP materials. The key parameters examined include the environmental temperature, background reflection, background color reflection, and surface emissivity. Additionally, we employed image processing techniques to classify composite defects and automatically highlight defective areas. The Tanimoto Criterion (TC) was used to evaluate the accuracy of LPT both for raw images and post-processed images. The results demonstrate that through parameter optimization, the depth defects in GFRP materials were successfully detected. The TC success rate reached 0.91 for detecting FBH depth defects in raw images, which improved significantly after post-processing using Canny edge detection and Hough circle detection algorithms. This study underscores the potential of optimized LPT as a cost-effective and reliable method for detecting defects in GFRP composites. [ABSTRACT FROM AUTHOR]

This study evaluated the properties of 3D-printed Onyx–fiberglass composites. These composites were 3D-printed with zero, one, two, three, and four layers of fiberglass. Ten samples of each configuration were printed for the tensile and flexural tests. The average tensile strength of the Onyx specimens was calculated to be 44.79 MPa, which increased linearly by approximately 20–25 MPa with each additional fiberglass layer. The elastic moduli calculated from the micromechanics models were compared with the experimental values obtained from the tensile tests. The experimental elastic modulus increased more significantly than the model prediction when more fiberglass layers were added. The flexural modulus of Onyx was 17.6 GPa, which increased with each additional fiberglass layer. This quantitative analysis of composites fabricated using 3D printing highlights their potential for commercialization and industrial applications. [ABSTRACT FROM AUTHOR]

This article deals with the possibility of using 3D-printed models as an input for the production of a mould for cast iron castings. This new progressive process is significantly faster (with sufficient accuracy) compared to the current way of making models for moulds. The need to create a wooden model is removed by this process. The quality of this wooden model was highly dependent on the experience and qualifications of the worker. This article describes the manufacturing process of the model and mould in detail. The key dimensions of the final parts are compared with the model and, thus, the accuracy of the chosen procedure is verified. A 3D-printing technology known as Multi Jet Fusion (MJF) was used to produce the model. The material used for the production of the model is polyamide PA12 with 40% glass fibre filling. This material has sufficient structural and strength properties to be used for the given application. Taking into account the dimensions of the part and the printing space of the printer, it was necessary to structurally modify and divide the part. The inlet cone of a turbine is used as an example This cone is produced from grey cast iron as standard. [ABSTRACT FROM AUTHOR]

Hole quality in composite materials is gaining interest in aerospace, automotive, and marine industries, especially for structural applications. This paper aims to investigate the quality of holes performed without a backup plate, in thin plates of glass fiber-reinforced polymer (GFRP). The samples were manufactured by two different technologies: vacuum bagging and an innovative method named vacuum mold pressing. Three experiments were designed choosing the control factors that affect the maximum cutting force, delamination factor, and surface roughness of drilled holes in composite materials based on twill fabric layers. Quality analysis of the hole features was performed by microscopy investigations. The effects of the main factors on the targets are investigated using the statistical design of experiments, considering control factors, such as support opening width, weight fraction (wf), feed per tooth, and hole area. The results showed that the feed per tooth and hole area had a more significant influence on the delamination factors and surface roughness (Sa). The best quality of the holes drilled in twill-based GFRP was achieved for a lower feed rate of 0.04 mm/tooth and used a support opening width of 55 mm. [ABSTRACT FROM AUTHOR]

This paper presents a study of the flammability and thermal decomposition products of glass fiber-reinforced epoxy resin (GFRER) with the addition of cardanol-based phosphorus-containing benzoxazine monomer (CBz) and graphene and their combinations in different proportions (up to 20 wt.%). The addition of CBz alone or in combination with graphene resulted in an increase in the limiting oxygen index (LOI) and self-extinguishing in the UL-94 HB test. The flame-retardant samples had better tensile mechanical properties than the sample without additives. The differential mass-spectrometric thermal analysis (DMSTA) of the thermal decomposition products of GFRER without additives and with the addition of CBz and graphene was carried out. CBz addition promoted the thermal decomposition of high-molecular-weight products of epoxy resin decomposition in the condensed phase and at the same time decreased the time of release of low-molecular-weight thermal decomposition products into the gas phase. Graphene addition resulted in an increase in the relative intensities of high-molecular-mass peaks compared to GFRER without additives. [ABSTRACT FROM AUTHOR]

In this study, two types of composites, polybutylene terephthalate (PBT) and epoxy resin (ER), reinforced with 20% of glass fiber (GF) are used as the comparative research objects. Their mechanical properties after thermal aging at 85~145 °C are evaluated by tensile strength and fracture morphology analysis. The results show that the composites have similar aging laws. The tensile strength of GF/PBT and GF/ER decrease gradually with the increase of aging temperature, while their elastic moduli are independent of the thermal treatment temperature. Scanning electron microscopy study of the fracture surface shows that separation of glass fiber from PBT and ER matrix becomes more obvious at higher aging temperature. The fibers on the matrix surface appear clear and smooth, and the whole pulled out GFs can be observed. As a main mechanical strength degradation mechanism, the deterioration of interface adhesion between the matrix and GF is discussed. A large difference in coefficients of thermal expansion of the matrix and GF is a main factor of the mechanical degradation. [ABSTRACT FROM AUTHOR]

In the present work, short glass fiber is superficially modified with different concentrations of polyhedral oligomeric silsesquioxanes (Trisilanol–Isobutyl, TSI-POSS) for processing as a filler in a polypropylene matrix (PP). It is observed that increasing the amount of TSI-POSS increases the fracture point and tensile strength; the opposite is the case for the strength impact property. The behaviors of both dynamic mechanical and thermal analyses are also observed. The flame behavior, i.e., the burning rate, decreases with increasing TSI-POSS in the polymers. [ABSTRACT FROM AUTHOR]

This study focuses on understanding the impact of different material compositions and printing parameters on the structural integrity of hybrid curved composite beams. Using the continuous filament fabrication technique, which is an advanced fused deposition modelling process, composite curved beams made of short carbon and various continuous fibre-reinforced nylon laminae were fabricated and subjected to four-point bending tests to assess their delamination characteristics. The results show that the presence of five flat zones in the curved region of a curved beam achieves 10% and 6% increases in maximum load and delamination strength, respectively, against a smooth curved region. The delamination response of a curved composite beam design consisting of unidirectional carbon/nylon laminae is superior to that of a curved beam made of glass fibre/nylon laminae, while the existence of highly strengthened glass fibre bundles is alternatively quite competitive. Doubling the number of continuous fibre-reinforced laminae results in an increase of up to 36% in strength by achieving a total increase in the beam thickness of 50%, although increases in mass and material cost are serious concerns. The hybrid curved beam design has a decrease in the maximum load and the strength by 11% and 13%, respectively, when compared with a non-hybrid design, which consists of some type of stronger and stiffer nylon laminae instead of short carbon fibre-reinforced conventional nylon laminae. Two-dimensional surface-based cohesive finite element models, which have a good agreement with experimental results, were also established for searching for the availability of useful virtual testing. The results from this study will greatly contribute to the design and numerical modelling of additively manufactured hybrid composite curved beams, brackets, and fittings. [ABSTRACT FROM AUTHOR]

The use of zinc (Zn) metal as an anode in aqueous batteries offers an eco‐friendly and cost‐effective energy storage solution. However, Zn dendrite formation severely restricts the cycle life of the battery toward practical application. Herein, a commercially hydrophilic polytetrafluoroethylene (PTFE) membrane is demonstrated as a separator to significantly extend the cycle life of the Zn metal anode. In contrast with the conventional fragile glass fiber separator, a wetted PTFE separator exhibited high mechanical strength (stress of 34.3 MPa at 41.4% strain) and favorable hydrophilicity, which both efficiently suppress dendrite growth. The uniform and robust pore structures are proven to facilitate a homogeneous Zn2+ ion flux and a high transfer number of Zn2+ (0.81), which has guaranteed reversible Zn plating/stripping. As a proof of concept, the PTFE separator extended the cycle life considerably to over 3000 h and promoted a Zn plating/stripping efficiency of 99.5% in the unmodified 2 m ZnSO4 aqueous electrolyte. This advancement underscores the significant potential of the PTFE separator for enhancement of the cycling durability of aqueous zinc‐ion batteries (AZIBs). [ABSTRACT FROM AUTHOR]

Moisture ingress in photovoltaic (PV) modules is a critical factor for performance degradation, therefore, a low water vapor transmission rate (WVTR) is highly desirable for polymers used to embed the solar cells, including backsheets, frontsheets, and encapsulants. With the advent of glass‐free modules for integration in building envelopes and vehicles, there is growing interest in polymer composite structures with embedded glass fibers to enhance rigidity. Furthermore, due to environmental concerns, there is increased interest in fluorine‐free polymers for PV applications. In this work, 21 samples with different base polymers, coatings, and/or surface treatments are investigated and their WVTRs are measured. The results show no good alternatives to existing fluoride‐based polymers/coatings for reducing WVTRs of backsheets and frontsheets among the investigated samples. In addition, glass fibers embedded within polymers to provide increased stability to backsheets or in composites for lightweight PV are shown to significantly increase WVTRs, especially, when fibers are not properly embedded, providing additional diffusion pathways for moisture ingress. [ABSTRACT FROM AUTHOR]

The desire for lightweight, carbon-negative materials has been increasing in recent years, particularly as the transportation sector reduces its global carbon footprint. Natural fibers, such as flax fiber and their composites, offer a compelling combination of properties including low density, high specific strength, and carbon negativity. However, because of the low modulus and high variability in performance, natural fibers can't compete with glass fibers as structural reinforcements in polymer composites. In this study, flax technical fibers were treated in supercritical CO2 (scCO2), and the effects of this treatment on the morphology and properties of flax fibers are reported. Treatment in scCO2 successfully resulted in higher fiber modulus and strength by 33% and 40%, respectively. Fiber porosity was reduced by 50% and morphological changes to the fibers were observed. Specifically, fiber lumen collapsed during treatment and micro/mesoporosity was reduced by 27%. Treated flax fibers were used to create 30 vol% unidirectional flax-epoxy composites. ScCO2 treatment raised composite modulus and strength by 33% and 25%, respectively. Because of the dependence between technical fiber size and mechanical properties, the relationship between fiber modulus and fiber size were created and applied to the rule-of-mixtures. This relationship were found to be viable representations of the fiber performance within each composite. Overall, the treatment developed in this study has the potential to significantly improve natural fiber properties, enabling their consideration for use in lightweight, semi-structural composites. [ABSTRACT FROM AUTHOR]

Highlights In this work, silicone polymer (PSOL)/glass fiber (GF)/epoxy (EP) composites were prepared by employing PSOL as interfacial modifier into GF/EP composites. The mechanical and dynamic mechanical properties of the composites were investigated to determine the optimal PSOL content. The effect of PSOL on the wettability of EP on GF was investigated. The micromorphology of the GF/EP composites was also examined by scanning electron microscope. The results demonstrate that the interfacial bonding between GF and epoxy resin was improved significantly by the addition of PSOL. Specifically, the interlaminar shear strength, tensile strength, elongation at break, and blending strength of the PSOL/GF/EP composites increased by 9.28%, 13.61%, 12.66%, and 19.22%, respectively. Moreover, the original thermal stability of the composites was improved by the incorporation of PSOL. This study highlights the effectiveness of PSOL as an interfacial modifier, enhancing the overall performance of GF/EP composites while improving their thermal stability. Silicone polymer (PSOL)/glass fiber (GF)/epoxy (EP) composite material is made of glass fiber and epoxy resin by hand paste molding. Silicon polymers as interface modifiers can improve the interface between glass fiber and epoxy resin. PSOL/GF/EP composites have good mechanical properties. The glass transition temperature of GF/EP composites was increased by silicon polymer. [ABSTRACT FROM AUTHOR]

Highlights Polyimide composites are easily degraded in high temperature and high humidity environments for long service, which reduces their reliability and stability in aerospace, electronic components, weapons, and other fields. In this paper, the inorganic and organic multiphase double‐layer coating was prepared. The insulating layer was made of vinyl polysilazane resin as the base material and hollow glass microspheres as the filler. The hydrophobic layer consisted of polydimethylsiloxane as the base material, hollow phenolic microspheres, and nano‐TiO2 as the filler. The heat resistance, hydrophobic properties, and aging resistance of the coated polyimide resin matrix composites were studied. The results showed that the thickness of the double‐layer coating was about 200 μm. Under the 200°C thermal insulation test, the maximum temperature drop can be achieved at 59.7°C. After adding 5 wt% TiO2, the static contact angle of composites was increased from 86.2° to 127.7°. Significantly, the hydrophobic performance was improved by 48.1%, which was due to the construction of micro‐nano structures in the surface layer coating. In the accelerated hydrothermal aging tests, the bending properties of coated composite materials can be improved by 8.5%, 3.2%, and 8.7% in water, alkali, and acid environments, respectively. The moisture absorption of glass fiber and the pyrolysis of polyimide led to the degradation of the mechanical properties. The existence of heat‐resistant and hydrophobic coating could effectively eliminate this adverse effect, which was of great significance for polyimide composites to cope with various service environments. A novel coating consisting of thermal insulating and hydrophobic layers was developed on glass fiber reinforced polyimide composites (G/PI) composites. The maximum temperature drop of coating can be achieved at 59.7°C. The static contact angle of coated G/PI composites was increased from 86.2° to 127.7°. In the aging tests, the protective effect of the coating resulted in improved mechanical strengths of G/PI composites. The microscopic damage morphology was performed to analyze the anti‐aging properties of the coating. [ABSTRACT FROM AUTHOR]

Benefiting from high safety, low cost, and competitive energy density, aqueous zinc ion batteries (AZIBs) have emerged as very promising technology for grid energy storage. However, the lifetime of AZIBs is severely affected by uncontrolled zinc dendritic growth and undesirable side reaction. To address the problem, natural aluminum silicate hydroxide covered glass fibers separator (AlSi‐GF) is prepared herein using a simple spraying method. Aluminum silicate hydroxide is a complex oxide, where a large number of adsorption sites can adsorb Zn2+ and guide its deposition process. In particular, the Maxwell–Wagner polarization of aluminum silicate hydroxide under an applied electric field contributes to homogenizing the electric field distribution around the interface, thereby modulating zinc deposition and reducing the nucleation overpotential. Impressively, AlSi‐GF separator enables high‐performance zinc‐metal batteries. The symmetric battery with AlSi‐GF separator has a stable voltage polarization and an ultra‐long cycle life of 2280 h at a current density of 1 mA cm−2, and the Zn//V2O5 full cell based on AlSi‐GF separator can exhibit a high specific capacity of 123 mAh g−1 after 1500 cycles at 1 A g−1. This study provides new insights into the design of reliable and cost‐effective separators for metal anodes in energy storage devices. [ABSTRACT FROM AUTHOR]

The present research investigated the flexural behavior of high‐strength fiber‐reinforced concrete (HSFRC) with six different types of fiber: hooked‐end and crimped steel fibers, chopped and pultruded glass fibers; monofilament and twisted polymeric fibers. An extensive experimental program with 108 specimens for 3‐point bending tests was carried out and the parameters analyzed were the fiber content (0.50%, 0.75% and 1.00% in volume), the fiber type and the compressive strength of the concrete (60 and 90 MPa). Statistical analyses were performed and showed that regardless of the fiber material, increasing the amount of fibers added to concrete increases residual strength and toughness. Limit of proportionality is not affected by the addition of fibers, while postcracking behavior, on the other hand, is controlled by the fibers. Increasing the compressive strength of the concrete matrix affect mainly the limit proportionality of all mixes and the postcracking behavior of the concrete reinforced with hooked‐end steel fibers. The classification of HSFRC and the conditions required for HSFRC for use in structural applications according to the fib Model Code 2010 were also discussed, and it was verified that such conditions are not consistent with the experimental results and should be revised for high‐strength fiber‐reinforced concrete. [ABSTRACT FROM AUTHOR]

AbstractThe environmental consequences of Portland cement (PC) manufacturing have prompted the exploration of alternative binders, such as the alkali activation of blast furnace slag (BFS), which is generated as a byproduct during the extraction of iron. While alkali-activated blast furnace slag (AAS) binders have some benefits over regular PC binders, they also suffer from disadvantages such as significant drying shrinkage. The study investigated the impact of Na dosage and curing conditions on alkali-activated blast furnace slag mortar (AASM). The consistency of the specimens was tested for fresh, hardened properties, and was conducted. The optimum Na dosage and curing conditions were selected. In the second stage, 0.1% and 0.2% glass and nylon fibers were added to the selected optimum mortar. Consistency, fresh, mechanical, and durability properties tests were conducted on the fiber mortars. The results showed that increasing the Na content increased the compressive and flexural strengths of AASM specimens. Thermal curing provided high compressive and flexural strengths, whereas fiber addition reduced water absorption and drying shrinkage. The drying shrinkage value was reduced by 26.82 % for AASM specimens with 0.2 % nylon fibers by volume compared to AASM without fibers. [ABSTRACT FROM AUTHOR]

The automotive industry is increasingly focused on reducing vehicle weight, leading to the widespread adoption of composite materials with high strength-to-weight ratios in both aviation and automotive sectors. These materials are gradually replacing traditional options like steel. Leaf springs, one of the oldest and most common suspension components, continue to be widely used in vehicles. This study aims to replace conventional multi-leaf steel springs with mono-composite leaf springs while preserving the same load-carrying capacity and stiffness. Composite materials, such as glass fiber and epoxy resin, provide advantages including higher elastic strain energy storage, superior strength-to-weight ratios, and enhanced corrosion resistance compared to steel. Consequently, the weight of leaf springs can be reduced without sacrificing performance. The steel and mono-composite leaf springs were modeled using Catia software, and their performance was evaluated using ANSYS 15.0 software. [ABSTRACT FROM AUTHOR]

To address the challenge of balancing load-bearing and electromagnetic (EM) wave absorption properties in aircraft composite skin, the outstanding mechanical and electrical characteristics of carbon fiber (CF) prepregs were utilized to construct a carbon fiber dual-polarized absorbing laminated structure (CFDALS). The bidirectional CF arrays were introduced into the glass fiber (GF) laminated structure, to endow the laminated structure with dual-polarized EM wave absorption performances. Additionally, the excellent load-bearing capacity of the CF reflector was used to enhance the mechanical properties. Simulation results indicate that, the CFDALS achieves an average absorptivity over 90% within the 8~18 GHz frequency band at incident angles of 0°~45°, and within the 5~18 GHz band at incident angles of 0°~60° for TE and TM polarized EM waves, respectively. The 3-point bending simulation results show that, the CFDALS exhibits higher specific flexural strengths and stiffnesses along 2 directions of the CF arrays while achieving dual-polarized EM wave absorption. Incorporation of bidirectionally arranged CF prepregs into GF prepregs enhances the dual-polarized EM wave absorption performance and the bidirectional flexural performance of the CFDALS simultaneously. The work provides a novel solution for the EM wave absorbing and load-bearing integrated design for aircraft composite skin applications. [ABSTRACT FROM AUTHOR]

The main challenges of using fiberglass composites are poor impact resistance and understanding of damage mechanisms during loading. This work focuses on improving the indentation resistance of glass/epoxy composites by the incorporation of industrial waste iron fillers with maximum concentration of 50 µm in size. Moreover, the quasi-static indentation test with acoustic emission (AE) monitoring was employed to study the damage initiation and propagation of baseline and optimized 10 wt.% of filler-loaded composites. Post-indentation performance was evaluated by conducting compression after indentation test. The result reveals that the stiffness, absorbed energy and strain energy density were increased by 32%, 59.2% and 18.02% in filler-loaded composites, whereas the residual dent was reduced from 0.9 to 0.5 mm as compared with baseline. As compared with 3 mm indentation displacement, the % of AE hits related to delamination and fiber failure was significantly reduced to 3.6% and 1% during 6 mm, respectively. Further, the sentry function results that shown very small two PII functions indicate a better indentation resistance in filler-loaded composites, which were well correlated with rear side photographic images. Besides, the filler-loaded composites exhibited least reduction in the residual compressive strength of 3.71% and 4.33% for 3 mm and 6 mm indented displacements, respectively. However, the microstructural analysis was used to validate the effect of iron fillers on glass/epoxy composites. Finally, this study concludes that the impact resistance of fiberglass composites was greatly improved by the addition of industrial waste iron fillers. [ABSTRACT FROM AUTHOR]

Owing to the importance of fibre architectures in the design of textile composite materials, understanding their effect on the failure mechanisms of these composites have taken more considerations. In this regards, non-crimp preform and 2/2 twill fabric have been manufactured from glass fibre by using pin-board and power loom machines respectively, and subsequently composites laminates from both preforms are manufactured via vacuum assisted resin infusion method. In addition, quasi-static tensile and compressive strength tests have been conducted for the composite laminates that have same volume fraction. Damage failure mechanisms that occurred in compressive strength in both composites have been examined by using scanning electronic machine (SEM). Findings show that the mechanical properties are primly determined by fibre architectures and the presence of fibre crimp can further weaken tensile and compressive strength values. It was noticed that the tensile strength of non-crimp composite was 610 MPa whereas that of twill fabrics composite laminates it was found to be 350 MPa and 440 MPa in warp and weft directions respectively. Moreover, in case of twill fabric composites, fibre crimp has a considerable effect on the mode and characteristics of damage in the compressive loading; this leads to fibre fracture and kinks that primarily happened in the intersection point of warp and weft yarns. Results also showed improved ductility, strain to failure and absorbing energy in the twill fabric composites compared to non-crimp composites under in-plane shear strength test. [ABSTRACT FROM AUTHOR]

In this study, the axial compressive stresses of hollow circular composite tubes were investigated. For this purpose, hollow circular composite tubes with various inner diameters (Ø12 and Ø13 millimeters), a height of 80 millimeters, and an outer diameter kept constant at Ø17 millimeters were fabricated using a fiber winding process. In the production of hollow circular tubes, epoxy was used as resin, and glass fiber, carbon fiber, and Kevlar fiber were used as reinforcement materials. Experimental investigations were carried out for three different reinforcement materials, two thin-wall thicknesses, and five orientation angles. Axial compression tests were performed to research the influences of reinforcement materials, thin-wall thickness, and orientation angles on the compressive stresses. The axial compressive strength of the samples was observed experimentally by applying the load in the vertical direction. The reinforcement material, orientation angle, and thin-walled thickness had an important influence on the axial compressive stress. The glass/epoxy reinforcement material was found to have the highest axial compressive strength at 204 Mpa. When the orientation angle increased from 45° to 88°, the axial compressive stress increased by 2.27 times in glass/epoxy, 2.36 times in carbon/epoxy, and 2.37 times in Kevlar/epoxy specimens, respectively. In addition, by increasing the specimen wall thickness by 0.5 millimeters, the axial compressive stress at an 88° orientation angle increased by 9.67 % glass/epoxy, 11.85 % carbon/epoxy, and 7.14 % Kevlar/epoxy specimens. [ABSTRACT FROM AUTHOR]

In this paper we derived an expression that allows the determination of the thermo-optic coefficient of weakly-guiding germanium-doped silica fibers, based on the thermal behavior of optical fiber devices, such as, fiber Bragg gratings (FBGs). The calculations rely on the full knowledge of the fiber parameters and on the temperature sensitivity of FBGs. In order to validate the results, we estimated the thermo-optic coefficient of bulk GeO2 glass at 293 K and 1.55 μm to be 18.3 × 10−6 K−1. The determination of this value required to calculate a correction factor which is based on the knowledge of the thermal expansion coefficient of the fiber core, the Pockels' coefficients (p11 = 0.125, p12 = 0.258 and p44 = −0.0662) and the Poisson ratio (ν = 0.161) of the SMF-28 fiber. To achieve that goal, we estimated the temperature dependence of the thermal expansion coefficient of GeO2 and we discussed the dispersion and temperature dependence of Pockels' coefficients. We have presented expressions for the dependence of the longitudinal and transverse acoustic velocities on the GeO2 concentration used to calculate the Poisson ratio. We have also discussed the dispersion of the photoelastic constant. An estimate for the temperature dependence of the thermo-optic coefficient of bulk GeO2 glass is presented for the 200–300 K temperature range. [ABSTRACT FROM AUTHOR]

Novel ultra-high-performance concretes (UHPCs) made with calcium-oxide-activated materials (CAM), modified synthetic macro (MSM) fibres, glass fibres and steel fibres were developed. The mechanical and durability properties of UHPC-CAM specimens made with the different fibre types were tested and compared. The microstructure of the samples was examined using scanning electron microscopy (SEM). The environmental impacts of the mix designs were assessed using the Impact 2002+ method, a life cycle assessment tool. The results showed that the UHPC-CAM made with glass or MSM fibres had a high compressive strength (>110 MPa) and improved ductility. These specimens also had low water absorption and high electrical resistance, indicating low corrosion risk. SEM analyses showed that the MSM fibres created a denser geopolymer matrix than the glass fibres. The UHPC-CAM was found to have a lower environmental impact than conventional UHPC in terms of human health, ecosystem quality, carbon dioxide footprint and use of resources. MSM fibres were determined to be the most eco-friendly fibres for UHPC-CAM production. [ABSTRACT FROM AUTHOR]

Interlayer hybrid foldcore sandwich structures have been introduced in this study. Both facesheets and foldcores were hybridized in the same ply sequence with two layers of plain woven carbon (C) and two layers of satin woven glass (G) fiber prepregs (Carbon-to-Glass ratio 1:1). Foldcore sandwich structures with six-ply combinations were designed including two symmetric layups (GCCG and CGGC) and four asymmetric layups (CGCG, GCGC, CCGG, and GGCC). The static compression and low-velocity impact performance of foldcore sandwich structures of different ply sequences were investigated. A user-defined material subroutine (VUMAT) was employed to characterize the damage evolution of composite materials based on selected failure criteria. The findings revealed that hybridization was effective in enhancing its energy absorption value of pure carbon fiber foldcore sandwich structures in terms of static compression performance. The damage degree of the interlayer hybrid foldcore sandwich structures increased gradually with the increasing impact energy. Moreover, the damage of facesheet was mainly caused by fiber tensile, matrix tensile damage and delamination, and damage of foldcore was mainly delamination. GCGC sandwich panel with asymmetrical cross-ply sequence has the optimal load bearing capacity, and CGGC sandwich panel with symmetrical layup has a strong energy absorption capacity under high-energy impact load. The foldcore sandwich structure showed smaller peak load, longer crushing distance, and more energy absorption value under larger oblique impact angle. The simulation and experimental results show good agreement in peak force, maximum energy absorption, and damage mode. [ABSTRACT FROM AUTHOR]

The use of fiber-reinforced metal laminates (FML) is increasing due to their special mechanical properties. Their properties depend on the type and thickness of the metal and reinforcing fibers. In this study, the mechanical properties of FML sheets with a 2 mm thickness stainless steel 420 intermediate layer reinforced with six layers of Woven and Mat glass fibers were investigated. The fibers were impregnated with a polyester resin and produced as three layers on the front and back of the steel sheet with different fiber angles (0°, 15°, 30°, and 45°). Finally, samples with 8 mm thickness were cut by water jet. Mechanical properties including static tensile and bending tests were performed, and after that a low-cycle dynamic tensile and bending test was also performed according to the obtained maximum static tensile and bending force for each sample. The obtained results varied depending on the fibers' angle, but in all tests, the highest strength was obtained for samples with fibers arranged at 0°. A charpy impact and high speed pressure test were performed to determine toughness and confirm the strength and adhesion between the samples' layers. SEM imaging of the fracture surface showed good adhesion and bonding between layers. [ABSTRACT FROM AUTHOR]

The sandwich panels are widely used in many industrial applications due to their high mechanical properties. Their core design is most important parameter in enhancing their mechanical strength. Flexibility in the design of the core structure leads to the achievement of high strength and light structures. In this paper, the results of the optimized geometry in the previous work are used to investigate the capability of the core geometry design with different materials. Therefore, using the different materials, the peak enhancement of strength-to-weight ratio in sandwich panels besides core behavior during pressure testing are investigated. To this end, a new lattice core is brought forth as the first level; then, three types of materials including AL3105, glass, and innegra fiber/epoxy composites are used to fabricate the cores, in order to compare the compressive strength and the peak. The Nano-clay cloisite 20A is also utilized in construction of sandwich panels. The result indicates that the AL3105 lattice core has the highest strength-to-weight ratio, while the innegra fiber composite core has the highest toughness. Applying curve studies and the SEM Fig. 13, it is concluded that the addition of Nano-clay to composites leads to an increase in both of the strain and the core strength. Comparing the results of experimental and finite element modeling (FEM) data (in ABAQUS software) represented that there is a suitable compliance between them. Our results with the positional variation in core design can pave way in designing advanced engineered sandwich structures in aerospace, shipping, automotive industries. Therefore, these structures will have wide applications in the field of light structure, heat and fluid transfer, sound and vibration control. [ABSTRACT FROM AUTHOR]

The work describes the preparation of bio‐based precursor carbon fibers (CFs) by a solvent‐free process. Fibers from lignin, cellulose acetate, and triacetin as plasticizer are successfully obtained by melt‐spinning showing a potential alternative to traditional precursor fibers from petroleum produced by wet‐spinning. Thermal, morphological, and structural properties of precursor fibers are studied. In particular, precursor fibers present glass transition temperatures lower than neat polymers, indicating the feasibility of using melt‐spinning due to an enhanced softening. Two stabilization thermal treatments with fast or slow heating are adopted to prepare the precursor fibers for carbonization. The CF yield achieves 32% for the materials at high lignin content. [ABSTRACT FROM AUTHOR]

Additive manufacturing, with its ability to assemble a variety of materials in complex and customized architectures, is developing rapidly. The integration of technologies and materials into a sustainable production, however, is still challenging. The present investigation offers new functional glass-based products, from nearly room temperature processing, based on direct ink writing (DIW) of pastes from 'light' alkali activation (2.5 M NaOH) of pharmaceutical glass waste, added with 20 wt% of TiO 2 nanoparticles. The inks were refined by the inclusion of porous glass microspheres (PGMs, 20–30 wt%), previously fabricated from fiber glass waste. Printed scaffolds, stabilized by simple drying (i.e. 'unfired'), were successfully applied in the photodegradation of methylene blue. The degradation efficiency reached 100% within 75 min, and the 3D-printed composites could be easily separated from the solution for subsequent reuse. The degradation efficiency declined only by 7.5%, after 5 cycles. [ABSTRACT FROM AUTHOR]

Because of the inhomogeneity and anisotropy of glass fibre reinforced plastics (GFRP), it is always a challenge to detect the real-time dynamic quality during manufacturing and service. In this paper, a virtual loading focusing enhancement technology (VLFET) based on time reversal (TR) theory is proposed to accurately locate the acoustic emission (AE) source in the GFRP. First, the focusing enhancement theoretical model with virtual reverse loading is deduced according to the TR theory. Then, after measuring the optimal detection range and the average acoustic velocity, the sensor array is positioned on the GFRP specimen. The excitation signals applied to simulate the AE source at some positions are produced by using lead breaking, and the detection signals are received by the sensor array. Finally, the signals received by the sensor array are processed according to the theoretical model, and the fluctuation image in the monitoring area is reconstructed with fluctuation amplitude of each pixel to evaluate the AE source position. The experimental results demonstrate that the excitation sources can be accurately evaluated with the VLFET. The location error with the proposed method is less than 3.1%, higher than that from the current AE instrument. The proposed technology can also be applied to the AE evaluation of other anisotropic materials. [ABSTRACT FROM AUTHOR]

Perianaesthetic dental trauma is a common anaesthesia-related complication. Theprevious studies have shown a lack of knowledge regarding mouthguard usage and controversial results related to perianaesthetic dental trauma prevention. This study aimed to conduct a finite element analysis of the compressive and tensile stresses on the tooth-periodontal ligament-bone complex using custom-made mouthguards of different thicknesses and glass fibre splints to prevent perianaesthetic dental trauma. Custom-fitted ethylene-vinyl acetate mouthguards of two different thicknesses (2 and 3 mm) and glass fibre splint were modelled. A linear static finite element analysis was performed by applying a rigid Macintosh laryngoscope to the palatal surface of the maxillary central incisors at 150 N. The model without a mouthguard and glass fibre splint showed the highest stress values at the palatinal root surfaces during the impact. Increasing the mouthguard thickness significantly decreased the stress-strain values regardless of the presence of the glass fibre splint. Maximum stresses in the group using the 3 mm mouthguard were the lowest compared with the other groups. [ABSTRACT FROM AUTHOR]

In vitro-In vivo correlation (IVIVC) is a main focus of the pharmaceutical industry, academia and the regulatory sectors, as this is an effective modelling tool to predict drug product in vivo performance based on in vitro release data and serve as a surrogate for bioequivalence studies, significantly reducing the need for clinical studies. Till now, IVIVCs have not been successfully developed for in situ forming implants due to the significantly different in vitro and in vivo drug release profiles that are typically achieved for these dosage forms. This is not unexpected considering the unique complexity of the drug release mechanisms of these products. Using risperidone in situ forming implants as a model, the current work focuses on: 1) identification of critical attributes of in vitro release testing methods that may contribute to differences in in vitro and in vivo drug release from in situ forming implants; and 2) optimization of the in vitro release method, with the aim of developing Level A IVIVCs for risperidone implants. Dissolution methods based on a novel Teflon shape controlling adapter along with a water non-dissolvable glass fiber membrane (GF/F) instead of a water dissolvable PVA film (named as GF/F-Teflon adapter and PVA-Teflon adapter, respectively), and an in-house fabricated Glass slide adapter were used to investigate the impact of: the surface-to-volume ratio, water uptake ratio, phase separation rate (measured by NMP release in 24 h post injection in vitro or in vivo), and mechanical pressure on the drug release patterns. The surface-to-volume ratio and water uptake were shown to be more critical in vitro release testing method attributes compared to the phase separation rate and mechanical pressure. The Glass slide adapter-based dissolution method, which allowed for the formation of depots with bio-mimicking surface-to-volume ratios and sufficient water uptake, has the ability to generate bio-relevant degradation profiles as well as in vitro release profiles for risperidone implants. For the first time, a Level A IVIVC (rabbit model) has been successfully developed for in situ forming implants. Release data for implant formulations with slightly different PLGA molecular weights (MWs) were used to develop the IVIVC. The predictability of the model passed external validation using the reference listed drug (RLD), Perseris®. IVIVC could not be developed when formulations with different PLGA molar ratios of lactic acid to glycolic acid (L/G) were included. The present work provides a comprehensive understanding of the impact of the testing method attributes on drug release from in situ forming implants, which is a valuable practice for level A IVIVC development. [Display omitted] [ABSTRACT FROM AUTHOR]

Since standard distributions do not fundamentally have an acceptable fit to all types of data sets, it is necessary to construct extensions of standard distributions to increase their capability in data modeling. As a result of this shortage in old ones, we proposed a novel generator based on the trigonometric function (Arctan). We selected the Frechet distribution as the baseline for the generator's applicability. This generator produces the "new Arctan Frechet distribution" (NATFD). The fundamental properties of the proposed distribution have been taken into consideration. Estimating the given distribution's parameters is accomplished using the maximum-likelihood method. A simulation study is carried out to evaluate the superiority of the proposed distribution, and two actual data sets are used. [ABSTRACT FROM AUTHOR]

Pineapple leaf fiber (PALF) is known as pineapple residue and has potential as a textile material. Typical yarn manufacturing adopts ring spinning technique, yet it is challenging for course fibers, including PALF. PALF has been used in clothing and paper production using textile thread. It has the highest modulus among leaf fibers, comparable to synthetic fibers such as aramid and glass, and possesses the greatest tensile strength among leaf fibers. PALF has high fineness index makes it ideal for industrial yarn and woven fabric applications. Using natural fibers offers benefits such as being environmentally friendly, cost-effective, and lightweight yet sturdy. This study evaluates the physical properties of PALF-cotton yarn at three twist speeds, two total drafts, and three PALF-cotton blending ratios. The methodology of this study involves carding, drawing, and ring spinning of the PALF-cotton fibers. The process starts with cutting and opening PALF before blending it with cotton fiber using a carding machine. The finding shows that the average diameter and fineness values range from 205 μm to 458 μm and 31.2 to 67.0 tex, respectively. The study also reported that twist speed, total draft, and blending ratio affect the diameter and fineness of the yarns. In contrast, the increment of twist speed and total draft decreases the fineness and diameter of PALF-cotton yarns. Pineapple leaf fiber (PALF) shows great potential in the apparel industry. Three regression models were presented to predict the future ring-spinning process, and pineapple waste can be repurposed into valuable products, reducing overall waste. [ABSTRACT FROM AUTHOR]

In view of the serious problem of recycling and insolubility of thermosetting resin matrix composites in automobile manufacturing, a curing agent containing dynamic imine bond was synthesized by using biovanillin and 4, 4-diaminophenylsulfone. It was further used to cure epoxy resins into a vitreous matrix for fiberglass composite that could be reprocessed and recycled. The composite shows excellent mechanical properties, with a tensile strength and modulus of 670 MPa and 29 GPa, flexural strength and modulus of 752 MPa and 27 GPa, and shear strength of 55 MPa, which are comparable to the commercial battery pack composite material such as BAC 449. This new vitrimer-based composite has better mechanical properties, and its flame retardant can reach UL-94 V-0 level. In addition, owing to the nature of dynamic imine bonds, this vitrimer-based composite can be chemically degraded so that the fiber and resin in the composite can be recycled and reused, helping with carbon reduction and environmental protection. It has potential application in the manufacturing of composite covers of battery packs for electric vehicles. [ABSTRACT FROM AUTHOR]