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The elastic, plastic, and in-plane damage evolutions of a carbon-fiber-reinforced epoxy composite fabricated via filament winding were studied based on continuum damage mechanics. The specific voids and resin-rich region distributions depended on the material and manufacturing conditions. The damage evolutions were expressed by a unified curve, indicating that the continuum damage mechanics approach gave a robust prediction of the damage evolution, although the critical damage at the ultimate failure depended on the material and manufacturing conditions. The damage coupling parameters were also affected by these conditions, which changed the damage evolution behavior under simultaneous shear and transverse damage development situations. [ABSTRACT FROM AUTHOR]

Continuously reinforced thermoplastic composites are widely used in structural applications due to their toughness, light weight, and shorter process cycle. Moreover, they provide flexibility in design and material selection. Unlike thermoset composites, continuous fiber content to maximize mechanical properties in thermoplastic composites has not been well investigated. In this paper, three thermoplastic systems are investigated to study the optimum content of continuous fiber reinforcement. These systems include carbon fiber/polyphenylene sulfide (PPS), glass fiber/PPS, and glass fiber/high-density polyethylene (HDPE). Tapes were made at several fiber contents, and samples were compression molded and tested using thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile, 3-point flexure, and short-beam shear tests. Results revealed that higher fiber content led to an increase in the glass transition and melt transition temperatures of the polymer. Some mechanical properties increased with fiber content and then began to decrease upon further addition of fibers, while other properties, such as ductility and interfacial bond strength, decreased with more reinforcement. Furthermore, the optimum fiber contents to maximize mechanical properties are different for different properties and different materials. [ABSTRACT FROM AUTHOR]

This study examines the use of waste and recyclable polyethylene terephthalate (rPET) along with micro-sized ground tire rubber (GTR) to produce a polymer matrix composite (PMC) material. The PMC materials are made in a Twin-screw extruder, with different ratios of rPET to GTR ranging from 90:10 to 50:50. In order to assess the performance of the newly created rPET-GTR matrix composite materials, the physical, mechanical properties are empirically observed. The thermal properties and crystallinity (Xc) of PMC materials are analysed using DSC. SEM and microscopic imaging are used to determine the characteristics of rPET-GTR composite materials, including elemental compositions like carbon, oxygen, and silicon. The functional group and chemical structure are confirmed through IR spectra analysis using FTIR techniques. The inclusion of micro-sized GTR has shown a significant effect on the physical (density = 1.306 - 1.208 g/cm3, water absorption = 1.76%–10.74%, and melt flow index = 8.12 - 12.79 gm/10 min), mechanical (tensile strength = 52.78 – 73.58 MPa, impact strength = 110.64 - 138.44 J/m, hardness = 56.14 - 76.37, and flexural modulus = 66.23 - 106.32 MPa), and thermal (melting temperature = 220.25°C–192.57°C, Xc = 20.30 to 30.58%) properties of rPET. These studies all work together to improve the performance of waste rPET and GTR materials by repurposing them. It helps to promote sustainability, cost-effectiveness, and expands the range of applications (automotive parts, building materials, sports equipment, electrical insulation and prosthetics) for rPET-based composites with potential uses in the polymer industries. [ABSTRACT FROM AUTHOR]

Polymer matrix composites are widely used in thermal management due to their advantages of light weight, corrosion resistance, easy processing and low cost. However, polymers typically have low thermal conductivities, and the addition of thermal conductive fillers is the main way to improve their thermal conductivities. The filler is one of the important factors that influence the thermal conductivity of composite materials. Therefore, the effect of the intrinsic structure of the filler on the thermal conductivity of polymer matrix composites is investigated to improve the utilization efficiency of the filler. According to the research idea of “topology optimization-simplification-verification”, the topology optimization is used to obtain the best structure of thermal conductivity filler by targeting the high thermal conductivity of the composite material. On the basis of this, the structure is simplified by considering the processability, and the thermal conductivity of the composite is verified by finite element analysis and infrared thermography. Results show that the composites present the best directional thermal conductivity when the shape of the filler is a dumbbell with two larger ends and a smaller center under the same graphite volume fraction. This paper provides a new idea for the structural design of highly efficient thermally conductive fillers and a new way to study the effect of the intrinsic structure of the filler on the thermal conductivity of composites and how to improve the utilization efficiency of fillers. [ABSTRACT FROM AUTHOR]

A high-performance Al2O3-PF composite coating was prepared on the surface of polymer matrix composite materials using supersonic high-energy plasma spraying technology. The bonding strength between the composite coating and the matrix was used as the evaluation index. The spraying process parameters were optimized using orthogonal experimental design method. Subsequently, the optimal process was verified based on single-factor experimental method, further exploring the influence mechanism of Ar flow rate, spraying current, spraying voltage, and second powder feeding position on the composite coating. Analysis shows that spray voltage, Ar flow rate, and spray current have a significant impact on the experimental results and are the main influencing factors; the second powder feeding position has a relatively small impact on the experimental results and is a secondary influencing factor. [ABSTRACT FROM AUTHOR]

Recently, additive manufacturing (AM) techniques like 3D printing have emerged as a potentially game-changing example of digital manufacturing. However, high entry barriers of a tiny material library, different processing defects, and unpredictable product quality are still holding back its widespread use in the industry. Due to its remarkable success in data tasks like classification, regression, and clustering, machine learning (ML) has recently gained a great deal of interest in the subject of the material library. This paper examines the current state of ML applications in several key areas of AM, including polymer matrix composite materials and machine parameter optimization. Composite filaments have been extruded using Polylactic Acid (PLA) as it is a biodegradable material and shows how High-Density Poly Ethylene (HDPE) enhances physical strength. All the parameters for the filament extruder have been designed by machine learning. Thermal stability is a significant concern for polymers that have been overcome by introducing Titanium Dioxide nanoparticles. The microstructure, surface texture, electro-mechanical behavior, and other general features of extruded filaments made from recycled plastics have been investigated. The extrusion temperature, approximated using ML, is in excellent agreement with the surface texture and microstructure of the polymers, as confirmed by FESEM, EDX, and Particle analysis. Extruded filaments experienced 2500 Vs and confirmed their non-conductivity up to 77.7GΩ. Tensile strength and elongation at break, two measures of mechanical properties, have been examined. Incorporation of Titanium Dioxide Nanoparticles improved mechanical properties significantly. When it comes to 3D printing, the physical properties and potential uses of each composite material are different.

Vulcanization is a process of joining the conveyor belt with high pressure and temperature. The machine consists of several components like stiffness bar, vertical supporting rod, heating plate, insulator, fasteners and particularly traverse bar which adds on to the weight of the machine. The machine consists of 5 to 10 traverse bar which is made aluminium 6061 alloy. In the present work, the weight of the vulcanization machine is reduced by reducing the weight of the traverse bar. This is achieved by choosing a less dense material. This research work mainly focused on reducing weight of the traverse bar by choosing polymer matrix composite material like epoxy carbon fiber and epoxy s-glass. A modelling and simulation work is conducted for aluminium alloy 6061 as well as composite material, deformation and stress are compared. I beam for epoxy carbon fiber deformation increased by 150 % and for epoxy s-glass increased by 366% comparing with traverse bar. In I beam with stiffener epoxy carbon fiber deformation is reduced by 38% for epoxy s-glass is increased by 6 %. Similarly, for equivalent stress composite materials for I beam is increased and for I beam with stiffener is decreased. The weight reduction from aluminium alloy to composite material is for epoxy carbon fiber is 81.70% and epoxy s-glass is 75.43%. In with stiffeners epoxy carbon fiber is 78.25% and epoxy s-glass is 70.81%. [ABSTRACT FROM AUTHOR]

Growing demand for electric energy in newly developed electronic systems causes increasing interest in research on piezoelectric nanogenerators (PENGs). Design and fabrication of such devices is challenging, considering cost of materials used in their construction. This is the main reason why intensive research has begun on 0‐3 composites with piezoelectric properties. One of the most promising constituent materials for composites fabrication are polymers, due to their low cost and easy processing. Herein, we present fabricated wearable PENG with good impact and vibration energy conversion properties. Correlation between matrix stiffness and piezoelectric properties of 0‐3 type composite is proposed. It was found that composite with 10 wt.% of BiFeO3 particles exhibits power output density for vibrations, finger tapping, and air stream pressure P = 11.12 nW cm−3, P = 4.83 μW cm−3, and P = 769.2 μW cm−3, respectively. Decrease in stiffness of epoxy matrix results at least in two‐times lower power output density for this same PENG. The obtained results demonstrate that the fabricated BFO/epoxy composites show the wide applicability and potential to be integrated with other functional devices, for example, as a part of wearable devices in smart shoes. [ABSTRACT FROM AUTHOR]

Polymer matrix composite (PMC) is widely applied in structural engineering mainly due to its high strength-to-weight ratio. Of many benefits, the transportation industry uses this type of material mainly due to its high strength-to-weight ratio. In many cases, this strength-to-weight ratio is higher than aluminum or steel base materials. Its manufacturing and fabrication, however, are challenging. For this reason, destructive and non-destructive tests to control product quality during the manufacturing process are worked out. The non-destructive test delivers many benefits since the finished product does not. This paper discusses the benefits of polymer matrix composite application in the structural engineering. In addition, this work also outlined the key parameters and comparison of various non-destructive tests applied for the PMC.

The BNNS-CNT/PVDF composite film with high in-plane thermal conductivity and insulation was prepared by using the strategy of hybrid synergy and orientation enhancement of different thermally conductive fillers. The boron nitride nanosheets(BNNS)/polyvinylidene fluoride(PVDF) fiber film by electrospinning was first prepared, and then surface sprayed carbon nanotubes(CNT) and multi-layer film hot pressing were used. Electrospinning technology enables BNNS to achieve in-plane orientation in PVDF films. The sprayed CNTs build an efficient thermal conduction path between the film layers and bridge the BNNS in the adjacent fiber films, which promotes the construction of in-plane thermal conduction network, but still maintains good insulation performance. As a result of the optimization of film preparation conditions, the in-plane thermal conductivity of the BNNS-CNT/PVDF composite film with 30%(mass fraction, the same below) BNNS and 3%CNT content reaches 3.25 W∙m-1∙K-1, which is 1104% higher than that of pure PVDF. Meanwhile, the film has an ultralow out-of-plane conductivity of 2.09×10-12 S∙cm-1. It is found that BNNS and CNT synergistically build an efficient thermal conductivity network, and the enhancement efficiency of 3%CNT for BNNS/PVDF is as high as 52.2% at 5%BNNS filling. At the same time, the thin film has good tensile strength and flexibility.

The paper presents algorithms for solving boundary value problems of electrical conductivity and magnetostatics for a cell of elastomeric composite materials (ECMs) by the finite element method. The algorithms enable one to determine both potential and strength of electromagnetic fields which are relevant in the development of the ECMs with specified functional properties. The values of electrical conductivity and magnetic permeability have been calculated by comparing their integral levels for the ECM cell (electromagnetic field energy and heat power loss) with those of the equivalent homogeneous material. [ABSTRACT FROM AUTHOR]

In this study, the effect of the addition of silica particles modified with silane agent on the mechanical properties of basalt fibers‐epoxy composites were studied with the interlayer shear strength (ILSS) test. In the first stage, silica fume particles were synthesized using the sol‐gel method and surface modified using tri mercaptopropyl trimethoxy silane agent. The results of the characterization showed that the synthesized powder is nanometric scale, amorphous and high purity. The surface‐modified silica fume particles (0, 2, 4, 6 wt.%) were distributed inside the epoxy matrix using a mechanical stirrer and ultrasonic waves. The hand lay‐up method was used to fabricate composite samples, then the effect of adding these particles on the mechanical properties of basalt fibers‐epoxy composites under interlayer shear loads was studied. The results of the research indicated that the addition of silica fume particles has a significant effect on improving the mechanical properties of basalt fibers‐epoxy composites, and the greatest improvement in mechanical properties was achieved by adding 4 wt.% of modified silica fume particles. In the case of composites without SF particles, the shear strength was 34 MPa, which was increased to 40 MPa by adding 4 wt.% of SF particles (about 20% improvement). On the other hand, results demonstrated that the optimal distribution of silica fume particles within the polymer matrix performs an impressive role in improving the mechanical response of composite samples. Highlights: The use of silica fume in the polymer composite is one of the research innovations.Silica fume is a super‐fine spherical powder that is collected as a by‐product.The silane is used to better distribute and optimal interaction of the silica fume in epoxy.Sol‐gel is one of the methods to synthesis of silica fume.ILSS test was done to investigate the strength of the interface of basalt fibers and epoxy. [ABSTRACT FROM AUTHOR]

The ultrahigh in‐plane thermal conductivity makes the graphene nanoplatelet a promising reinforcement filler for improving the thermal conductivity of polymer materials. Up to now, the highest thermal conductivity enhancement has been achieved by aligning the nanoplatelets along the heat flux direction. In this work, extensive molecular dynamics simulations are carried out to understand the thermal conductivity enhancement capabilities of different architectures of the graphene nanoplatelets within the polyamide‐6 matrix. Surprisingly, we find that the orthogonally arranged graphene nanoplatelets offer even better thermal conductivity enhancement than the simply aligned graphene nanoplatelets. An in‐depth investigation shows that the orthogonal structure can achieve a balance between the global percolation and the alignment of graphene nanoplatelets. Specifically, such an orthogonal structure can take advantage of both thermal percolation and graphene's ultrahigh in‐plane thermal conductivity. Moreover, we have systematically investigated the effects of the size and number density of the nanoplatelets on the thermal conductivity enhancement capability of the orthogonal configuration. Finally, by proposing a validated analytical model, we have identified the pathways to maximize the thermal conductivity of the orthogonally arranged graphene nanoplatelets. The conclusion of this work points out the possible way to develop the graphene‐polymer composite system with exceedingly high thermal conductivity. Highlights: Different graphene configurations are constructed for polymer composite.Chemical reactions at the edge of graphene nanoplatelets are considered.High‐throughput molecular dynamics simulations are conducted to measure thermal conductivity.Competition between graphene alignment and thermal percolation is identified.A theoretical model is established for graphene‐polymer composite. [ABSTRACT FROM AUTHOR]

As sensor materials for structural health monitoring (SHM, a nondestructive test for the continuous evaluation of the conditions of individual structural components and entire assemblies), magnetostrictive materials, piezoelectric materials, and optical fibers have attracted significant interest. In this study, the mode I interlaminar fracture load and crack self-detection potential of glass fiber-reinforced polymer (GFRP)–embedded magnetostrictive Fe–Co fibers were investigated via double cantilever beam testing. The results indicated that by controlling the amount of Fe–Co fibers introduced into GFRP, the number of Fe–Co fibers could be reduced without compromising the performance of GFRP. Furthermore, the magnetic flux density increased significantly with crack propagation, indicating that the magnetic flux density change could determine crack propagation. [ABSTRACT FROM AUTHOR]

This present study investigates the role of adding sugarcane bagasse biosilica (SBB) fine particle on Opuntia dillenii fibre (ODF)-reinforced epoxy resin composite and its mechanical, thermal and laminar shear strength properties. In this study, the biosilica particles were prepared from Indiana sugarcane bagasse via thermo-chemical process. The fibre and particles were silane surface-treated (SST) using 3-aminopropyltrimethoxysilane via acid hydrolysis process. Hand layup was used to create the composites, which were then post-cured at 120 °C for 48 h. The composites were characterized using ASTM standards in order to evaluate the mechanical, thermal and laminar shear strength properties. The tensile strength of SST fibre and particle produced the highest strength of 178 MPa for 40 vol.% of fibre and 2 vol.% of particle in epoxy resin. Similarly, the SST fibre and particle retained high thermal stability than as-received fibre and particle in the composite. The laminar shear strength of SST fibre shows the highest value of 33 MPa against shear load. The SEM morphology shows highly adherence surface between SST fibre and resin. Thus, in the process of making biocomposites using plant-based fibres, the silane treatment is mandated in order to achieve high performance. [ABSTRACT FROM AUTHOR]

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Standard Digital Volume Correlation (DVC) approaches enable quantitative analyses of specimen deformation to be performed by measuring displacement fields between discrete states. Such frameworks are thus limited by the number of scans (due to acquisition duration). Considering only one projection per loading step, Projection-based Digital Volume Correlation (P-DVC) allows 4D (i.e., space and time) full-field measurements to be carried out over entire loading histories. The sought displacement field is decomposed over a basis of separated variables, namely, temporal and spatial modes. In the present work, the spatial modes are constructed via scan-wise DVC, and only the temporal amplitudes are sought via P-DVC. The proposed method is applied to a glass fiber mat reinforced polymer specimen containing a machined notch, subjected to in situ cyclic tension and imaged via X-ray Computed Tomography. The P-DVC enhanced DVC method employed herein enables for the quantification of damage growth over the entire loading history up to failure. [ABSTRACT FROM AUTHOR]

The thermal, the electrical conductivity, and electromagnetic shielding properties of low cost high-performance expanded graphite (EG)-filled polybenzoxazine matrix nanocomposites produced by a solution blending and compression molding technique were investigated. At 2.26 vol.% EG, a percolation threshold was detected, at which the electrical conductivity increased by nine orders of magnitude in comparison to the unfilled matrix. The electrical conductivity values increased from 1.35 S.cm−1 to 28.3 S.cm−1 by increasing the EG ratios in the nanocomposites from 7 wt.% and 15 wt.%. In addition, the morphological analysis results revealed good nanofiller dispersion and the formation of 3D-conductive pathways of EG into the polybenzoxazine matrix, which are responsible for the electrical conductivity improvement. Moreover, the electromagnetic interference (EMI) shielding efficiencies, in the X-band, of these nanocomposites have been significantly improved, reaching 57.2 dB at a 15 wt.% EG ratio. Furthermore, the inclusion of EG nanofiller significantly improved the thermal properties of the nanocomposites in terms of first degradation temperatures, char yields, and thermal conductivities. Because of these exceptional properties, these nanocomposites are ideal for high thermal EMI shielding applications. [ABSTRACT FROM AUTHOR]

Novel composite comprising of Kulkual fibers and Titanium diboride (TiB2) filler reinforced epoxy composites is investigated in the current work. Kulkual also known as Opuntia ficus‐indica is a plant abundantly found throughout Ethiopia are utilized in the form fibers in combination with TiB2 as reinforcement to synthesize epoxy matrix composites. Six types of composites including neat epoxy are fabricated using varying content of Kulkual fibers (0, 2.5, 5, 7.5, and 10 vol%) and fixed TiB2 content of 5 vol%. The fibers were obtained by drying the leaf‐like stem of Kulkual and collecting the skeleton structure found in cladodes. Alkaline treatment of Kulkual fiber to study its physical properties was also investigated. All composites' tensile moduli rise with increasing fiber content and are between 21% and 162% higher than the pure epoxy. All the composites tensile strength increase in the range from 43% to 211% compared to neat epoxy with EK‐10 composite revealing the greatest improvement. Flexural properties of all the composites increase with increase in Kulkual fiber content in comparison with neat epoxy. Good bonding of constituents and alkaline treatment of fibers results in enhanced properties of composites. Finally, fractured surfaces are analyzed with scanning electron micrographs to recognize structure property correspondences. [ABSTRACT FROM AUTHOR]

Fotovoltaik (FV) modüller, üzerine düşen güneş ışınlarından elektrik üretimini sağlayan ve yüzeyinde birden çok FV hücre bulunan yapılardır. FV hücreler, sadece direkt gelen ışınları değil, yüzeye gelen tüm ışığın belirli dalgaboyu aralığını enerji üretimi için kullanabilirler. FV modüller, yapıları gereği sıcaklıkları, ortam sıcaklığına kıyasla daha fazla olmakta ve bu durum FV hücrelerin elektriksel verim ve güç üretim düşümüne neden olmaktadır. Bu sebeple, FV modüllerde depolanan ısı enerjisinin dışarıya transferi konusunda akademik çalışmalar son yıllarda ivme kazanmıştır. Örneğin, FV modüllerden ısı enerjisi elde edilerek sıfır enerji tüketim hedefi altında konutların ısıtma yükü karşılanmakta ve ilerleyen çalışmalar ile birlikte sistem/enerji verimi arttırılmaktadır. Bu çalışma, FV modüllerin ısı iletim performansının geliştirilmesine yönelik polimer esaslı takviye malzemelerin kullanımı ile oluşturulan kompozit yapılar incelenerek, FV modülde depolanan ısı enerjisinin azaltılmasını hedef almıştır. Bu amaçla, takviye malzemeler araştırılmış ve karbon, cam elyaf, aramid (kevlar) takviye malzemelerinin iki farklı parametre altında araştırılması uygun görülmüştür. Bu iki parametre, herbir takviye malzemenin farklı tabaka kalınlıklarındaki ve birbirleri ile oluşturduğu hibrit yapıdaki sahip oldukları ısı iletim performansını araştırmaktadır. Araştırma sonucunda karbon elyaf takviye malzemesi ile oluşturulan yapının 6,51 W/mm2 ısı akısı ile birlikte optimum yapı olduğu elde edilmiştir. Isı iletim performansında karbon elyafı cam elyaf (0,013 W/mm2) ve aramid (4.10-4 W/mm2) takip etmiştir. Bu araştırma polimer kompozit malzemeler ile lamine edilmiş FV modül ve konvansiyonel tip FV modül arasındaki ısı akısı farkını 0,0242 W/mm2 olarak elde ederek FV modüllerden elde edilebilen ısı enerjisinin arttırımına katkıda bulunmuştur.

The work is focused on the mechanical behavior description of porous filled composites that is not based on simulations or exact physical models, including different assumptions and simplifications with further comparison with real behavior of materials with different extents of accordance. The proposed process begins by measurement and further fitting of data by spatial exponential function zc = zm · p1b · p2c, where zc/zm is mechanical property value for composite/nonporous matrix, p1/p2 are suitable dimensionless structural parameters (equal to 1 for nonporous matrix) and b/c are exponents ensuring the best fitting. The fitting is followed by interpolation of b and c, which are logarithmic variables based on the observed mechanical property value of nonporous matrix with additions of further properties of matrix in some cases. The work is dedicated to the utilization of further suitable pairs of structural parameters to one pair published earlier. The proposed mathematical approach was demonstrated for PUR/rubber composites with a wide range of rubber filling, various porosity, and different polyurethane matrices. The mechanical properties derived from tensile testing included elastic modulus, ultimate strength and strain, and energy need for ultimate strain achievement. The proposed relationships between structure/composition and mechanical behavior seem to be suitable for materials containing randomly shaped filler particles and voids and, therefore, could be universal (and also hold materials with less complicated microstructure) after potential following and more exact research. [ABSTRACT FROM AUTHOR]

Polymer matrix composite (PMC) is advantageous in the unmanned aerial vehicle (UAV) field because of the phenomenal lightweight structural material injunction with the high specific strength/stiffness. In this study, a special type of PMC used in UAV as a structural material has been investigated. The microstructure revealed a uniform distribution of the reinforcement (E-glass fiber) in the matrix (epoxy) fabricated by the lay-up process. The study focuses on adjusting the matrix by investigating the effect of the solvent (methyl hydroxide) on the polymer matrix. Four compositions have been investigated by varying the methyl hydroxide content. Evidence of cross-link increase has been detected by Fourier transform infrared spectroscopy. The results show that the net resin achieved higher stability by adding methyl hydroxide in specific amounts that has shown an optimum enhancement on the matrix, reflected by the mechanical testing resulting in tensile strength and flexural strength. Aluminum oxide has been added to the optimum composition as a secondary reinforcement to increase the rigidity explained by the microstructure where a noticeable decrease in tensile/flexural strength is evident in the composite. [ABSTRACT FROM AUTHOR]

This work presents the results of a tribological examination of polymer matrix composites reinforced with carbon foams with different porosity. The application of open-celled carbon foams allows an easy infiltration process by liquid epoxy resin. At the same time, carbon reinforcement remains its initial structure, which prevents its segregation in polymer matrix. Dry friction tests, conducted under 0.7, 2.1, 3.5 and 5.0 MPa loads, show that higher friction load results in higher mass loss, but it strongly lowers the coefficient of friction (COF). The change in coefficient of friction is related to the size of the pores of the carbon foam. Open-celled foams with pores size below 0.6 mm (40 and 60 ppi), used as a reinforcement in epoxy matrix, allow to obtain COF twice lower than composite reinforced with 20 ppi open-celled foam. This phenomenon occurs due to a change of friction mechanisms. In composites reinforced with open-celled foams, general wear mechanism is related to destruction of carbon components, which results in solid tribofilm formation. The application of novel reinforcement, in the form of open-celled foams with stable distance between carbon components, allows the decrease of COF and the improvement of stability, even under a very high friction load. [ABSTRACT FROM AUTHOR]

Properties of particulate-filled polymer matrix composites are highly dependent on the spatial position, orientation and assembly of the particles throughout the matrix. External fields such as electric and magnetic have been individually used to orient, position and assemble micro and nanoparticles in polymer solutions and their resulting material properties were investigated, but the combined effect of using more than one external field on the material properties has not been studied in detail. Applying different configurations of electric and magnetic fields on geometrically and magnetically anisotropic particulates can produce varying microarchitectures with a range of material properties. Experimentally and with simulations, we systematically probe the effect of combined electric and magnetic fields on the microstructure formation of geometrically and magnetically anisotropic barium hexaferrite (BHF) in polydimethylsiloxane (PDMS). The magnetic and dielectric properties resulting from different microstructures are characterized and microstructure-property relationships are analyzed. Our results demonstrate that a variety of microarchitectures can be produced using multi-field processing depending on the nature of the applied external field. For example, the application of an electric field creates macro-chains where the orientation of the BHF stacks inside the macro-chains is random. On the other hand, application of a magnetic field rotates the BHF stacks within the macro-chain in the direction dictated by the magnetic field. In simulations, the dielectrophoretic, magnetic, and viscous forces and torques acting on the particles show that particle anisotropies are central to the ability to control orientation along the orthogonal magnetic and geometric axes, mirroring experimental results. The authors refer to the ability to manipulate particle orientation along orthogonal axes as 'orthogonal control'. Using this technique, not only are a variety of microstructures possible, but also a range of dielectric and magnetic properties can result. For example, for 1 vol% BHF-PDMS composites, the experimental dielectric permittivity is found to vary from 2.84 to 5.12 and the squareness ratio (remnant magnetization over saturation magnetization) is found to vary from 0.55 to 0.92 (from 0.52 to 0.99 in simulations) depending on the applied external stimuli. The ability to predict and produce a variety of microstructures with a range of properties from a single material set will be particularly beneficial for resin pool based additive manufacturing and 3D printing. [ABSTRACT FROM AUTHOR]

In electrically conductive composites placed in an electric field, heat is released and non-uniform temperature fields are formed. This circumstance, in turn, induces strains and stresses in such composites. The article solves a sequence of unrelated boundary value problems: electrical conductivity in a field of direct electric current, thermal conductivity, thermoelasticity. It is shown that when an electric current flows in copper-graphite and copper-filled polymer composites, displacements, deformations, and stresses occur even in the case when the components of the composite do not have a piezoelectric effect. [ABSTRACT FROM AUTHOR]

As sensor materials for structural health monitoring (SHM, a nondestructive test for the continuous evaluation of the conditions of individual structural components and entire assemblies), magnetostrictive materials, piezoelectric materials, and optical fibers have attracted significant interest. In this study, the mode I interlaminar fracture load and crack self-detection potential of glass fiber-reinforced polymer (GFRP)–embedded magnetostrictive Fe–Co fibers were investigated via double cantilever beam testing. The results indicated that by controlling the amount of Fe–Co fibers introduced into GFRP, the number of Fe–Co fibers could be reduced without compromising the performance of GFRP. Furthermore, the magnetic flux density increased significantly with crack propagation, indicating that the magnetic flux density change could determine crack propagation.

Environmental pollution has become one of the major challenges to overcome in recent decades. Disposing waste materials has caused great concern by creating a landfill burden and increased environmental pollution. Utilizing or recycling wastes is one of the approaches considered that could bring positive environmental and economic benefits. Eggshells are among the understated waste materials that have great potential to impact the material world. In the present work, Habesha eggshells native to Ethiopia are utilized to prepare epoxy based composites. Five types of composites by varying the Habesha eggshell content (0, 2.5, 5, 7.5, and 10 vol%) are investigated. Physical characterization in terms of density and void content estimations, and eggshell particle size analysis are carried out. Mechanical characterization in terms of normal and quasi‐static compression tests are performed. Results infer the density of eggshell particles to increase with increasing eggshell content, while quasi‐static compression tests infer that modulus and strength of eggshell/epoxy composites are sensitive to variations in the strain rate. However, irrespective of the strain rates, all the eggshell/epoxy composites depict higher modulus as compared with neat epoxy specimens. At 1.43, 0.1, and 0.001 strain rates, increase in modulus of composites are in the range of 17%–57%, 3%–107%, 30%–114%, respectively. Further, compressive yield strength of all the Habesha eggshell/epoxy composites is low compared with epoxy specimens for all the strain rates investigated. Scanning electron micrographs of test specimens for different loading conditions reveal reinforcing egg shell particles assists in absorbing the loading effectively. [ABSTRACT FROM AUTHOR]

The low-velocity impact behavior of thick and thin unidirectional E-glass fiber-reinforced laminated composite plates with three different stacking sequences subjected to three different impact energies have been investigated. The test specimens were produced by the Vacuum Assisted Resin Injection (VARI) method in a laboratory environment. The thick specimens contained 50 layers of unidirectional E-glass fibers and the thin ones — 16 layers of unidirectional E-glass fibers. The low-velocity impact tests were carried out using a CEAST Fractovis drop-weight impact test device. The contact force–time and energy–time graphics were plotted and the experimental results were interpreted in detail. [ABSTRACT FROM AUTHOR]

Standard Digital Volume Correlation (DVC) approaches enable quantitative analyses of specimen deformation to be performed by measuring displacement fields between discrete states. Such frameworks are thus limited by the number of scans (due to acquisition duration). Considering only one projection per loading step, Projection-based Digital Volume Correlation (P-DVC) allows 4D (i.e., space and time) full-field measurements to be carried out over entire loading histories. The sought displacement field is decomposed over a basis of separated variables, namely, temporal and spatial modes. In the present work, the spatial modes are constructed via scan-wise DVC, and only the temporal amplitudes are sought via P-DVC. The proposed method is applied to a glass fiber mat reinforced polymer specimen containing a machined notch, subjected to in situ cyclic tension and imaged via X-ray Computed Tomography. The P-DVC enhanced DVC method employed herein enables for the quantification of damage growth over the entire loading history up to failure.

abstract: In this study the creep behaviour and its dependence on moisture content in injection moulded hybrid composites reinforced with carbon fibres and carbon nanotubes was investigated. The tensile tests and the scanning electron microscope images confirmed that the presence of carbon fibres helped the uniform distribution of carbon nanotubes in the matrix. In the composites reinforced only with carbon fibres, the creep rate was lower than in any of the composites reinforced with only carbon nanotubes. Synergistic effects were observed when carbon nanotubes were added to the composite besides the carbon fibres: the creep rate was even lower and decreased with the increase in nanotube content. In the composites only reinforced with carbon nanotubes, crystallinity decreased, and moisture absorption increased with increasing nanotube content, but in the hybrid composites, the decrease in crystallinity and moisture absorption was much lower, thus the disadvantageous effect of moisture on the creep rate was much smaller in the hybrid composites.

This data article presents experimental data on the in-plane mechanical behavior of a carbon-epoxy twill woven composite. Properties under tension, shear, and compression are measured and reported, which include force vs. stroke curves, stress vs. strain curves, in-plane on-axis and off-axis moduli, in-plane shear modulus, tensile and compressive strengths, post-peak residual stress under compression, and on-axis and off-axis Poisson ratios. Laminate plates of the composite were ordered from a commercial vendor and specimens of desired dimensions were cut using a waterjet cutter. Tests were conducted in accordance with ASTM standards D3039 and D6641, under on-axis and off-axis tension, and under on-axis compression. The data represents a complete set of in-plane mechanical properties for the composite and can be used directly as lamina level input to numerical FEA models and design analyses with woven composite laminates. It can also serve as benchmark for the calibration and validation of these models. It can be used to calculate properties for other off-axis configurations using transformation equations. Since the data is intended to be a lamina level input, it can be used to determine and model the in-plane behavior of any laminate layup with this composite. The data also serves to demonstrate the marked anisotropy and tension compression asymmetry exhibited by woven composites.

A synthetic composite material membrane was synthesized using Polyether ether ketone (PEEK) as a polymer matrix, reinforced with nano-Hydroxyapatite (nHAp) as the ceramic for intended use as a hip bone implant material. Notwithstanding its close resemblance with hip bone material, PEEK is chemically and biologically inert and comes with limited biocompatibility. HAp has chemical and crystallographic similarity with carbonated apatite like human bones. In the present work it was used as reinforcement with PEEK in varying weight percentages, of 2, 5, 8 and 10 to determine the optimum mix for application as a bio hip implant material. HAp reinforcement beyond 10 wt. % was not considered as it resulted in agglomeration and reduction in mechanical properties. The polymer was sulphonated to facilitate chemical interactions with the hydroxyl (-OH) group of HAp to overcome poor interfacial bonding between PEEK and nHAp. The sulphonation also reduced the chances of wear debris from implant site getting resorbed into the body. These synthetic composite samples were then characterized using techniques such as x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope and energy dispersive x-ray spectroscopy, to ascertain its conformity in structure and morphology. Mechanical tensile tests were also carried out to determine tensile strength, yield strength and elastic modulus of the composite membranes. The synthesized sample, with 8 wt. % of HAp reinforcement, demonstrated the most suitable properties. The work propounds a fresh approach towards synthesizing a composite membrane using Polyether ether ketone, subjected to sulphonation (SPEEK), for intended application as a hip implant. The superior surface wetting, obtained on account of sulphonation of PEEK matrix, facilitated more intimate contact with nano-hydroxyapatite (nHAp) reinforcements and assisted in establishing superior, homogeneous and improved mechanical properties throughout the membrane. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) modules are structures that produce electricity from the sun's rays falling on them and have more than one PV cell on their surface. PV cells can use not only direct rays, but also a certain wavelength range of all light coming to the surface for energy production. Due to their nature, PV modules have a higher temperature compared to the ambient temperature, which causes a decrease in the electrical efficiency and power generation of the PV cells. For this reason, academic studies on the transfer of heat energy stored in PV modules to outside have gained momentum in recent years. For example, by obtaining heat energy from PV modules, the heating load of the houses is met under the target of zero energy consumption, and the system/energy efficiency is increased with further work. This study aimed to reduce the heat energy stored in the PV module by examining the composite structures formed using polymer-based reinforcement materials to improve the heat conduction performance of PV modules. For this purpose, reinforcement materials were investigated, and it was found appropriate to investigate carbon, glass fiber, aramid (Kevlar) reinforcement materials under two different parameters. These two parameters investigate the heat conduction performance of each reinforcement material in different layer thicknesses and in the hybrid structure formed with each other. As a result of the research, it has been obtained that the structure formed with carbon fiber reinforcement material is the optimum structure with a heat flux of 6.51 W/mm². In heat conduction performance, carbon fiber was followed by glass fiber (0.013 W/mm²) and aramid (4.10-4 W/mm²). This research contributed to the increase of the heat energy that can be obtained from PV modules by obtaining the heat flux difference between the PV module and the conventional type of PV module laminated with polymer composite materials as 0.0242 W/mm². [ABSTRACT FROM AUTHOR]

The achievement of well-performing pressure sensors with low pressure detection, high sensitivity, large-scale integration, and effective analysis of the subsequent data remains a major challenge in the development of flexible piezoresistive sensors. In this study, a simple and extendable sensor preparation strategy was proposed to fabricate flexible sensors on the basis of multiwalled carbon nanotube/polydimethylsiloxane (MWCNT/PDMS) composites. A dispersant of tetrahydrofuran (THF) was added to solve the agglomeration of MWCNTs in PDMS, and the resistance of the obtained MWCNT/PDMS conductive unit with 7.5 wt.% MWCNTs were as low as 180 Ω/hemisphere. Sensitivity (0.004 kPaâˆ'1), excellent response stability, fast response time (36 ms), and excellent electromechanical properties were demonstrated within the pressure range from 0 to 100 kPa. A large-area flexible sensor with 8 Ă— 10 pixels was successfully adopted to detect the pressure distribution on the human back and to verify its applicability. Combining the sensor array with deep learning, inclination of human sitting was easily recognized with high accuracy, indicating that the combined technology can be used to guide ergonomic design. [ABSTRACT FROM AUTHOR]

With recent developments in conductive composites, new possibilities emerged for 3D printed conductive structures. Complementary to a vast number of publications on materials properties, here we investigate the influence of printing parameters on the resistance of 3D printed structures. The influence of printing temperature on the resistance is significant, with too low value (210 °C) leading to nozzle clogging, while increasing the temperature by 20 °C above the recommended printing settings decreases resistivity by 15%, but causing degradation of the polymer matrix. The limitations of the FDM technique, related to the dimension accuracy emerging from the layer-by-layer printing approach, greatly influence the samples' cross-section, causing irregular resistivity values for different layer heights. For samples with layer thickness lower than 0.2 mm, regardless of the nozzle diameter (0.5–1 mm), high resistance is attributed to the quality of samples. But for a 1 mm nozzle, we observe stabilized values or resistance for 0.3 to 1 mm layer height. Comparing resistance values and layer height generated from the slicer software, we observe a direct correlation—for a larger height of the sample resistance value decrease. Presented modifications in printing parameters can affect the final resistance by 50%. Controlling several parameters simultaneously poses a great challenge for designing high-efficiency structural electronics. [ABSTRACT FROM AUTHOR]

In the present investigation, the fatigue life detection of composite material by adding copper particle of less than 25 μm diameter with 0, 5, 10, 15 % volume fraction, as a reinforcements into the unsaturated polyester polymer composite material on fatigue life detection of composite material were studied experimentally and numerically. Composites were made using hand lay-up technique and evaluated for mechanical and fatigue properties in accordance with ASTM standards. The experimental results of the tensile test showed that adding 15% of copper particle in unsaturated polyester gives maximum ultimate tensile stress. Fatigue tests including test rod specimens made of composite materials under completely reversed cyclic loading in a rotating cantilever reversed bending machine. It is found that, the fatigue life and fatigue strength increase with increasing in the copper percentage volume fraction in unsaturated polyester resin. The experimental work was compared with numerical work, which was done by using ANSYS/19 and good agreement has been found. The maximum overall difference between the experimental and numerical work was around 9 %.

In this present study, the effect of silane treated ramie fiber addition along with organically‐modified montmorillonite (OMMT) nano clay in epoxy resin composite was investigated in drop load impact, shear loading, and high‐speed drilling. The main aim of this research study was to develop a high‐laminar shear strength epoxy structural composite for various engineering applications. To improve the laminar adhesion the fiber was treated using silane via acid hydrolysis technique. The OMMT nanoclay also added with fiber in order to improve the load bearing effect and adhesion phenomenon. The composites were prepared using hand layup method with postcuring. The adhesion behavior of composites was tested based on American society for testing and materials standards and compared. According to the results, the treated ramie fiber possesses high resistance to impact loading. The ballistic resistance of composite is increased three fold when compare with as‐received fiber‐epoxy composites. The interlaminar shear strength of composite designation C1.5 gives highest shear strength of 35 MPa. The drilling study revealed highest dimensional stability for treated fiber. No fiber chip off and pull out at the drilled hole surface. The fractography analysis confirms no lamina delamination occurs even at high‐speed drilling. These delamination resistance epoxy‐based composites are suitable in automobile, structural and defense gadget manufacturing applications. [ABSTRACT FROM AUTHOR]

Surface treatments on polymer-based materials are frequently used to enhance mechanical and physical properties. Cold spray is a metallisation technique that provides a viable solution to overcome the main drawbacks of conventional thermal spray processing techniques related to surface degradation at high temperatures. This review provides a critical overview on the metallisation of polymers and polymer matrix composites using cold spray. It offers an informative read on different approaches, bonding mechanisms, spraying procedures and parameters that influence the deposition efficiency, and the features of the coating. The future scope section broadly highlights potentially relevant areas for further developments using the method for metallising polymer-based substrates. [ABSTRACT FROM AUTHOR]

Polyester based hybrid composites is developed using 75 µm sized wood charcoal and periwinkle shell as particulate reinforcements in various proportions of mixture. Hardness, dry sliding wear and morphological examinations were performed on the hybrid composite samples using Brinell hardness tester, pin-on-disc tribometer and SEM-EDX techniques respectively. The results from the study revealed that all the hybrid composites have improved properties over the unreinforced polyester resin and polyester sample reinforced with only wood charcoal at 5 wt% reinforcement concentration. Optimal combination of hardness and wear properties was obtained by the hybrid composite sample reinforced with equal proportions of wood charcoal and periwinkle shell particles. Further additions of periwinkle shell particles over the content of wood charcoal powder in the 25:75 ratio, induced a sharp decrease in hardness and wear properties of the hybrid composites below that of the unreinforced polyester resin. SEM-EDX analysis revealed the presence of varying proportions of carbon, calcium, silicon, potassium, iron and aluminium as the major elements, which resulted in the observed hardness, and wear properties of the hybrid composites. Optimal reinforcement weight fraction and combination of wear parameters required for minimum wear rate and improved hardness was established using one factor RSM design.

Soft robotic gloves that assist people in acquiring hand movement and gesture for various applications have been developed by various design and manufacturing methods over the decades. Major concerns in the recent development of gloves involve finger-related sensibility and effectiveness of movement acquisition as applied by various means for different applications. Also, remarkable progress in developing advanced materials and structures has resulted in promising design and fabrication using different methods. This paper reports a hybrid 3D printing approach that can be realized by an integrated design and manufacturing (IDM) scheme with direct ink writing (DIW) and fused deposition modeling (FDM) sequentially. Preparing a conductive polymer matrix composite (PMC) incorporating graphene and graphite with silicone rubber, the DIW sensor of the PMC embedded onto an FDM robotic glove of thermoplastic polyurethane was illustrated to demonstrate the piezoresistive effect on deformation of the structure in which an essential change in the electrical resistance was detected during bending and recovering. It showed remarkable sensibility over the deformation of the resistors and the fingers' bending with various degrees. In the future, innovative composites and structures of robotic gloves based on DIW and FDM of the present IDM scheme could be further explored in applications such as human-machine interfaces. [Display omitted] • A soft robotic glove was embedded with sensors via an integrated design and manufacturing process. • Conductive polymer matrix composites were prepared for direct ink writing of the resistive sensors. • Thermoplastic polyurethane was utilized to fabricate the soft glove using fused deposition modeling. • Piezoresistive performances of the five bent fingers in the glove were characterized and analyzed. [ABSTRACT FROM AUTHOR]

Cellulose, due to its excellent mechanical and tribological properties and eco-friendliness, is suitable for environmentally friendly applications. However, its application is limited due to susceptibility to wear and damage under stress during usage. This study introduces nanosized aluminum, copper, alumina, and copper oxide into composite materials to tackle the challenges of wear and damage. This approach aims to improve the tribological performance of Hydroxypropyl methylcellulose (HPMC) composite coatings significantly. The additive particles enhanced the load-bearing capacity and wear properties of cellulose-based composite coatings. The velocity accommodation mode was provided by nano-metals through S3M2 (interaction of metal particle additives through a third-body mechanism), while for nano-oxides, it was S3M4 (expulsion of nanoparticles from the wear mark to the outer contact zone). Due to the higher specific stiffness and strength of oxides, nanofillers in the composite offered better load resistance than nano-metals, resulting in a smaller actual contact area during wear. Therefore, metal oxide nanofillers enhanced tribological properties more effectively than metal nanoparticles. Finally, detailed explanations of the tribological evidence and discussions on the mechanism were conducted. • Utilizes cellulose, an eco-friendly biopolymer, for advanced lubricant coatings • Enhances hydroxypropyl methylcellulose (HPMC) coatings with Al, Cu, and metal oxide nanoparticles • Analyzes wear volume and friction coefficient of nanoparticle-enhanced HPMC coatings • Demonstrates improved wear resistance with increased nanoparticle concentrations • Provides nano-level insights into wear mechanisms through third-body theory detailed FESEM imagery [ABSTRACT FROM AUTHOR]

The work is focused on the mechanical behavior description of porous filled composites that is not based on simulations or exact physical models, including different assumptions and simplifications with further comparison with real behavior of materials with different extents of accordance. The proposed process begins by measurement and further fitting of data by spatial exponential function zc = zm · p1b · p2c, where zc/zm is mechanical property value for composite/nonporous matrix, p1/p2 are suitable dimensionless structural parameters (equal to 1 for nonporous matrix) and b/c are exponents ensuring the best fitting. The fitting is followed by interpolation of b and c, which are logarithmic variables based on the observed mechanical property value of nonporous matrix with additions of further properties of matrix in some cases. The work is dedicated to the utilization of further suitable pairs of structural parameters to one pair published earlier. The proposed mathematical approach was demonstrated for PUR/rubber composites with a wide range of rubber filling, various porosity, and different polyurethane matrices. The mechanical properties derived from tensile testing included elastic modulus, ultimate strength and strain, and energy need for ultimate strain achievement. The proposed relationships between structure/composition and mechanical behavior seem to be suitable for materials containing randomly shaped filler particles and voids and, therefore, could be universal (and also hold materials with less complicated microstructure) after potential following and more exact research.