Manufacture Of Composite Materials Research Articles

Recovering recycled carbon fiber by pyrolysis of cured prepregs

Due to the rapid growth of the composite market, several European laws have emerged to minimize their environmental impact (EU 2000/53 / EC, End of life vehicles), as well as to make rational use of landfills (EU 1999/31 / EC). For example, in the aeronautical sector, composites can reach 50% by weight of the aircraft. Consequently, recyclability is a key issue. The objective of this work is the study of the recycling techniques of carbon fiber composites with thermoset polymer matrix in order to obtain fibers with similar properties to the original ones. In this way, the fibers could be reused in new composites by themselves or together with flass fibers in the manufacture of new hybrid composite materials. By this hybridization, materials with properties far superior to the GFRP would be obtained, but at much lower cost than the original CFRP. Therefore, this recycling and reprocesing strategies provides great economical attractiveness.  The main objective of the project is to study and optimize the recyclability of cured carbon fiber / epoxy prepregs for use in hybrid materials. Starting from a pyrolysis in a controlled atmosphere reactor, followed by a oxidation, carbon fibers with properties similar to virgin fibers are obtained, with a loss less than 20% of the tensile strength. An evaluation of the different parameters of the recycling process has been carried out in order to optimize the procedure. The characterization of the fibers includes tensile tests, scanning electron microscopy and Raman spectroscopy.

Manufacture of aluminum composite materials reinforced with carbon fibers

Manufacture of aluminum composite materials reinforced with carbon fibers

ГИБРИДНЫЕ МЕТАЛЛИЧЕСКИЕ КОМПОЗИЦИОННЫЕ МАТЕРИАЛЫ НА ОСНОВЕ МЕДИ (обзор)

The article presents a scientific and technical literature review of copper-based hybrid composite materials (CM). Common combinations of reinforcing components for the manufacture of hybrid composite materials are presented. The main methods for fabricating copper-based hybrid CMs are briefly mentioned. The influence of a combination of various types of reinforcing components and their volume or mass content on the mechanical, thermophysical and tribological properties of hybrid CMs based on copper is considered. A comparison of the characteristics of hybrid CMs with matrix alloys or metallic CMs of similar systems is given.

Fabrication and characterization of epoxy composites reinforced with jute fibers and coconut fibers: A mechanical study

Fiber-reinforced composites are gaining popularity in various industries including automotive, aerospace, leisure and construction. Acts as a loading element in the matrix of a composite structure as a natural fiber reinforcement. Matrix materials tend to not only help keep the fibers into right position and appropriate orientation, but too help in stress removal and environmental stability. In the manufacture of fiber composite materials, various methods of manufacturing composite materials are used. The type of matrix (i.e. thermoset thermoplastic or elastomer) generally determines how it is manufactured. In this research work plant wastes such as coconut and jute fibres were being used as reinforcements in an epoxy resin composite made by hand layup method. After fabrication mechanical properties similar to tensile strength, impact strength and flexural strength were experimentally tested in test equipments as per the ASTM standard at room temperature. The outcome depicts that the jute fiber reinforced epoxy composite gives enhanced mechanical properties compare to former coconut and mixed fiber composite samples.

Design and manufacture of automotive components in thermoplastic composite (Part I)

Due to the increasing demands in environment regulations related to gases emissions, the automotive sector has gradually increased the plastic consumption in vehicles.The objective is to introduce in the market structural components made in latest generation composite materials in a serial and competitive way with the functionality of the present metallic parts. In this work the redesign of two automotive metallic components that will be produced via thermoplastic RTM (Part II) is presented. This technology allows the manufacturing of high performance long fibre composite materials with shorter cycle times. Based on the specifications of the components and the actual metallic solutions performance a new concept of a brake pedal and a control arm consistent with the manufacturing via a RTM thermoplastic process is adressed. For the calculations of both components, carbon or glass fibre with poliamide matrix (APA6) based solutions are used.

Virtual fatigue analysis of epoxy based composite reinforced with sugarcane fibre, fly ash and carbon nano tubes

AbstractComposites are widely used as a lightweight material in automotive, aerospace, transportation, wind turbines and leisure industries. Since the current research trend focuses on making eco‐friendly composites, objective is shifted towards manufacture of better composite materials with available/excess resources to contribute towards a more sustainable environment. This paper highlights fatigue life predictions and interaction among sugarcane, fly‐ash and carbon nano tubes. Instead of reinforcing synthetic materials in the polymer composite, an attempt is made in this work to reinforce biodegradable, recyclable, reusable materials in the polymer composite. Materials like sugarcane, carbon nano tubes and fly‐ash are chosen due to this corresponding nature. The influences of wt.% of sugarcane, carbon nano tubes, fly‐ash on fatigue behaviour of composite are determined. Fatigue analysis of materials prepared using different wt.% is carried out using ANSYS. Response surface methodology and design of experiments approach were implemented to decide on number of ANSYS simulations. Analysis of variance is used to find the influences of different parameters such as wt.% of sugarcane, carbon nano tubes, fly‐ash on fatigue behaviour of composites and obtained their optimized levels. Regression equation was found to determine the number of cycles to failure of the composite.

Reprocessable, repairable and reciclable thermoset composites

Composites based on epoxy resin are a class of high performance structural materials with great potential in a wide variety of industrial sectors. However, being thermoset resins, despite their great benefits in lightness and mechanical performance, they present the great disadvantage that once cured they can not be reprocessed, repaired or recycled. This is hindering the rapid growth of composite materials in applications such as automotive. In order to overcome the disadvantages of thermosetting resins, this paper presents the development of a new generation of dynamic thermoset epoxy resins able to be reprocessed,  repaired and recycled thanks to the incorporation of reversible bonds within its reticulated structure. As resins containing dynamic bonds, the cured material presents new properties previously unthinkable for thermosetting materials. These new resins have been developed for the manufacture of composite materials reinforced with both glass fiber and carbon fiber. It has been shown that these new composites have mechanical properties equivalent to those of conventional thermosetting composites, but unlike the latter, they are recyclable, repairable and reprocessable, which is a step forward and the creation of new opportunities for sectors such as automotive .

Reprocessable, repairable and reciclable thermoset composites

Composites based on epoxy resin are a class of high performance structural materials with great potential in a wide variety of industrial sectors. However, being thermoset resins, despite their great benefits in lightness and mechanical performance, they present the great disadvantage that once cured they can not be reprocessed, repaired or recycled. This is hindering the rapid growth of composite materials in applications such as automotive. In order to overcome the disadvantages of thermosetting resins, this paper presents the development of a new generation of dynamic thermoset epoxy resins able to be reprocessed,  repaired and recycled thanks to the incorporation of reversible bonds within its reticulated structure. As resins containing dynamic bonds, the cured material presents new properties previously unthinkable for thermosetting materials. These new resins have been developed for the manufacture of composite materials reinforced with both glass fiber and carbon fiber. It has been shown that these new composites have mechanical properties equivalent to those of conventional thermosetting composites, but unlike the latter, they are recyclable, repairable and reprocessable, which is a step forward and the creation of new opportunities for sectors such as automotive .

Effect of B4C particle reinforcement on tensile properties of Al7075/B4C composites

The tensile properties of the composite materials are of most interest in the application of composite materials in specific environment. The production of composite material plays an important part in deciding the mechanical properties of the composite material. The process parameters selected during the manufacturing of composite material decides the tensile properties of the material. This work is oriented towards developing a new composite material with Aluminium 7075 as the matrix material and reinforcing it with boron carbide as the reinforcing material. The reinforcement substantial is varied in weight percentage and the tensile strength is studied at different compositions for better results. High purity Al7075 is reinforced with 5%, 10% and 15% weight with commercial grade boron carbide. The results demonstrate that the B4C particulates are dispersed in Al7075 matrix phase. With increasing reinforcement weight fraction, tensile strength decreases initially and increases. From ANOVA it has been found that mixing time and B4C weight percentage have more influence on tensile strength. Maximum tensile strength obtained at mixing time of 9 min, B4C weight percent of 15% and with reinforcement particle size of 9 mm.

Binders Used for the Manufacturing of Composite Materials by Liquid Composite Molding.

Binders, or tackifiers, have become widespread in the production of new composite materials by liquid composite molding (LCM) techniques due to their ability to stabilize preforms during laying-up and impregnation, as well as to improve fracture toughness of the obtained composites, which is very important in aviation, automotive, ship manufacturing, etc. Furthermore, they can be used in modern methods of automatic laying of dry fibers into preforms, which significantly reduces the labor cost of the manufacturing process. In this article, we review the existing research from the 1960s of the 20th century to the present days in the field of creation and properties of binders used to bond various layers of preforms in the manufacturing of composite materials by LCM methods to summarize and synthesize knowledge on these issues. Different binders based on epoxy, polyester, and a number of other resins compatible with the corresponding polymer matrices are considered in the article. The influence of binders on the preforming process, various properties of obtained preforms, including compaction, stability, and permeability, as well as the main characteristics of composite materials obtained by various LCM methods and the advantages and disadvantages of this technology have been also highlighted.

Analysis of Long-Term Prestress Loss in Prestressed Concrete (PC) Structures Using Fiber Bragg Grating (FBG) Sensor-Embedded PC Strands

This study aims to develop a prestressed concrete steel (PC) strand with an embedded optical Fiber Bragg Grating (FBG) sensor, which has been developed by the Korea Institute of Civil Engineering and Building Technology since 2013. This new strand is manufactured by replacing the steel core of the normal PC strand with a carbon-fiber-reinforced polymer (CFRP) rod with excellent tensile strength and durability. Because this new strand is manufactured using the pultrusion method, which is a composite material manufacturing process, with an optical fiber sensor embedded in the inner center of the CFRP Rod, it ensures full composite action as well as proper function of the sensor. In this study, a creep test for maintaining a constant load and a relaxation test for maintaining a constant displacement were performed on the proposed sensor-type PC strand. Each of the two tests was conducted for more than 1000 h, and the long-term performance verification of the sensor-type PC strand was only completed by comparing the performance with that of a normal PC strand. The test specimens were fabricated by applying an optical fiber sensor-embedded PC strand, which had undergone long-term performance verification tests, to a reinforced concrete beam. Depending on whether grout was injected in the duct, the specimens were classified into composite and non-composite specimens. A hydraulic jack was used to prestress the fabricated beam specimens, and the long-term change in the prestress force was observed for more than 1600 days using the embedded optical fiber sensor. The experimental results were compared with the analytical results to determine the long-term prestress loss obtained through finite-element analysis based on various international standards.

Applied computer vision for composite material manufacturing by optimizing the impregnation velocity: An experimental approach

The application of the cutting edge industrial solutions in composite manufacturing are optimizing the processes, quality control and resources usage. Computer vision is currently used in many quality control stages, although its potential advantages have not been applied in the process control. In this paper, computer vision is used to control the impregnation velocity in VARI (Vacuum Assisted Resin Infusion) process. As it is known, there is a relationship between the impregnation velocity and the final mechanical properties in LCM (Liquid Composite Manufacturing) processes. Constant and optimum flow front velocity mean optimum mechanical properties, although the nature of the process makes it difficult to keep these conditions. Then, a methodology has been proposed to identify and use the optimum velocity during the manufacturing process. Firstly, the flow front recognition algorithm was calibrated to be used in different reinforcement and fluid systems. Then, tensile and impact specimens have been manufactured and tested at different controlled and uncontrolled velocities. As a result, the tensile modulus has been increased up to 12.6%, as the tensile strength has increased up to 8.7%. Similarly, the maximum reaction force during the impact test has been increased up to 6.5%, as the damaged area has been reduced by 8.8%. For stitched laminates, force results increase up to 3.2%, as the damaged area has been reduced up to 31% when the optimum velocity is used. The experimental results have demonstrated the advantage of using mechanisms to control the impregnation process to achieve improved mechanical properties of composite materials.

Extrusion-based additive manufacturing of fungal-based composite materials using the tinder fungus Fomes fomentarius

BackgroundRecent efforts in fungal biotechnology aim to develop new concepts and technologies that convert renewable plant biomass into innovative biomaterials. Hereby, plant substrates become metabolized by filamentous fungi to transform them into new fungal-based materials. Current research is thus focused on both understanding and optimizing the biology and genetics underlying filamentous fungal growth and on the development of new technologies to produce customized fungal-based materials.ResultsThis manuscript reports the production of stable pastes, composed of Fomes fomentarius mycelium, alginate and water with 71 wt.% mycelium in the solid content, for additive manufacturing of fungal-based composite materials. After printing complex shapes, such as hollow stars with up to 39 mm in height, a combination of freeze-drying and calcium-crosslinking processes allowed the printed shapes to remain stable even in the presence of water. The printed objects show low bulk densities of 0.12 ± 0.01 g/cm3 with interconnected macropores.ConclusionsThis work reports for the first time the application of mycelium obtained from the tinder fungus F. fomentarius for an extrusion-based additive manufacturing approach to fabricate customized light-weight 3D objects. The process holds great promise for developing light-weight, stable, and porous fungal-based materials that could replace expanded polystyrene produced from fossil resources.

The Manufacturing of Composite Materials in the Matrix of Modified Phenol-Formaldehyde Resins

The Manufacturing of Composite Materials in the Matrix of Modified Phenol-Formaldehyde Resins

Modeling of Mechanical Properties of the Polymeric Composite Reinforced with Braided Preform

Braided composite structures based on preforms are widely used in various industries. Owing to use of such preforms high speed and efficiency of the process of manufacturing of polymeric composite materials and structures on their basis can be provided. Knowledge of their properties in the design allows optimizing the production of structures with the specified parameters. The paper gives the review of three approaches to the description of physical and mechanical characteristics of the composite with braided fixtures – based on the classical theory of layered media, rod-based model, and the method of polynomial approximation. The necessary estimated dependencies were derived in order to predict the elastic and structural behavior of the composites under study at any reinforcement angle according to the known characteristics of predetermined angles. Synthesized design parameters, as distinct from the existing ones, allow predicting strength characteristics of the composite based on the braided hoses depending on the positioning and location of the material on the shape-generating surface. For the verification of theoretical results, a number of experimental studies have been carried out with the formation of samples of the material with the different reinforcing angles. Comparison of the analytical and experimental results allows drawing the conclusions that rod-based model gives the best results for the description of elastic behavior of the polymeric composite materials, whereas the obtained polynomial dependences are recommended for the structural behavior. The results of the work represent the basis for solving the problems of calculation of strength of the structures made of composite materials based on the braided preforms

Recent Progress in Carbon Fiber Reinforced Polymers Recycling: A Review of Recycling Methods and Reuse of Carbon Fibers.

The rapid increase in the application of carbon fiber reinforced polymer (CFRP) composite materials represents a challenge to waste recycling. The circular economy approach coupled with the possibility of recovering carbon fibers from CFRP waste with similar properties to virgin carbon fibers at a much lower cost and with lower energy consumption motivate the study of CFRP recycling. Mechanical recycling methods allow the obtention of chopped composite materials, while both thermal and chemical recycling methods aim towards recovering carbon fibers. This review examines the three main recycling methods, their processes, and particularities, as well as the reuse of recycled carbon fibers in the manufacture of new composite materials.

Analysis of Tensile Strength of Citronella (Cymbopogon Nardus) Fiber Reinforced Composite Materials

The use of synthetic fibers in composite materials has a negative impact on the environment. One way to reduce this impact is to replace synthetic fibers with natural fibers. A natural fiber that has the potential as a mixed material in the manufacture of composite materials is citronella (Cymbopogon nardus) fiber. This study aims to determine the effect of volume fractions 40%, 50%, 60%, and 70% of citronella fiber with polyester resin matrix BQTN 157 on tensile strength. The process of making composites used the hand lay-up method. The specimen was formed according to the ASTM D3039 standard and the tensile strength of the specimen was tested by using a Universal Testing Machine (UTM). From the results of the study, the maximum tensile strength was found in the fiber volume fraction 70% of 77.35 MPa, the strain is 6.57%, and the modulus of elasticity is 1.177 GPa. This study indicates that fiber volume fraction affects the tensile strength of composite materials. Hence, the manufacture of composite materials which have good strength is influenced by many things such as raw materials, matrices, mixture composition, and methods.

Bio-Based Rigid Polyurethane Foam Composites Reinforced with Bleached Curauá Fiber.

This study aims to evaluate the influence of using a bleached Curauá fiber (CF) as filler in a novel rigid polyurethane foam (RPUF) composite. The influence of 0.1, 0.5 and 1 wt.% of the reinforcements on the processing characteristics, cellular structure, mechanical, dynamic-mechanical, thermal, and flame behaviors were assessed and discussed for RPUF freely expanded. The results showed that the use of 0.5 wt.% of CF resulted in RPUF with smoother cell structure with low differences on the processing times and viscosity for the filled pre-polyol. These morphological features were responsible for the gains in mechanical properties, in both parallel and perpendicular rise directions, and better viscoelastic characteristics. Despite the gains, higher thermal conductivity and lower flammability were reported for the developed RPUF composites, related to the high content of cellulose and hemicellulose on the bleached CF chemical composition. This work shows the possibility of using a Brazilian vegetable fiber, with low exploration for the manufacturing of composite materials with improved properties. The developed RPUF presents high applicability as enhanced cores for the manufacturing of structural sandwich panels, mainly used in civil, aircraft, and marine industries.

Mechanical Properties of Composite Materials from Waste Poly(ethylene terephthalate) Reinforced with Glass Fibers and Waste Window Glass

After primary uses of the plastic product, most developing countries like Ethiopia are facing a shortage of postconsumer disposal waste sites and it became a very serious problem on environmental pollution due to its nonbiodegradable nature. For this reason, regenerating and using the waste product as resources and reducing environmental pollutions are a great opportunity. This research is aimed at the manufacturing of composite materials from waste poly(ethylene terephthalate) (PET) bottles reinforced with glass fibers and filled with waste glass powder for floor tile applications. The tile composites were prepared by the melt-mixing method followed by compression molding. The effect of filler, fiber, and PET matrix loading on the composite was investigated using their tensile, compression, and flexural strength tests. The sample was characterized using a universal testing machine. PerkinElmer FTIR instrument was also used. For this, eleven samples prepared by varying the glass fiber weight % from 0 to 10, PET matrix weight % from 70 to 85, and glass powder filler weight % from 5 to 20. The measurement results of the composite were maximum tensile strength (81.625 MPa) and flexural strength (1067.59 MPa) recorded at 10%weight of glass fiber, 85% weight of PET matrix, and 5%weight of window glass filler. The maximum compressive strength is 1876.14 MPa at 10% weight glass fiber, 70 wt% PET matrix, and 20 wt% window glass filler. Based on this, the tensile strength and flexural strength increased with increased weight % of glass fiber and decreased with increased window glass filler. The FTIR spectrum shows some of the groups that have been removed from the recycled PET; this explains the brittleness of the recycled PET as compared to the waste bottle PET. The microstructure was uniformly distributed, and the material became opaque, probably because the decrease in chain length improves chain packing, increasing the crystallinity degree and crystal size.

Analysis of the subsolidus structure in the Al2O3 – FeO – TiO2 system

The study of the subsolidus structure of multicomponent systems for the synthesis of composite materials with specified phase composition and properties is urgent. Insufficient knowledge of the Al2O3 – FeO – TiO2 system arouses research interest in the structure of the system, as well as in the processes that occur in the system in different temperature ranges.
 A thermodynamic analysis of the Al2O3 – FeO – TiO2 system was carried out and it was found that the partition of the system into elementary triangles changes in five temperature ranges: I – up to a temperature of 1413 K, II – in the temperature range 1413 – 1537 K, III – 1537 – 1630 K, IV – 1630 – 2076 K and V – above the temperature of 2076 K. The main geometrical-topological characteristics of the subsolidus structure of the system and its phases were analyzed: the areas of elementary triangles, the degree of their asymmetry, the area of regions in which phases exist and the probability of the existence of phases. It was found that the FeAl2O4 – Fe2TiO4 – FeO elementary triangle with a relatively large area and a fairly small degree of asymmetry remained unchanged up to a temperature of 2076 K and the FeAl2O4 phase had the highest probability of existence above a temperature of 1413 K; all this indicates the reliability of predicting the phase composition of synthesized materials in this area and does not require special technological conditions for the accuracy of dosing and the time for homogenization of precursors. In the temperature range 1537 – 1630 К, the Al2TiO5 – FeAl2O4 – TiO2 elementary triangle has the largest area, but rearrangement of the connections occurs above a temperature of 1630 K. In this range, researchers may be interested in the FeTi2O5 – Al2TiO5 – FeTiO3 elementary triangle, which has the smallest area and the greatest degree of asymmetry. Of course, it is possible to perform additional calculations to determine whether the compositions belong to the joint area of two elementary triangles Al2TiO5 – FeAl2O4 – TiO2 and FeTi2O5 – Al2TiO5 – FeTiO3, special technological methods of mass preparation and synthesis must be strictly observed in working in this area. For corundum refractories and corundum-based materials with increased heat resistance, it is advisable to calculate whether the compositions belong to the joint region Al2O3 – Al2TiO5 – FeAl2O4 (in the temperature range 1537 – 1630 K) and Al2TiO5 – FeTiO3 – Al2O3 or FeTiO3 – Al2O3 – FeAl2O4 (above a temperature of 1630 K). The calculated data obtained above a temperature of 2076 K, as a consequence of non-proving the existence of the Al4TiO8 compound, are of recommendatory nature and require further theoretical and practical studies.
 Based on the results obtained, recommendations are given on the range of compositions that are optimal for obtaining new materials with the required phase composition and desired properties. This will contribute to the development of the latest resource-saving technologies for the manufacture of composite materials.