Properties Of Composite Materials Research Articles

The Effect of Expanded Graphite Content on the Thermal Properties of Fatty Acid Composite Materials for Thermal Energy Storage.

The mass content of expanded graphite (EG) in fatty acid/expanded graphite composite phase-change materials (CPCMs) affects their thermal properties. In this study, a series of capric-myristic acid/expanded graphite CPCMs with different EG mass content (1%, 3%, 5%, 8%, 12%, 16%, and 20%) were prepared. The adsorption performance effect of EG on the PCMs was observed and analyzed. The structure and thermal properties of the prepared CPCMs were characterized via scanning electron microscopy, differential scanning calorimetry, thermal conductivity measurements, and heat energy storage/release experiments. The results show that the minimum mass content of EG in the CPCMs is 7.6%. The phase-change temperature of the CPCMs is close to that of the PCMs, at around 19 °C. The latent heat of phase change is equivalent to that of the PCM at the corresponding mass content, and that of phase change with an EG mass content of 8% is 138.0 J/g. The CPCMs exhibit a large increase in thermal conductivity and a significant decrease in storage/release time as the expanded graphite mass content increases. The thermal conductivity of the CPCM with a mass content of 20% is 418.5% higher than that with a mass content of 5%. With an increase in the EG mass content in CPCMs, the heat transfer mainly transitions from phase-change heat transfer to thermal conductivity.

Thermomechanical bending of functionally graded carbon nanotubes reinforced composite plate by meshless method

AbstractFunctionally graded (FG) carbon nanotubes (CNTs) reinforced composite possessing continuously varied material properties have received extensive concern in the area of aviation, automotive, military, and spaceflight. The nonlinear bending of FG CNT composite is performed by developing a novel meshless model on the base of Smoothed Particle Hydrodynamics (SPH) method. The equivalent temperature relative material properties of composite is established in the light of the extended rule of mixture model. Different gradient dispersions of CNTs are taken into account and modeled. The governing equations are explored using the Mindlin theory and discretized though a symmetric SPH method with high prediction ability. The developed model is verified by analyzed several examples and compared to the solution obtained in literature. Influences of CNT dispersion, content, plate aspect ratio, boundary conditions and lamination angle on the bending response are elaborated. The present study provides an alternative potential method to solve the mechanical performances of FG CNT composites based on the meshless SPH formulation.Highlights Thermo‐mechanics of FG‐CNTRC is firstly solved by SPH method. The model is verified by solving the benchmarks in literature. Nonlinear bending behaviors of FG‐CNTRC are demonstrated. The minimum deflection take place in FG‐X type composite. For laminate plate, the smallest deformation occurs in 0° CNTRC.

Microstructure, Texture, and Mechanical Properties of 0.4GNPs–Mg–8Al–1Sm Composites Prepared by Pulse Current‐Assisted Multidirectional Forging

The present study investigates the evolution of the microstructure and texture of a hot‐pressed sintered 0.4GNPs–Mg–8Al–1Sm (mass fraction, %) composite material during a pulsed current‐assisted multidirectional forging process. Additionally, this study explores the use of the pulse current‐assisted multidirectional forging mechanism for strengthening the mechanical properties of composite materials. The results indicate that as the cumulative strain (ΣΔε) increases, the amount of Mg17Al12 and Al2Sm gradually increases while their size decreases. Furthermore, the fraction of the recrystallization area increases. The recrystallization mechanism is dominated by continuous dynamic recrystallization and discontinuous dynamic recrystallization. The refinement of the alloy grain size is attributed to dynamic recrystallization. Specifically, at ΣΔε = 3.15, the compressive strength and fracture strain of the multidirectional forged 0.4GNPs–Mg–8Al–1Sm composite reach 461.5 MPa and 18.8%, respectively. By quantitatively analyzing the strengthening mechanism of the alloy, it is determined that fine‐grain strengthening is the most significant mechanism contributing to the strength of the 0.4GNPs–Mg–8Al–1Sm composite.

Application and performance analysis of advanced materials in engine lightweight

This paper discusses the application and performance analysis of advanced materials in engine lightening. Firstly, we analyze the properties of high performance aluminum alloy, titanium alloy and composite materials, including their composition, mechanical properties and high temperature resistance. Then, the practical application effects of these materials in key components such as automobile and aero-engine are analyzed through concrete cases. For example, the introduction of micronutrient and improvements in heat treatment processes have significantly increased the strength and corrosion resistance of high-performance aluminium alloys. Titanium alloy is widely used in the key parts of aero-engine because of its high strength and light weight, which greatly improves the performance of engine. The low density and high strength of the composite make it an ideal choice for reducing engine weight. Finally, we discuss the current challenges and future directions, and explore solutions to reduce costs, improve processing efficiency and develop new alloys, in order to provide guidance and reference for the further development of engine lightweight technology.

Guided Ultrasonic Wave Monitoring of Damage in Anisotropic Composites

Lightweight, carbon fibre reinforced composites are often employed for the manufacture of aerospace components due to their good strength to weight ratio. However, due to poor interlaminar strength, composite components are prone to barely visible impact damage, caused by low velocity impacts, during aircraft operation. Guided-wave-based structural health monitoring (SHM) techniques, using a network of distributed sensors, is an important Structural Health Monitoring (SHM) tool for the detection and localization of in-service impact damage in composite structures. However, the material anisotropy of composite laminates influences guided wave propagation and scattering. These anisotropic effects, if unaccounted for, could lead to inaccurate localization of damage, and potential regions of the structure where guided waves cannot propagate with sufficient amplitude, reducing damage sensitivity. Defect characterization can be improved by considering the scattering characteristics of various damage types for the sparse array signal processing. Guided wave scattering (A0 Lamb wave mode) was investigated around an artificial insert delamination in a quasi-isotropic CFRP panel. Permanent magnets, mounted on an undamaged region of the plate, were also used as scattering targets and compared to the delamination case. Full 3D Finite Element (FE) simulations were performed for both the delamination and magnet cases and compared to wavefield data obtained from non-contact laser Doppler vibrometer (LDV) measurements. Individual ply layers were modelled using unidirectional composite material properties to accurately capture the anisotropy effects. Good agreement was found between the experimental measurements and simulations. Scattered guided wave amplitudes around each damage type show strong directional dependency with energy focusing along the fiber directions of the outer ply layers of the laminate. Distinct scattering behavior was observed for each damage type. Implications of anisotropy and angular scattering on sparse array SHM of different defect types are discussed.

A theoretical study on the electronic and optical properties of M-TiO2/ZnO (M=Li, Na, K, Fe) toward application in photocatalysis

This study employs the tight-binding density functional method GFN1-xTB to investigate the structural and electronic properties of TiO2-ZnO and TiO2-ZnO composite materials modified by Li, Na, K, and Fe metals. Computational analyses reveal the formation of weak covalent bonds between the TiO2 and ZnO components within the composite system. Doping TiO2-ZnO with metals induces significant alterations in the electronic structure, particularly in terms of ionization energy and global electrophilic index. The UV-VIS spectra are calculated using real-time time-dependent density functional theory with xTB Hamiltonians. The obtained results demonstrate minimal impact of metal presence on the absorption spectrum of TiO2-ZnO, but significant influence on the recombination potential of photogenerated charge carriers. It is suggested that Fe/TiO2-ZnO and Li/TiO2-ZnO will demonstrate higher photocatalytic activity than the pristine TiO2-ZnO material.

The Impact of Internal Structure Changes on the Damping Properties of 3D-Printed Composite Material

This article investigates the impact of changes in the internal structure of composite materials on their dynamic properties. The present research focuses on 3D-printed specimens with different reinforcement fiber arrangements. The specimens are printed on a Markforged Mark Two 3D printer. The base material is nylon filled with chopped carbon fibers (Onyx) and the reinforcement is in the form of long carbon, glass and Kevlar fibers. The experiment is carried out by the impact method. The principle of this method is to expose the specimen to a short impulse of force while monitoring its frequency response. The obtained results determine the natural frequencies and internal damping of the individual structures. We found that the highest damping is achieved by specimens with glass and Kevlar fibers in 45°, 90° and ±45° configurations. On the other hand, the lowest damping is achieved by specimens with carbon fibers and 0° and 0°,90° configurations. Also, the specimens with circumferential reinforcement show lower damping coefficient values. The knowledge and results of this work can be used in the development of new components; for example, in the transport industry, where the low weight and sufficient strength of components are important factors. These components have to absorb vibrations from various sources, such as motors and external influences.

Research on mechanics and acoustic properties of Jute fiber composite material

In this study, the loss of quality from the oxidative thermal decomposition of jute fiber was explored during the production of reinforced composite materials. Amino silicone oil was used to modify jute fiber, which was then subjected to thermogravimetric analysis. The modified fiber's thermal decomposition temperature was found to be 271 °C, enhancing the composite's thermal stability. The study also investigated how different jute fiber content affected the mechanical and sound absorption properties of composite materials. Results showed that jute fiber composites had better mechanical properties than pure polypropylene materials, and the average sound absorption coefficient of jute polypropylene composites increased with fiber content. Adding jute fiber to polypropylene effectively improved the sound absorption and noise reduction performance of the material. The average sound absorption coefficient of the composite material at a mass content of 20 wt% was 120 % higher than that of the polypropylene matrix material.

Thermoelectric properties and effective medium theory analysis on the (GeTe)1-x(InTe)x composites

We employed the p-type semiconductor InTe as an extrinsic phase mixing in the GeTe matrix for thermoelectric properties investigations on the (GeTe)1-x(InTe)x (x=0, 0.02, 0.04, 0.06, and 0.08) composites. We observed notable phenomena that a small amount of InTe has a significant influence on the thermoelectric properties as the primary host matrix in the (GeTe)1-x(InTe)x (x=0.02, 0.04, 0.06, and 0.08) composites. Even for small concentrations of InTe which possess lower thermal and electrical conductivities compared to those of GeTe, the thermoelectric properties of the (GeTe)1-x(InTe)x (x=0.02, 0.04, 0.06, and 0.08) composites are primarily influenced by the properties of InTe. We systematically elucidated the electrical conductivity of the (GeTe)1-x(InTe)x (x=0.02, 0.04, 0.06, and 0.08) composites through the application of effective medium theory (EMT). It is found that the effective media of the (GeTe)1-x(InTe)x (x=0.02, 0.04, 0.06, and 0.08) composites is an asymmetric medium insulator. The addition of InTe into GeTe reveals a significant decrease in total thermal conductivity due to reductions in both electronic and lattice thermal conductivity. Particularly, the decrease in lattice thermal conductivity was attributed to an increase in internal strain within the lattice induced by the addition of InTe. Consequently, the ZT values of the composite significantly increase across all temperature ranges. This study suggests that developing composites is an effective approach for enhancing thermoelectric performance, comparable to elemental doping, and demonstrates the ability to analyze the electrical properties of composite materials using EMT.

Combining thermodynamic modeling and experiments to characterize the effect of ceramic polishing powder in cement-based materials

Ceramic polishing powder (CPP), a by-product of ceramic tile production, has the potential to prepare building materials. While the hydration and thermodynamic properties of CPP remain largely unexplored, thereby limiting its widespread application. This study utilized R3 tests to demonstrate that CPP exhibits pozzolanic activity comparable to that of fly ash. Then it analyzed the effects of substituting 10–20 % of cement with CPP on the hydration products, microstructure, and mechanical properties of composite materials, utilizing a synergistic approach that combines thermodynamic simulations with experimental investigations. The findings showed that adding CPP does not generate new crystalline products but enhances the formation of C-S-H through the pozzolanic reaction, which consumes calcium hydroxide. However, adding over 25 % CPP significantly lowered the pH of the pore solution, altering hydration products and causing volume contraction. In addition, CPP improved the microstructure at later ages, particularly by increasing micropores, leading to enhanced mechanical properties at 28 and 90 days. For instance, at a w/b ratio of 0.5, the 90 days compressive strengths of composite mortars CPP10, CPP15, and CPP20 were recorded at 67.0 MPa, 63.3 MPa, and 65.1 MPa, respectively. These values represented increases of 17.3 %, 10.9 %, and 14.0 % over the control group (57.1 MPa). Conversely, this also resulted in increased autogenous shrinkage due to higher capillary pressure. Notably, the 6 days shrinkage of CPP15 and CPP20 was about 50 % higher compared to that of the pure cement mortar. These findings highlight the necessity of balancing CPP content for optimal performance.

A thermogravimetric analysis of residual char formation by gilsonite-filled, polyfurfuryl alcohol composites: acid treatment of gilsonite

Gilsonite (GLS), a natural bitumen containing a considerable amount of asphaltenes, is expected to leave heavy char after pyrolysis; however, its high potential as an efficient filler to enhance the thermal properties of composite materials is surprisingly neglected throughout the literature. On the other hand, polyfurfuryl alcohol (PFA) has attracted much attention as a thermosetting resin due to its excellent char-leaving characteristics, the renewable nature of the monomer(s), and high accessibility at an affordable cost. This study aimed to investigate the thermal stability and char-forming performance of composites made of a PFA resin matrix filled with chemically modified GLS. To modify the ash and sulfur contents of GLS, the nitric acid leaching process was performed according to a D-optimal experimental design approach. The nitric acid concentration (10, 20, and 30 wt.%), treatment time (30, 75, and 120 min), and reaction temperature (30 °C, 50 °C, and 70 °C) were set as the input variables. The morphology (SEM), chemical structure (FTIR), thermal stability (TGA), sulfur content, and ash content of the GLS particles were characterized before and after acid treatment. Thermogravimetric analysis revealed the lowest ash content for GLS after treatment with 10 wt.% acid conc. at 75 °C for 75 min. The nitric acid concentration, reaction temperature, and time were the most influential parameters for improving the ash content of GLS according to their order of appearance. In addition, the inorganic form of sulfur, pyrite, was separated through the acid leaching process. Then, the PFA resin matrix was filled with modified GLS particles at different weight percentages (5, 10, 15, and 20 wt.%) and cured in the presence of an acid catalyst. The thermal stability of the PFA resin was negatively affected by the presence of GLS, probably due to oxidation reactions and disruption of the integrity of the resin structure.

The effect of CNT grafting on the mechanical properties of the UHMWPE fiber/HDPE composite

In order to improve the mechanical properties of the ultra‐high molecular weight polyethylene (UHMWPE) fiber‐reinforced high‐density polyethylene (HDPE) composite, carbon nanotube (CNT) was grafted on the UHMWPE fiber. The UHMWPE fiber/HDPE composite was prepared by injection molding process, and the effects of CNT contents on the mechanical properties of composite materials were studied. The results show that the mass fraction of CNT will significantly affect the mechanical properties of the composite. When the CNT content is 4 wt%, the tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength of the UHMWPE fiber/treated CNT/HDPE composite increased compared to the UHMWPE fiber/CNT/HDPE composite and UHMWPE fiber/HDPE composite. When the CNT content is 4 wt%, the above‐mentioned performance is the best. Pull‐out and fracture, bridging effect, and crack deflection effect are the main mechanisms of CNTs in UHMWPE fiber/HDPE composites. This study provides new insights into the interface design of UHMWPE fiber/HDPE composites and paves the way for their further development.

A Multi-Objective Optimization of Neural Networks for Predicting the Physical Properties of Textile Polymer Composite Materials.

This paper explores the application of multi-objective optimization techniques, including MOPSO, NSGA II, and SPEA2, to optimize the hyperparameters of artificial neural networks (ANNs) and support vector machines (SVMs) for predicting the physical properties of textile polymer composite materials (TPCMs). The optimization process utilizes data on the physical characteristics of the constituent fibers and fabrics used to manufacture these composites. By employing optimization algorithms, we aim to enhance the predictive accuracy of the ANN and SVM models, thereby facilitating the design and development of high-performance textile polymer composites. The effectiveness of the proposed approach is demonstrated through comparative analyses and validation experiments, highlighting its potential for optimizing complex material systems.

Investigating thermal and free vibrational properties of fabric sandwich composite materials for car hood application

Textile fabric wastes are the second most polluting materials in the world after plastic. This study investigated the thermal and free vibrational properties of the sandwich composites prepared from recycled fabric materials. Grey cotton fabric(C) and wool garment waste (G) reinforced a polyester matrix in a different layer arrangement (CCCC, CGCG, CGGC, GCCG, GGGG, and chopped). Thermogravimetric analysis (TGA) and dilatometry were performed to determine the thermal properties. TGA results showed similar initial weight loss for GCCG, CCCC, and CGGC (within a range of 25 °C–800°C) and for GCGC, GGGG, and chopped arrangements. All composites exhibited thermal stability up to 305°C. Between 310°C and 405°C, a gradual mass loss was observed, followed by more significant degradation above 405°C and residual mass loss observed at 655°C. Dilatometry tests reveal minimal volume change up to a heating temperature of 300°C for all durations (20 min, 40 min, and 60 min). In addition, the free-vibration analysis indicated poor energy-absorbing properties for CCCC, while CGGC sandwich composite specimen exhibited better energy-absorbing properties. Based on these results, it can be concluded that these composite materials are suitable for applications such as car hoods, which typically function below 105°C temperatures.

The Study of Composite Materials Properties Based on Polymers and Nano-Additives from Industrial Wastes from Kazakhstan.

This research is aimed at studying the properties of polymer anticorrosion coatings based on ED-20 resin widely used in practice and industrial wastes. In this work, three basic types of nanoscale nanofillers were chosen: dispersed particles-microsilica, microspheres obtained at Kazakh enterprises, and carbon nanotubes. Physicochemical research methods were used in the research: a laser analyzer for studying the dispersibility of industrial waste and spectrometric research methods. The properties of materials were investigated by standardized methods. The obtained results show that the introduction of microsilica and microspheres obtained at Kazakhstani enterprises, used as additives, improves both the physical and mechanical properties of epoxy composites compared to the standard (control) material. The results of experiments have shown that the optimal content of additives of microsilica and microspheres provides an improvement in the physical and mechanical properties of epoxy composites in comparison with the standard (control) material. Studies have shown that the introduction of microspheres into ED-20 polymer increases impact toughness. The introduction of microsilica into the matrix contributes to the increase of elastic modulus. Experimental studies of optical properties of samples of carbon composite polymer films based on polystyrene (PS) with additives of carbon nanotubes C60 and C70 and multilayer carbon nanotubes were also carried out. The experimental results obtained for the optical properties of polymer composites based on basic polymers from solid waste and carbon nanotubes showed that the optical properties of polymer composites undergo noticeable changes.

Durability and mechanical characteristics of unidirectional jute/banana and synthetic fiber reinforcement epoxy composite

Corrosive environments affect the physical and mechanical properties of natural fiber-reinforced epoxy composites. In such a context, this study focuses on the durability and corrosive impact on the mechanical properties of bast fiber-based composites. Synthetic glass fiber, and aluminium foil were also used for hybridization. The composites and hybrids were made using unidirectional jute and banana-fiber mats. Composites were immersed in a NaCl solution to create a corrosive environment, and their mechanical properties were investigated. Hybridization with glass fiber has the lowest impact on corrosive conditions. However, in a saline environment, it substantially alters the mechanical properties of composite materials. XRD and SEM were also performed for dry samples, and samples immersed in pH 8. XRD analysis revealed that adding synthetic fiber to natural fiber decreases the crystallinity. Hence, this study shows that hybridizing bast fiber with glass fiber is a noble approach to use in corrosive environments. The experimental results were verified by finite element analysis using ABAQUS.

Facile preparation and application of ternary hybrid of POSS/DOPO/F macromolecular as highly-effective epoxy modifier

In order to easily achieve the multifunctionality of epoxy resin, this paper designs and synthesizes a ternary hybrid copolymer containing POSS/DOPO/F. This method not only facile combines POSS with DOPO, but also introduces F element to further reduce the surface energy of epoxy composite materials. Research has found that the POSS/DOPO/F ternary hybrid copolymer can achieve a UL-94 flame retardant rating of V-0 with just 5 wt% of the modifier, and the limit oxygen index of epoxy composites is 32% (23.1% higher than pure epoxy resin). The residual char after combustion is denser and the carbonization rate is higher. Furthermore, we conducted an in-depth analysis of the flame retardant mechanism of POSS/DOPO/F ternary hybrid copolymer epoxy composites using TGA-FTIR technology and EDS. In addition, the introduction of ternary hybrid polymers effectively improves the mechanical properties of epoxy composite materials and significantly reduces the surface energy of the composite materials.

MODIFICATION OF SODIUM HUMATE WITH ALUMINUM DIHYDROPHOSPHATE DEPENDING ON TIME AND THE RATIO OF SOLID AND LIQUID PHASES

Due to their high chemical activity, humic compounds participate in various reactions. A large number of functional groups opens up wide possibilities for the humic compounds chemical modification. Most studies on the modification of humic substances are focused on studying the structure of humic substances, as well as on the factors influencing the completeness of the release of one humic substances fraction. The purpose of the work is to study the patterns of modification processes of sodium humate with aluminum dihydrogen phosphate, to determine the composition and properties of the resulting organomineral composite materials. Methods. Chemical analysis, infrared spectroscopy, X-ray analysis. Results and discussion. The composition and properties of organo-mineral composite materials obtained by conversion of sodium humate with aluminum dihydrogen phosphate have been determined. With an increase in the S:L ratio from 1:0.5 to 1:1.5, the yield of humic compounds increases from 15.62 to 21.92%, and the amount of phosphorus and nitrogen, on the contrary, the S:L=1:1.5 decreases, that is, the amount of phosphorus decreases from 37.51 to 32.19%, and the amount of nitrogen decreases from 1.78 to 1.11%. This is due to the improvement of diffusion conditions by reducing the medium viscosity and increasing the rate of primary components interaction. And the reduction in the amount of nitrogen occurs due to a decrease in ammonia consumption due to the humic substances neutralizing ability. Conclusion. It has been shown that the conversion of humic compounds with aluminum dihydrogen phosphate leads to a change in its composition and properties; the resulting products are enriched with phosphorus and nitrogen, and have good physicochemical and physicomechanical properties. After the macromolecules of humic compounds modification with aluminum dihydrogen phosphate, the number of oxygen-containing functional groups increases as a result of which the ion-exchange, complexing, sorption, detoxification and growth-stimulating properties is observed.

Numerical Analysis of Laminated Veneer Lumber Beams Strengthened with Various Carbon Composites.

Among the many benefits of implementing numerical analysis on real objects, economic and environmental considerations are likely the most important ones. Nonetheless, it is also crucial to constrain the duration and space necessary for conducting experimental investigations. Although these benefits are clear, the applicability of such models must be appropriately verified. This research subjected validation of numerical models depicting the behavior of unstrengthened and strengthened laminated veneer lumber (LVL) beams. As a reinforcement, a carbon fiber reinforced polymer (CFRP) sheet and laminates were used. Experiments were conducted on full-scale members within the framework of the so-called four-point bending testing method. Numerical simulations were performed using the Abaqus software. Two types of material models were examined for laminated veneer lumber: linearly elastic and linearly elastic-perfectly plastic with Hill's yield criterion. A distinction was made in the material properties of carbon composites based on their location on the height of the cross-section. The outlined numerical models accurately depict the behavior of real structural elements. The precision of predicting load-bearing capacity amounts to a few percent for strengthened beams and a maximum of eleven percent for unstrengthened beams. The relative deviation between numerical and experimental values of bending stiffness was at a maximum of seven percent. Applying the elastic-plastic model enables accurate representation of the load versus deflection relation and the distribution of stress and deformation of strengthened beams. Based on the findings, directives were provided for further optimization of the positioning of composite reinforcement along the span of the beam. Reinforcement design of existing laminated veneer lumber members can be made using presented methodology.

Uniaxial compression behavior of glass fabric/epoxy composites sprayed with nano titanium dioxide

ABSTRACT In this study, we have tried to study the compression behaviour of composites by a different technique of spraying nano – TiO2 on glass fibre fabrics with vinyl resin as binder and epoxy resin as matrix. It was found that the air spraying method was effective in loading the nanoparticles onto the fabrics and improving their wetting properties with the resins. The experimental results showed that the compressive strength of the modified specimens was lower than that of the untreated ones, while their compressive strength was increased. On this basis, the fracture process of the material was observed using microscopy, and electron microscopy observations revealed that the degree of interfacial bonding between the material and the substrate was improved, while the bond strength demonstrated the strong toughening effect of nano – TiO2 on the substrate. Electron microscopy tests also showed that the composites modified by nano- TiO2 showed significant improvement in matrix fracture, fibre breakage and delamination. This study provides a theoretical basis for the study of the mechanical properties of composite materials used as supports under uniaxial compression.