Properties Of Composite Materials Research Articles

Prediction of particle-reinforced composite material properties based on an improved Halpin–Tsai model

This paper introduces an improved Halpin–Tsai model to predict the mechanical, thermal, and electrical properties of silicon-carbide-reinforced polypropylene composites. The model considers the influence of porosity and corresponding silicon-carbide volume fractions and derives relationships between material property shape factors and the aspect ratio, silicon-carbide volume fraction, and porosity. The improved model’s predictions exhibit errors of 4.00% for mechanical properties, 2.13% for thermal properties, and 2.24% for electrical properties when compared to finite element analysis. This study demonstrates that the improved Halpin–Tsai model can effectively predict the properties of silicon-carbide-reinforced polypropylene composites, aiding in the design and optimization of these materials.

The impact of ternary hybrid fibers on the mechanical characteristics of cement-based composites with waste andesite dust substitution

With the growing utilization of andesite stone in diverse construction uses, the effective handling and disposal of dust generated during its processing in manufacturing facilities have become more important to mitigate environmental effects. The primary objective of this research is to effectively employ waste andesite dust (WAD) in the creation of an environmentally friendly material. The study investigates how integrating a ternary hybrid fiber composition, combined with replacing a portion of cement with WAD, affects the mechanical properties of cement-based composite materials. To accomplish this goal, WAD was utilized in combination with ternary hybrid fibers within cement-based blends, substituting 0–30% of the weight of cement at four varying levels. In total, 12 different blend configurations were formulated by incorporating ternary hybrid fibers at 0.5%, 1%, and 2% proportions for each WAD substitution rate. The experimental results indicated that reducing the WAD substitution rate positively impacted strength measurements, while an increase in the substitution rate led to higher elongation and deflection capabilities. With the increase in hybrid fiber content, there was an increasing trend in flexural and tensile strengths, and for samples without WAD substitution, the strength values of the samples in which the fiber amount was used the least (0.5% by weight) compared to the samples in which it was used the most (2% by weight) increased by 57% and 7%, respectively. Based on the findings from the experimental investigations, the sample with 30% WAD substitution and 2% hybrid fiber content exhibited an increase of 32.30% in midpoint deflection capacity and 46.71% in tensile strain values compared to the reference sample. When analyzing the collective results of the study, it becomes evident that by incorporating WAD and a ternary hybrid design at optimal ratios, the mechanical properties can be enhanced, contributing to the mitigation of WAD disposal issues.

A novel rapid generation algorithm for Representative Volume Element (RVE) in composite materials considering pore geometrical parameters

Pore defects are inevitable in the manufacturing process and significantly affect the mechanical properties of composite materials. In this work, a novel algorithm capable of concurrently generating both ellipsoidal and gourd-shaped pores in composite materials is proposed and the interference detection procedure is optimized for efficient interference detection between the generated geometrical bodies. Besides, the algorithm is integrated with RVE-based finite element (FE) simulation to explore the effects of various pore types, volumes, aspect ratios, and porosity on the elastic properties of unidirectional C/C composites. The present work provides a valuable reference for generating general pore defects and investigating their resulting effects on mechanical properties of related composite structures.

Nonlinear Free Vibration Analysis of Functionally Graded Porous Conical Shells Reinforced with Graphene Nanoplatelets

The nonlinear vibration analysis of functionally graded reinforced with graphene platelet (FG-GRC) porous truncated conical shells surrounded by the Winkler-Pasternak elastic foundation is presented in this paper. An improved model for evaluating the material properties of porous composites is proposed. Three types of porous distribution and three patterns of graphene nanoplatelets (GPLs) dispersion are estimated. Coupled with the effect of the Winkler-Pasternak elastic foundation, the nonlinear governing equations are developed by using the Hamilton principle. The Galerkin integrated technique is employed to obtain the linear and nonlinear frequencies of the shells. After the present method is validated, the effects of the pores, GPLs, the Winkler-Pasternak foundation, and the semi-vertex are investigated in detail. The results show that the linear frequency can be raised by increasing the values of the mass volume of the GPL and foundation parameters. In contrast, the ratio of nonlinear to linear frequency declines as the mass volume of the GPLs and foundation parameters rises. Furthermore, it is found that the minimum ratio of nonlinear to linear frequency can be obtained as the semi-vertex angle is about 55º, and the effect of porosity distribution on the linear and linear frequencies might be neglected.

Effect of Fiber Content on the Mechanical Properties of Jute Fiber Reinforced Perlite/Gypsum Composites

Fiber reinforcement is one of the ways for the improvement of the mechanical properties of composite materials. Previously, it was seen that the fiber content in composites played a vital role in the mechanical properties of fiber-reinforced composites. Considering the benefits of natural fiber, in this work, jute fiber reinforced perlite/gypsum composites were manufactured with five different fiber contents ranging from 2.41 % to 4.82 %. The ratios of gypsum to perlite and gypsum to water were kept constant, and only fiber content was varied. The compression and flexural tests were conducted to investigate the effect of jute fiber content on the mechanical properties of jute fiber-reinforced perlite/gypsum composites. Results showed that both the compressive and flexural properties were improved up to certain jute fiber content. The compressive strength, modulus, and energy absorption of the jute fiber-reinforced composite were found to be the maximum at 3.01 % fiber content. The compressive strength of the composite with 3.01 % jute fiber content was 35.23 % higher than the composite with 2.41 % fiber content. The flexural strength, modulus, and energy absorption were maximum at 3.61 % jute fiber content. This study demonstrated that the addition of jute fiber to perlite/gypsum composites results in improved mechanical properties up to a certain percentage of jute fiber, beyond which the properties deteriorate.

Nanocarbon/Co3O4/Epoxy Composites for Microwave Shielding and Absorption

The epoxy composite materials (CMs) with a random distribution of nanosized Co3O4 and carbon nanoparticles (graphite nanoplatelets GNP and carbon nanotubes CNT) are fabricated. Complex permittivity, permeability, and shielding properties of composite materials with 30 wt% of Co3O4 and (2–5) wt% of nanocarbon are measured in the frequency range of 1–67 GHz using the transmission–reflection method. A significant increase of microwave permittivity and presence of several peaks on the dependencies of the imaginary part of permittivity on the frequency are found for three‐phase nanocarbon/Co3O4/epoxy CMs. The observed microwave shielding efficiency of three‐phase epoxy composites is enhanced compared to two‐phase nanocarbon–epoxy composites. Such enhancement of shielding efficiency correlates with the increase of DC conductivity of these three‐phase composites. The measured complex permittivity and permeability spectra for nanocarbon/Co3O4/epoxy CMs are used for modeling the reflection loss for studied composites. It is shown that the most preferable for microwave absorption is the composites containing 2 wt% of nanocarbon filler for a sample thickness of 0.5–0.7 mm. The highest reflection loss = 30 dB with an absorption bandwidth of 15 GHz is found for epoxy composite filled with 2 wt% of GNP and 30 wt% of Co3O4 for a sample thickness of 0.5 mm.

Accelerated estimation of the very high cycle fatigue strength and life of polymer composites under ultrasonic cyclic three-point bending

Ultrasonic fatigue testing (UFT) offers a strong potential to accelerate the testing time of fatigue experiments of materials up to very high cycle (VHCF) and giga-cycle (GC) fatigue regimes. This can especially be useful during the materials selection processes when designing load-bearing structures. In this study, one increasing- and three constant-amplitude fatigue experiments were conducted using a UFT system on three different composites consisting of woven Carbon fibers with Poly-Ether-Ketone-Ketone (CF-PEKK), Polyphenylene Sulfide (CF-PPS), Epoxy (CF-Epoxy) as polymer matrix materials. The surface temperature data obtained from these experiments were used to evaluate the heat dissipation rate and fracture fatigue entropy (FFE) range of the three composite materials. The fatigue strength estimated using this FFE range for CF-PEKK (normal stress), CF-PPS (shear stress), and CF-Epoxy (shear stress) composites were 26.3 MPa, 4.7 MPa, and 15.1 MPa, respectively. The fatigue life comparison between the estimation model adopted in this study and the experimental results found in the literature was in reasonable agreement for all three composites. The FFE concept is adapted to the UFT method to rapidly estimate the VHCF properties of composite materials used in load-bearing structures within three weeks.

An Eight-Node Non-Conforming Generalized Partial Hybrid Element and Its Application in Stress Analysis of Repaired Composite Laminate Structures

To ensure the overall continuity of displacement and out-of-plane stress in composite laminate structures and to quantitatively analyze the mechanical properties of composite materials after damage or repair, a finite element solution method is applied based on the modified generalized H–R variational principle. This method utilizes an eight-node non-conforming generalized partial hybrid element (NCGPME8). The partial hybrid model established with this hybrid element can accurately satisfy the out-of-plane stress boundary conditions of the structure, ensuring the continuity of out-of-plane stress. Numerical examples are used to validate that this hybrid model can effectively compute thick and thin laminate structures with high accuracy and rapid convergence of out-of-plane stress. Finally, considering the insensitivity to irregular meshes and the accuracy in calculating in-plane stress, this method is propagated by element coefficient deduction or element material replacement, then employed to analyze the in-plane and out-of-plane stress distributions of laminates with damage from stepwise grinding perforations, and laminates repaired in a stepwise fashion. Stress and displacement at different locations on the laminates are compared and analyzed, leading to a quantitative assessment of the impact of damage and repair on the stress distribution of the laminates.

Synthesis of CoMn‐LDH@MXene Hybrid Materials as Flame Retardant to Effectively Improve the Fire Safety of Thermoplastic Polyurethane

AbstractIn recent years, MXene 2D materials have shown good performance in enhancing the flame retardant properties of composite materials, but it is still tricky to improve the compatibility with the polymer matrix. This work explores a simple method for the synthesis of MXene based nanohybrids (CoMn‐LDH@MXene) by hydrothermal synthesis using MXene and layered double hydroxides (CoMn‐LDH) to construct a flame retardant system with excellent performance. The results show that the MXene nanosheets are less built up and more dispersed in the TPU collective due to the inclusion of LDH, giving the TPU composites excellent flame retardant and smoke suppressant properties. Compared to TPU without flame retardant, TPU composites with 2 wt% CoMn‐LDH@MXene reduced PHRR by 33.7 % and THR by 28.7 %. The TPU/2wt %CoMn‐LDH@MXene composites also showed better flame and smoke suppression performance, PSPR, TSP, PCO and PCO2 were reduced by 44.4 %, 22.7 %, 37.7 % and 27.2 % respectively, the production of Hydrocarbons and HCN were also reduced. Barrier effect of transition metal oxide catalysed carbon layer formation, combustion blocking effect of hybrid material nanosheets, cooling effect of water vapour from thermal decomposition of LDH and the gas phase dilution effect are the main reasons for the increased fire safety of TPU composites.

Influence of Interfacial Interaction and Composition on Fracture Toughness and Impact Properties of Carbon Fiber-Reinforced Polyethersulfone.

In this study, the interlaminar fracture toughness and impact strength of polyethersulfone reinforced with continuous carbon fibers were studied. Interlaminar fracture toughness tests were performed using the double cantilever beam method. It was shown that surface modification using the thermal oxidation method of the carbon fibers can strongly increase the interlaminar fracture toughness of the obtained composites. Thus, the maximum value reached 1.72 kJ/m2, which was 40% higher than the fracture toughness of the composites reinforced with initial carbon fibers. Moreover, fractographic analysis using a scanning electron microscope allowed us to highlight the main reasons for the dependence of fracture toughness on fiber content and surface modification conditions of the carbon fibers. It was shown that the main factor that allowed for an increase in fracture toughness was the enhanced interfacial interaction between the fibers and polymer matrix. Additionally, it was found that expectedly, there was a good correlation between interlaminar fracture toughness and interlaminar shear strength results. However, a negative influence of surface modification on the impact properties of composites was found. Such behavior occurred because of higher structural stability and lower exposure to delamination in multiple layers of the composites reinforced with the modified carbon fibers. It was found that impact energy reached ~150 kJ/m2 for the polyethersulfone-based composites reinforced with initial fibers, while the composites reinforced with modified carbon fibers showed impact energy values of only ~80 kJ/m2. Nevertheless, surface modification of carbon fibers using the thermal oxidation method can be an effective method for improving the performance properties of polyethersulfone-based composite materials.

High-temperature tensile strength of C/SiC composite under laser-induced high heating flux in an aerobic environment

Based on the advantages of laser high brightness, a high-temperature mechanical property measuring device has been developed, which can measure the high-temperature strength of C/SiC composites under the condition of short-term high-temperature rise rate and solve the problem of over-oxidation of materials in conventional high-temperature mechanical properties experiments. The experimental results show that the maximum temperature rise rate is 260 ℃/s at the initial heating stage, and the test time is controlled within 35 s. The tensile strength of the prepared C/SiC composites decreased first and then increased at high temperatures and laser-induced high temperatures. The experimental results are similar to those in the literature under the inert atmosphere. Oxidation has less of an effect on the mechanical characteristics of materials under conditions of rapid temperature rise. The system can be used to test the mechanical properties of composite materials at high temperatures and as a simulation platform for the thermal response of specific thermal protection systems subjected to a constant heat flux. This study can provide a new idea for testing ultra-high temperature mechanical properties of C/SiC materials and provide key technical support for the engineering application and high-temperature testing of C/SiC materials in high-temperature environments.

Study on projectile impact resistance of carbon-glass hybrid bioinspired helical composite laminate

Mantis shrimp dactyl clubs have excellent impact resistance due to their special helical structure. Meanwhile, hybrid fibre has become increasingly popular to improve the mechanical properties of composite materials. Based on the helical structure of the periodic region of mantis shrimp dactyl clubs and hybrid fibres, in this study, a hybrid fibre helical lay-up laminate (HHL) is designed. The laminates are prepared using unidirectional carbon fibre prepregs and unidirectional glass fibre prepregs. To study the protective performance and damage process of HHL, a light gas gun impact test and numerical simulation calculations were carried out on the specimens. The harvested protective capability of the HHL specimen was then compared with those of carbon fibre unidirectional lay-up laminate (CUL), carbon fibre helical lay-up laminate (CHL), and hybrid fibre unidirectional lay-up laminate (HUL) specimens. The ballistic protection capability of HHL at different helical lay-up angles was also explored. The testing results show that HHL has the best ballistic protection performance. HHL’s ballistic limiting velocity is 228.5 m/s, which is 49.5%, 30.8%, and 19.9% higher than those of CUL (152.8 m/s), CHL (174.7 m/s), and HUL (190.5 m/s), respectively. Finally, hybrid fibres with a 90° interlaminar helix angle were found to have the highest ballistic limiting velocity. The reason is that the larger interlaminar angle allowed more fibres to be involved in the protection, increasing the energy loss of the projectile and enhancing the protection of the laminate.

Investigation of Microstructures and Mechanical Properties of Al2024/6061/7075-Graphene Composites

This study aimed to compare the mechanical properties and microstructures of Al2024-graphene, Al6061-graphene, and Al7075-graphene composites produced by the powder metallurgy and induction heat treatment method. The effects of graphene content (0.15, 0.30, and 0.45wt.%), heat treatment (sintering and induction heat treatment), and matrix material (Al2024, Al6061, and Al7075) on the microstructure and mechanical properties of composites were investigated. Compared to Al2024, Al6061 and Al7075 alloys, the compressive strength of Al2024-0.15graphene, Al6061-0.15graphene and Al7075-0.15graphene composites increased by 33.74%, 24.9% and 32%, respectively. The highest hardness (164±1.5 HV), compressive strength (506±5 MPa), and apparent density (2.65 g/cm3) were achieved in sintered and induction heat-treated Al7075-0.15%graphene composite. As a result, it was determined that graphene is an effective reinforcement element. It has been determined that induction heat treatment improves the microstructure and mechanical properties of composite materials. Therefore, it has been stated that induction heat treatment significantly affects the mechanical properties of composites.

Plasma-Enhanced Alginate Pre-Treatment of Short Flax Fibers for Improved Thermo-Mechanical Properties of PLA Composites

This research centered on enhancing the mechanical properties of sustainable composite materials made from short flax fibers. Challenges associated with fiber–matrix adhesion and moisture absorption were systematically addressed. A water–alginate pre-treatment, combined with plasma modification, was employed to stabilize the fibers, ensuring their optimal preparation and improved compatibility with biopolymers. A thorough investigation of the effect of the plasma modulation using a duty cycle (DC) was conducted, and extensive physicochemical and mechanical analyses were performed. These efforts revealed conditions that preserved fiber integrity while significantly improving surface characteristics. Techniques such as optical emission spectroscopy (OES), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and Dynamic Mechanical Analysis (DMA) were utilized, providing a comprehensive understanding of the transformations induced by the plasma treatment. The findings underscored the critical role of alginate and precise plasma settings in enhancing the mechanical properties of the composites. Ultimately, this study made a substantial contribution to the field of eco-friendly materials, showcasing the potential of short flax fibers in sustainable composite applications and setting the stage for future advancements in this area.

Investigation of rheological properties of extruded composites based on UHMWPE

The influence of the CO-4 stabilizer on the rheological properties of polymer composite materials based on UHMWPE has been studied. It has been shown that the addition of a CO-4 stabilizer to polymer matrices significantly affects the rheological properties of materials and their extrudability. There is a change in the conformations of macromolecular chains, the absence of dependence of the viscous component on the relaxation process of the dispersed system, an increase in the complex viscosity, which led to a deterioration in the processability of the material. Based on the Han curves, it is shown that the addition of a CO-4 stabilizer leads to a deterioration in the miscibility of mixtures, i.e., the phase separation of the components of the obtained samples increases.

Polymer composite materials based on a binder from renewable raw materials: the effect of a filler on the physical and mechanical properties

Polymer composite materials have been developed using polyester-urethane-acrylate resin based on 2,5-furandicarboxylic acid obtained from plant biomass and a number of synthetic (carbon, glass, and aramid fibers) and mineral (basalt) fibrous fillers. The high operational characteristics of the obtained PCMs are demonstrated. The effect of hybridization of synthetic fibers with natural cellulose fibers (cotton) on the physical and mechanical properties of polymer composite materials has been studied. An increase in tensile strength with a simultaneous decrease in the density of PCM using a carbon fi ber/cotton hybrid filler is shown.

Effect of reduction rate on microstructure and properties of laminated steel/aluminium low density composites prepared by hot pressing

ABSTRACT A multi-layer composite material consisting of 316 L steel and Al6061 aluminium was prepared via hot pressing. The mechanical properties of this heterogeneous layered composite material were studied under various reduction rates. The results revealed that the overall performance of the material initially improved and then declined as the reduction rates increased. Notably, at a hot pressing temperature of 400°C, the material exhibited optimal performance at a reduction rate of 32%. Furthermore, finite element simulations of the material processing process were performed using ABAQUS software, and the stress-strain state was analysed. The findings indicated that the overall performance of the material is influenced by both the presence of intermetallic compounds (IMCs) at the interface and the shear stress at the interface. In comparison to the aluminium layer, the performance of the steel layer undergoes more pronounced changes at the same reduction rate.

High-strength and high-toughness alkali-activated composite materials: Optimizing mechanical properties through synergistic utilization of steel slag, ground granulated blast furnace slag, and fly ash

In this study, the synergistic utilization of steel slag (SS), ground granulated blast furnace slag (GGBS), and fly ash (FA) was investigated to optimize the mechanical properties of high-strength and high-toughness alkali-activated composite materials (AAM). The research focused on understanding how varying ratios of these components affect the workability, compressive strength, elastic modulus, tensile strength, and tensile deformation capacity of high-strength and high-toughness AAM. A key part of the study involved optimizing the SS-GGBS-FA ternary cementitious system in high-strength and high-toughness AAM using the simplex-centroid design methodology. The findings reveal that changes in the proportions of SS, GGBS, and FA predominantly influence the flowability of high-strength and high-toughness AAM to a limited extent. Notably, the amount of GGBS in the cementitious mix significantly affects the compressive strength and elastic modulus of the material. A synergistic enhancement of the tensile properties was observed due to the combined effect of SS, GGBS, and FA. An optimal tensile deformation performance was achieved with approximately 15% SS. For an ideal balance of properties, including tensile strength above 8.1 MPa, ultimate tensile strain exceeding 6.4%, and compressive strength over 95 MPa, the study recommends maintaining SS between 7.5% and 11.5%, GGBS between 31.5% and 35.5%, and FA between 55.5% and 58.5%. These insights are crucial for the design and practical engineering applications of the SS-GGBS-FA ternary cementitious system in high-strength and high-toughness AAM.

Study on microstructural and mechanical properties of cementitious materials composed of fly ash and dacite powder

The hydration reaction of mass concrete seriously endangers the structural safety. At present, the concrete production relies excessively on fly ash due to hydration reaction. In view of the problem that the demand of fly ash exceeds the supply, this paper proposes to use dacite powder to partially replace fly ash as the raw material for preparing cementitious materials. Through comprehensive tests and microstructure tests, various properties of dacite powder and fly ash composite cementitious materials are studied. The results show that: 1. The dacite powder with a specific surface area of 650 m2/kg, a fineness of 15% under laser particle size and a ball-milling time of 1.0 h has the best performance. 2. It is advisable to mix dacite powder and fly ash. The total amount of dacite powder should not exceed 30% of the cementitious material. It has the best performance when the amount of dacite powder and fly ash is the same. 3. The alkali activity of aggregate can hardly be inhibited by mixing dacite powder alone. The recommended measures to inhibit the alkali activity of aggregate are: i) mixing more than 20% fly ash alone. ii) mixed with 25% dacite powder and more than 15% fly ash.

Random processes in modeling durability of building and structure

The problem of buildings and structures durability during their long-term operation in aggressive environments is discussed. It is closely connected with the problem of destruction of composite materials as a random process of birth, development, and death of defects at chemical corrosion. The content of the study is to analyze the influence of non-stationary chemical reactions occurring in real conditions on these processes. The analysis is carried out taking into account the incidental physical phenomena affecting corrosion, the most important of which is the diffusion of initial substances and reaction products occurring under different hydrodynamic conditions, i.e., the nature of fluid motion and its pressure which stimulates corrosion. The synthesis of three processes – chemical kinetics, diffusion, and hydrodynamics – allows us to study one of the possible scenarios of corrosion process development as a Markov process based on the statistical theory of the “weakest” link and the joint distribution of the random material and geometric parameters. Numerical analysis of changes in elastic and electrical properties of composite materials under these conditions allows us to substantiate the technology of non-destructive control of changes in the state of the structure. The research results are based on mathematical and statistical modeling.