Mechanical Properties Of Composite Materials Research Articles

Study on the mechanical properties of layered gradient structure PBT-based flame retardant composite materials

Abstract To enhance the flame retardancy of Polybutylene Terephthalate (PBT) based composite materials and overcome the decrease in mechanical properties due to the high content of nano-antimony trioxide (nano-Sb2O3), this study initially applies a composite modification method to treat the surface of nano-Sb2O3. Subsequently, composite materials with a gradient distribution of nano-Sb2O3 are prepared through lamination hot-pressing technology, and their mechanical and flame retardant properties are investigated. The results show that the modifiers CTAB and KH560 are successfully grafted onto the surface of nano-Sb2O3, altering its surface properties. Through lamination hot-pressing technology, a gradient distribution from the surface to the core is achieved. Compared to the homogeneous distribution P666, G828 exhibits a 6% increase in Limiting Oxygen Index (LOI), improving the flame retardancy of the composite material. As nano-Sb2O3 enriches on the composite material's surface, the amount of char residue increases. The tensile strength, bending strength, and impact strength of G828 composite material increase by 19.7%, 37.1%, and 103%, respectively, compared to the homogeneous composite material P666, proving the significant effect of G828's gradient distribution in enhancing the mechanical properties of the composite material.

Study of mechanical properties of composite materials reinforced with aluminum fibers

This study investigates the mechanical properties of composite materials reinforced with aluminum fibers of varying lengths and concentrations. The research aims to evaluate the effects of fiber reinforcement on both flexural and compressive strengths, using fibers of three distinct lengths (2×20 mm, 2×30 mm, and 2×40 mm) and four different concentrations (0.5%, 1%, 1.5%, and 2%) by weight within the composite matrix. Mechanical tests were performed after 28 and 56 days of curing to assess the influence of fiber reinforcement over time. The results demonstrate that increasing fiber length and concentration generally improves the flexural and compressive strengths, with the most notable gains observed at moderate fiber content. However, the study also finds that excessively high fiber percentages may lead to diminishing returns in strength performance, possibly due to fiber agglomeration or stress concentration effects. These findings provide valuable insights into optimizing the design of fiber-reinforced composite materials for various structural applications, enhancing both performance and material efficiency.

Influence of dammar resin on the mechanical properties of composites reinforced with corn husk and paper waste

This study aimed to investigate the influence of dammar resin on the mechanical properties of composite materials reinforced with corn husk and paper waste laminates. Different percentages of dammar resin (50%, 60%, and 70%) were added to the matrix while keeping the reinforcement constant. For all samples, the ratio was maintained at 40% matrix and 60% reinforcement. With the experimental results obtained, statistical analyses were conducted: two-way analysis of variance (ANOVA), Levene’s test, Shapiro-Wilk test, and ANOVA post hoc (with Bonferroni correction). The null hypothesis stated that dammar resin does not influence the mechanical properties. For all tests considered, the null hypothesis was rejected (p < 0.05), the variances were homogeneous (p > 0.05), and the data followed a normal distribution (p > 0.05). It was found that dammar resin had a significant influence on the mechanical properties as the percentage increased from 50% to 70% (p < 0.0083). For each test, based on already known premises, an explanation of the phenomenon that could occur due to the insertion of dammar resin was provided, serving to complement and validate the statistical estimations.

Influence of carbon nanotubes on the absorption performance and mechanical behavior of basalt fiber composite materials

AbstractBasalt fibers (BF) are widely used in shipbuilding due to their excellent corrosion resistance. However, basalt fibers do not possess good electromagnetic wave absorption properties, failing to meet the stealth performance requirements of ships. Therefore, this study focuses on basalt fiber composite materials, modifying the matrix by adding different amounts of carbon nanotubes (CNTs). Carbon nanotube‐basalt fiber‐epoxy resin absorptive composite materials are prepared using Vacuum Assisted Resin Transfer Molding (VARTM) technique to investigate the influence of CNT content on the materials. Samples with added CNTs can effectively absorb electromagnetic waves in the low‐frequency range, reducing surface reflectivity. In the high‐frequency range, the impedance matching value of the samples initially increases slowly. When the CNT content reaches 1.5 wt%, at a thickness of 2.5 mm and a frequency of 9.6 GHz, the minimum reflection loss of the sample is −14.40 dB, with an effective absorption bandwidth of 0.7 GHz. Also, CNTs can enhance the mechanical properties of composite materials. With increasing CNT content, both the bending strength and tensile strength of the composite materials are improved. When the CNT content reaches 1.5 wt%, the average tensile fracture strength of the material increases by 21%, and the bending strength increases by 9%.Highlights Enhanced low‐frequency electromagnetic wave absorption from CNTs and reduced polarization. Improved impedance matching and attenuation at high frequencies with CNTs. Significant enhancement in flexural and tensile strength due to CNTs and basalt fibers.

Effect of utilising of sugarcane bagasse fibers on mechanical properties of composite materials ـــ a review

Effect of utilising of sugarcane bagasse fibers on mechanical properties of composite materials ـــ a review

Preparation and formation mechanism of (W) WC/Fe bundle reinforced iron matrix composites

To address the issue of strength and toughness inversion in traditional metal matrix composites, which are reinforced by uniformly distributed ceramic particles, this research developed a novel space bundle configuration of reinforced iron matrix composite using tungsten wire (W) and tungsten carbide (WC). This composite was prepared using a lost foam casting process combined with in-situ reaction. Microstructural analysis revealed that WC particles are distributed along the tungsten wire, with larger particles at the center and smaller ones at the edges. The formation of the reinforcement occurs in two stages: first, a solid-liquid reaction between the solid tungsten wire and molten iron during the lost foam casting process, promoting WC formation at high temperatures and carbon potential; second, an in situ solid-solid reaction where Fe diffuses and Fe3W3C decomposes, forming a composite structure of WC and α-Fe. The composite obtained at 1100°C for 9 hours exhibited a compressive strength of 836.59 MPa and a fracture strain of 18.69%, representing increases of 48.46% and 48.69% respectively compared to grey cast iron (GCI). The (W) WC/Fe bundle reinforcement effectively enhances the strength and toughness of the composite through the high volume fraction and gradient distribution of WC particles, combined with the synergistic effect of α-Fe. This research provides a new strategy for improving the mechanical properties of composite materials and resolving the issue of strength-toughness inversion.

Molecular dynamics simulation of nanocellulose and cement matrix composites

The interfacial properties of nanocellulose and cement matrix are the key factors affecting the mechanical properties of composite materials. However, it is challenging to study the interface combination through conventional experiments and microscopic characterization techniques. Molecular dynamics simulation (MD), as a nanoscale analytical method, can be used to calculate and analyze the strength, deformation, destruction and interfacial interaction of materials on the atomic scale. Since the existing methods of C-S-H modeling and fiber pull-out from the matrix in molecular dynamics simulations were not suitable for cellulose/C-S-H composite models. In this paper, a molecular dynamics simulation method for nanocellulose cement matrix composites was proposed. Based on the embedded composite model, the tensile stress-strain, interfacial interaction energy, hydrogen bond, and interface failure mode were studied when cellulose was pulled out of the matrix. The results showed that adding cellulose could improve the local ductility and tensile strength of cement matrix materials. The interfacial interaction energy between cellulose and C-S-H was approximately −1.09 J/m2, which was much higher than that between carbon nanotubes and C-S-H. Cellulose would adsorb hydrogen and oxygen atoms on H2O, OH− and silica tetrahedron in C-S-H. In the pull-out simulation of cellulose in C-S-H, C-S-H on the surface of cellulose would be destroyed and attached to the cellulose surface and moved along with it, indicating that cellulose could play a good bridging role in the matrix. The simulation results revealed the action mechanism of cellulose in cement matrix materials.

Evaluation of Mechanical Properties of Composite Material with a Thermoplastic Matrix Reinforced with Cellulose Acetate Microfibers.

Low-density polyethylene (LDPE) has been widely used in various applications due to its flexibility, lightness, and low production cost. However, its massive use in disposable products has raised environmental concerns, prompting the search for more sustainable alternatives. This study aims to investigate the mechanical properties achievable in a composite material utilizing low-density polyethylene (LDPE), potato starch (PS), and cellulose microfibrils (MFCA) at loadings of 0.05%, 0.15%, and 0.30%. Initially, the cellulose acetate microfibrils (MFCA) were produced via an electrospinning process. Subsequently, a dispersive mixture of the aforementioned materials was created through the extrusion and pelletizing process to form pellets. These pellets were then molded by injection molding to produce test specimens in accordance with ASTM D 638, the standard for tensile strength testing. The evaluation of the properties was conducted through mechanical tensile tests (ASTM D638), hardness tests (ASTM D 2240), melt flow index (ASTM D1238), and scanning electron microscopy (SEM). This study determined the influence of cellulose acetate microfibril loadings below 0.3% as reinforcement within a thermoplastic LDPE matrix. It was demonstrated that these microfibrils, due to their length-to-diameter ratio, contribute to an enhancement in the mechanical properties.

Analysis of mechanical properties of basalt fabric reinforced fly ash filled vinyl ester composites using multi criteria decision making technique

The current research was to examine the mechanical properties of composite material made of vinyl ester filled with fly ash of various weight percentages. Before fabrication the amount of fly ash and resin were identified by using the Multi Criteria Decision Making technique (MCDM). The best filler weight percentage of 5 wt% is determined by using Weighted Aggregate Sum Product Assessment (WASPAS) which is one of the MCDM methods. The virgin samples of vinyl esters are mixed with weight of 5 wt%fly ash by incremental of 5 wt% up to 20 wt%. All the mechanical tests of the specimen were conducted as per ASTM standards. Subsequently based on the results from the WASPAS method of fly ash content, the basalt fabric was reinforced with fly ash filled vinyl ester to fabricate the hybrid composites. By the mixing of fly-ash with vinyl ester the strength of the fly ash filled composites has been found to be enhanced in the filler. The results from the mechanical testing signified that fly ash can be used as filler material in basalt fabric reinforced vinyl ester resin. The fly ash infused basalt fibre reinforced yields significant development in mechanical performance contrast to the other fabricated composites.

Enhancing wear resistance, mechanical properties of composite materials through sisal and glass fiber reinforcement with epoxy resin and graphite filler

This study investigates the mechanical and wears properties of sisal and glass fiber-reinforced epoxy composites with graphite as filler material. We assessed the mechanical properties of the hand-layup-fabricated composite materials, including hardness, tensile strength, flexural strength, and impact strength, by ASTM standards. We also performed wear evaluations using a pin-on-disc apparatus. The results showed that the weight fractions of sisal fiber, glass fiber, graphite, and epoxy resin significantly affected the mechanical properties of the composites. In contrast to composites reinforced with individual fibers, hybrid composites exhibited enhanced mechanical properties. The optimized compositions showed improvements in tensile, flexural, impact, and hardness properties. The wear analysis revealed that a variety of factors, including the weight percentage of reinforcement, sliding velocity, load, and sliding distance, had an impact on the composites' wear resistance. The SEM images provided significant insights into the composite material's micro structural characteristics and failure mechanisms. In general, this research showcases the potential of graphite filler-reinforced sisal and glass fiber epoxy composites for use in applications that demand exceptional abrasion resistance and mechanical strength. Further refinement of the composition and processing methodologies could lead to the development of composites tailored to specific application demands.

Development of Aluminum Alloys 6061(AA6061) Silicon Carbide (SiC)-Graphite (GR) and Hybrid Composite for Automotive Applications

The microstructure and mechanical properties of composite materials made of Silicon carbide (SiC) and Graphite (GR) reinforcement, known as Aluminum Alloy 6061(AA6061) Matrix were developed. Using the stir casting method, the hybrid composites were prepared with 6 weight percent of the reinforcements in the ratio of 0:1,1:3,1:1,3:1,and 1:0. It was determined how the reinforcement particles affected the microstructures and mechanical characteristics of these materials. The microstructure displays a uniformly distributed fine particles of α-Al grains and Mg2Si phase with in the matrix alloy. The microstructure amply demonstrates the presence of the reinforcing particles (SiC and GR) and dendritic development was noted. There are very few indications of particles clusters, and the particles are very dispersed throughout the matrix. Sample A2 (AA6061 25% SiC/ 75% GR) had the highest recorded hardness value of 123.34 HRB4.8,9.33, while the base alloy had the lowest value of 70.36 HRB when compared to the base alloy, the developed hybrid composites showed improved tensile strength. In contrast to the base alloy, which displayed a strength of 115.67N/mm2, Sample A3 demonstrated a maximum strength of 143.88 N/mm2 as compared to the base alloy which showed strength of 115.67 N/mm2. The hard reinforcement particles sharp edges serve as a nucleation site, which is why the strength of samples A4 and A5 decreased when SiC reinforcement is added, the materials extension decreases when the developed hybrid composite materials with samples were compared with the base alloy. In comparison to the created hybrid composite materials, the base alloy displayed a maximum extension of 2.4mm, with sample A5 showing the lowest extension value of 1.23mm. Sample A2 displayed the highest structures rate of 0.060, while sample A5 displayed the lowest strain rate of 0.031. The impact strength values increases from 2.76 (Base alloy) to 4.77j (Sample A5) with the addition of the reinforcement particles. The obtained mechanical properties indicate that the reinforced alloy performed favorably well but not significantly better than the ones in the literature.

CNN-based prediction of microstructure-derived random property fields of composite materials

The simulation of random spatial variation in the mechanical properties of composite materials using random fields derived from their microstructure can be computationally demanding, since it often requires numerical homogenization of a large number of stochastic volume elements (SVEs). These SVEs are usually extracted from an initial image of the composite microstructure by using a moving window technique and their homogenized properties constitute the discrete data points of the random field at the centroid of each SVE. By replacing the expensive and highly repetitive homogenization procedure with a convolutional neural network (CNN), it is possible to perform nearly instant computations of random property fields. In this work, a CNN is proposed, that takes as input an SVE image and returns its apparent mechanical properties, and can therefore be applied along with the moving window technique. Training is performed on randomly generated SVEs with varying volume fractions and inclusion positions, which are representative of the SVEs obtained during processing of the initial large composite image. It is shown that the proposed CNN can accurately predict the mechanical properties of SVEs and it is subsequently applied for the prediction of random property fields derived from computer simulated and real microstructure images. Results show that, with the proposed methodology, it is possible to make accurate predictions of random fields within a few seconds, a procedure which could potentially require hours of computation time with the finite element based approach.

Mechanical properties of composite materials with low-covered polyrotaxane and plasma-surface-modified hexagonal boron nitride

An effective method for fabricating flexible materials containing thermally conductive fillers, such as hexagonal boron nitride (hBN), utilizes plasma surface modification and polyrotaxane (PR) with movable cross-linking points. This study demonstrated that lowering the coverage rates of PR composites increased the mobility of the cross-linking points. Plasma surface modification improved the dispersion of hBN and enabled homogeneous deformation of the PR composites owing to movable cross-linking points. Studying the deformation with a model including a finite extension effect indicated that the sliding range in the low-covered PR composites was extended compared to that in the high-covered PR composites, resulting in a smaller Young’s modulus, longer extension, and higher toughness.

Effect of nano-TiC/TiB2 and final thermo-mechanical treatment on microstructure and properties of 7185 alloy

In this study, a new generation of ultra-high strength 7185 aluminum alloy and nano-sized TiC+TiB2 particles reinforced 7185 alloy matrix composites (PRAMCs) were prepared, and its thermos-mechanical treatment (TMT) was studied. The electron probe microanalyzer, electron back scattered diffraction, and transmission electron microscope are used to study microstructure evolution. Tensile tests are used to investigate the mechanical properties of composite materials. The results showed that the grain can be refined significantly by adding particles. The grain size of the quenched state is very fine. The strength and plasticity of the alloy are significantly improved. After the final TMT, many dislocations were introduced, and the precipitation phase and dislocation intertwined with each other during the aging process. This increased the dislocation density and promoted the precipitation process. Thus, the strength and corrosion resistance are improved, but the plasticity is reduced. The yield strength, tensile strength, and elongation of the PRAMCs designed in this study after final TMT are 483.6 MPa, 520.4 MPa, and 9.1 %, respectively. The inter-granular corrosion layer depth is 47.2 μm. The grade of exfoliation corrosion for 6 h and 24 h is PC, and EA, respectively. This study can provide strategies for the performance optimization of PRAMCs.

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.

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.

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.

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.

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.

Emerging continuous SiC fibers for high-temperature applications

Silicon carbide (SiC) fibers are responsible for the ultimate strength and toughness of SiC-fiber reinforced composites in harsh environments. The development of a new generation of continuous SiC fibers continues to advance the mechanical properties of composite materials. Tyranno™ SA4 fiber was recently released as a successor of Tyranno™ SA3 fiber. Laser-driven chemical vapor deposition (LCVD) has been adopted as an alternative fiber processing route to synthesizing high-strength SiC fiber with tailorable small diameters and chemical compositions. Both Tyranno™ SA4 and laser-driven CVD fibers show very high tensile strength, about 4 GPa in the as-fabricated condition. The degradation of thermal stability and strength due to annealing in an inert environment were similar for Tyranno™ SA3 and SA4 fibers because of their similar carbon-rich, crystalline microstructure. Silicon-rich fibers produced by LCVD possessed heterogeneous crystallinity, which was attributed to laser power distribution and showed microstructural instability at 1500 °C and above. The new SiC fibers demonstrated an increase in as-fabricated strength but faced the same challenges in environmental resistance as the traditional SiC fibers do.