Mechanical Properties Of Composite Materials Research Articles

Synergistically Optimized Thermoelectric and Mechanical Properties of Mg3.2Bi1.5Sb0.5-SiC Composites.

Motivated by the surging demand for low-temperature waste heat harvesting, materials with both prominent thermoelectric and good mechanical properties are preferred in practical applications. In this present work, the composite exploration of Te-doped Mg3.2Bi1.5Sb0.5-x vol % nanosized SiC (x = 0, 0.05, 0.1, 0.2, and 0.5) was carried out, where nanosized SiC is physically dispersed in the matrix in the form of a second phase. SiC second phase compositing further optimized the matrix carrier concentration, resulting in a higher power factor in the service temperature range (the highest value from 28.9 to 31.7 μW cm-1 K-2), and the (ZT)ave from 0.91 to 0.96 compared with the matrix sample. In addition, the SiC second phase effectively enhanced the mechanical properties of composite materials, including flexural strength, microhardness, and modulus. Because of the simultaneous optimization of thermoelectric and mechanical properties, the overall performance of Te-doped Mg3.2Bi1.5Sb0.5-0.05 vol % SiC composite is leveraged to meet special requirements of power generation. It is expected that the addition of SiC should be broadly applicable to address the physical performance in other thermoelectric systems.

Extraction and characterization of nano-silica particles to enhance mechanical properties of general-purpose unsaturated polyester resin

Abstract Unsaturated polyester resin (UPR) is the most versatile liquid polymer with a wide range of applications in every aspect of the industry but it has low impact strength, low elongation at break, and low toughness. Its mechanical properties can be enhanced with the addition of an optimum percentage of nano-silica fillers by using ASTM polymer test standards, which have been followed by various research groups. For this research, enhanced mechanical properties of the resin have been tested for 0.5, 1, 2, 3, and 4% amount by weight fraction of the nano-silica as fiber nanomaterial. The sugar cane bagasse ash was collected from the Wenji Sugar Factory and extracted with the required size of the particle, which is 10 nm. The ability of extraction is used to manipulate the particle size as the researcher needs. The aim is to determine the enhanced mechanical properties of the UPR by the addition of optimum nano-silica particles. Nanoparticles have the effect of filling porous regions, crack path deflection, and crack bridging capability of the material, which provides good adhesion with the matrix to increase the mechanical properties of composite materials. Experimental result dictates that 0.5% nano-silica addition with 10 nm particle size performs best by enhancing the mechanical properties of composite material up to 30.45% for tensile, 33% for compression, 17.8% for flexural, a slightly 10% improvement for impact test and it shows an overall 27% better performance than the pure UPR. Thermal stability and glass transition temperature were not influenced by the addition of nano-silica.

Repercussion of natural silk fibers from spider and silkworms on the mechanical properties of composite materials

Costly synthetic fibers like kevlar, glass, and carbon lead to expensive production costs for products made from these materials, necessitating the development of alternate materials. As a more sustainable and affordable substitute for synthetic reinforcement materials like glass, carbon, and kevlar, natural fiber has gained popularity. Silk fiber obtained from spiders and silkworms is one type of natural fiber that has excellent mechanical properties such as tensile strength, tensile modulus, and breaking elongation. Its mechanical and biocompatibility characteristics are unmatched by those of other synthetic and natural fibers. This article discusses various silk fiber-related topics such as chemical composition, mechanical properties, and applications with respect to spiders and silkworms. Also, the requirement for silk fiber to be used as a reinforcement in composite materials is highlighted. Furthermore, the mechanical properties of silk fiber-reinforced composites (SFRCs) are also explored in this review. It is acceptable to draw the conclusion that the use of SFRCs in the creation of useful and possibly lucrative applications as novel materials in many industrial areas is inevitable.

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.

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.

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.

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.

An Analysis Using the Taguchi Optimization Process to Statistically Investigate the Mechanical Properties of Composite Materials

An Analysis Using the Taguchi Optimization Process to Statistically Investigate the Mechanical Properties of Composite Materials

Synthesis of hydroxyapatite matrix Ag and CNT particle reinforced hybrid biocomposites with improved mechanical and antibacterial properties

Abstract Hydroxyapatite is an important biomaterial for orthopaedic applications due to its high structural similarity to human bone. However, weak mechanical and antibacterial properties limit the use of hydroxyapatite compared to metallic implants such as Ti and 316L alloys for direct use in the human skeleton. To overcome these shortcomings, we have prepared hydroxyapatite matrix silver and carbon nanotube reinforced biocomposites. Silver particles have beneficial effects on biomaterials due to their effective antibacterial activity. In addition, CNT particles are known for their high strength and their ability to improve the mechanical properties of composite materials. To prepare the hydroxyapatite-based composites, the powder blends with different reinforcement types (Ag, CNT) and ratios were ground using a planetary ball mill. The biocomposite powders were then cold pressed under 500 MPa pressure to obtain green samples. The sintering process was carried out at 1200 °C for 4 h. The microstructural and structural investigations were carried out by scanning electron microscopy and X-ray diffraction, respectively. In order to better evaluate the mechanical properties of the samples, hardness measurements, compression and fracture tests were carried out. Antibacterial tests were also carried out against various micro-organisms. Both types of reinforcement were found to be effective in improving the mechanical properties. In addition, it was observed that CNT reinforcement slightly increased the antibacterial resistance, but silver-reinforced samples provided excellent antibacterial resistance.

Tubular Nanoclay-Enhanced Calcium Phosphate Mineralization and Assembly to Impart High Stiffness and Antimicrobial Properties.

Achieving superior mechanical properties of composite materials in artificially engineered materials is a great challenge due to technical bottlenecks in the size and morphological modulation of inorganic nanominerals. Hence, a "bioprocess-inspired fabrication" is proposed to create multilayered organic-inorganic columnar structures. The sequential assembly of halloysite nanotubes (HNTs), polyelectrolytes (PAAs), and calcium phosphates (CaPs) results in organic-inorganic structures. PAA plays a crucial role in controlling the formation of CaP, guiding it into amorphous particles with smaller nanosizes. The introduction of HNT induces the assembly and maturation of CaP-PAA, leading to the formation of a highly crystalline hydroxyapatite. Poly(vinyl alcohol) was then woven into HNT-encapsulated hydroxyapatite nanorods, resulting in composite materials with basic hierarchical structures across multiple scales. The fabricated composite exhibits exceptional hardness (4.27 ± 0.33 GPa) and flexural strength (101.25 ± 1.72 MPa), surpassing those of most previously developed biological hard tissue materials. Additionally, the composite demonstrates effective antibacterial properties and corrosion resistance, attributed to the dense crystalline phase of CaP. This innovative approach showcases the potential of clay minerals, particularly HNT, in the advancement of biomaterial design. The outstanding mechanical and antimicrobial properties of clay-based composites make them a promising candidate for applications in hard tissue repair, offering versatility in biomedicine and engineering.

Influence of the Size of the Dispersed Particles on the Physical and Mechanical Properties of Composite Materials with an Optimal Type of Dispersed Structure Based on Linear Polyethylene

Influence of the Size of the Dispersed Particles on the Physical and Mechanical Properties of Composite Materials with an Optimal Type of Dispersed Structure Based on Linear Polyethylene

Overview of the research work of Prof. Koyanagi and the composite materials laboratory

Materials at the quantum scale are highly unpredictable, making it impossible to predict certain measurements. There are also limitations to numerical simulations and modelling techniques for understanding advanced materials at the molecular scale. Professor Jun Koyanagi, Koyanagi Laboratory, Tokyo University of Science, Japan, is working to establish a quantitative link that connects the nanoscale simulations to the metre scale. This involves developing methods and techniques that accurately relate the behaviour observed at the molecular level to the macroscopic properties of the material. In order to do this, a comprehensive understanding of the underlying physics and mechanics at each scale is required. Koyanagiâ–™s team is hoping to apply multiscale numerical simulations that will help to ensure the long-term reliability of a range of advanced materials. A key focus of the research is carbon fibre reinforced plastic (CFRP) and Koyanagi wants to pave the way for the widespread use of CFRP in aerovehicles in the near future. The team will conduct multiscale numerical simulations and advanced material development to ensure the reliability and long-term durability of CFRP. This will allow them to confidently incorporate CFRP into the construction of aerovehicles and these will be more sustainable and environmentally friendly as the lightweight nature of CFRP will significantly contribute to enhancing fuel efficiency and reducing emissions. The researchers are using analytical and experimental methods to evaluate the thermal and mechanical properties of composite materials.

Testing and Analysis of Frictional Performance of Carbon Fiber/Metal Composite Materials

In order to enhance the friction and wear performance of carbon fiber/steel composite structures, experiments were conducted to adjust the ratio of thermosetting epoxy resin and C12-C14 glycol ether. A modified liquid was developed that could fully fill the gaps in the carbon fiber and enhance the adhesion characteristics between the fiber surface and 18CrMnTiH round steel material. The effects of self-made modified epoxy adhesive and single-component epoxy adhesive on the mechanical properties of composite materials were compared using ISO814-86 determination of the bond strength of sulfur-cured rubber to metal—two-plate method and international standard ISO1747-1976 determination of the shear strength of sulfur-cured rubber bonded to rigid metal plates—four-plate shear method. The friction and wear performance test analyzed the friction coefficient of composite materials under different pretreatment times. The results showed that the pretreatment treatment effectively reduced the friction coefficient of carbon fiber and effectively extended the service life of the material. This study has certain reference significance for extending the friction and wear resistance performance of carbon fiber-reinforced relative motion metal parts.

Influence of Carbon Nanotubes Concentration on the Mechanical Properties of Cement Mortars

In recent decades, mechanical properties of composite materials containing carbon nanoparticles, in particular single-walled or multi-walled carbon nanotubes (SWCNTs or MWCNTs), have been researched, taking into account their excellent physical and mechanical characteristics. In this work, the influence of the concentration of MWCNTs (0.1, 0.2, 0.3, 0.35 wt.%) on compressive and flexural strengths of the cement mortar was investigated. The results of the research show that the compressive and flexural strengths of the 7 and 28-day curing period samples reach their maximum value at 0.3% of nanotube concentration. In comparison to the control sample, the compressive strength increased by 10.93% within 7 days and by 32.0% within 28 days. And in the case of flexure, the strength of the test samples increased by 33.67% within 7 and by 36.50% within 28 days. It can be concluded that in the case of the selected carbon nanotubes and the material composition at 0.3% of MWCNTs, the compressive and flexural strength reach their maximum values.

An embedded digital element model to simulate the wrinkle defects driven by the consolidation of composites

Understanding the mechanisms of fiber wrinkling during the compaction process is of paramount importance as fiber wrinkling significantly affects the mechanical properties of composite materials. This study introduces an embedded digital element model for simulating the consolidation process of prepreg. Flexible digital element chains are employed to simulate the reinforcing effect of fibers on resin, accounting for the viscoelastic constitutive behavior of uncured resin. The simulation captures intra-layer wrinkles and in-plane waviness defects in the consolidated prepreg, thereby uncovering the mechanism behind fiber wrinkle formation during composite material prepreg consolidation. The accuracy of the model is validated through compression experiments on flat plates and L-shaped structures. The results demonstrate that the proposed embedded digital element model accurately predicts wrinkle defects. Factors such as interlayer friction of the prepreg, consolidation temperature, and mold curvature radius significantly influence the shape and size of wrinkles.

Mechanical Characterization of NaOH-Treated Agel Fiber-Cotton Composites

Composites comprising two or more distinct materials are fabricated to enhance the mechanical properties of the constituent materials. A common approach for generating composites is vacuum infusion. This technique enables the infusion of two materials utilizing a vacuum. In the field of composite science, textile composites have emerged as an important new development. Agel rope, derived from twisting agel fibers, exhibits inferior bending strength and elongation compared to ropes fabricated from synthetic fibers. Moreover, agel rope is susceptible to bacterial decay. This study aims to characterize the mechanical properties of textile composites comprising woven agel rope subjected to NaOH treatment. Specimens in the longitudinal (warp) shows maximal load bearing capacity, as determined by experimental results. Samples treated with 5% NaOH tolerated peak loads of 51.12 N prior to failure, with an associated deflection of 3.18%. Specimens in the transverse (weft) of the woven cotton demonstrated maximum load of 40.75 N at 0.9% deflection. The maximum stress was 25.67 MPa. Similar to agel rope, NaOH treatment removes adhering contaminants from cotton fibers, thereby enhancing their strength. However, NaOH concentrations exceeding 7.5% extract cellulose, damaging the fiber ultrastructure.

Structural modeling and analysis of three-dimensional cross-linked braided preforms

Abstract Rotary braiding is widely used in the preparation of high-performance fiber composites. However, neither conventional rotary two-dimensional braiding nor rotary three-dimensional braiding can prepare three-dimensional preforms with low porosity and dense surface yarns. This article designs a three-dimensional cross-linked braiding equipment, describes the mechanism of carrier motion of three-dimensional cross-linked braiding, and obtains a numerical model of three-dimensional cross-linked braided preforms by establishing the spatial coordinate system of the braided chassis and using cubic B-spline curve fitting. The reasons for the large difference between the numerical model of preform and the real fabric are analyzed, and an optimization algorithm is proposed to make the fabric compact by gathering the yarn to the center of the fabric. The experimental samples are braided on a three-dimensional cross-linked braiding machine, and the reliability of the optimization algorithm is verified by comparing the yarn coordinates of the experimental samples with those of the optimized numerical model. The accurate establishment of the geometric model of the preform provides a solid foundation for carrying out the prediction of the mechanical properties of composite materials.

Process‐property relationship in polylactic acid composites reinforced by iron microparticles and 3D printed by fused filament fabrication

AbstractPolylactic acid (PLA) is the most widely used material in the fused filament fabrication (FFF) technique, which is a biocompatible thermoplastic. However, PLA's usefulness is limited by its narrow processing window and relatively low mechanical properties. Therefore, PLA composites have been developed to enhance its properties for FFF printing. A key challenge in producing composite parts via this method is to find the correlation between the mechanical properties of the parts and the process parameters. This knowledge is essential for optimizing the printing process to achieve the desired mechanical properties for composite parts industries such as aerospace, automotive, and medical, where high‐performance composite materials are crucial. The ability to control and predict the mechanical properties of FFF‐printed composite parts is critical for their successful integration into these industries. In this study, the effect of nozzle temperature (NT), printing speed (PS), and nominal porosity (POR) on the impact strength and specific impact strength of PLA/iron composites was examined using FFF. Response surface methodology (RSM) was used to optimize the experimental design. The results revealed that POR had the most significant effect on the impact resistance data, while NT had the least effect. Reducing the POR led to improved impact resistance in the samples. Multi‐objective optimization results showed that the lowest NT (190°C), the lowest POR (30%), and a PS of 50 mm/s were the optimal conditions for multiple objectives. RSM was also utilized to develop mathematical models of impact properties, focusing on varying NT, POR, and PS, which can be used to predict desired impact properties.Highlights Nominal porosity has the most influence on the impact strength of PLA/iron composites. Optimum values were temperature of 190°C, nominal porosity of 30%, and speed of 50 mm/s. RSM was effective in enhancing the mechanical properties of composite materials. RSM models provide a predictive tool for future FFF‐printed composite parts. Maximum impact strength of 4.44 kJ/m2 was achieved.