Mechanical Performance Of Composites Research Articles

Simulation and mechanical testing of 3D printing shin guard composite materials

ABSTRACT This study critically examines the composite material's mechanical properties and performance for 3D-printed shin guards. It contains a thermoplastic polymer matrix with short carbon fibre reinforcement. Shin guard stress and deformation under impact loading were modelled using FEA models. The composite material was 3D-printed and tested for tensile, flexural, and impact properties. The entire cycle of FEA models and careful mechanical testing allows for the development and evaluation of new composite materials and designs. The finite element analysis, such as maximum von Mises stress, is 2890.5 MPa. The carbon fibre-reinforced composite's mechanical properties, including tensile strength, flexural strength, and impact resistance, showed a considerable improvement over those of the unreinforced polymer. The solid design could be heavier and less adaptable than the pattern. Compared to unreinforced polymers, carbon fibre improves strength, stiffness, and impact resistance for the 3D-printed composite. This result thus proves that 3D-printed carbon fibre-reinforced composites could make superior sports protective equipment like shin guards. The FEA calculations and extensive mechanical testing provide a dependable framework for creating and testing these new composite materials and systems.

Surface modification of Cu-coated carbon fiber for improved mechanical performance of Acrylonitrile Butadiene Styrene composites using 3-Aminopropyl triethoxy silane

This study investigates the use of 3-Aminopropyl triethoxy silane as a surface modifier for Cu-coated Carbon Fibers. The modified fibers were subsequently incorporated into Acrylonitrile Butadiene Styrene matrix composites through melt blending and high-temperature compression molding. The research evaluates the effect of 3-Aminopropyl triethoxy silane on the interfacial structure and mechanical performance of these composites. Results demonstrate a substantial enhancement in the wettability and surface energy of Cu-coated Carbon Fibers, with the static contact angle reduced from 111.2° to 84.5° and surface energy increased from 44.67 mN·m−1 to 56.66 mN·m−1. These surface modifications contributed to an 82.7 % increase in tensile strength and a 76.4 % improvement in tensile modulus of the resultant composites.

An efficient ultrasound vibration strategy for suppressing intra-bundle pores and regulating pore morphology in carbon fiber-reinforced composites

The competitive resin flow between intra- and inter-bundles, always causes the generation of intra-bundle pores during resin transfer molding (RTM), thereby weakening composite mechanical performance. Accordingly, an ultrasound vibration strategy is originally developed to efficiently suppress and improve the spatial morphology and distribution of intra-bundle pores in RTM manufacturing. The effects of ultrasound vibration on the spatial evolution of intra-bundle pores are systematically investigated, furthermore, the suppression mechanisms of intra-bundle pores are revealed. Additionally, an empirical model that predicts porosity under ultrasound vibration, is established and well validated for the developed ultrasound vibration strategy, which provides a feasible path for effectively manufacturing composites. X-ray micro-computed tomography experiments verify that applying a short period of ultrasound vibration balances the dual-scale flow by regulating the modified capillary number, thereby significantly reducing porosity by up to 59.4 %. Numerical analyses indicate that the acoustic cavitation and acoustic flow induced by the ultrasound vibration, facilitate the collapse and transverse migration of larger bubbles, thereby remarkably suppressing the connected pores and larger pores. In particular, the ultrasound vibration strategy completely removes the pores larger than 300 μm. Besides, the collective effects of vibration, compression, and shear forces contribute to forming near-circular pores, which are beneficial for ensuring the expected mechanical performance of composites.

Fibre misalignments in the split-disk test represented by random fields

Fibre misalignment is a major type of manufacturing defect in fibre-reinforced composite materials which has an adverse effect on the mechanical performance of composites. The present paper utilises stochastic models based on the random fields of fibre misalignment in the finite element analysis (FEA) of the split-disk test for filament wound composites. Local fibre misalignment characteristics are determined experimentally using X-ray micro-computed tomography (μ-CT) and then used to generate spatially correlated anisotropic random fields further mapped to finite element mechanical properties. The model predicts pronounced stress and strain non-homogeneity, an expected reduction in the overall modulus and pre-mature damage initiation. This leads to the evaluation of effect-of-defects and allowable for manufacturing tolerances in hoop layers of composite pressure vessels.

One-Step Synthesis of Graphene-Covered Silver Nanowires with Enhanced Stability for Heating and Strain Sensing.

Solution-processed silver nanowire (AgNW) networks have been considered as promising electrode candidates for next-generation electronic devices. However, they suffer from poor thermal and electrical stability and low mechanical properties, hindering their practical applications. In this work, graphene nanosheets are successfully introduced into AgNW via a facile one-step solvothermal process. Benefiting from increased conductive paths, the resultant AgNW/graphene films exhibit high electrical conductivity. More importantly, the interlocking NW morphology can be maintained under high temperature and applied voltage due to suppressed Ag migration, which is enabled by the introduction of graphene. This feature leads to enhanced thermal and electrical stability, making them suitable for use as transparent heaters. Furthermore, the composite films present excellent mechanical performance, and negligible resistance change is observed after 10 000 repeated bending cycles. To demonstrate their feasibility toward sensor applications, sandwiched strain sensors are designed, which can endure larger tensile strains and show higher sensitivity and repeatability compared with pure AgNW-based device. Furthermore, various hand gestures can be easily recognized by the resultant sensors based on unique combinations of sensing response. This work not only provides a low-cost method to realize large-scale synthesis of AgNW/graphene composites but also offers guidance to prepare high-performance electrodes for advanced electronics.

Synthesis of boronized Ti6Al4V/FHA composites by microwave sintering for dental applications

Boronized Ti6Al4V/FHA composites were prepared by microwave sintering of mixed powders of Ti6Al4V, TiB2, and synthesized fluorine-substituted hydroxyapatite (FHA) with variable compositions at 1050 °C for 30 min. The unique “lens effect” of microwave facilitated the in-situ transformation of nanoscale TiB2 into TiB, serving as the reinforcing phase within the composites. Increasing the theoretical fluorine substitution percentage of FHA from 0% to 50% caused less thermal decomposition of hydroxyapatite during sintering, promoting densification and thereby mechanical properties of the composites. However, elevating the substitution percentage to 100% led to excessive grain growth and FHA agglomeration, deteriorating the composite mechanical performance. The boronized Ti6Al4V/FHA composite produced using FHA with the theoretical fluorine substitution of 50% exhibited the highest compressive strength (397.7 MPa), proper compressive modulus (10.65 GPa) and maximum microhardness (385.3 HV). Furthermore, it showed excellent hydrophilicity and good cell adhesion, confirming its superior bioactivity for dental applications.

Sustainable lignin-based carbon fibre reinforced polyamide composites: Production, characterisation and life cycle analysis

This work presents the first production, characterisation and life cycle analysis of composite materials produced from injection moulded polyamide reinforced with short lignin-based carbon fibre (CF). To produce these composites many challenges associated with the production of lignin CF have been resolved through the utilisation of thermoplastic polyurethane blend with Alcell organosolv lignin. These CFs have been utilised to reinforce polyamide 66 (PA66) and their performance as a reinforcement have been compared with a textile grade PAN CF. Composites have been prepared using short CF and injection moulding with results compared in terms of interfacial interactions, and composite mechanical performance. It was found that lignin-based CF increases crystallinity in the PA66. The increased matrix affinity of the lignin-based CF may be attributed to increased oxygen on the lignin CF which has been retained from the lignin precursor fibre. When considering that the lignin CF reach equivalent diameter to the PAN CF, the mechanical properties of lignin based CF are comparable to that of PAN CF. Life cycle analysis modelling predicts that the replacement of PAN CF with lignin CF reduces the global warming potential by 54 % for these materials.

Enhancing mechanical properties of selectively laser sintered SiC/Si composites printed using electrostatic spraying microspheres with fine particles

The SiC/Si composites were prepared via selective laser sintering (SLS) combined with reactive melt infiltration (RMI) of liquid Si, using fine SiC particles with original particle sizes of 0.05, 0.8 and 5 μm. A novel electrostatic spraying combined with phase inversion (ES-PI) method was developed to assemble SiC particles into spherical powders (40–60 μm in diameter) before SLS, enabling SiC with excellent flowability. Commercial coarse SiC microparticles (∼40 μm) were also adopted to prepare the SiC/Si reference composite for comparison. Then the effects of the fine original particle sizes of SiC on the microstructures, as well as mechanical performance of composites were studied. Compared to commercial SiC microparticles, the ES-PI SiC microspheres show superior sphericity and fluidity but a relatively high porosity. However, the pores in ES-PI SiC microspheres, which are potentially detrimental to mechanical properties of composites, will be totally filled and eliminated in the SiC/Si composites after RMI. The mechanical performance of the SiC/Si composites printed using the fine nano (0.05 μm) and submicron (0.8 μm) original particles was effectively improved than the reference composite. When printed using the ES-PI SiC microspheres with 0.05 μm original particles, the flexural strength of the SiC/Si composite was enhanced by 25 %. This is attributed to the cracks deflection as well as the fracture mode transition from transgranular to intergranular rupture by the use of nano- or submicro-sized original SiC particles. This work provides an effective solution for preparing high strength SiC/Si composites with fine nano- or submirco particle sizes for space-based lightweight optical mirror using SLS.

Optimizing the Mechanical Performance of Green Composite Materials Using Muti-Integrated Optimization Solvers

Natural fiber composites are potential alternatives for synthetic materials due to environmental issues. The overall performance of the fiber composites depends on the reinforcement conditions. Thus, this work aimed to optimize the reinforcement conditions of the natural fiber composites to improve their mechanical performance via applying an integrated scheme of Genetic Algorithm (GA), Particle Swarm Optimization (PSO), and differential evolution (DE) methods considering various reinforcement conditions including fiber length, fiber loading, and treatment time for optimal characteristics of the composite mechanical performance. The B-Spline approximation function was adopted to predict the experimental performance of green composites. The B-Spline approximation function demonstrated incomparable accuracy compared to linear or quadratic regressions. The function is then optimized using an integrated optimization method. Results have demonstrated that optimal reinforcement conditions for the maximized desired mechanical performance of the composite were achieved with high accuracy. The robustness of the proposed approach was approved using various surface plots of the considered input-output parameter relations. Pareto front or the non-dominated solutions of the desired output mechanical properties were also obtained to demonstrate the interaction between the desired properties to facilitate finding the optimal reinforcement conditions of the composite materials.

Effects of Shear Studs and Openings in The Mechanical Performance of Composite Floor Deck using Finite Element Analysis

The composite floor deck system is the most popular floor system used in the construction industry, especially in industrial structures. A composite floor deck is a floor system that consists of a steel deck bonded with concrete. The shear bond between the steel deck and concrete slab normally controls the shear capacity of a composite floor deck system. In the current construction industry, shear studs are normally used to improve the shear performance of the structure. However, the literature review shows that there were very limited studies on identifying the efficiency of these shear studs and their effects on the composite floors' mechanical performance. In addition, there were always openings for M&E equipment in the floor deck system, which needs further analysis to determine their effects on themechanical performance of the composite floor deck system. Thus, the main objective of this study was to identify the effects of shear studs and openings on the mechanical performance of composite floor decks. The method adopted in this study was the Finite Element Analysis (FEA) using ANSYS software. The outcome of the result has shown that the presence of shear studs improves the mechanical performance of a composite floor deck while the presence of openings reduces the mechanical performance of a composite floor deck system.Keywords: composite floor deck, opening, shear studs, mechanical performance

A RECENT REVIEW OF THE SANDWICH-STRUCTURED COMPOSITE METAMATERIALS: STATIC AND DYNAMIC ANALYSIS

Metamaterials, commonly known as synthetic composites with exotic dynamic characteristics, have recently generated increasing interest. A short description of composite metamaterial and their types, applications, and manufacturing techniques was reported. Contrary to all previous research, this investigation focuses on the recent studies of static and dynamic analysis of composite metamaterial structure and mechanical performance using experimental and finite element method analyses. Furthermore, the literature has described several methods for constructing composite sandwiches, properties, and advantages over conventional materials. Due to the wide variety of materials and configurations used in the final product, there is a corresponding diversity in manufacturing techniques. Therefore, the current research has mainly concentrated on a wealth of information that should be important to all researchers interested in keeping up with the most recent developments in composite metamaterial sandwich structures. Consequently, this study can be considered a guideline for researchers who intend further research on the mechanical behavior analysis and technology of designed composite metamaterial structures.

Microstructure-based simulation on the mechanical behavior of particle reinforced metal matrix composites with varying particle characteristics

The mechanical performance of metal matrix composites strengthened with particles is predominantly contingent upon the attributes of the incorporated particles. Attaining the optimal particle size, morphology, and interfacial bonding within the composites is paramount for improving the comprehensive properties. In this study, an experimentally congruent model was devised to validate the feasibility of the model predicated on the actual microstructure of the composite. The modeling procedure encapsulated matrix and particle failure, as well as surface-based cohesive damage at the interface, to precisely portray the mechanism of action for the particle characteristics. Additionally, the mechanical behavior and failure evolution mechanism of the composites were simulated by manipulating the pertinent particle factors, including size distribution, interfacial strength, and morphology. The findings demonstrated that an appropriate size distribution between particles and more rounded particles can mitigate stress and strain concentration within the matrix interstitial to particles, resulting in a considerable enhancement in the mechanical performance of the composites. As the interfacial strength decreases, the initial failure progression of the composite shifts from initial cracking within the matrix induced by stress-strain concentration to interfacial failure caused by interfacial debonding, ultimately accelerating the failure of composite. This research will bolster the comprehension of the correlations between microstructural features and mechanical performance in metal matrix composites strengthened with particles, providing an innovative simulation-assisted experimental approach for the rapid development and preparation of novel metal matrix composites.

Laser-induced heating, property changes, and damage modes in carbon fiber reinforced polymer matrix woven composites

Despite numerous efforts to understand mechanical damage in carbon fiber reinforced polymer matrix composites, there are minimal experimental and computational efforts that incorporate temperature effects on mechanical performance of composites. Recent studies have shown temperature changes can be readily monitored and predicted under relatively low heat fluxes. The present study augments such prior work by exploring effects of higher heat fluxes and increased heating rates. Plain-woven composites with T650 carbon fibers in a bismaleimide 5250-4 matrix were heated with a continuous wave laser (3.0 cm diameter flat-top beam profile at 1.0692 μm). Laser powers and durations were designed to reach temperatures near, and exceeding, matrix decomposition temperatures. Three duplicates of specimens were irradiated with four powers and two durations, yielding an irradiance range of 4.2 – 12.7 W/cm2. Resulting spatial and temporal temperature changes were measured with calibrated infrared cameras for both composite surfaces. Post-test surface photography and X‐ray CT scans were used to assess morphology changes and damage characteristics. Two key findings are reported herein: (i) delamination events dramatically impacted thermal transport, and (ii) TGA data and appropriate kinetic models can be used to account for temperature- / rate- dependent thermal responses and damage behaviors in the composites.

Synergistic Effects between Multiphase Thermal Insulation Functional Phases on the Mechanical and Heat Insulation Properties of Silicone Rubber Composites.

This work utilizes the synergistic effect between three different functional phases of thermal insulation, i.e., hollow ceramic microspheres (HCMs), hollow silica microspheres (HSMs), and hydroxy silicone oil blowing agent, to prepare a flexible and efficient thermal insulation composite with low thermal conductivity and high structural strength. First, the effects of the three phases on the mechanical and thermomechanical properties of silicon rubber (SR) were analyzed using a scanning electron microscope (SEM), a thermogravimetric (TG) analyzer, a thermal conductivity meter, and a universal testing machine, respectively. Then, the thermal insulation mechanism of multiphase thermal insulation composite materials was analyzed. The results show that the thermal stability and mechanical performance of composites were significantly enhanced, particularly for sample 18H, whose Tmax and char yield reached 621.3 °C and 77.5%, respectively, representing a respective increase of 12.1 and 35.3% compared to those of pure SR. After heat treatment at 1000 °C, the linear shrinkage of the sample diameter was about 9.4%, while the thermal conductivity was as low as 0.064 W/(m·K), which was 53.2% lower than that of the pure matrix SR. We believe that this work can serve as a reference for the preparation of heat insulation and protection materials with low thermal conductivity and high structural strength.

The effect of heat-treatment temperature (HTT) on the carbon matrix development of both polyarylacetylene-and phenolic-derived carbon–Carbon (C/C) composites

Phenolic resins have been successfully used in the manufacture of C/C Composite hardware. However, they require costly, multiple impregnation–carbonization cycles due to their low char yield. Polyarylacetylene (PAA) resin is a promising alternative carbon precursor that possesses numerous advantages due to its higher char yield and low mass loss. In addition, both thermoset-derived carbons are non-graphitizable and rely on stress graphitization for matrix development, which ultimately dictates composite mechanical performance. The stress graphitization behavior of both composite systems was investigated and related to their mechanical behavior. PAA and phenolic-derived/T50 C/C composites were processed to a series of heat-treatment temperatures (HTTs), (1100°, 1800°, 2800°C) and compared. Increases in localized graphitization as verified by image analysis, AFM, and Raman were observed with increasing HT for both systems, though notably to a much higher degree for the phenolic system. We believe this to be a result of the larger degree of matrix pyrolysis shrinkage experienced at the fiber-matrix interface promoting molecular alignment. The mechanical properties of both composites were strongly affected by the HTT, primarily due to a weakening of the fiber-matrix interface. However, the phenolic-derived composite exhibited a 40% greater increase in fiber strength utilization over the PAA-derived composites after 2800°C, which is attributed to this highly oriented microstructure which contributes favorably to intra-matrix failure and crack deflection. Although there are benefits in utilizing high char yield carbon precursors that reduce manufacturing timelines, one must also account for possible differences in microstructure development when designing these composites for next generation systems.

Investigation of Chemical Treatments to Enhance the Mechanical Properties of Natural Fiber Composites

A sustainable approach to composites is leading to the use of natural fibers rather than synthetic materials, like carbon or glass, for reinforcement. However, the higher moisture absorption of natural fibers impairs the composite’s mechanical properties. Therefore, to improve the mechanical properties, some chemical treatments like silane and fluorocarbon can be performed to reduce the moisture absorption of natural fibers. In this study, flax was used as reinforcement, and epoxy was used as a matrix. In the first part of the study, flax reinforcement was treated with different concentrations of silane (20, 40, and 60 g/L) and fluorocarbons (80, 100, and 120 g/L). Moisture regains (MRs), absorbency, and tensile strength were measured at reinforcement levels. According to the results, reinforcements treated with 60 g/L silane (S3) and 120 g/L fluorocarbons (F3) exhibited the lowest MR values of 7.09% and 3.06%, respectively, whereas water absorbency was significantly reduced. The sample treated with 120 g/L fluorocarbons required 300 seconds extra time to absorb the water as compared with the untreated sample, whereas samples S3 and F3 showed an increase in tensile strength by 20.16% and 34.80% when compared with untreated reinforcement flax reinforcement. In the second part of the study, untreated and treated flax reinforcements were combined with an epoxy matrix for composite fabrication. MR and mechanical tests (tensile, flexural, and Charpy impact tests) were performed. Results revealed that treated flax-reinforced composites exhibited lower MR values 0.86% for F3 and 0.42% for S3, respectively. The tensile, flexural, and pendulum impact strengths of silane-treated reinforced composite sample C.S3 were increased by 15.07%, 117%, and 20.01%, respectively, compared with untreated reinforced composite samples. Consequently, both chemical treatments improve composite mechanical performance as well as service life.

Numerical and Experimental Analysis of Mechanical Properties in Hybrid Epoxy-Basalt Composites Partially Reinforced with Cellulosic Fillers.

The current work is focused on numerical and experimental studies of woven fabric composites modified by hybridisation with biological (cellulosic) filler materials. The mechanical performance of the composites is characterized under tensile, bending and impact loads and the effect of hybridisation is observed with respect to pure and nonhybrid composites. Numerical models are developed using computational tools to predict mechanical performance under tensile loading. The computational prediction results are compared and validated with relevant experimental results. This research is aimed at understanding the mechanical performance of basalt-epoxy composites partially reinforced with micro-/nano-sized bio-fillers from cellulose and intended for various application areas. Different weave structures, e.g., plain, twill, matt, etc., were investigated with respect to the mechanical properties of the hybrid composites. The effects of hybridizing with cellulose particles and different weave patterns of the basalt fabric are studied. In general, the use of high-strength fibres such as basalt along with cellulosic fillers representing up to 3% of the total weight improves the mechanical performance of the hybrid structures. The thermomechanical performance of the hybrid composites improved significantly by using basalt fabric as well as by addition of 3% weight of cellulosic fillers. Results reveal the advantages of hybridisation and the inclusion of natural cellulosic fillers in the hybrid composite structures. The material developed is suitable for high-end applications in components for construction that demand advanced mechanical and thermomechanical performance. Furthermore, the inclusion of biodegradable fillers fulfills the objectives of sustainable and ecological construction materials.

Improving the interface compatibility and mechanical performances of the cementitious composites by low-cost alkyl ketene dimer modified fibers

Natural fibers-reinforced cement composites have recently attracted more interest due to the trend in the development of sustainable construction materials. However, the poor fiber–matrix interface compatibility, which is caused by the swelling-shrinking behavior of hydrophilic natural fiber, negatively affects the mechanical properties of the composites thereby hindering their practical application. In order to promote interfacial compatibility, a new fiber surface treatment is needed. A low-cost alkyl ketene dimer (AKD) is adopted in this work, aiming at replacing the relatively expensive silane agents. This study focuses on fiber surface treatment and the resulting effects on the interface compatibility and mechanical performances of the composites. The effect of the fiber modification was characterized by FTIR and water absorption test; The interfacial compatibility of the composites was evaluated by the compatibility index calculation and SEM observation; A series of strength properties of the composites were carried out considering the influence of interface compatibility on mechanical performance. Results show a clear improvement in both interface compatibility and mechanical properties of the composites when AKD-modified fibers are used as reinforcement. The compressive and flexural strength are effectively increased up to 53 MPa and 8 MPa, respectively. Moreover, the approach of the low-cost AKD modification could further be applied to any natural fibers in cementitious composites, allowing cost-effectiveness in practical applications.

Uniaxial Rotational Molding of Bio-Based Low-Density Polyethylene Filled with Black Tea Waste.

In this paper, the possibility of obtaining uniaxially rotomolded composite parts was discussed. The used matrix was bio-based low-density polyethylene (bioLDPE) filled with black tea waste (BTW) to prevent the thermooxidation of samples during processing. In rotational molding technology, the material is held at an elevated temperature in a molten state for a relatively long time, which can result in polymer oxidation. The Fourier transform infrared spectroscopy (FTIR) shows that adding 10 wt% of black tea waste has not led to the formation of carbonyl compounds in polyethylene, and adding 5 wt% and above prevents the appearance of the C-O stretching band connected with degradation of LDPE. The rheological analysis proved the stabilizing effect of black tea waste on the polyethylene matrix. The same temperature conditions of rotational molding did not change the chemical composition of black tea but slightly influenced the antioxidant activity of methanolic extracts; the detected changes suggest degradation is a color change, and the total color change parameter (ΔE) is 25. The oxidation level of unstabilized polyethylene measured using the carbonyl index exceeds 1.5 and gradually decreases with the addition of BTW. The BTW filler did not influence the melting properties of bioLDPE; the melting and crystallization temperature remained stable. The addition of BTW deteriorates the composite mechanical performance, including Young modulus and tensile strength, compared to the neat bioLDPE.

Experimental investigation of the mechanical behaviour of jute/glass fiber composite infused with MWCNT

Composite materials have attracted significant attention due to their superior properties, and this has led to extensive research in the field. To enhance their performance and reduce costs, hybridization of natural and synthetic fibers has become increasingly popular. The current study investigates the mechanical behaviour of jute and glass hybrid composites reinforced with multiwalled carbon nanotube (MWCNT) particles. The composites were manufactured with varying reinforcement fractions (0.5%, 0.75%, 1%, and 2%), and their tensile and flexural strength were evaluated. Additionally, the study examined the influence of hybridization between jute and glass fibers with different fiber stacking sequences, fiber orientations (0°, 30°, 45°, 60°, 90°), and various nano filler percentages. The results indicate a significant improvement in the mechanical performance of composites with increasing reinforcement weight fraction. Specifically, the tensile strength improved by 25% and flexural strength improved by 30% with a reinforcement weight fraction of up to 1 wt%, after which decreasing values were observed due to the agglomeration of nano particles in the matrix. These findings contribute to an understanding of the mechanical behaviour of jute and glass hybrid composites reinforced with MWCNT particles and provide insights for the development of advanced composite materials.