Volume Fraction Of Reinforcement Research Articles

Free vibration analysis of CNT reinforced plates using higher order shear deformation theory

With the stringent requirements of lightweight and high stiffness in space technology and spacecraft, the research on frequency characters of carbon nanotubes (CNTs) reinforced structures is particularly urgent. In this paper, based on the Reissner-Mindlin higher-order shear deformation theory (HSDT), a vibration model for a CNT functionally graded (FG) plate is developed, and influences of the reinforcements distribution form, reinforcement volume fractions, and various boundary conditions of the structure are considered in this established model. Subsequently, the model’s convergence test was presented first with a rectangular plate structure. Finally, the vibration characteristics and modal shapes of the CNT-FG plate structure are carried out by using this model.

Investigation of the effects of volume fraction, aspect ratio and type of fibres on the mechanical properties of short fibre reinforced 3D printed composite materials

AbstractMechanical behaviour of 3D-printed composite parts is affected by the volume fraction, aspect ratio and type of fibre reinforcement. Although in the literature experimental approaches have been used to characterise the effects of the above factors on the mechanical properties of 3D printed parts, time and cost of the manufacturing process as well as the uncertainty associated with a large number of experimental techniques are the key issues. This study aims to address these challenges by developing a methodology based on a multi-scale Finite Element (FE) analysis of representative volume element (RVE) of 3D printed composite parts to predict the effective orthotropic properties. To account for the effects of fibre features, RVEs were modelled considering variables of volume fraction, aspect ratios and type of short fibres. To study the main and interaction effects of the above variables on the mechanical properties of 3D printed composite parts, a structured approach based on the Design of Experiments is used. The FE stress analysis of the RVE provides an understanding about the potential failure modes such as interfacial debonding between fibres and matrix, interlayer and intralayer delamination that may occur in load-bearing 3D printed composite parts. The FE computed mechanical properties are validated against experimental data through a series of mechanical testing of flexure, Iosipescu, and short beam shear which were conducted in conjunction with the Digital Image Correlation technique. As a result, certainty is obtained in using the proposed approach for a fast iterative design of 3D printed composite parts prior to industrial applications.

Analysis of sandwich graphene origami composite plate sandwiched by piezoelectric/piezomagnetic layers: A higher-order electro-magneto-elastic analysis

This work applies a higher order thickness-stretched model for the electro-elastic analysis of the composite graphene origami reinforced square plate sandwiched by the piezoelectric/piezomagnetic layers subjected to the thermal, electric, magnetic and mechanical loads. The plate is manufactured of a copper matrix reinforced with graphene origami where the effective material properties are calculated based on the micromechanical models as a function of volume fraction and folding degree of graphene origami, material properties of matrix, reinforcement, and local temperature. The governing equations are derived using the virtual work principle in terms of the bending, shear and stretching functions, in-plane displacements, electric, and magnetic potentials. The numerical results including various displacement components, maximum electric, and magnetic potentials are presented with changes of volume fraction, folding degree of reinforcement, electrical, magnetic, and thermal loading. A verification investigation is presented for approve of the methodology, and the solution procedure. The main novelty of this work is simultaneous effect of the thickness stretching and the multi-field loading on the electromagnetic bending results of the sandwich plate. Another novelty of this work is usage of graphene origami nano-reinforcement as a controllable material in a sandwich structure subjected to multi-field loadings. The results show an increase in bending, shear, and stretching deflections with an increase in electromagnetic loads, and folding degree as well as a decrease in volume fraction of reinforcement.

Design and preparation of WBX/Al composites for nuclear radiation protection

As the utilization of nuclear energy continues to expand, there is a growing focus on the development of lightweight and efficient nuclear shielding composites. In this paper, novel WBX/Al (x = 1, 2, 4) composites were designed based on shielding performance. The effects of reinforcement type, volume fraction, and material thickness on the 60Co and 137Cs γ-rays, fast and thermal neutron shielding performances were simulated. The results show that WB/Al composites offer better development potential compared to WB2/Al or WB4/Al composites. Additionally, a predictive model for the γ-ray shielding effectiveness of WB/Al composites, based on the areal density of tungsten, was proposed. The fabrication process involved mechanical ball milling and spark plasma sintering to fabricate 30 vol% WB/Al composites, with optimization of ball milling time, sintering temperature, and holding time. As a result, a novel nuclear radiation protection composite with uniform composition, a relative density of 97 %, and flexural strength of 527 MPa was acquired.

Friction surfacing of AA6061 on AA5083 aluminum alloy with adding 316 stainless steel powders: Effect of volume fraction of reinforcements

The present work aims to study the effect of the 316 stainless steel reinforcement volume fraction during friction surfacing of AA6061 on the AA5083 alloy by tool's rotation, traverse speed, and feeding rate of 1000 rpm, 150 mm/min, and 100 mm/min to improve the tribological and mechanical behaviors of deposited layers. It was found that a fully bonded interface without any void or defect at the bonding interface was formed between the deposited layer and substrate. It was also found that an increase in the number of holes from one to two in the tool resulted in the betterment of the strength of the coating layer by about 18% from 219 MPa to 259 MPa that can be attributed to the complete bonding between the deposited layer/substrate and better scattering of 316 stainless steel reinforcements.

Determination of short carbon fiber orientation in zirconium diboride ceramic matrix composites

In fiber-reinforced components, the fiber alignment and orientation have paramount influence on the thermo-mechanical properties of the resulting composite, for both short and continuous fiber. Here we present the case of an ultra-refractory matrix intended for extreme environment applications, ZrB2, reinforced with 20 vol% and 50 vol% short carbon fibers. In both cases, fibers tend to align perpendicular to the uniaxial pressure applied during shaping and sintering of a pellet, although the fiber tilt across the pellet thickness is difficult to determine. Moreover, for high volume fractions of reinforcement, the spatial distribution of the fibers is heterogeneous and tends to have domains of preferential orientations. We compare the information on the fiber distribution as collected by scanning electron microscopy images, X-ray computed tomography and synchrotron X-ray refraction radiography (SXRR). The three techniques prove to be complementary.Importantly, we demonstrate that SXRR yields the most statistically significant information due to the largest field of view, yet with a sensitivity down to the nanometer, and that can be successfully applied also to heavy matrix materials, such as zirconium boride.

Mechanical and interfacial analysis of 3D-printed two-matrix continuous carbon fibre composites for enhanced structural performance

Two-matrix continuous carbon fibre composites are recognized for enhancing structural and mechanical properties. However, a comprehensive investigation into their interfacial behaviour and potential has yet to be undertaken. Based on the 3D printing process, this study uses experimental and simulation techniques to analyse the mechanical and interfacial performance across multiple scales. The flexure properties under different processing parameters are studied at the macro level. Meso and micro-structural characterization are evaluated by scanning electron microscopy, optical microscopy and molecular dynamics simulation. The disparities in simulations and experimental results are attributed to macroscopic defects and reinforcement volume fraction. This yields insights into strategies for optimising performance, culminating in a comprehensive understanding of the fracture mechanism of two-matrix continuous carbon fibre composites. Our study provides an approach to creating and analysing other systems with multiple matrix composites and enabling new engineering applications for composites.

Effect of Milling Time and Reinforcement Volume Fraction on Microstructure and Mechanical Properties of SiCp-Reinforced AA2017 Composite Powder Produced by High-Energy Ball Milling.

The influence of milling time and volume fraction of reinforcement on the morphology, microstructure, and mechanical behaviors of SiCp-reinforced AA2017 composite powder produced by high-energy ball milling (HEBM) was investigated. AA2017 + SiCp composite powder with different amounts of SiC particles (5, 10, and 15 vol%) was successfully prepared from gas-atomized AA2017 aluminum alloy powder with a particle size of <100 μm and silicon carbide (SiC) powder particles with an average particle size of <1 μm. An optical microscope (OM), X-ray diffraction (XRD), and scanning electron microscope (SEM) were utilized to characterize the microstructure of the milled composite powder at different milling periods. The results indicated that the SiC particles were homogeneously distributed in the AA2017 matrix after 5 h of HEBM time. The morphology of the particles transformed from a laminar to a nearly spherical shape, and the size of the milled powder particles reduced with increasing the content of SiC particles. The XRD analysis was carried out to characterize the phase constituents, crystallite size, and lattice strain of the composite powders at different milling periods. It was found that with increasing milling time and SiC volume fraction, the crystallite size of the aluminum alloy matrix decreased while the lattice strain increased. The average crystallite sizes were reduced from >300 nm to 68 nm, 64 nm, and 64 nm after 5 h of milling, corresponding to SiC contents of 5, 10, and 15 vol%, respectively. As a result, the lattice strain increased from 0.15% to 0.5%, which is due to significant plastic deformation during the ball milling process. XRD results showed a rapid decrease in crystallite size during the early milling phase, and the minimum grain size was achieved at a higher volume fraction of SiC particles. Microhardness tests revealed that the milling time has a greater influence on the hardness than the amount of SiC reinforcements. Therefore, the composite powder milled for 5 h showed an average microhardness three times higher than that of the unmilled powder particles.

High-entropy alloy reinforcement in aerospace-grade aluminum 7075: A study of yield strength and elastic modulus

This research aims to identify an appropriate theoretical model for assessing the yield strength and elastic modulus of a composite material consisting of aerospace-grade aluminum 7075 base matrix reinforced with nanocrystalline high-entropy alloy particle (HEAp) composed of CrCuFeMnNi. To fabricate the aluminum composite with a high-entropy alloy base, an innovative casting method was utilized. This method involved the use of a modified bottom-pouring stir casting furnace, integrated with a mechanical supersonic vibrator and a squeeze infiltration setup. The measured theoretical density was higher than the actual density, while the cast specimen exhibited porosity below 6.6%. Scanning electron microscopy (SEM) images revealed the presence of strengthening precipitates and a uniform dispersion of HEAp in the composite. Comparing the developed HEAp composites (CH2, CH3, and CH4) with the base AA7075 cast CH1 (AA7075 + 0 wt.% CrCuFeMnNi-HEAp), the ultimate tensile strength increased by 4% for CH2 (5 wt.% CrCuFeMnNi-HEAp), 21% for CH3 (10 wt.% CrCuFeMnNi-HEAp), and decreased by 9% for CH4 (15 wt.% CrCuFeMnNi-HEAp). Similarly, the yield strength increased by 10% for CH2, 24% for CH3, and decreased by 5% for CH4. The elongation showed an increasing trend of 5% for CH2, 12% for CH3, and 2% for CH4. The flexural strength of the HEAp composites (CH2, CH3, and CH4) increased by 2%, 5%, and 10%, respectively. The proposed model yielded similar yield strength values that closely aligned and were consistent with the experimental value within a deviation of 3.32%. The modified Halpin-Tsai models agreed with experimental value up to a reinforcement volume fraction of 4.89% when calculating the elastic modulus. The proposed model and the Hashin-Shtrikman upper bound also agreed on values up to a 3.32% reinforcement volume fraction.

SiO2 coating on CNTs to fabricate the Al4O4C-Al composite with superior Young's modulus

To produce nanoparticles with a larger volume fraction and stronger interfacial bonds, silica nanoparticles (SiO2) were deposited on the surface of CNTs through the sol-gel process to provide sufficient oxygen for the in-situ transition of CNTs into Al4O4C nanoparticles. Oxygen measurements and microstructural evaluations revealed that the CNT@SiO2 hybrid reinforcement, with a weight ratio of 1:4, presents the most uniform coating and contains adequate oxygen for the transformation into Al4O4C nanoparticles. The Al4O4C-Al composite exhibited superior mechanical properties over CNT-Al and CNT@SiO2-Al composites. The Al4O4C-Al composite presented a high Young's modulus of 86.82 GPa, which was about 13% higher than the CNT-Al composite with the same CNT content (0.5 wt%). The remarkable increase in reinforcement volume fraction and the formation of strong covalent bonds induced by the in-situ transition of CNTs@SiO2 reinforcements into Al4O4C nanoparticles were responsible for significant the improvement in Young's modulus.

Static, dynamic and buckling behavior of functionally graded beams with tunable inclusions

The introduction of microstructurally tunable materials endorses functionally graded (FG) beams with distinctly inspiring functionalities and mechanical properties. In order to facilitate the multiscale design of FG beams and evaluations of corresponding mechanical behavior, analytical solutions are developed in the present research on the static, dynamic and buckling responses of FG beams reinforced with graphene platelets, porosity or origami inclusions, etc. To facilitate the analytical derivation as well as numerical extension, this paper establishes a theoretical framework, firstly formulating the principle of virtual work and reciprocal theorem of work for the FG beams, and then deriving and proving the principles of minimum potential and complementary energies, the former of which is used for the establishment of the variational principles for the static bending, free vibration and buckling phenomenon in the present work. Following the proposed variational principles and considering Timoshenko beam theory, the strong-form partial differential governing equations as well as the corresponding boundary conditions can be obtained for static bending, free vibration and buckling responses of FG beams. The Ritz method is finally employed to obtain the explicit expressions of transverse bending and rotation as well as the frequencies and critical loads for FG beams with different boundary conditions. What’s more, it should be noted that the FG of the beams is achieved through tailoring micromechanical parameters, such as volume fraction and distribution of reinforcement, which are usually unevenly distributed. The mechanical responses of FG beams are also predicted through micromechanics approaches, such as Halpin-Tsai expression. Conventional GPL distributions as well as graphene origami (GOri) distributions with negative Poisson's ratios (NPR) are also presented to validate the analytical derivation and solutions. Finally, the proposed solutions are employed to investigate the effect of the microstructural parameters on the effective behavior of FG beams.

High-speed laser cladding: new developments for wear and corrosion protection

Fusion-bonded and low-diluted overlay welded coatings are frequently very thick (>1mm), which results in high material consumption (kg/m2) and expenses. High-speed laser cladding is a novel process, which can produce thin fusion-bonded and low-diluted coatings with high coverage rates and low heat input. Coating materials utilized in high-speed cladding have varied from soft Ni-based superalloys to harder martensitic stainless steels and base materials from low alloy steels to austenitic stainless steels. The ultimate objective has been to develop crack-free alternatives to environmentally hazardous hard-chrome plating. In this paper, high-speed laser cladding was used to fabricate relatively thin Ni-based coatings on various cast irons for corrosion protection and Ni-based hard-faced coatings reinforced with chromium (Cr3C2) and tungsten carbides (WC/W2C), for the first time, onto low-alloy structural and quenched & tempered steels for wear applications. Obtained coatings were characterized with X-ray diffraction (XRD), optical (OM), and scanning electron microscopy (SEM). Corrosion performances were explored in long-term salt spray tests. Mechanical and wear properties were tested with Vickers microhardness measurements and three-body dry-sand rubber wheel abrasion tests (RWAT). It was shown that soft low-diluted Ni-based coatings protected the cast iron base materials in salt spray tests. Ni-based hard-faced coatings with hardness up to 1200 HV1 exhibited high wear resistance in low-stress three-body abrasion better than hard-chrome plated coating, which was attributed to the high volume fraction of hard carbide reinforcements.

Role of process parameters in defining the characteristics of copper surface composites fabricated via friction stir processing

This research deals with investigating the effects of amount of hybrid reinforcement, rotational speed and traverse speed on the mechanical and wear characteristics of copper surface composites fabricated via friction stir processing. Aluminum oxide and boron carbide at 1:1 ratio was dispersed onto copper substrate at various volume fractions (5, 10 and 15 vol. %) at different traverse speed (40, 60 and 80 mm min−1) and rotational speed (800, 950 and 1300 rpm). Microstructural characterization of developed copper surface composites dispersed with varying volume fraction of hybrid reinforcement proved reduction in grain size and homogenous distribution of ceramic particles. Results stated that the percentage of particles dispersed, traverse speed and rotational speed have high impact in defining the property of developed copper surface composites. A positive trend in mechanical strength was observed throughout the study. Increase in hybrid reinforcement dispersion and traverse speed increase the microhardness value of developed surface composites while increase in rotational speed leads to reduction in microhardness value.

Squeeze infiltration processing of lightweight smart aluminum graphite functionally graded composite for enhanced wear resistance

Aluminum - Graphite functionally graded metal matrix composites (A356-Gr FGMMC) with 20‐60 volume percentage (vol%) of natural graphite (Gr) as reinforcement are developed by liquid metal squeeze infiltration technique. The density of A356-Gr FGMMC with 60 % Gr is reduced by 27 % (1.968 g/cm3) in particle rich region from the value of the base A356 alloy (2.68 g/cm3) making the FGMMC lighter. In comparison to monolithic A356 alloy, the coefficient of thermal expansion (CTE) of composites decreases with an increase in the volume fraction of Gr reinforcement. The CTE value is significantly reduced from 22.24 × 10−6/°C for A356 alloy to 9.62 × 10−6/°C for the composite with 60 % Gr. With the addition of Gr from 20 % to 60 %, the microhardness is found to be decreased from 74 HV to 46 HV and the compressive strength decreased from 364 MPa for the unreinforced matrix to 42 MPa for A356-Gr FGMMC with 60 % of Gr addition. Wear studies carried out on A356-Gr FGMMC using pin-on-disc tribometer shows excellent wear resistance with the addition of Gr particles compared to matrix alloy. The wear rate reduces with increasing Gr vol%, reaching a minimum at 60 % Gr. The scanning electron microscopy (SEM) analysis of worn surfaces indicate the formation of self-lubricating tribolayer which limits the interaction between matrix metal and the counter surface leading to the development of a smart composite with functionally graded properties in the particle rich region.

Feasibility of additively manufacturing synthetic bone for sports personal protective equipment applications

Human limb surrogates, of varying biofidelity, are used in the performance assessment of sports personal protective equipment (PPE). Such biofidelic surrogates have incorporated soft tissue simulants (silicones) and synthetic bone (short fibre filled epoxy). Testing surrogates incorporating realistic synthetic bone could help to further our knowledge of fracture trauma mechanics, and applications such as the effectiveness of sports PPE. Limb surrogates with embedded synthetic bone are rarely tested to fracture, mainly due to the effort and cost of replacing them. This paper proposes additive manufacturing of synthetic bones, with appropriate bone like fracture characteristics, potentially making them more accessible and cost effective. A Markforged® X7™ printer was used as it prints a base filament (Onyx™) alongside a continuous strand of reinforcement (e.g., carbon fibre). The properties of specimens from this printer vary with the type, volume fraction and position of reinforcement. Bar specimens (10 × 4 × 120 mm) with varying amounts of carbon fibre reinforcement were printed for three-point bend testing to determine the feasibility of achieving mechanical properties close to compact bone (bending modulus of ∼15 GPa, bending strength of ∼180 MPa). Bending strength for the various bar specimens ranged from 32 to 378 MPa, and modulus values ranged from 1.5 to 25.8 GPa. Based on these results, four 140 mm long oval shaped cylindrical specimens of ø14 and ø16 mm were printed to represent a basic radius bone model. Three-point bend testing of these bone models showed similar bending modulus (3.8 to 5.3 GPa vs. 3.66 to 14.8 GPa) to radius bones reported in the literature, but higher bending strength (147 to 200 MPa vs. 80.31 ± 14.55 MPa).

Predicting the electrical conductivity of short carbon fiber/graphene nanoplatelet/polymer composites

The current work examines the effect of graphene nanoplatelet (GNP) additives upon the electrical conductivity of short carbon fiber (SCF)-reinforced polymer multifunctional composites. GNPs and SCFs are randomly dispersed into the representative volume element of the composite. A multi-step physics-based approach is developed to determine the effective electrical conductivity of SCF/GNP/polymer composites. Outcomes of the current work are compared with the available experimental data and other numerical results to verify its accuracy. Changes in the volume fraction and geometry of multi-scale reinforcements, interphase characteristics, barrier height, nanofiller tunneling distance and fiber material property are considered to reflect the influence of microstructures on the electrical conducing behavior of SCF/GNP/polymer multifunctional composites. It is found that the electrical conductivity of the multifunctional composite enhances by the increase of volume fraction and aspect ratio of GNP as well as the reduction of its thickness. Moreover, the multifunctional composite shows a higher electrical conductivity with the increase of fiber aspect ratio. The electrical conductivity of the SCF/GNP-reinforced composite depends on the interphase such that its value increases by the increase of interphase thickness. The developed method can be adopted to provide useful guidelines for the design and optimization of multifunctional composites filled by hybrid reinforcements.

Hybrid all-cellulose reinforcement in polypropylene matrix biocomposites for injection moulding - influence of particle geometry and volume fraction on hybrid effect

The presented study is focused on evaluation of influence of reinforcement volume fraction and geometry on the occurrence of positive hybrid effect by the hybridisation of man-made cellulose fibres (rayon viscose) with cellulose microparticle fillers applied in polypropylene matrix. Four volume fractions of reinforcement were used at 1:1 combination of short man-made cellulose fibres with cellulose microfillers of different aspect ratio. The highest volume fraction was applied for a comparison of four types of cellulose microfillers characterised by different aspect ratios. Proportional volume content of compatibiliser to volume of reinforcement and manufacturing conditions were maintained for all composites. Positive hybrid effect present in tensile and flexural performance was found to result from different factors such as: favourable combination of reinforcement owing to their similar stress–strain characteristic, decreased void fraction, slightly improved orientation of short rayon viscose fibres in hybrid and reduced relaxation of stresses during deformation.

Nanocomposites for Aircraft Applications

The steady increase in jet fuel prices in recent years has accelerated the quest for greater economy in airline operations. While improvements in aerodynamic efficiency, engine fuel efficiency, etc., have been sought, lighter and stronger materials for aircraft structural components remain a very important goal. The percentage of advanced composites, utilizing carbon fibers, in modern aircraft has reached 50 percent. The trend now is to use nano reinforcements such as graphene and carbon nanotubes to further reduce the structural weight. Due to the difficulties in fabricating nanocomposites with a high enough volume fraction of nano reinforcement, the nano reinforcements are either added to the polymer matrix or grown on the carbon fibers. The nano reinforcements are multi-functional; thus, in addition to contributing strength, they contribute to other properties such as electrical conductivity which in turn enhances the lightning strike protection, electrostatic discharge, electromagnetic shielding, etc. This paper summarizes these aspects and also describes the applications of nanocomposites in aircraft interiors, brake components, aircraft repair, etc.

A Novel Approach for Analyzing the Effects of Almen Intensity on the Residual Stress and Hardness of Shot-Peened (TiB + TiC)/Ti-6Al-4V Composite: Deep Learning.

In the present study, the experimental data of a shot-peened (TiB + TiC)/Ti-6Al-4V composite with two volume fractions of 5 and 8% for TiB + TiC reinforcements were used to develop a neural network based on the deep learning technique. In this regard, the distributions of hardness and residual stresses through the depth of the materials as the properties affected by shot peening (SP) treatment were modeled via the deep neural network. The values of the TiB + TiC content, Almen intensity, and depth from the surface were considered as the inputs, and the corresponding measured values of the residual stresses and hardness were regarded as the outputs. In addition, the surface coverage parameter was assumed to be constant in all samples, and only changes in the Almen intensity were considered as the SP process parameter. Using the presented deep neural network (DNN) model, the distributions of hardness and residual stress from the top surface to the core material were continuously evaluated for different combinations of input parameters, including the Almen intensity of the SP process and the volume fractions of the composite reinforcements.

A future prospects and current scenario of aluminium metal matrix composites characteristics

This paper provides a synergistic review of the current scenario and future prospects of aluminum metal matrix composites (AMMCs). AMMCs are advanced materials that have garnered significant attention in recent years due to their unique characteristics, including high strength, low density, and excellent wear resistance. This review covers various aspects of AMMCs, including processing techniques, mechanical and physical properties, microstructural features, and applications. The review begins with an overview of different processing techniques for AMMCs, including stir casting, powder metallurgy, and infiltration methods. It then discusses the mechanical and physical properties of AMMCs, such as tensile strength, hardness, and thermal conductivity, and how these properties are influenced by various factors such as reinforcement type, size, and volume fraction. Furthermore, the microstructural features of AMMCs, including the distribution of reinforcements, are discussed in detail. The review also highlights the potential applications of AMMCs in various industries such as aerospace, automotive, and electronics. Finally, the review concludes by discussing the current scenario and future prospects of AMMCs. It highlights the challenges that need to be addressed to enhance the performance of AMMCs and the potential areas of research that could lead to the development of advanced AMMCs with superior properties. Overall, this review provides a comprehensive overview of the current status and future prospects of AMMCs and highlights the importance of continued research and development in this field.