Reinforcement Volume Research Articles

Finite element modeling of sub-surface damage while machining aluminum based metal matrix composites

Sub-surface damage during machining of aluminum-based metal matrix composites (MMCs) has been modeled using finite element models. These models are based on reinforcement particles size and volume fractions and particles are distributed uniformly in the metal matrix. In order to simulate particle debonding cohesive zone elements (CZE) have been incorporated along the parting line. In addition, failure criteria based on brittle fracture have been added for ceramic particles to simulate particle fracture. To reduce computational time and simplify the model both CZE and particle fracture is limited to the reinforced particles along the parting lines facing the tip of the cutting tool. The damage depth beneath the machined surface is measured by using the non-zero plastic strain values in the equivalent plastic strain contours obtained from the FE models. The results were compared against published experimental data and found to be in good agreement.

Strength Behavior of Flat and Folded Fly Ash-Based Geopolymer Ferrocement Panels under Flexure and Impact

This paper presents the impact of fiber and wire mesh layers on the strength behavior of flat as well as folded fly ash-based geopolymer ferrocement panels. The behaviors, namely, flexural strength, impact strength, ductility, stiffness, and cracking patterns, are observed. With the objective of decreasing CO2 emissions, concrete utilizes wastes such as fly ash disposed by industrial sectors. Six panels (three flat and three folded) were cast utilizing a fly ash-dependent geopolymer mortar of size 1000 mm × 400 mm × 30 mm in addition to two panels of each type for the impact study. Heat curing in a temperature-controlled chamber maintaining 75°C to 80°C for 24 hours was done after 24 hours of the resting period. The experimental results indicated that the flexural strength got enhanced by 33 percent by increasing the quantity of wire mesh layers, but the ductility got decreased by 30 percent for the flat panels; however, there was no noticeable impact in the case of folded panels. The flexural strength of the folded panel was found to be three times greater than that of the flat panels. In addition, it is noticed that the behavior of the fiber-reinforced flat as well as folded panels of single layer mesh is stronger than the double layer wire mesh panels regarding cracking and ultimate load. Furthermore, the impact strength of the folded panels was found to be 90% greater than that of flat panels, and the energy absorbed at failure was directly proportional to the volume of reinforcement provided in the panels. Moreover, the failure pattern of the impact tested specimens showed punching shear as the predominant factor.

Evaluation of the vacuum infusion process objectives at the early stages of computer simulation

Increasing the quality and reliable reproducibility of large-size composite structures molding using the vacuum infusion method, which is gaining popularity in various industries, is achieved in practice through numerous tests by try and errors that require significant costs and time. The purpose of these tests is to determine the layout of the ports for the resin injection and vacuum supply, as well as the temperature regime that ensures the absence of isolated non-impregnated zones, the minimum porosity and the required reinforcement volume fraction in the composite. The proposed approach removes the simplifying assumptions used in commercial software for modeling the process, which reduce the accuracy of reconstruction of its dynamics and the sensitivity to the formation of unrepairable defects such as dry spots. It involves multiphysics modeling of resin filling in a porous preform by describing the resin front dynamics by the phase field equation, pressure distribution in an unsaturated porous medium by the Richards equation, the evolution of the degree of cure by the convection / diffusion / thermokinetics equation, and thermal processes by the heat transfer equation using modified models of viscosity, the diffusion coefficient of the degree of cure, the boundary condition for the vacuum port. To reduce the finite element computation time of the investigated variants of the process, which is necessary for its computer optimization, the predictive partial sub-criteria were used, which give a reliable prediction before the beginning of the resin gel and solidification. Due to this, a gain in computation time is 30-50% with a significant prediction accuracy of quality objectives and the presence of possible defects.

Mechanical Properties of PolyJet 3D-Printed Composites Inspired by Space-Filling Peano Curves.

This paper proposes a design of novel composite materials inspired by the Peano curve and manufactured using PolyJet 3D printing technology with Agilus30 (flexible phase) and VeroMagentaV (rigid phase) materials. Mechanical properties were evaluated through tensile and compression tests. The general rule of mixture (ROM) for composites was employed to approximate the tensile properties of the hybrid materials and compare them to the experimental results. The effect of reinforcement alignments and different hierarchies are discussed. The results indicated that the 5% inclusion of the Peano reinforcement in tensile samples contributed to the improvement in the elastic modulus by up to 6 MPa, but provided no obvious enhancement in ultimate tensile strength. Additionally, compressive strengths between 2 MPa and 6 MPa were observed for compression cubes with first-order reinforcement, while lower values around 2 MPa were found for samples with second-order reinforcement. That is to say, the first-order reinforcement has been demonstrated more effectively than the second-order reinforcement, given the same reinforcement volume fraction of 10% in compression cubes. Different second-order designs exhibited slightly different mechanical properties based on the ratio of reinforcement parallel to the loading direction.

Effect of Synthesis Procedure on Particle Dispersion and Hardness of Al- Sic Functionally Graded Metal Matrix Composite

Abstract Fabrication of Functionally Graded Metal Matrix Composites (FGMMC) especially with high ceramic reinforcement's volume fraction is highly challenging. Depending on the processing technique and process parameters various defects may arise. This research aims to find the best procedure to make FGMMCs with the highest quality and minimum cost. A new method is proposed that incorporates lost-foam and melt infiltration with semicentrifugal casting to produce FGMMC. Experiments were performed to in-situ fabricate 6061-Aluminum alloy reinforced with gradient distributed Silicon carbide particles (Al/SiC FGMMC). Effect of SiC %, Al pouring temperature and rotational speed on the fabricated specimens hardness and reinforcement gradient were investigated using design of experiments and regression analysis. Results reveal the optimum procedure and process settings based on desired properties/gradient required. Mathematical model formulated captures the effect of these process parameters on process cost, and cost of poor quality. Improper selection of those parameters may lead to extensive losses due cost of poor quality which is 12 times higher than the material cost. The proposed manufacturing process proved satisfactory in ensuring proper dispersion. A desirability function can by used to determine the process parameters and volume fraction that minimizes the defects and gives superior properties for a specific application.

APLIKASI BIM PADA PEMBANGUNAN PROYEK JEMBATAN UMBUL KAJI KABUPATEN MALANG

Technological progress is one of the challenges in the field of civil engineering. BIM (Building Information Modeling) is one example of technological advances that can be used for the implementation of construction projects. The BIM applications used are Infraworks Autodesk, Naviswork Autodesk and Revit Autodesk applications. The application of BIM is centered on the construction of the Umbul Kaji bridge project, Malang Regency. The use of the Infraworks Autodesk application is intended to facilitate the placement of facility buildings by directly placing buildings according to topographic conditions. Furthermore, the Naviswork Autodesk application is used to visualize the scheduling progress according to the plan. Then the Revit Autodesk application is used for 3D modeling to get the construction volume, reinforcement volume and construction project implementation price. Based on the results of planning and calculations, the organizational structure used is a functional organizational structure. Site layout is based on Travelling Distance (TD) and Safety Index (SI), so an alternative 3 placement is chosen with a TD value of 100131 and an SI of 730. The bridge implementation method for erection girder uses the launching gantry method. In the preparation of the schedule with the help of Microsoft Project and Naviswork Autodesk, the project implementation time was 230 days. And with the help of Revit Autodesk, the cost of implementing the Umbul Kaji Bridge project is Rp. 46.591.603.677,-.

Equation of hole arrangement for concrete beam demolition using soundless chemical demolition agent

Soundless chemical demolition agents (SCDAs) provide a reliable alternative for demolishing concrete structures in densely populated areas. However, research on the demolition of reinforced concrete member using SCDAs has not been conducted in detail. In this study, 12 concrete beam segments with different parameters were prepared to investigate the method of demolishing concrete beam using SCDAs. The arrangement of single row holes perpendicular to the upper surface of the beam segment was adopted, and the stirrups at the top of the beam segment were cut off along the hole connecting line and its extension line before grouting. The results showed that owing to the defect caused by cutting stirrups, the crack on the upper surface of the beam segment developed at the cutting seam, and the vertical crack on the end surface of the beam segment was also formed at the cutting seam and extended to the bottom of the beam segment. Besides, the average volume expansion rate of SCDAs in all boreholes in the beam segment (i.e. volume expansion rate of SCDAs) was determined to evaluate the impacts of the concrete compressive strength, hole spacing, and hole diameter on the crushing effect. Finally, a new equation for computing the hole spacing was derived, considering the time after grouting, concrete compressive strength, hole diameter, tie reinforcement ratio, ambient temperature, and volume expansion rate of SCDAs. The solution obtained using the proposed equation was in good agreement with the experimental results and was expected to provide guidance for the engineering application of SCDAs.

Attainment of high specific hardness and specific modulus in spark plasma sintered aluminium‐copper‐silicon carbide‐titanium carbide hybrid composite

AbstractAluminium matrix hybrid composites have been consolidated effectively by spark plasma sintering with new combinations of reinforcement and high volume percentage of ceramic particulates to maximize specific hardness and specific modulus through the powder metallurgy route. The aforementioned techno‐scientific accomplishment with regard to metal matrix composite aims to meet a continuous increase in the global demand for a material with minimum structural weight and high‐modulus for structural (automotive and aerospace) applications. The new aluminium based hybrid composite developed by incorporating ceramic particulate reinforcements (12.5 wt.% silicon carbide and 12.5 wt.% titanium carbide) along with 22.5 wt.% copper as the metallic reinforcement attains significantly high specific hardness (85 HV/gcm−3), specific Young's modulus (33.56 GPa/g cm−3), specific bulk modulus (27.97 GPa/g cm−3) when compared with the reported range of specific hardness (13 HV/g cm−3–89 HV/g cm−3), specific Young's modulus (24 GPa/g cm−3–27 GPa/g cm−3) and specific bulk modulus (20 GPa/g cm−3–22 GPa/g cm−3) possessed by structural steels. This is accredited to the genesis of a novel microstructure that consists of fine copper, silicon carbide and titanium carbide particulates together with a nominal in‐situ originated aluminium‐copper equilibrium phases distributed in a highly substructured aluminium based matrix with a significant dislocation density (7.56 ⋅ 1014 m‐2).

Deformation mechanism in particulate metal matrix composites

A new approach based on modified stress and strain with considering micromechanics and dislocation theory, has been extended to find the deformation mechanism during hot deformation of particulate metal matrix composite. The impact of main influential processing parameters, such as temperature, strain, and strain rate in addition to reinforcement characteristics, i.e., particle size, and volume fraction, were successfully taken into account in the calculation of deformation activation energy and stress exponent. Besides, the effect of particle fracture, and diffusion relaxation around particles, were participated in the presented formulation. To evaluate the applicability of the developed formulation, different aluminum matrix particulate composites with different particle sizes and volume fractions were subjected to investigation. Using the modified recovery stress for calculating the activation energy, results in reduction of the stress exponent to a meaningful range. It was shown that deformation mechanisms in metal matrix composite and unreinforced alloy are the same. It was also found that for the low value of stress, i.e., the low strain rate and high temperature, the stress relaxation, and for the high value stress, the particle fracture, disturb the load transfer mechanism and reduce the impact of reinforcement on activation energy.

Waffle Slab Behavior Subjected to Blast Load

Over the previous years, the use of structure roof systems which can be implemented with long column spans has been welcomed by manufacturers. One of the most widely used roofs is the waffle slab system. Therefore, by reviewing previous studies in the field of roof collapse in reinforced concrete structures under blast, the absence of studies on the performance of waffle slab and comparing its behavior with blast affected RC slabs is observed. Laboratory simulation of this problem requires high cost, high accuracy in model building and much time. In this study, after preliminary model validation with experimental research and two numerical studies in LS-DYNA software, the behavior of waffle slab subjected to blast load and compare its performance with RC slab is investigated. It should be noted that because the blast load is applied to the structure in a very short time, it has a high loading rate. Therefore, the strain rate effects on concrete and reinforcement are considered for achieving real material behavior. The identical volume of concrete and reinforcement used in all roofs is considered in order to evaluate and compare the behavior of the roofs reasonably. Then, the effect of the geometric dimension of waffle molds and the effect of the supporting condition on the Waffle slab responses are studied. Other parameter investigated in this study includes the effect of concrete compressive strength on the behavior of roof under blast load. The mass of the explosive and its distance from the roof surface are other parameters considered in this study. The effect of bar size on the behavior of the roof is also investigated. The results of this study are presented as diagrams and tables showing that given the same volume of concrete and reinforcement in the RC slab and the waffle slab, the central displacement of Waffle slab are reduced to a desirable level. This shows the better behavior of the waffle slab in comparison with the RC slab with the same volume of material under the blast load.

Mechanical and Tribological Properties of Co-Electrodeposited Particulate-Reinforced Metal Matrix Composites: A Critical Review with Interfacial Aspects.

Particulate-reinforced metal matrix composites (PRMMCs) with excellent tribo-mechanical properties are important engineering materials and have attracted constant scientific interest over the years. Among the various fabrication methods used, co-electrodeposition (CED) is valued due to its efficiency, accuracy, and affordability. However, the way this easy-to-perform process is carried out is inconsistent, with researchers using different methods for volume fraction measurement and tribo-mechanical testing, as well as failing to carry out proper interface characterization. The main contribution of this work lies in its determination of the gaps in the tribo-mechanical research of CED PRMMCs. For mechanical properties, hardness is described with respect to measurement methods, models, and experiments concerning CED PRMMCs. The tribology of such composites is described, taking into account the reinforcement volume fraction, size, and composite fabrication route (direct/pulsed current). Interfacial aspects are discussed using experimental direct strength measurements. Each part includes a critical overview, and future prospects are anticipated. This review paper provides an overview of the tribo-mechanical parameters of Ni-based co-electrodeposited particulate-reinforced metal matrix composite coatings with an interfacial viewpoint and a focus on hardness, wear, and friction behavior.

Dynamic response and optimization of functionally graded porous nanocomposite cylinders using a meshfree method

AbstractA new class of advanced ultralight composite materials has recently emerged through the use porous polymer matrix reinforced by carbon nanotubes. In this article, the dynamic response of functionally graded porous polymeric cylinders, reinforced by randomly oriented single‐walled carbon nanotubes, using a meshfree method is studied. Three different porosity distribution patterns are investigated: symmetric distribution (SYD), unsymmetric distribution, and uniform distribution. A thorough study on the effects of reinforcement volume fractions and porosity distribution patterns on the dynamic response of the structure has been carried out using the radial point interpolation meshfree method based on the 2D theory of elasticity. In addition, a Pareto front solution is obtained through a multiobjective optimization aimed at minimizing the weight and maximizing the natural frequency of the structure with porosity and reinforcement volume fraction as design variables. From a design perspective, the results indicate that the SYD porosity type is the best candidate for relatively thick cylinders because of its smaller mass and higher stiffness compared to the other distribution types. The current research presents a reliable computational framework to help provide an insight into the design of an optimum structure subject to dynamic loading.

Study on Fabrication and Properties of Graphite/Al Composites by Hot Isostatic Pressing-Rolling Process.

Graphite/Al composites have attracted much attrition due to their excellent thermal properties. However, the improvement of thermal conductivity (TC) is limited by the difficulty in controlling the orientation of graphite and the poor wettability between graphite and aluminum. In this study, a novel process for fabricating the Graphite/Al composites is proposed, which involves fabricating graphite film and aluminum foil into laminate material. Then, taking a rolling method, the fractured and well oriented graphite film can help the composite achieve high TC while maintaining a certain strength. The result reveals that both single and total reduction have a significant influence on the diameter and orientation of the graphite, and by adjusting the process parameters, composites with high TC can be acquired at a relatively low reinforcement volume. This near-net-forming process can directly meet the thickness requirements for electronic packaging and avoids the exposure of graphite to the surface during secondary processing, which is promising to promote the application for high TC Graphite/Al composites in thermal management.

Process evaluation, tensile properties, mathematical models, and fracture behavior of 3D printed continuous fiber reinforced thermoplastic composites

Continuous fiber reinforced thermoplastic composites with advantages of high strength, long life, corrosion resistance, and green recyclability have been widely used in aerospace, transportation and high-precision processing equipment, etc. 3D printing is an advanced additive manufacturing technology that enables the rapid manufacture of complex structures and high-performance composites. The aim of this study is to evaluate the precision and stability of 3D printed continuous fiber reinforced thermoplastic composite structures and construct suitable mathematical models to predict tensile properties. Samples evaluated in this study were produced by varying the volume fraction and distribution mode (average and central mode) of fibers within the printed structures. The measured data proved the continuous fiber reduced the printing precision on width and thickness and the printing stability on thickness, while it improved the width stability in the XY horizontal plane. The printing precision and stability of samples with an average mode were slightly better than those of samples with a central mode. The tensile results of 3D printed continuous fiber reinforced thermoplastic composites demonstrated that an increasing volume of fiber reinforcement resulted in the increasing stiffness and ultimate strength of tested samples. The average elastic modulus and ultimate tensile strength of samples with the average mode were higher than those of samples with the central mode, while the average strain at break was quite the opposite. Mathematical models of elastic modulus were established to achieve the relative errors 0.06% and 2.14% for checked samples, while relative errors of the mixing rule were up to 76.15% and 81.71%, respectively. Some typical defects affecting the surface quality and the fracture behavior of 3D printed samples were researched by the analysis of micromorphology.

Mechanical and microstructural characteristics of Aluminium 6063 Alloy/Palm Kernel shell composites for lightweight applications

The mechanical properties and microstructure of AA6063 alloy reinforced with palm kernel shell (PKS) powder were studied. AA6063 matrix composites reinforced with varying weight fractions of palm kernel shell particles (ranging from 2.5% to 15% at 2.5 intervals) were prepared using the stir compocasting technique. The mechanical properties and microstructure of the developed composites were analysed and compared with the matrix alloy. The experimental results showed that palm kernel shell reinforcement influenced the structure of AA6063 alloy through grain refinement as it remained homogeneously dispersed within the matrix, and the mechanical properties of the composites were improved. The mechanical stirring action employed during composite fabrication was an effective factor that influenced the enhancement of the mechanical properties of AA6063-PKS matrix composites. AA6063-PKS composites had improved mechanical properties compared to AA6063 alloys without reinforcement. The mechanical properties increase with increasing weight fraction of PKS particle in terms of the ultimate tensile strength (78.93% at 7.5%pks), yield strength (98.82% at 7.5%pks),%elongation (32.2% at 12.5%pks), and impact strength (12.92j to 31.96j at 10%pks), while hardness decreases with increasing content of PKS particle (from 2.5%-15%pks), but maintained values higher than that of the unreinforced base alloy. This progressive decrease in hardness as the reinforcement increases was due to agglomeration and non-homogeneity at higher reinforcement volume.

Effect of grain refining by cyclic extrusion compression (CEC) of Al-6061 and Al-6061/SiC on wear behavior

Cyclic extrusion compression (CEC) is an effective fabrication process for producing fine, ultrafine grains with superior physical and mechanical properties.In the present work, CEC process was applied on Al alloy 6061 and its silicon carbide (SiCp) composite containing 5 and 10 wt. % SiCp. . The specimens were pressed at room temperature up to 6 cycles for Al alloy 6061, 5 cycles for Al 6061 5 wt. % and 4 cycles for Al 6061 10 wt. % SiC corresponding to plastic strains of 3.72, 3.1 and 2.48 respectively. The evolution of microstructure, hardness and dry sliding wear tests were conducted. The samples were investigated before and after the CEC process by optical microscope, and the worn surfaces were investigated by Scanning Electron Microscope (SEM) and (EDX) analysis. The CEC cycles reduced the grain size, porosity % and SiC particle size. These microstructural parameters were reflected on the increase in hardness and reduction in wear rate and a slight reduction in coefficient of friction. In general, this improvement in properties is associated with the following parameters; grain refining, reinforcement volume fraction, size and distribution of SiCp as well as the number of CEC cycles. Regarding the composite samples, a significant improvement in wear resistance was obtained and the Al 6061 10 wt. % SiC, showed the best performance. The wear mechanism was also affected by the CEC process.

Dynamic behaviour of pretwisted metal matrix composite blades

In this first attempt, a unified, consistent and accurate numerical solution is obtained for the dynamic behaviour of a metal matrix composite (MMC) blade. The MMC blade is made of Titanium (Ti6Al4V) and reinforced with Silicon Carbide (SiC) fibers. The present nonlinear formulations take into account airfoil profile of the blade, profile pretwist angle, fiber orientation, reinforcement volume fraction, coupling of bending and torsional displacement fields, and centrifugal stiffening. Three aspects of the work are considered. The first is concerned with the development of a unified approach to describe the blade’s dynamic behaviour. The second with the determination of the effective properties of the MMC blade using micromechanical homogenisation. The third with the discretization of the displacement field and its treatment using Gaussian quadrature. The developed model is used to examine the effect of angle of pretwist, blade thickness, fiber volume fraction and fiber orientation on the dynamic response of the blade. The results reveal that a significant increase in the natural frequencies of the blade can be obtained with the reduction of its weight as a result of the SiC reinforcement. They also show that the bending and torsional natural frequencies are governed by the pretwist angle.

Data-driven shear strength prediction of steel fiber reinforced concrete beams using machine learning approach

The incorporation of steel fibers in a concrete mix enhances the shear capacity of reinforced concrete beams and a comprehensive understanding of this phenomenon is imperative to have an accurate estimation in engineering designs. Although significant studies have been carried out on shear capacity estimation, mechanics-based models are not yet available due to the complex underlying phenomenon. This paper presents a data-driven approach to the shear strength of SFRC beams and incorporates the largest database compilation of 507 experimental data. Input features considered in this study are the ratio of shear span to effective depth, concrete compressive strength, longitudinal reinforcement ratio, volume fraction, aspect ratio, and type of fiber. Eleven machine learning (ML) models, namely linear regression, ridge regression, lasso regression, decision tree, random forest, support vector machine, k-nearest neighbors, artificial neural network, XGBoost, AdaBoost, and CatBoost, are evaluated to examine their shear strength estimation of SFRC beams. The XGBoost is resulting in the most accurate predictions (85%) with the lowest root mean squared error and low mean absolute error. A study on the importance of the input parameters reveals that shear span to effective depth ratio, longitudinal reinforcement ratio, concrete strength, and volume fraction of fiber are the most influential parameters of shear strength of SFRC.

Effects of particles size on the overall strength of nanocomposites: Molecular Dynamics simulations and theoretical modeling

We perform Molecular Dynamics simulations to investigate the strength properties of particulate reinforced nanocomposites. For a fixed reinforcement volume fraction, the effective strength increases as the inclusion size decreases. We further develop a kinematic limit analysis approach, which delivers theoretical estimates of the effective strength. The model is first assessed in the absence of size effects by comparison with data from available literature. An extension to nanocomposites is then proposed, accounting for the presence of surface stresses at the matrix/inclusion interface. Numerical data are used to calibrate the interfacial strength, which is found to be a size-dependent property.

Computational Modeling of Compressive Behavior of Wire-Reinforced Bulk Metallic Glass Matrix Composites

The effect of wire type and volume fraction on the compressive behavior of wire-reinforced bulk metallic glass (BMG) matrix composites were investigated using the finite element method. The composites and test procedure were simulated in the ABAQUS software, and analyses on stress propagation and extracted compressive stress–strain curves were performed, which showed an acceptable agreement with experimental results. The results exhibited that Ta, Mo, W and Stainless Steel type 302 as the reinforcement wires significantly improved the plastic strain of the composites. Meanwhile, W wires sustained the composite strength in the same level of monolithic BMG, without sacrificing noticeable plastic strain of the composite in comparison with other reinforcements. The different volume fractions of W wires showed that the trend of plastic strain progress with increase in the second phase reaches a maximum at 65% of reinforcements. This behavior is caused by the fracture mechanism of the composites which is in its optimum condition when the reinforcement volume fraction is equal to 65%. The mechanical properties of the wire-reinforced BMG composites can be modeled by using the iso-strain Voigt model, which allows the prediction of the mechanical properties of a composite from the volume-weighted averages of the components properties. The above-mentioned findings corroborate the experiments elsewhere and may be considered as a valuable starting point to lead the future researches.