Reinforcement Size Research Articles

Development and strengthening mechanisms of bulk ultrafine grained AA6063/SiC composite sheets with varying reinforcement size ranging from nano to micro domain

The bulk ultrafine grained (UFG) AA6063/4 wt.%SiC composite sheets with varying reinforcement size of SiC (12 μm (coarse), 1 μm (fine) and 45 nm (nano)) have been developed with a novel hybrid process of stir casting and cryo-severe plastic deformation process (cryorolling). The influence of SiC particle size during development of UFG composites and its effect on microstructural modification, strengthening mechanism and failure mechanism was studied in detail. The resultant effect of cryorolling and size of SiC particles has resulted in significant microstructural refinement (less than 350 nm in all UFG composites) and accumulation of high dislocation density; which resulted in improvement in tensile strength as 88%, 108% and 141% in UFG composites reinforced with coarse, fine and nano particles respectively as compared to the unreinforced base alloy. A good agreement in theoretical and experiment yield strength of UFG coarse and fine composites is observed with a variation in UFG nano composite.

Computational Analysis on Flexural Behavior of Precast Aerated Concrete Panel Incorporating Polypropylene Fiber

Precast system has great advantages in terms of its speed of construction, strength and durability. In this research, Precast Lightweight Aerated Concrete Panel, PACP, incorporating polypropylene fibers were utilized and tested to analyze its structural behavior under flexural load. Finite element analysis (FEA) using LUSAS software was utilized to simulate the PACP models under flexure load adopting nonlinear and transient analysis. The dimension of PACP panel was 200mm thickness, 500mm breadth, 1400 mm length. The FEA results were com-pared to theoretical results in terms of the panel’s ultimate load. Different thicknesses and reinforcement diameters were utilized in the FEM simulations to determine the optimum values for both parameters which confirm the stability of the panel. The outcomes demonstrated that 300 mm thickness is the optimum thickness while 12 mm diameter was the optimum size of reinforcement in the PACP panel.

Dynamic instability assessment of carbon nanotube/fiber/polymer multiscale composite skew plates with delamination based on HSDT

We carried out a dynamic instability assessment of carbon nanotube reinforced composite (CNTRC) and carbon nanotubes/fiber/polymer composite (CNTFPC) skew plates with delamination based on the high-order shear deformation plate theory (HSDT). The multiscale interactions between carbon nanotube (CNT) ratios, skew angles and delamination sizes on the dynamic instability for various length-thickness ratios are studied using a two-dimensional finite element delamination model developed for this study. The results were verified by those reported in the literature for undelaminated cases show the interactions between the CNT reinforcement and delamination sizes in the skew laminate. Numerical examples show the importance of CNT reinforcement when assessing the dynamic instability of CNTRC and CNTFPC skew plates with delamination.

Parametric study of interaction effect between closely-spaced nozzles in a thin cylindrical pressure vessel

The presence of nozzle openings in process vessels gives rise to stress concentration due to localization of stresses around openings. Introduction of second nozzle in vicinity of first nozzle will generate its own stress contours and will interact with stress contours of primary nozzle. To investigate the effect of a secondary nozzle, computational simulation has been carried out. The simulation is validated with established benchmarks. Geometry of vessel and nozzle openings, size of reinforcement and other geometric parameters like centre to centre distance, axial distance, etc. affecting maximum stress have been studied. Result for each case is plotted and discussed in detail.

Vibration of laminated composite quadrilateral plates reinforced with graphene nanoplatelets using the element-free IMLS-Ritz method

This paper investigates free vibration of graphene nanoplatelet (GPL) reinforced laminated composite quadrilateral plates using the element-free IMLS-Ritz method. The effective material properties including Young's modulus, mass density and Poisson's ratio are determined by the modified Halpin–Tsai model and rule of mixture. The first-order shear deformation theory (FSDT) is employed for formulation of the energy functional. Based on the IMLS-Ritz approximation, the discrete vibration equation of the laminated composite quadrilateral plates is derived. The accuracy of the IMLS-Ritz results is examined by comparing with the published values. A comprehensive parametric study is carried out, with a particular focus on the effects of weight fraction, distribution pattern, geometry and size of GPL reinforcements, total number of layers and geometric parameters of quadrilateral plates on the natural frequencies of GPL reinforced laminated composite quadrilateral plate.

Experimental study and theoretical analysis on axial compressive behavior of concrete columns reinforced with GFRP bars and PVA fibers

There have been some studies on the axial compressive behavior of concrete columns reinforced with fiber-reinforced polymer (FRP) bars. But most studies focused on normal concrete without fibers. In this paper, 10 concrete columns reinforced with glass fiber-reinforced polymer (GFRP) bars and polyvinyl alcohol (PVA) fibers were designed to investigate the influence of reinforcement type, longitudinal reinforcement ratio, spacing and size of GFRP ties on the axial compressive behavior of the specimens. Analytical and numerical studies were explored in this paper. The test results indicated that the concrete column reinforced with GFRP bars and PVA fibers (GFRP PVA-FRC column) and the concrete column reinforced with steel bars and PVA fibers (steel PVA-FRC column) had the similar failure processes and failure modes. The axial bearing capacity and brittleness of the GFRP PVA-FRC columns increased with the increasing longitudinal reinforcement ratio. When the volumetric ratio was constant, the confinement efficiency and ductility of the specimens using GFRP ties with smaller diameter and closer spacing were higher than that using GFRP ties with larger diameter and larger spacing. A new stress-strain constitutive model for PVA fiber reinforced concrete confined by GFRP bars was proposed. The numerical results showed that the concrete in the columns reinforced with GFRP longitudinal bars and GFRP ties could give full play to its strength. The conclusions could be references for the engineering application.

Effect of Molybdenum on the Wear Properties of (Ti,Mo)C-TiB2-Mo2B Particles Reinforced Fe-Based Laser Cladding Composite Coatings

(Ti,Mo)C, TiB2, and Mo2B particles reinforced Fe-based composite coatings were fabricated by laser cladding process. The effects of Molybdenum (Mo) on the microstructure and wear properties of the coatings were investigated. The results show that block-like or cuboidal TiB2, Mo2B and flower-like (Ti, Mo)C ceramics reinforcements were formed in the coatings. The size of reinforcements reduced with the increasing of FeMo70. However, cracks were found in the coating, while the addition of FeMo70 exceeded 9 wt %. The laser cladding coating presented a good wear resistance with a 9 wt % addition of FeMo70. With the increasing of FeMo70, the coatings enhanced the capability of resisting microcutting, microplowing, and surface plastic deformation.

Friction stir processing of spark plasma sintered aluminum matrix composites with bimodal micro- and nano-sized reinforcing Al2O3 particles

Spark plasma sintering (SPS) allowed to produce Al-based nanocomposites with 10% of Al2O3 particles where the ratio between nanosized and microsized particles was varied during production. The microstructural and mechanical behavior of the material after SPS was studied as a function of the reinforcement size and relative percentage. The SPSed composites were friction stir processed (FSPed), the processing forces and the heat input in the materials were analyzed. The microstructural and mechanical behavior of the processed materials is shown to be strongly dependent on the starting materials properties and on the employed processing parameters during FSP. Friction Stir Processing was feasible in the heat input range 2800–5700 J/mm. Nanosized ceramic particles acted as recrystallization sites during processing leading to the strength increase in the FSPed materials.

Quantitative determination of size and properties of interphases in carbon nanotube-based multiscale composites

Experimental investigations are carried out to quantify the effect of filler composition, filler diameter and carbon nanotube (CNT) grafting on the properties of interphase in epoxy matrix composites. To this end, epoxy is reinforced with stainless steel (SS) wire, brass wire(s) and carbon fiber (CF) before and after CNT growth on their surface. Surface morphology, elemental composition and thickness of interphase in unsized (ar) and CNT grafted composites is studied using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The size and mechanical properties of the interphase are evaluated through nanoindentation and pull-out tests. It is observed that interphase properties depend on material and geometry of reinforcing filler. Moreover, CNT grafting on the filler surface improves the size and stiffness of interphase and increases the interfacial shear strength (IFSS). The relative improvement in interphase properties and IFSS due to grafting of CNTs on the surface of wires and carbon fiber found to be a function of interfacial chemistry between reinforcement and epoxy. SEM analysis of pulled out wires and fibers reveals that the interface fails differently in the presence and absence of CNTs on their surface. Moreover, increase in CNT growth time from 15 to 30 min inside chemical vapor deposition (CVD) reactor increases the interphase thickness but has an adverse effect on the IFSS in CF/epoxy composites. It is shown that the size and composition of reinforcement and grafting of CNTs on their surface are the variables which provide a handle to suitably design the interphase in multiscale composites.

Experimental Behavior of Hybrid Steel and Polypropylene Fiber Reinforced Concrete Deep Beam Containing Openings

Twelve simple span reinforced concrete deep beams were tested under symmetrically two points top load to examine the effect of steel fiber and polypropylene fiber and influence of the transverse circular openings on their behavior. The variables investigated involve beams with and without openings, the volume fraction of fibers, shear span to effective ratio a/d, and inclined reinforcement around the openings. All the beams had the same overall dimensions, flexural reinforcement and opening size. Many mixes have been used by combination between steel fibers and polypropylene fibers with different percentages of (1%SF-0%PPF), (0.75%SF-0.25%PPF), (0.5%SF-0.5%PPF), (0.25%SF-0.75%PPF), (0%SF-1%PPF) in addition to mix without fibers. The test results showed that fibers greatly increase the diagonal cracking strength and shear strength of reinforced concrete deep beams, where the variation of the type of concrete from normal concrete to hybrid concrete for deep beam contains openings led to increase the ultimate strength by about 30%. In addition, it was found that the shear capacity of deep beams increased when the shear-span/effective depth ratio decreased. The inclined reinforcement around the opening was observed to be very efficient in improving the ultimate load capacity and deflection response.

New improved metaheuristic approaches for optimum design of posttensioned axially symmetric cylindrical reinforced concrete walls

SummaryTwo novel hybrid approaches are presented for optimum design of axially symmetric cylindrical walls subjected to posttensioning loads using metaheuristic algorithms such as harmony search (HS), flower pollination algorithm (FPA), and teaching learning based optimization (TLBO). The objective function of the optimization problem is to minimize the total cost of the wall subjected to constraints on the basis of sectional capacities (bending moment, shear force, and axial tension), ACI 318 (building code requirements for structural concrete) requirements and design variables such as wall thickness, compressive strength of concrete, location and intensities of posttensioning cables, size, and spacing of reinforcement. In the optimum design, the performance of the iterative population based metaheuristic algorithms, HS, FPA, and TLBO are compared and tested by taking wall thickness as discrete and continuous variable. In order to improve the efficiency on finding global optimum results, hybrid forms of the HS combined with FPA and TLBO are effective for the optimization problem.

Characterization of new composite material based on date palm leaflets and expanded polystyrene wastes

In the aim of environmental protection and valorization of vegetal resource, an experimental study on an innovative Wood-Plastic Composite material (WPC) based on Date Palm and expanded Polystyrene, EPS, Wastes is performed. Date palm leaflets waste are used as the reinforcement and EPS waste dissolved in gasoline is used as a matrix. Several combinations of reinforcement sizes (0.1–0.315 mm, 0.315–0.5 mm and 0.5–1 mm) and fiber-to-matrix weight ratios (70, 75 and 80 wt%) were considered to investigate the properties of the Leaflets-Polystyrene Composite (LPC). In this study, physical, mechanical, thermal and morphological characterizations were carried out in order to determine: the bulk density, the flexural modulus, the maximum stress and the thermal conductivity of LPC. Therefore, Pycnometer density measurement, three-point bending test were performed and transient plane heat source (hotdisc) method was used. Furthermore, a characterization by scanning electron microscopy (SEM) was realized to observe the fibers/matrix bond. The LPC showed good adhesion state of the fiber–matrix interface and acceptable mechanical properties with a flexural modulus and a maximum stress that can achieve 0.78 GPa and 2.84 MPa, respectively. The LPC has a density between 542 and 824 kg/m3 which are comparable to those of usual materials like hard-and-soft wood, MDF and other WPC found in the literature. The thermal characterization tests of the LPC have shown also an average thermal conductivity within the range of 0.11 and 0.16 W/m·K. The LPC can be used in the field of building construction as a good thermal insulation as well as a structural component in sandwich structures. Moreover, LPC material is obtained from wastes and can be totally recycled at the end of its useful life.

Experimental study of Bamboo Reinforced Concrete beams having various frictional properties

In this study trials have been made for the use of bamboo reinforced concrete beams which are simple, efficient and economical for rural constructions. This is comparative study of bamboo reinforced concrete beams with various frictional properties. The frictional properties of bamboo reinforced concrete beams have been achieved by rolling the bamboo reinforcements with sand, G.I wire and coir. The web material essentially consists of steel stirrups which helps in resisting shear of bamboo reinforced concrete beams. Eighteen such beams have been tested to failure under four-point bend test. Flexural strength of 28, 45 and 60 days has been taken into consideration for comparison purpose. At failure, it has been observed that beams subjected to higher curing period and greater reinforcement size perform better as compared to beams with lower curing period and smaller reinforcement size. Moreover, higher bond stress has been achieved for beams with G.I rolled bamboo reinforcements. Hence it can be recommended that bamboo can act as a good potential reinforcement for low cost housing and can replace steel conveniently thereby saving natural resources to a considerable extent.

Fabrication, Characterization and Mechanical Behaviour of A356/ Copper Particulate Reinforced Metallic Composites

Metal-matrix composites find applications where high strength to low weight ratio is obligatory. To overcome the limitations with metal ceramic composite systems metallic composite systems were developed. These systems serene of two different metals having good solubility and may give a good, uniform and attuned interface, when they are used as matrix and the reinforcement. The limited solubility led to the alloy formation passing solid solution strengthening while the undissolved particles help achieving dispersion strengthening. A356 alloy and pure copper powders has been used as matrix and reinforcements. The composites (5 to 15 wt.% reinforcements) fabricated by stir casting technique by adding pure copper powders of 53 microns. A decrease in reinforcement size was identified by escalating the volume fraction of the reinforcing particulates. Composites exhibited improved hardness compared to the matrix of the alloy. The mechanical properties of the composite, like ultimate tensile strength, yield strength, modulus of elasticity and ductility were improved when compared to the alloy.

Transport of aromatic solvents through styrene butadiene rubber composites reinforced with modified peanut shell powder

In the pesent work, molecular transport of three aromatic solvent (benzene, toluene, and xylene) through Peanut shell powder (PSP) filled Styrene butadiene rubber composites were studied at three different temperatures by conventional weight gain experiments. The diffusion process depends on free volume within the matrix, nature of the polymer, nature of filler, temperature, penetrant size, and degree of reinforcement The impacts of concentration of filler and the effect of modification by silane treatment on PSP on the diffusion properties were analyzed. The swelling rate and diffusion coefficient decreases with increase in filler loading and increase with temperature. The relationship between diffusion behavior and morphology was analyzed from SEM studies. The mechanism of transport phenomenon was also investigated.

Fabrication of Ceramic Reinforcement Aluminium and Its Alloys Metal Matrix Composite Materials: A Review

This paper emphasizes a summary of work on Fabrication of Aluminum and its alloy Metal Matrix Composites reinforced with different typical Ceramic powder materials. Today Aluminum and its alloys Metal Matrix composites have prominent demand in the Automobile, Aerospace and Nuclear industry due to its physical and mechanical properties appropriately. In current Scenario there are numerous fabrication processes but Stir casting is the most favorable due to its Simplicity, Flexibility and applicable to mass production with cost effective. Further Stir casting assisted with other process like electromagnetic generation device, Ultrasonic device, Heat treatment (T6), forming process, sintering etc. to refine the grains and also studied the effect of particle Size and percentage of reinforcement on mechanical properties like Hardness, Tensile strength and Lower the percentage ductility of Composite Materials.

Effect of beryl on wear and thermal expansion behavior of Al-beryl MMCs

Powder metallurgy process was employed to fabricate Al-beryl metal matrix composites by varying percentage of beryl content from 5 to 15 wt.%. The effects of beryl content (5, 10 and 15 wt%) and beryl particle size (38 μm and 108 μm) on tribological and thermal properties of the composites were investigated. In the present investigation coefficient of thermal expansion of Al-beryl MMC was determined in the temperature range between 50°C to 360°C. Wear rate of Al-beryl MMCs and effect of reinforcement content and size on wear rate were studied. The results show the wear rate and thermal expansion decreased with increasing beryl content. Thermal expansion of Al-beryl MMCs with 5, 10 and 15 wt.% of beryl was 21 ppm, 18.2 ppm/k and 16.8 ppm/k at temperatures of 360°C, which was very much lower compared to pure Al having thermal expansion coefficient of 29.4 ppm/k at the same temperature. Wear rate of Al-beryl MMCs decreased with the increase in beryl content which can be attributed to increase in strength following higher beryl percentage.

Wear Characteristics of LM13 Alloy with Course Size of Rutile Reinforcement

Wear Characteristics of LM13 Alloy with Course Size of Rutile Reinforcement

Nanoindentation characterization of Al-matrix nanocomposites produced via spark plasma sintering

Abstract Spark plasma sintering has been recognized in the recent past as a very useful tool capable of producing materials with high strength and low porosity when compared to the traditional powder metallurgy technologies. In addition, the possibility of producing metal-matrix composites with enhanced mechanical and wear properties has been demonstrated. Obviously, the final properties of spark plasma sintered composites depend on the reinforcement type, size and percentage. The present paper analyzes the possibility of producing spark plasma sintered aluminum-based composites with various types and sizes of reinforcement (Al2O3 nanosized and microsized particles blended with aluminum in different percentages). A strong variation in the microstructural behavior, in mechanical properties and in deformation mode has been observed by varying the type, percentage and combination of reinforcements in the aluminum matrix. The material evolution was deeply analyzed through nanoindentation, X-ray diffraction and scanning electron microscopy.

The effects of reinforcer magnitude in the preceding and upcoming ratios on between-ratio pausing in multiple, mixed, and single fixed-ratio schedules.

Hens responded under multiple fixed-ratio schedules with equal response requirements and either a 1-s or a 6-s reinforcer. Upcoming reinforcer size was indicated by key color. Components were presented in a quasirandom series so that all four component transitions occurred. Postreinforcement pauses were affected by the upcoming and preceding reinforcer size, with longer pauses after large reinforcers followed by small reinforcers than when followed by large ones, and longer pauses after small reinforcers that were followed by small reinforcers rather than large ones. Pauses increased with fixed-ratio size and the effects of reinforcer size were larger the larger the ratio. When reinforcer size was not signaled-mixed fixed-ratio schedules-pauses were shorter after small than after large reinforcers. Signalling the upcoming reinforcer attenuated the effect of the previous reinforcer size on pause duration when small was followed by small and when either small or large by large, but enhanced the effect when large was followed by small. There was no effect of reinforcer size on pause duration when single fixed-ratio schedules were arranged. The effects of reinforcer size on pauses depends on the size and range of the fixed ratios as well as the exact procedures used in the study.