×
The submission system is temporarily under maintenance. Please send your manuscripts to
Go to Editorial ManagerBehavior of composite beams with headed stud shear connectors subjected to monotonous and displacement controlled non-reversible repeated loadings has been evaluated through studying influences of the cross-sectional proportioning, the degree of partial interaction, and the level of ductile deformability in the post-yielding stage, in addition to the state of loading (whether monotonous or repeated). Eleven one- third scaled composite beams (with their push-out segments) were manufactured and tested in five pairs (each comprising the two loading cases representing one varying studied parameter) beside the single standard composite beam dedicated to verify accuracy of the test results by comparing them to the prototype ones (three authorized experimental and analytical investigations) where no distinction (other than 7 % difference) between the results of the three authorized refereed investigations (experimental, analytical and Eurocode) and the present one.Regarding the flexural resistance in repeatedly loaded composite beams, it has been found that lowering the neutral axis (by adding bottom steel plate) has significantly increased the beam flexural resistance by an average of 24.7 %. Meanwhile, the intensity of headed studs distribution in stiffened repeatedly loaded composite beams has revealed a vital role in controlling the severity of the post-ultimate flexural weakening, where decreasing number of the headed studs to the half has increased the value of that unfavorite parameter by 160.58%. Furthermore, that specified decrease of headed stud intensity has lowered the advantageous residual cyclic flexural ductility by 19.37 % and 11.48 % without and with stiffening bottom steel plates, respectively. Regarding the effect of the lengthening the headed stud on behaviour of the repeatedly loaded composite beams it has been found that lengthening the medium-length headed studs by 72% has raised the flexural stiffness by 41.1 %, while it has decreased the residual cyclic slippage index by 54.3 %.
Al2O3 is a major reinforcement in aluminum-based composites, which have been developing rapidly in recent years. The aim of this paper is to investigate the effect of alumina phases and amounts on the physical properties of fabricated Al-Al2O3 composite. Alpha micro and gamma nano of alumina with particle size of 30µm and 20 nm respectively reinforced aluminum matrix of 45 µm. The percentage of reinforcement material were in the range of (5, 10 and 15wt.%) fabricated by powder metallurgy technique. Specimens dimensions were a disc specimens with 11mm diameter and 5 mm thickness. The green density was achieved under compaction pressure of 500MPa, and then sintered under pressure less sintering at 500ºC in a vacuumed tube furnace for two hours Physical properties of the composite samples have been studied such as relative density, sintered density, porosity, microstructure characteristics, particles distribution, agglomeration, grain sizes and granularity accumulation distribution. It has been noticed that at the micro alumina phase, its relative densities are decreased when there is an increase in amount of micro alumina addition, on the contrary in case of nano composites, where the relative density are increasing along with the increase in nano alumina addition. At micro and nano composites, the produced relative densities are less than the pure aluminum relative density. Agglomeration are increasing with the increase in amount of reinforcement, while its more obvious with nano composite. Grain size reduced with the increase in amount of alumina in micro and nano composites, while, the obtained average grain size diameter is less in nano composite than in micro composites. It is obvious from the results that the variation in physical properties and microstructure of Al-Al2O3 composite are depends on both of alumina phases (size) and percentages. At 15wt.% of nano alumina higher relative density and lower porosity will be obtained.
Strengthening elastomers by the Nano-fillers, for example, Graphite subordinates, have high embellishments on their attributes. In the present work, Graphene Oxide (GO) nano-sheets have scattered in huge rubbers was Nitrile Butadiene Rubber (NBR). Enhancement the vulcanization procedure on (GO/NBR) nano-composite elastic was performed by arrangement blending strategy and rumination blending method. Scattering of GO into NBR was homogenous, where affirmed by Scanning Electron Microscopy (SEM) and X-beam Diffraction (XRD) test. Breaking down the useful gatherings by Fourier-Transformed Infrared Spectrophotometry (FTIR) has been explored as well. Diverse stacking wt% of GO inside NBR has clear impacts on the rigidity and flexibility conduct of the nano-composite. Impact of GO on the electrical conductivity and persuasive properties of GO/NBR nano-composite elastic portrayed too. The GO presence has upgraded the crosslinking trademark in GO/NBR nano-composite elastic and enhanced its properties.
A theoretical and experimental investigation pertaining to the buckling behavior of slender fiber reinforced polymer columns subjected to axial loading under varying temperatures (from room temperature to 50?). Two groups of composite materials were used for manufacturing of test specimens, the first consist of perlon fiber as a reinforcement and acrylic resin as a bonding matrix, while the second consists of a combination of perlon and carbon fibers as reinforcement. The composite specimens were fabricated by vacuum molding technique and cut according to ASTM D-638 for conducting tensile test. The data from tensile test were used to calculate the effective slenderness ratio and defining the column as Euler buckling column. An experimental rig was designed, manufactured and calibrated to study the effect of thermal and buckling load subjected to columns.Numerical analyses pertaining the buckling behavior for both groups were conducted. The results show that the temperature has a considerable effect on properties of fiberreinforced polymer composites where the value ofcritical load and Young's Modules decrease withthe increase of temperature for both groups.Perlon & Carbon reinforcement composites gavebest mechanical properties, which make them thebest candidate to improve the buckling resistancecharacteristics of composite materials.
In this work it had been focused on the possibility of replacement of steel spring in suspension system by fiber reinforced polymer composite that is responsible for light weight of spring which leads to reduces the weight of vehicle and improve fuel efficiency. This type of spring used in motor cycles, light weight vehicle. The design will be simulated by ANSYS workbench. Then, E-Glass fiber has been used to fabricate helical compression spring of 40% fiber volume fraction of glass. with polyester resin. The deflection of glass reinforced composite spring is more than steel spring but within permissible limit. weight of composite spring is reduced by 57% than of steel.
Aluminum metal matrix composites are widely employed for improving the mechanical properties. Various fabrication routes like liquid state, solid state and liquid-solid state are currently available for producing these materials. The objective of the present work is the fabrication of nano particulate composites AA7075-Al2O3 with different amount of nano particles (20-30 nm) reinforced material Al2O3 (2, 4 and 6 wt%) using stir casting technique at three stirring speeds (300, 850 and 1500 rpm). Tensile tests of these composites were carried-out to obtain the mechanical properties (ultimate strength and ductility). Vickers hardness tests were also performed to obtain the hardness number (VHN) of these materials. All tests were performed at room temperature. The microstructures of the best mechanical properties’ composites were examined for the three stirring speeds. It was revealed that the ultimate strength (?u) and Vickers hardness (VHN) for the composite containing 6 wt% Al2O3 fabricated at 850 rpm show the best properties compared to the other composites fabricated at 300 and 1500 rpm and the matrix. The ?u and VHN were increased by about (36.6 %) and (24.5 %) respectively. Ductility of the strongest composite (6 wt% Al2O3 at 850 rpm speed), however, was the least when compared to other composites and the matrix. With increasing the amount of Al2O3, ?u and VHN, an increasing trend was noticed while the ductility shows a reduction trend. The maximum reduction in ductility occurred for the composite containing 6 wt% Al2O3 obtained at 850 rpm. The ductility of the developed composite was reduced by (23 %). The optical microstructures of unreinforced, as-cast Aluminum alloy AA7075 and 6 wt% Al2O3 composites for all stirring speeds show dendrite microstructure resulting from the casting process, but the composite at the stirring speed of 850 rpm shows a more refined microstructure.
In this study, the mechanical properties of an epoxy, unidirectional woven carbon and fiberglass composite were investigated experimentally. ASTM used for preparing the composite specimen. Different ranges of mixing ratios of woven carbon and fiberglass with epoxy are studied. Tensile, impact and bending test are carried out to investigate the mechanical properties for produced new composites. After testing the mechanical properties of the specimens, it is noted that adding of unidirectional woven carbon layers will leads to strengthens the samples. The mechanical properties of woven carbon composite are far superior to those of woven carbon composite with fiberglass.
The purpose of this research is to investigate how the fiber orientation and loading axis of a composite material affect its behavior. Consideration was given to two different fiber-to-matrix ratios in order to improve the mechanical properties. Hand lay-up samples were produced in accordance with ASTM D790 for flexural testing. On UTM, tensile and flexural tests were performed on the sample. The effect of fiber orientation modifies the composites' mechanical properties. As the fiber orientation increased, the tensile strength of the composite would reduce. This carbon/epoxy composite test demonstrates better strength than those conducted at (30, 5, 60, and 90 degrees). For flexural tests, a three-point bend at 30 degrees demonstrates excellent strength. Utilizing the three-point bend method, the flexural strength and flexural modulus have been determined. The tensile strength, young's modulus, elongation percentage, maximum load to break the composite, peak load, and flexural strength of single- and double-layered carbon fibers were compared and examined. As the number of layers increased, the adhesion between layers of epoxy and fiber carbon, and glass fiber weakened, causing a decrease in almost all mechanical properties. The fabricated 2024-T3 and epoxy glass fiber had higher fatigue strength than aramid reinforced and lower density than steel alloy utilized in aircraft manufacture.
Hybrid metal composite materials, combining diverse metal components, have emerged as promising alternatives in engineering applications, offering a unique synergy of mechanical properties. This review comprehensively examines the fatigue life of hybrid metal composites, delving into the intricate interplay of materials, manufacturing processes, and environmental factors. Drawing from a rich array of literature, the review explores the evolution of hybridization strategies, emphasizing their impact on fatigue resistance. Key factors influencing fatigue behavior, including material selection, manufacturing techniques, and environmental conditions, are systematically analyzed. The article highlights the significance of strategic hybridization in enhancing fatigue characteristics, reducing costs, and optimizing the overall performance of metal composites. The insights presented contribute to advancing the understanding of fatigue mechanisms in hybrid metal composite materials, offering valuable guidance for future research and engineering applications. Hybrid metal composite materials, characterized by the combination of diverse metal components, have garnered significant attention in engineering applications due to their potential to provide a unique synergy of mechanical properties. This comprehensive review delves into the intricate aspects of the fatigue life of hybrid metal composites, offering a thorough analysis of the interplay between materials, manufacturing processes, and environmental factors.
Consider polymers and polymer matrix composite are the basis of the most prevalent material in all industrial and medical fields because of its properties qualify to occupy an advanced position among other engineering materials because of its good properties._x000D_ Therefore, This work focuses on the preparation of base polymer matrix composite materials and study non-saturated polyester as matrix has been strengthened by zeolite particles different grain sizes (25 - 65 - 75) µm and different volume fractions (1,5 - 3 - 4,5 - 6 - 7,5 - 10) % was strengthened by Carbon short fibers and constant volume fraction (8%),the tests tensile and bending according to ASTM specifications, respectively. Through the results it was observed that the maximum tensile strength improved through hybrid reinforcement when reached the maximum value when the grain size (25 µm ) and at volume fraction (7.5%), reaching ( 94 N/mm2 )compared with the rest of sizes and at the same volume fraction reaching (78 N/mm2 for 65 µm , 69 N/mm2 for 75 µm), As for the bending test has been getting maximum Flexural resistance at grain size (25 µm) at volume fraction ( 6%) reached to(111 N/mm2) ,if compared with the rest of sizes at the same volume fraction reaching (100 N/mm2 for 65 µm,79 N/mm2 for 75 µm) while was obtained on the maximum bending modulus at grain size (25 µm) and at volume fraction (10%) reach to (8099 N/mm2) if compared with the rest of sizes at the same volume fraction reaching (7466 N/mm2 for 65 µm, 6666 N/mm2 for 75 µm ). Through the results we note that for the particle size and fiber effect in improving the mechanical behavior of the composite material prepared.
In this study, an experimental comparison has been made between the traditional plastic materials (Polypropylene and Polyethylene) and selected composite materials (Perlon-Carbon-Perlon and Hybrid Carbon fiber-Glass fiber) to manufacture a long life Partial Foot Prosthesis. To improve the mechanical properties, increase the lifetime of the prosthesis, and reduce the cost to the patient, two types of composite materials were used and compared with plastic materials. Samples were manufactured and tested with different test methods (Tensile, flexural, and fatigue test). All tests were performed at room temperature.The results showed that the composite materials achieve a large increment in mechanical properties such as (?y, ?ult, E, ?b, and Ef) whichwere increased to a percentage of (200% - 261%),(330% - 243%), (295% - 203%), (276% - 270%),and (413% - 301%) in Perlon-Carbon-Perlonlamination as compared with Polypropylene andPolyethylene respectively. However theincreasing percentage in Hybrid Carbon fiber-Glass fiber was (353% - 270%), (470% - 347%),(388% - 267%), (203% - 199%), and (244% -178%) as compared with Polypropylene andPolyethylene. At the same time, the fatigue lifewas sharply increased in both of the Perlon-Carbon-Perlon and Hybrid Carbon fiber-Glassfiber.
Due to their very good mechanical properties of composite materials which led to a huge increase in its application in a lot of fields.Epoxy/ PS(polysulfide) composite materials behavior in fatigue was reported. different weight fraction of PS (2%,4% and6%) were studied .Surface roughness properties of the blended composites were found for all weight fraction of PS and their fatigue properties are studied .Fatigue test was carried with rotating bending method. The loading in the test was sinusoidal wave type. The loading wave ratio is R = -1 and the frequency of loading is applied to avoid temperature rise with a frequency equal to 5Hz. Fatigue strength ,fatigue life and fatigue limit of the tested composites from standard curves are calculated. The addition of PS resulted in an enhancement in the fatigue values and cause the surface roughness to decrease at a considerable rate, the blend hardness is reduced considering shore A test.
The human body poses the most important aim for many researchers. In nowadays, the science complex required the involvement of many resources and the coordinated team work of doctors, engineers, and other from the specialists. In the case of dental medicine, due to the nature of teeth material, their dimension and geometrical position, very important problems, like cavities that led to tooth losses. In this study, both the Experimental methods as well as the numerical finite element method have been used to analyze the stress within human teeth under forces similar to those that usually occur during chewing process with different type of food in experimental work. It was manufactured a device Resembling chewing process with vertical movement by converting circular movement into reciprocating. And used DAQ system (strain gauge sensor, DAQ and LABVIEW program) to measure the stress and strain resulted from tooth during the mastication process. Models of Natural lower first molars teeth were collected. All the teeth were cleaned from the soft tissue and stored in saline at room temperature. The teeth were randomly divided into two experimental groups according to the treated cavities shape (class I and class II) each class restored with two type of dental fillings material (Nanohybrid composite and Microhybrid composite), and then strain gauge was bonded at a buccal surface of tooth used. Their installed in acrylic jaws and applied different vertical loads. With used various morsels with different elastic modulus. The stress was calculated at the crown. In numerical 2D model of teeth were created by software Auto CAD (V.14) using wheeler 's data were transfer to ANSYS mechanical APDL (V. 16), subjected load at model similar at that applied at the Experimental work. Class I exhibited the highest stresses compared with class II, in two case Nanohybrid bear stress higher than microhybrid composite. At class I the stress at Nanohybrid is higher than Microhybrid for all morsels by rate (12.96%, 21.48%, 41.8%, 16.56%, 16.86% and 15.74%) at (E1, E2, E3, E4, E5 and E6) respectively, and the stress at Nanohybrid is higher than Microhybrid by almost (36.67%, 45.69%, 47.89%, 34.21%, 41.2% and 165.01%) respectively at the same morsels used at class II. _x000D_ Keywords: , , .
In this work, nine types of laminated composite materials used for experimental study to investigate the tensile and fatigue properties of partial foot prosthetic socket which fabricated by using vacuum pressure system . The composite material matrix were Lamination 80:20and reinforced with nine types of laminations (perlon, n-glass, fiber glass and carbon) by variation of thickness according to lamination. Results show that the mechanical properties were improved by increasing the two layers of carbon fiber, fiber glass and n-glass layers instead of zero layer with six layers of perlon lead to the increased in(yield strength ?y, ultimate tensile strength ?ult and modules of elasticity E with (71% ,76% and 58%) respectively for carbon fiber, (20% , 19% and 40%) for fiber glass and ( 22% , 5.5% and 29% ) for n-glass. Results show that (3perlon+2carbon fiber+3perlon) gives the best value of mechanical properties and has higher Endurance limit stresses (?e) which increase lifetime for the patient . It is recommend to use this type of lamination for the layup partial foot prosthetic socket because it meets the demand lamination layers for acceptable mechanical properties and its minimizing the cost of socket lamination to suitable costing value.
The microstructural analysis and electrochemical measurements tests were used to investigate the behaviors of (TiO2) and (HAp)-coated Ti-6Al-7Nb alloy in the SBF solution .By using RF sputtering, a thin TiO2 layer coated the substrate, while a thick layer of HAp coated the outer side of surface. The generated middle layer consist of the composite of TiO2 and HAp which is by AFM characterized as uniformly distributed coating system with nano size. The images of the scan electron microscopy (SEM) shows that there is no any cracking observed in the outer layer of tested samples due to the use of thin film TiO2 as mid lead to reduce the difference in the thermal expansion between the HAp material and Ti-6Al-7Nb substrate .The HAp upper layer significantly improve the bioactivity of the Ti-6Al-7Nb alloy. In this study, the bonding strength and the corrosion resistance was improved by using thin layer of TiO2. From electrochemical impedance spectroscopy (EIS) study Bod plot, the composite layer of TiO2 and HAp was suggested by the capacitive act as barrier layer coated substrate and prevent the relays of the ion from metallic. The results shows the values of Rox (309.2 k? cm2)are greater than for Rct(19.2 k? cm2), by assumes the presence oxide film increases for coated substrate are greater than that of uncoated, which is a result of the presence of coated film that improve the corrosion resistance of the sample.
In this paper an experimental works conducted to study the behavior of R.C. beam with large web opening at different locations and fortified with reactive powder composite (RPC) at the extreme tension zone (bottom edge of opening) and/or extreme compression zone (Top edge of opening). The experimental study is investigate the behavior of twelve beams and study the ability of using normal strength concrete together with RPC in the same section to exploit the advantages of these two materials in optimal way. The main variables are RPC layers locations in tension zone and/or in compression zone and the locations of openings. The ultimate loads, load mid-span deflection behavior and strain for steel and concrete were discussed. The experimental results showed that the ultimate strength was decreased with increasing number of opening about 4% for beams with two openings located in shear zone and 21% for beams with three openings, thus indicating that the stiffness decreases accordingly. The using RPC layers effectively enhanced performance of hybrid beams when compared with using the normal strength concrete layers only. The using RPC layers in compression and tension zones increased the ultimate load about 47 % for beams with two opening located in shear zone, when using RPC in the tension zone and normal strength concrete in the compression zone the ultimate flexural load and ultimate deflection increase little compared with normal concrete.
In this research, polymer polymethyl methacrylate PMMA composite with nano ceramic Zr and HAp material were used to manufacture one part of the implant system (femoral ball head of hip implant). Three set of hybrid materials were fabricated and tested for this study; the first mixtures which contains 100% (PMMA), the second mixtures which contains (90% (PMMA) + 8% (Zr) + 2% (HAp)), and the third mixtures which contains (80% (PMMA) + 18% (Zr) + 2% (HAp)) were investigated. The mechanical properties for these mixtures increased with the increasing of nano ceramic concentration (Zr and HAp) composite material in the polymer compared to pure polymer PMMA sample. However, an increase in the concentration of Zr from 8% to 18% content cause a considerable decrease of the hardness where a drop of homogeneity in Zr- matrix PMMA contact occurred, V Hardness value are (68 ,80 and 70) Kg.mm for three mixture respectively. The wear test was in agreement with results of the hardness test. The weight loss of the above samples of the wear test were (0.041, 0.035 and 0.037) respectively. According to mechanical properties, the best sample contains (90% (PMMA) + 8% (Zr) + 2% (HAp)). The Scanning electron microscopy resolute showed the particles forming semi-continuous network along grain boundaries polymer for second sample mixtures containing (90% (PMMA) + 8% (Zr) + 2% (HAp)), provides a low atomic packing and high energy. This will make the grain boundaries more reactive and strengthen mechanical performance. The Optical microscopy, Scanning electron microscopy and Xray spectroscopy analysis for In vitro test using SBF shows the growth of HAp layer with an increase in concentration of Ca and P elements formed on the surface of the second sample. This display of good results is a proof of the biocompatibility of the polymer sample.
The composite opened web steel joist supported floor systems have been common for many years. It is economic and has light weight and can embed the electrical conduit, ductwork and piping, eliminating the need for these to pass under the member, consequently eliminate the height between floors. In order to study the joist strength capacity under the various conditions, it had been fabricated seven joists composed of the steel and concrete slab connected to the top chord by shear connectors (headed studs). These joist have 2820 mm length c/c of the supports and 235 mm overall depth. In the present study, six variable parameters are adopted (Studs distribution, Degree of shear connection, Degree of the web inclination, Shape of the web, Density of concrete for slab and length of the shear connector). The test results exhibited that minimum strength capacity was 160kN for light weight joist and maximum capacity was 225kN for joist of long shear connectors at failure. The results were compared by ultimate flexural model by Azmi.
The toxicity of permanent implants is the main concern. The release of ions from the substrate leads to toxicity. Because of how the human body works biologically, the toxicity of corrosion compounds is a byproduct of wear and fretting debris. aimed to improve the corrosion resistance of a 316L stainless steel substrate. Bio ceramic Nano-hydroxyapatite (HA) was coated using the Electrophoretic Deposition (EPD) technique. Stainless steel has good mechanical properties and high compatibility, but it suffers from body fluid attack due to its chloride content, which can penetrate the passivation layer, resulting in the release of chromium and nickel ions. Tissues and organs are damaged by the ions and debris that are released. To address this problem, it was coated with bioceramic using the EPD method. Suspensions of various powders—hydroxyapatite, magnesium oxide, zinc oxide, and the composite—were prepared and coated by electrophoretic deposition. The coated samples were dried at room temperature to ensure a homogeneous coating structure. The zeta potential test for magnesium oxide and hydroxyapatite suspensions was positive, while zinc oxide and complex suspensions were negative. One of the important parameters for achieving electrolyte and implant balance is the open circuit potential (OCP). A substantial change towards a more noble direction (less negative) was seen in the OCP-coated (316 L) alloy, suggesting excellent thermodynamic stability. Tafel extrapolation analysis was used to obtain the corrosion potential (Ecorr) and corrosion current density (Icorr) values of composite-coated stainless steel 316L, which are generally derived from the polarization curve. The findings that are in line with the MgO, HA, and ZnO coatings show a significant decrease in corrosion current (Icorr), an increase in corrosion potential (Ecorr), and a decrease in corrosion rate from (4.386 × 10-¹ mm/y) Stainless Steel 316 L to (1.417 × 10-² mm/y) MgO Coated and (1.222 × 10-³ mm/y) (65%MgO+25%ZnO+10%HA coated).
In this study, the analytic model (Azmi Model) had been considered for computation the load capacities of the composite open web steel joists and compared them with those obtained from experimental tests. The capacities of seven joists had been studied, each including one of the following variables (distribution of headed studs, connection degree of the connectors, inclination of the web, shape of the web, density of slab concrete, length of connectors).Theoretically, according to the Analytic model, the referenced joist of (45° web inclination , uniformly distributed ,over connected ,short headed studs) exhibited maximum load capacity of (18.45) ton, while the joist of (45° web inclination, uniformly distributed, under connected, short headed studs) exhibited minimum load capacity of (16.23) ton at yield point of bottom chord. Experimentally, the referenced joist exhibited maximum load capacity of (15.51) ton, while the joist of (34° web inclination, uniformly distributed, over connected, short headed studs) exhibited (12.49) ton load capacity. The load capacities values of the tested joists ranged between (67%-85%) of the predicted values according to the analytic model.
Double skin composite (DSC) construction or Steel/concrete/steel sandwich construction (SCSS) is an innovative and relatively new form of composite construction that can be used in submerged tube tunnels, bridges deck, nuclear structures, liquid and gas containment structures, offshore and onshore structures, military shelters, and shear walls in buildings. The system consists of a plain concrete core sandwiched between two steel plates interconnected together by various types of mechanical shear connectors. The DSC construction perceives advantages that the external steel plates act as both formwork and primary reinforcement, and also as impermeable, blast and impact resistant membranes. The major duty of the shear connectors is to withstand longitudinal shear force and beam/slab separation, while in the bi-steel type where shear connectors are friction welded at both their two ends to two parallel steel plates, the longitudinal and transverse shear force, as well as plate buckling are resisted. The present paper highlights the previous prime researches concerning the subjects of SCSS composite construction, specifically on the conducted tests (push-out tests, tensile, direct shear tests, and bending tests) in which the components of partial interaction (uplift and slip forces) are resisted by various types of shear connectors.
In this research, we successfully obtained Ni/SiC micro-composite coatings with various contents of SiC particles of particle size(10 ?m), by using electrodeposition method from nickel watts bath in which the SiC particles suspend. The effects of the current density, temperature, and particle loading(PL) of SiC particles in the electrolyte on the morphology, texture, and vol% of SiC in deposit were investigated. The morphological and structural analysis show uniform distribution of SiC particles within the composite coatings. It was found that the depositing conditions affect the microstructure of deposited nickel and the SiC vol% in deposit. Furthermore, the vol% of SiC increases in deposit by increasing the particle loading(PL) in the bath, while decreased by increasing the current density. Also the higher values of SiC vol% were obtained at temperature (50°C).
Particles filled polymer composites started to be essential because of their wide applications in addition to reducing the cost of polymer, which is a main problem. The aim of this work is studying the insulation of particulate composites resulting from the addition of filler (glass or porcelain) waste powder to reinforced epoxy matrix. Samples with and without filler were exposed to some tests to decide the influence of the filler contents on the characteristics of epoxy. Epoxy is synthesized with filler particles having (90 micron) particle sizes as reinforcement. Composites of epoxy with varying percentage (0 to 40 weights %) of filler were prepared by using hand lay-up method. The nondestructive tests consist of thermal conductivity; ultrasonic test and water absorption test have been investigated. The composite showed an improvement in physical properties with the addition of filler according to their percentages. The result show the addition of the filler in all proportions to the epoxy increased the density of the composite, leading to the ultrasonic pulses velocity ranges between 2100 m/s and 2800 m/s. Increase glass and porcelain percentage cause increase in density which increases the acoustic impedance. While the thermal conductivity decrease with glass powder percentages in the composite increase, unlike the increase in porcelain percentage which causes an increase in thermal conductivity. The 40% percentage of glass in the epoxy had higher effect on reduce the thermal conductivity. As well as from the results the epoxy reinforced by porcelain powder would have lower water absorption than epoxy reinforced by glass powder.
The effect of defect on structures and machines has negative consequences on them and it always takes researchers concern and attention in order to find feasible solutions to trace and detect the location of the defect accurately.In this research, the effect of a hole with different diameters on a square composite plate is studied as well as the effects of both the boundary condition and the plate thickness, furthermore, Vibration analysis of composite plate has been studied numerically and experimentally. The Numerical analysis has been carried out by using FEM by building MATLAB program as well as (ANSYS 15). The experimental part of this research is done by using vibration measuring instruments. The rate of error among the experimental tests and the numerical solution is less than 15%. These results have been used an inputs to the Genetic Algorithm model that the defect is located by, with a high percentage of success.
The purpose of this study is to reduce weight and improve the mechanical properties of aircraft wing using Hybrid materials known as fiber metal laminates (FMLs). In this study, seven layers were used to produce the FMLs that consist of aluminum alloy2024-T3 reinforced by carbon and glass fibers bonded with blend of epoxy-resole. The Carbon Glass Reinforced Aluminum Laminates (CAGRALLs) was used as FMLs. The results showed that The CAGRALLs gave good mechanical properties because of increasing in tensile strength, elongation at fracture and impact toughness except flexural strength by comparing with other FMLs using commercial epoxy. The increasing in layers led to weaken adhesion force between layers of FMLs caused decreasing almost mechanical properties. The FMLs has good mechanical properties by using carbon and glass fibers by comparing with carbon and jute fibers. The CAGRALLs have higher numbers of cycles at failure under cyclic loadings than Aramid Reinforced Aluminum Laminates (ARALLs). The CAGRALLs have lower density by comparing with aluminum alloy 2024-T3 that used in manufacturing of aircraft wing.
In this paper the ability of fabricating laminate composites by manual layup was discussed. Heating method was used to manufacture the composites; heat was applied to approximately 12 hours with specific heat temperature. There were four types of laminate composites fabricated and studied in this research, containing Aluminum alloy 6061 as the common element in all types, two types of fibers; woven Carbon fiber with two different orientations: ±45°, ±60°, random fiberglass and with two types of resin; epoxy resin and polyester resin. Different types of composites were made to determine the effect of CNC milling machine to the measured surface roughness and for specified parameters. The weight fraction ratio of the fibers is 37%, polymer is 34% and 29% for Aluminum. The parameters selected are spindle speed, feed rate and depth of cut. The L9 Taguchi orthogonal arrays, signal to noise (S/N) ratio and analysis of variance (ANOVA) are selected to determine the effect of these parameters; it was analyzed by MINITAB 17 program. The results showed that the parameter were significant more to the epoxy resin specimens than polyester resin specimens. The optimal milling parameters for good surface finish for Aluminum – Carbon fiber composite are at 3000RPM, 1200mm/min, 1.2mm, and for Aluminum – Fiberglass composite are 5000RPM, 1800 mm/min, 2.0mm.
The traditional electric poles in Iraq are usually made from steel materials. Such materials induced high weight, corrosion, permanent deformation caused by high wind speed, etc. The study aimed to numerically examine the strength of few poles made from different materials. The pole subjected to pressure developed by actual measured wind speed of 140 km/h. The numerical model of different materials and cross sections, an octagonal section electric pole made from composite material FRP–HDPE–FRP is suggested to replace the traditional one. The results showed high safety factor, approximately 5.51 besides the low ratio of high strength to weight as compared to steel materials. Using HDPE as reinforced material resulted in pole elastically deformed with only 0.222 mm. Therefore, it can be assumed that the suggested pole acts partially as a damper. Straight octagonal cross - section of pole promoted high reduction (74.22%) in maximum Von–Misses stress of that obtained in cylindrical three-stage pole. High reduction (5.87 times) in maximum deformation value was obtained when composite octagonal pole was used as compare to tapered pole made from steel.
Orthoses and prostheses were Chosen and laminated based on their high Yield, ultimate stresses, bending stresses, and fatigue limit. Response Surface Methodology (RSM) was utilized to find the best values for two parameters reinforcement perlon fiber and percent of Titanium Nanoparticle coupled with the matrix resin during optimization. The response surface methodology combined the expertise of mathematicians and statisticians to construct and analyze experimental models. Using this method, we identified 13 different lamination samples comprising a wide range of perlon number and Ti nano Wt% in their Perlon layer composition. All lamination materials defined by RSM methods and produced by a vacuum system were subjected to a battery of tests, with fatigue tests performed on the ideal laminating material in contrast to laminations created in the first study (Tensile test, Bending test, and Fatigue tests according to the ASTM D638 and D790 respectively). In comparison to the other 12 laminations tested using Design Expert version 10.0.2, the lamination with ten perlon layers and 0.75 percent Ti nano proved to be the strongest overall in terms of Yield, ultimate, and bending loads. This study used composite materials and titanium nanoparticles to characterize and fabricate ankle foot orthoses. Strength in bending should amount to about 70 MPa, around 85 MPa in tensile tension. Two empirical quadratic equations for the models of peak bending strength and maximum tensile stress with 95% confidence were created using the response surface approach and analysis of variance within the design of experiments software.
Recently, considering polymer composite in manufacturing of mechanical parts can be caused a fatigue failure due to the very long time of exposure to cyclic loading and may at environmental temperatures higher than their glass transition temperature; therefore, in this paper, a comprehensive investigation for bending fatigue behavior at room and elevated temperatures equal to 60 °C, 70°C, and 80 °C will be done. Rotating bending test machine was manufactured for this purpose supplied with a connected furnace to perform fatigue tests at elevated temperatures. The obtained results appeared that the increase in applied stress and temperature caused a clear reduction in fatigue life; also the addition of carbon nanotubes enhanced the fatigue life at different temperatures by 183%, 205%, 218%, and 240%, respectively while the addition of short carbon fibers improved fatigue life by 324%, 351%, 387%, and 415%, respectively. As well as, Polyamide 6,6/carbon fiber composite appeared fatigue limit at temperatures equal to 20°C and 60°C and stresses approximately equal to 55 MPa and 38 MPa respectively.
CFDSST Concrete Filled Double-skinned steel tubular columns are composite columns consisting of two concentric circular steel tubes with concrete filler in between. Finite elements method is considered through the use of the computer program ABAQUS to model CFDSST columns numerically under cyclic axial compression. Damage plasticity model was considered to model the concrete while elastic-plastic model used to model the steel tubes. six CFDSST specimens and three ordinary Concrete Filled Steel Tubular (CFST) specimens were analyzed under static axial compression, while three CFDSST specimens were considered for analysis under cyclic axial compression. The numerical results were presented in terms of axial load axial strain displacement curves. It was found that the ultimate axial load carrying capacity calculated numerically in good agreement with that of the experimentally tested specimens. Also it was concluded that Damage plasticity model used for simulating the behavior of concrete and metal plasticity model used for simulating the behavior of steel produced accurate results as compared to the experimental results.
This research is devoted to study the influence of different weight percent concerning to the additions of Ti and Cu on mechanical and tribological properties of AA6061. The composite materials consist of different weight percentage of Ti (0.2, 0.4, and 0.6) wt% and constant weight percentage of Cu (0.2) wt% which were fabricated by liquid metallurgy route technique. Microstructural characterization and phases have been examined by using SEM (scanning electron microscopic).SEM examination showed uniform distribution of nano Ti and Cu in AA6061. The consequences of mechanical tests demonstrated clear enhancement in mechanical properties, such as ultimate tensile strength, yield strength, young modulus, ductility% and hardness at additive percentage of 0.4% Ti+0.2%Cu nano particles incorporated into molten AA6061. Percentage of enhancement ultimate tensile strength is about 73.3%, yield strength about 82.7%, young modulus is about 21.2%, the Vickers hardness about 42.6% and the decreasing in ductility was about 25.2% compared with the metal matrix (AA6061). The wear rate test was performed by using pin on disc rig for both hybrid nano composite and base metal (AA6061) under various loads (10,15and 20) N with sliding speed (1.282) m/sec at a (10) min’s time. The results showed a decrease in wear rate at 0.4%Ti+0.2%Cu compared with the base metal (AA6061). Improvement percentage of wear rate is about 105% at 20 N load.
This work involved two major parts: the first one is the experimental part which included treatment of scoliosis deformity by manufacturing thoracolumbosacral orthosis, measuring the cobb angle of deformity, measuring the gait cycle data and walk path for both legs and suggesting a composite material to improve the mechanical properties of the orthosis and finally the interface pressure between trunk and orthosis is measured for twelve points covering of the total TLSO surface area by using f-socket devise. The second part of this study is the numerical simulation part during which the stresses are calculated using Ansys software for calculating stresses due to interface pressure loading boundary condition. The result shows no deference in gait cycle phases but the clear difference noted in walking path due to deviate center of mass, maximum pressure recorded left thoracic region with 900KPa due to correct spinal deformity while the minimum pressure recorded at right chest with l40KPa because of it is tissue region and Maximum value of stress was recorded at the left thoracic region with 2.81MPa due to Maximum interface pressure at this point.
In this research, binary blends have been prepared from epoxy resin (EP) and different weight percentages of polysulfide rubber (PSR) (0%, 2.5%, 5%, 7.5 and 10%), and then compression, impact, and hardness tests were evaluated. The experimental results showed that the addition of polysulfide rubber in the epoxy resin decreased the compressive strength, Young's modulus, and hardness, while increased the impact resistance. It was found that the weight percentage 5% of polysulfide was the best percentage, which gives the best mechanical properties for the blend matrix. The advantage of this blend matrix is that, it mediates between the brittle properties of epoxy and the flexible properties of a blend matrix with the highest percentage of PSR. Short fibers (Carbon & Glass) with different volume percentage (2.5%, 5%, 7.5%, and 10%), were used to reinforce the best blend matrix obtained separately and randomly, and then the same mechanical tests conducted on these composites. The experimental results showed that the addition of fibers increased the compressive strength, Young's modulus, impact resistance and hardness. It was also observed that the composites materials reinforced with carbon fibers have significantly higher mechanical properties values than the composites materials reinforced with glass fibers.
Box-Wilson experimental design method was employed to optimize bioethanol production from low grade, unclassified, waste Iraqi dates. The optimization process was based on four independent relevant parameters-initial sugar concentration (50-100 g/l), pH (4.5-6.5), fermentation time (48-96 hrs), and temperature (25-35?). A maximum bioethanol yield of 33.9 g/l was practically achieved following thirty different experimental runs, as specified by 24-Central Composite Design (CCD). The optimum values for the aforementioned four parameters, corresponding to the maximum yield, were: 75g/l, pH 5.5, 72 hrs, 30?, respectively. The obtained experimental data were utilized to develop a semi-empirical model, based on a second-degree polynomial, to predict bioethanol yield. The model was tested using ANOVA software (Design expert® 9) and found acceptable (R2=0.9025). Yield response surface and contour plots were created using the developed model, which revealed the presence of high-yield plateaus whose specifications will be useful in controlling pilot-or industrial scale future units to ensure economical feasibility.
Industrial activities significantly affect the environment by releasing many organic pollutants, including industrial dyes, phenols and antibiotics, which produce wastewater. Effective removal of these substances from wastewater has appeared as a noticeable research field owing to its environmental significance. Exorbitant operational expenses and the potential generation of supplementary pollutants load conventional techniques like adsorption, membrane separation, and coagulation. Semiconductor-based photocatalysis has effectively degraded organic contaminants into less toxic or biodegradable compounds. The construction of robust visible-light-sensitive photocatalytic hybrids for environmental decontamination is an inspiring task for researchers. The exceptional photocatalytic performance of silver halides (AgX, where X is I, Cl, and Br) has recently attracted significant consideration as photocatalysts. Moreover, the combination of silver halides with other photo-active semiconductors to create efficient visible-light-driven photocatalyst heterojunctions has significantly promoted the broader application of the photocatalysis process with enhanced efficiency. Ag-silver halides/semiconductors heterojunctions have developed as crucial components in efficient composites for photocatalysis through surface plasmonic actions, helping with visible light absorption. The current study overviews the most recent Ag and silver halide-based composite photocatalysts. Additionally, it provides an essential understanding of their promoted photocatalytic performances and their main applications in organic pollutant degradation. Moreover, the photocatalytic mechanisms and environmental applications of AgI and composites were discussed.
Flexible and rigid pavements are commonly built for airport pavements to support the moving loads of aircraft during the pavement design life. Airport pavements represent a cornerstone of the aviation world. Their condition profoundly impacts safety, operational efficiency, airport capacity, and financial well-being. These meticulously engineered surfaces must withstand the immense stresses generated by aircraft during takeoff, landing, and taxiing. At the planning stage, the pavement structure, materials, aircraft loads, environmental conditions, and pavement damage models should be evaluated. Comparing with road pavement design, airport pavement structural design is unique in terms of the traffic loads supported by pavements with high load magnitude, significant tire pressure, and dynamic traffic conditions. Over time, deterioration stemming from environmental exposure, aircraft loading, and other factors becomes inevitable. This study aims to explore the various factors influencing airport pavement performance, review the existing methodologies for pavement design and maintenance, and propose enhancements to current practices to ensure long-term durability and safety of airport pavements. This study aims to explore the various factors influencing airport pavement performance, review the existing methodologies for pavement design and maintenance, and propose enhancements to current practices to ensure long-term durability and safety of airport pavements.
Reinforcement process of epoxy has been widely used to improvement of mechanical properties. Therefore, this work is concerned with the reinforcement of epoxy by adding natural materials (Pomegranate peel and Licorice particles) at epoxy. Different percentages of particles (5, 10, 15 and 20%) were used. The mechanical testing were included tensile, bending, hardness and impact tests. Hardness of epoxy was increased at increasing of Pomegranate peel (PP) and Licorice (L) percentages. Impact resistance of epoxy with Pomegranate peel (PP) has reached the highest at (10%), while with Licorice (L) has reached the highest at (5%). The results of tensile strength represent that increases of tensile strength at all percentages of (L), while (PP) showed that decreases at (5%) and increases at others percentage. Bending strength of epoxy has increased as increasing of (PP) at all percentage that used, but it has increased at (5, 10 and 20%) of (L), while it has dropped at (15%).
This study involves the addition of nano silica (NS) with average particle size 12nm, micro high reactivity mitakaaolin (MHRM) particle size ? 0.554 ? 1.271 µm, micro ground granulated blast-furnace slag (MGGBFS) particle size ? 0.365 <2.932 µm and micro carbon fibers, the length of the fiber 8.5 mm and a diameter of 0.001 mm to cementations mixtures to investigate their effect on the impact strength with used magnetic water or normal water in mixing blends._x000D_ The results have shown that cementitious mixtures used in the mixing magnetic water containing 10% MGGBFS, 10% MHRM or 2.5% NS and reinforced with 2% micro carbon fiber have improved greatly in impact strength as the absorbed energy to the emergence of the first crack at age 28 days reaches to (231.55, 209.49 and 199.49) kN.m respectively, whereas for the reference cementitious mixtures it has been 1.574 kN.m
Biodiesel produced from vegetable oils is a good alternative clean diesel. The present study was conducted because there are some variations or contradictions in literature on the use of CaO heterogeneous catalyst. In this study, biodiesel was produced from sunflower vegetable oil and methanol in presence of commercial calcium oxide catalyst in batch mechanical stirrer reactor. The effect of three operating conditions, methanol mole ratio (4-12), reaction time (0.5-2.5 h) and catalyst amount (2-10 %), on the yield of biodiesel was studied at constant reaction temperature of 60 oC. Response surface methodology (RSM) was used with central composite design (CCD) of experiments. Polynomial correlation was found for the dependent variable of the process (yield of biodiesel), satisfactorily predicted at 95% confidence level. The optimum yield biodiesel was about 98% and at operating condition of methanol ratio 10, reaction time 2 h and catalyst amount 8 %. The reaction time was found to be the most effective operating condition. Kinetics study of the process showed that first order reaction with triglyceride concentration and zero order with methanol concentration gave best fit with the experimental data, triglyceride with a reaction rate constant k= 1.53 h-1.
Solar panels are constantly evolving, with changes occurring in the materials used, panel shapes, and the method used to attach solar cells to the panels. Solar radiation consists of two components: photovoltaic energy, which is used to generate electricity via photovoltaic panels, and thermal energy, which, on the other hand, can reduce the efficiency of photovoltaic panels. Thermal photovoltaic panels are a recent breakthrough in the industry as they use light to generate energy and heat to reheat cryogenic liquid for a variety of purposes. One subtype that is gaining popularity is hybrid photovoltaic thermal panels, which are designed to enhance heat use by adding a heat storage medium, with phase change materials being a noteworthy example. Despite their numerous benefits, these materials have limited heat conductivity, necessitating substantial research efforts to improve this attribute. However, most research focus solely on enhancing conductivity without applying the findings to PV panels in a comprehensive manner. This study fills this gap by reviewing the phase change materials accessible locally, picking Iraqi wax, researching additions, selecting micro- particles of aluminum oxide (Al2O3), investigating the mixing procedure, and calculating the ideal mixing ratio (6% additive to wax). The combination is then placed to a normal solar panel, resulting in a hybrid photovoltaic panel with a complicated phase transition material reinforced with aluminum oxide.
Active vibration controlling loop with proportional - Integral (PI) controller was tested numerically and experimentally for delta wing with three different manufacturing materials; aluminum, [0/90] composite and aluminum foam, both P and PI loop were tested separately. Numerical work was performed in ANSYS v.15 where controller with piezoelectric transducers was totally integrated in program macro. Experimental wings where fabricated to be tested under simulated excitation. Labview 2015 program with high speed Data acquisition were used besides actuators to perform controlling circuit experimentally. Good suppression in wing oscillation was performed where 72% of wing's time of vibration was eliminated for aluminum foam wing. Noticeable agreement was achieved between experimental and numerical responses.
The purpose of this research is to manufacture and test adjustable sockets for below-knee amputation. This article studies using the pnuematic–pads for adjustable sockets. The manufacturing of an adjustable socket with pneumatic pads goes through several stages: In the theoretical design of the adjustable socket, the suggested materials were studied for the pneumatic pads, tubes, and pneumatic pump which should be suitable for the suggested application. In the experimental work, using composite materials for manufacturing the socket consisting of perlon and resin to achieve the rigid shape and required flexibility for the prosthetic user with the pneumatic pads. After assembling the adjustable socket parts, the pneumatic pads, the pump and the tubes, the socket were tested for several times on the patient. In the last stage, the pressure between the socket and the residual limb was measured using F-socket, and it was found that the results were: anterior (160kPa), lateral (167kPa), posterior (153kPa) and medial (348kPa). By comparing these results with what was previously studied, the pressure between the socket and the residual limb is within the acceptable range. The design provides good suspension and more adaptability to the change in stump volume. A posative feedback was given by the patient who used the prosthetic patient for several days as a trial to measure its safety and comfortablty.
Friction Stir welding (FSW) parameters, which play a vital principle, that impact on the mechanical, microstructural properties of the weldment because of the warmth produced by the contact between the instrument and work-piece, An AA6061-T6 aluminum composite plate with measurements (186*150*4) mm3 welded through various rotational paces 800, 1000, 1200 and 1450 rpm, the created heat measured through thermocouples embedded in study zones of the Weldment, a Finite Element model have been executed by utilizing ANSYS 12.1 bundle charges to ponder the temperature appropriation amid stay stage, the outcomes demonstrates a decent assention between the after effects of exploratory and hypothetical tests. The most extreme temperature measured at this condition was 0.71 from the liquefying temperature of the sample at a maximum rotational speed of (1450) r/min.
The mixing technique was applied in this study to enhance the strength performance of the cement. The addition of 3% by weight of hydroxyapatite (HA) nanoparticles were mixed with 97% polymethyl methacrylate (PMMA) acrylic polymer, which has a nano size to serve as the matrix material. The surface roughness and continuous porosity of the bone cement were found to be slightly increased by the incorporation of nanoparticles, which enhanced bone-implant osseointegration and ingrowth. Atomic force microscopy (AFM) analysis revealed that the addition of hydroxyapatite (HAp) nanoparticles resulted in a surface roughness value (Sa) of 16.25 nm, which is similar to that of natural bone. The energy-dispersive X-ray spectroscopy (EDS) mapping results discover precentor material and uniform distribution. The Sample exhibited promising results in the antibacterial test, showing efficacy against bacteria both with and without sterilization, confirming its antibacterial properties. The mechanical tests conducted on the sample, including tensile, compression, bending and Vickers hardness tests, yielded favorable results and indicated that the sample is suitable for its intended application. In the theoretical works the design of the bone, screw, and bone plate was conducted using SolidWorks, followed by an analysis using ANSYS under both axial and bending load conditions. The theoretical analysis revealed that the safety factor was less than 1 when an axial load of 13 N was applied and a bending load of 2 N was applied, indicating that the structure may not be able to withstand these loads safely. Under both ambient and physiologically relevant conditions in the human body, HA and PMMA have demonstrated to be excellent choices for enhancing the clinical performance of bone cement. This, in turn, can lead to increased longevity of implants, decreased patient risk, and lower healthcare costs