A numerical study regarding stress, strain, and deflection of a composite plate is presented. The plate, consisting of three layers of Carbon-, Boron-, and Graphite-Epoxy, was fixed at one end and loaded at the other end in a conventional cantilever configuration. Six arrangements were examined and the spatial distribution of stress, strain, and deflection of the upper surface were calculated. Generally, it was found that the order, by which the three layers are arranged, has a great effect on the response of the plate and the maximum stiffness (in terms of deflection) is achieved when using Epoxy with Graphite-Carbon-Boron as the top-central-bottom layers of the plate.
Plates with interior openings are often used in both modern and classical aerospace, mechanical and civil engineering. The understanding of the effects of two cutouts on the stress concentration factor, maximum stress and deflections in perforated clamped rectangular plates, were considered. Parameters such as location, size of cutout and the aspect ratio of plates are very important in designing of structures. These factors were presently studied and solved by finite element method (ANSYS) program. The results based on numerical solution were compared with the results obtained from different analytical solution methods. One of the main objectives of this study is to demonstrate the accuracy of the analytical solution for clamped square plate. In general, the results of the square clamped plates with two cutouts come out in good agreement. The results presented here indicated that the maximum stress, deflection of perforated plates can be significantly changed by using proper cutouts locations and/or size. The results show that the rectangular plate containing two cutouts arranged along the width is stronger and stiffer than when arranged along the length at a given spacing, and the square plate is always stronger and stiffer than an equivalent rectangular plate for the same loading condition.
This research presents an experimental and theoretical investigation of the effect of cutouts on the stress and strain of composite laminate plates subjected to static loads. The experimental program covers measurement of the normal strain at the edges of circular and square holes with different number of layers and types of composite materials by using strain gages technique under constant tensile loads. A numerical investigation has been achieved by using the software package (ANSYS), involving static analysis of symmetric square plates with different types of cutouts. The numerical results include the parametric effects of lamination angle, hole dimensions, types of hole and the number of layers of a symmetric square plate. The experimental results show good agreement compared with numerical results. It is found that increasing the number of layers reduces the value of normal strain at the edges of circular and square holes of a symmetric plate and the maximum value of stress occurs at a lamination angle of (30o) and the maximum value of strain occurs at a lamination angle of (50o) for the symmetric square plates subjected to uni-axial applied load. The hole dimensions to width of plates ratio is found to increase the maximum value of stress and strain of a symmetric square plate subjected to uniaxial applied load. Moreover, the value of maximum stress increases with the order of type of circular, square, triangular and hexagonal cutout, whereas the value of maximum strain increases with the order of type of circular, square, hexagonal and triangular cutout.
Enhancing the hydrothermal performance of plate-fin microchannels heat sink (PFMCHS) promises smaller size and lighter weight, and then improve the heat removal in consequently increase the speed of electronic devices. In this numerical study, an innovative hydrothermal design of PFMCHS is suggested by inserting elliptic pins inside microchannels in different; aspect ratio (AR) of pin, pin number ratio (ψ) in order to optimize the hydrothermal design of this kind of heat sinks. The main objectives of this study are; investigating the effect of pins on the performance of PFMCHS by investigating the best geometry in the pinned-fin MCHS and which is higher, thermal or hydraulic performance of this kind of heat sinks and what is the optimal number of pins numerically and what about the pressure drop penalty in the proposed design, little, modest or high increase. It is seen that the thermal resistance of the pinned fin MCHS is about 50% lower, and pressure drop of it is much higher than that of the (PFMCHS) under the condition of equal wind velocity. Maximum mechanical fan power reduction obtained is about 57% for the pinned fin MCHS with ψ = 1 and Dh = 1 ×10-3 m compared to the corresponding original channel heat sink. To show the overall performance of the two parameters; aspect ratio (AR), pin number ratio (ψ), the overall JF factor is estimated and the concrete findings shows that the best hydrothermal performance is obtained at the greater aspect ratio which is around overall JF = 1.2. In addition, the trend of overall JF is going down with the pin number ratio, starting from 1.2 to 1.15. And the concrete findings show that pinned fin MCHS provides thermal performance of 1.42 times greater than the smooth one under the corresponding conditions when one pin is used in each channel
An experimental study is achieved to study the thermal performance of forced unglazed solar air collector supplied with perforated absorber flat plate. The study is carried under Iraqi circumferences in Al-Ramadi city .The collector is inclined (90o) on horizontal for the simplicity of setting such type of collector on the wall building and minimize its weight. The measurement is recorded on Winter season for two sunny days and two cloudy days in (January 2012). The results show that its possible to use this type of collectors for heating in Winter time because the maximum out air temperature reach to (34oC) when ambient air temperature at (17oC) in sunny days. A good agreement is shown with the published studies Finally its obtained a good effectiveness for perforated flat plate absorber with high system efficiency.
Since FGM orthotropic structures have such striking qualities as high strength, exceptional stiffness, stiffness-to-weight ratio, reduced cost, and high strength-to-weight ratio, they are employed extensively in the mechanical, aerospace, and civil engineering sectors. Thick plates and shells have more noticeable shear deformation effects. Therefore, in recent years, there has been a lot of interest in the vibration and buckling investigation of FGMs orthotropic plates and shells. Moreover, researchers have developed a variety of approaches and procedures for the examination of orthotropic FGM plates and shells. The majority of the literature review in this publication is focused on orthotropic FGMs plate and shell buckling and linear and nonlinear free vibration. In engineering practices, it is customary to use material-oriented or orthotropic materials in several domains to optimize the structures and maximize material properties, which is especially crucial for FG constructions. Solutions for the orthotropic FGM structure are studied analytically and numerically with different plate and shell theories.
A finite element method for free vibration analysis of generally laminated composite plateswith central crack and clamped edges have been studied using ANSYS 5.4 program. The fiber-reinforced composite materials are ideal for structural applications where highstrength-to-weight and stiffness-to-weight ratios are required, where structures must safelywork during its service life. But damages initiate a breakdown period on the structures.Cracks are among the most encountered damage types in the structures. The non-dimensionalfundamental frequency of vibration decreases with presence of cracks because, therigidity of cracked plate decreases. The natural frequency of plates depends on size andshape of the cracks, the effect of number of layers is found to be insignificant beyond fourlayers and the change of fiber orientation increasing the fundamental frequency of vibration.The results obtained have been compared with the available published literature with goodagreement results
In this current experimental research, the amount of improvement in the thermal conductivity of HEC hybrid epoxy resins was studied by adding copper oxide nanoparticles CuONp and carbon nanotubes (CNTs) as hybrid additives in different proportions to select the sample with the highest thermal conductivity value to include it in the design of the Flat Plate Solar Collector FPSC as Thermal Interface Material TIM reduces thermal resistance between the absorber plate and the tube. Four groups of samples were prepared using a mass balance with a sensitivity of 0.01g and a magnetic mixing device, then poured into cubic plastic molds to take the shape of the sample. The first group consists of one sample of pure epoxy to calibrate the thermal properties testing device through it. The second group consists of five samples of epoxy loaded with CNTs by weight (1, 3, 5, 7.5, 10) %. The third group consists of five samples of epoxy loaded with CuONp with weight percentages of (1, 3, 5, 7.5, 10) %. The fourth group consists of five samples of epoxy loaded with CuONp and CNTs combined in weight percentages of (1, 3, 5, 7.5, 10) %. The thermal conductivity of the samples was measured experimentally using the hot disk analyzer technique to measure thermal specifications. After comparing the thermal conductivity values of the samples, the highest value was 1.57 W/mK for the HEC sample loaded with 10% CNTs, which represents 9.23 times higher than pure epoxy
This paper deals with the transient interlaminar thermal stress analysis of angle-ply SIC/LAS composite cantilever plate due to sudden change in the thermal boundary conditions .The transient interlaminar thermal stresses are computed by using the finite element method for different intervals of time. The effects of the fiber volume fraction, fiber orientation angle and stacking sequence are studied. The results are compared with previous studies with a good agreement
RSM and DOEs approach were used to optimize parameters for hypoeutectic A356 Alloy. Statistical analysis of variance (ANOVA) was adopted to identify the effects of process parameters on the performance characteristics in the inclined plate casting process of semisolid A356 alloy which are developed using the Response surface methodology (RSM) to explain the influences of two processing parameters (tilting angle and cooling length) on the performance characteristics of the Mean Particle Size (MPS) of α-Al solid phase and to obtain optimal level of the process parameters. The residuals for the particle size were found to be of significant effect on the response and the predicted regression model has extracted all available information from the experimental data. By applying regression analysis, a mathematical predictive model of the particle size was developed as a function of the inclined plate casting process parameters. In this study, the DOEs results indicated that the optimum setting was approx. (44) degree tilt angle and (42) cm cooling length with particle size (30.5) μm
The main purpose of this search is to study the punching shear behavior of fourteen specimens of Reactive Powder Concrete (RPC) two-way flat plate slabs, half of these slabs have been exposed to a high temperature up to 400 C° by using an electric oven. All slabs have dimensions of (400x400x60) mm, with steel reinforcement mesh of (Ø6mm) diameter. Laboratory tests show that there is an increase in the value of First Crack Loading (FCL) and Ultimate Load (UL) by (208, and 216.67) % and a decrease in deflection by (56.85) % due using slab with complete reactive powder relative to a slap made of normal concrete. The use of the (RPC)mixture in layers in slabs gave results close to the slab which consists of full (RPC) this gives the benefit of more than the use of a slab that contains full reactive powder concrete in terms of cost, the increase was in FCL and UL by (130.8, 169.23, 102.7 and 135.135) % and a decrease in the value of deflection by (37.17, 47.64) %. The use of a partial reactive powder mixture also showed good results, and by increasing the dimensions of the RPC area, the results were better. the increase in FCL and UL by (54, 116, and 185) % and (53, 116.67, and 166.67) % and a decrease in value of deflection by (36.12, 42.4, and 50.26) % from reference slab. When slabs are subjected to high temperatures, there may be a decrease in the value of the FCL and UL and an increase in the value of deflection when compared to models not exposed to high temperature. But when compared to the reference slab with the same circumstance showed an increase in the value of the FCL and the rate ranged between (50- 200) % and the UL was the ratio ranged between (51.35-208.1) % and a decrease in the value of the deflection where the ratio ranged (21-46) %
The research studies the prediction of thermal characteristics for open designer shape of solar collector of flat plate of area 2.34m2, connected to water tank of 85 liter capacity . Mathematical model was represented and made the system of private accounts, transactions and through the creation of mathematical equations and solved numerically using the method of Finite Difference Method (FDM).The results of research is to obtain hot water at average temperatures up to 520C at mid-day during February month, as the water temperature is at its lowest value in this month in Baghdad city, with an average efficiency of the system up to 53.6% .This predictive study is compared with a previous measurement work and confirmed that the results match well.
The Cooper-Harper rating of aircraft handling qualities has been adopted as a standard for measuring the performance of aircraft. In the present work, the tail plane design for satisfying longitudinal handling qualities has been investigated with different tail design for two flight conditions based on the Shomber and Gertsen method. Tail plane design is considered as the tail/wing area ratio. Parameters most affecting on the aircraft stability derivative is the tail/wing area ratio. The longitudinal handling qualities criteria were introduced in the mathematical contributions of stability derivative. This design technique has been applied to the Paris Jet; MS 760 Morane-Sualnier aircraft. The results show that when the tail/wing area ratio increases the aircraft stability derivative increases, the damping ratio and the natural frequency increases and the aircraft stability is improved. Three regions of flight conditions had been presented which are satisfactory, acceptable and unacceptable. The optimum tail/wing area ratio satisfying the longitudinal handling qualities and stability is (0.025KeywordsLongitudinal Handling---Stability---Tail Design
In recent years, the elastomer forming technique has found acceptance on the shop floor and is used increasingly as a pressure- transmitting medium for various metal-forming operations. This is due mainly to the introduction of a new range of materials and of new concepts in tooling, which have served to kindle industrial interest in the process. The purpose of this paper is to study the sheet formability with compressible die (natural rubber). The forming was occurred using hemi-spherical punch and rubber die. Experimental tests were used to know the mechanical properties for rubber and sheet materials which were brass and aluminum. After that several forming processes were prepared with a 58 mm diameter steel ball as a punch to form 0.5 thickness brass and aluminum dishes with different diameters (15-40 mm). Force-stroke history was plotted through forming to find the stiffness of formed plate with rubber die and later to compare this parameter for different diameters. Wrinkling and springback were pointed for the formed dishes. It was found that the stiffness of the formed dish increases with diameter until reaching to the diameter at which wrinkling will takes place (about 33 mm for aluminum and 28mm for brass), and then the stiffness will decreases with diameter above this value. It was found that the springback ratio (ratio of final high to the stroke) was increased with diameter until wrinkling takes place, and this ratio is greater for aluminum than that for brass. The results show that it is able to use natural rubber as a die for sheet metal forming with limitation of using small sheet thickness
The present research studies experimentally the effect of the ratio of the centurial hollow on the average of laminar convective heat transfer and the thermal gradation of the thermal boundary layer of three square flat plates. An experimental set-up was made for this purpose containing basically three uniformly Aluminum flat plates of a centurial hollow representing (0.25,0.5,0.75) of the entire surface area of each plate. Each of the three plates were heated by a constant heat flux for a rang of Rayleigh number of (5.62x105≤Ra≤1.67x106).The study showed that increasing the hollow ratio causes to increase the average of convective heat transfer by increasing the average Nusselt number, and the increasing average from a ratio to another decreases by the increases of the hollow ratio. The increasing between the two surfaces at (m=0.25&m=0.5) reached (39.6%) and for (m=0.5&m=0.75) was less than that and reached (29.2%).The increase average between the biggest and smallest hollow ratio was (78%).The study also showed that the maximum thermal gradation was on the out side edge of the plates and increases with the increase of Rayleigh number and the hollow ratio.
This paper presents the experimental results of composite slabs under static and impact loading. Total of six specimens classified one specimen test under static loading and the remaining five were tests under impact dynamic loading with different parameters as type of connections and degree of interaction of composite slab. Low - velocity impact test was adopted by select the falling mass (4 kg) made from steel material and formed as ball shape without nose. The ball dropped freely from height of (2.4 m) and strikes the top of composite slab. The designed dimensions of specimens is (500×500×60 mm) as reinforced concrete slab that reinforced by mesh of (RBC) and the steel plate is (3 mm) in thickness. Deflection due to first crack is recorded, number of blows caused first crack and failure were counted. The test results showed that the welded stud connectors gives high strength capacity and resistance under static and impact dynamic loadings than other than type of connections, also, full interaction as degree of interaction is better than others
Experiments were carried out on natural convection heat transfer from longitudinal trapezoidal fins array heat sink subjected to the influence of orientation. A trapezoidal fins heat sink with various orientations tested under a controlled environment. Test results indicate that the sideward horizontal fin orientation yield the lowest heat transfer coefficient. However the sideward vertical fin orientation gave the best performance on the natural cooling. From the experiments Nu is determined as a function of Ra at Pr=0.7 for each orientation with Ra ranging between (1400 and 3900).From the results; Heat transfer coefficient of the sideward vertical fins is higher by (12%) than the heat transfer coefficient of the upward while it is higher than the heat transfer coefficient of the downward by (26%) and by (120%) with the sideward horizontal fins. Orientation affected the temperature distribution along the fins, therefore the temperature along the sideward vertical fins have the best performance with uniform distribution, while in sideward and downward the temperature increased in the positions near the base plate surface because of the complication in moving the heated air.
In this paper, the effect of using the strengtheners on the stress and deflection under the effect of a certain weight falling on plates made of aluminum alloys (Al Mg3)has been studied. The study was carried on through two aspects; experimentally and theoretically; theoretically by using (F.E.M LS. DYNA) program. After comparing the theoretical aspect and experimental aspect, greatly- close results at point of contact were found out, as follows: When using one strengthener, the stresses reduce by (14 %) and the deflection by (70%) with comparison of without stiffener case .When using two strengtheners at the ends, stresses reduce (77%) and the deflection (65%) .When using two strengtheners 8 cm apart, stresses reduce (56 % ) and the deflection ( 18%) . When using two strengtheners 4 cm apart, stresses reduce (60 %) and the deflection (31%)
Composite laminate plates, fabricated by bonding fiber–reinforced layers, were dynamically analyzed under different combinations of number of layers, type of cutout, hole dimensions, angle of lamination and type of dynamic loading . This work was achieved by the well–known engineering software (ANSYS). The toughness of composite plates was evaluated in terms of the normal stress in the direction of loading at the periphery of the cutout. The toughness was found to increase by increasing the number of layers, by setting the lamination angle at around 40o,by selecting hole dimensions to width of plate ratio of around 0.4 and by employing square cutouts or avoiding triangular cutouts. Also, composite plates were found to be more strain-rate-sensitive in ramp loading, with least number of layers and with triangular type of cutout.
An experimental study was done on a solar water heater which consists of two prisms of orthogonal triangle cross-section with a 210 liters capacity . The heater was easy to make and has a low cost when comparted with other types of solar water heaters that it usually the collector separate on the water store. The study included experimental investigations , the experimental investigation was done under the Iraqi environmental conditions at Baghdad for the period in summer and winter seasons in 2006 but the calculation for only two days 15/7/2006 and 6/12/2006 . The study included testing the heater with & without loading and it tested in 13/12/2006and14/12/2006. draining hot water from storage tank at different rates . The experimental result show the ability to get hot water at 46oC at December i.e. a temperature rise at 30oC with 16oC initial temperature .
The aim of current work is to investigate the tensioned composite plates with two types of cutouts. Many industrial applications use composite matrix with reinforcement fiber to obtain better properties. The objective of this work is divided into two parts, first the experimental work covers the measuring of the normal strain (εx) at the edges of (circular & square) holes that are perpendicular to the direction of the applied loads with different number of layers and types of cutouts of composite materials by using strain gages technique under constant tensile loads to compare with the numerical results. The second part is numerical work, which involves studying the static analysis of symmetric square plates with different types of cutout (circular – square). In static analysis, the effect of the following design parameters on the maximum stress (σx), strain (εx) and deflection (Ux) is studied. This part of investigation was achieved by using the software finite element package (ANSYS 5.4).