Research Paper
Optimization
Meraj Rajaee; Mina Jalali
Abstract
The solar tree is a combination of technology and art that is considered as the application of solar energy in the art of urban architecture. This study aims to combine solar technology with architectural style and art, help urban beautification and investigate the increase in solar panels' efficiency ...
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The solar tree is a combination of technology and art that is considered as the application of solar energy in the art of urban architecture. This study aims to combine solar technology with architectural style and art, help urban beautification and investigate the increase in solar panels' efficiency by focusing on the optimal slope and no shading in the form of a new solar tree structure. In this paper, the best angle for placing panels on tree branches to increase Shiraz's maximum efficiency has been calculated. The best angle is done with the help of the NRI mathematical model. Also, the Fibonacci sequence, which originates from nature and real trees, has been used to minimize shadows on this tree. The panels' optimal slope calculations are performed using MATLAB software. Also, the monthly efficiency changes resulting from the optimal slope have been calculated and displayed. By analyzing the computational relationships and their implementation by PVsyst simulator, the optimal annual slope of solar panels obtained 30 degrees. By implementing it in the solar tree structure, the proposed model's annual efficiency has increased by 12% compared to the fixed state. This article examines the technical methods of using solar systems in urban architecture with emphasis on integration methods. In the proposed and implemented solar tree model with the ability to adjust the optimal angle and beautify passages, parks and recreation centers, it is possible to charge electronic equipment such as mobile phones, tablets, and electric bicycles through clean solar energy.
Research Paper
Heat and Mass Transfer
Ravi Kumar
Abstract
< p>Theoretical investigation of Ohmic heating (Joule heating) and radiation on MHD Jeffery fluid model with porous material along the tapered channel with peristalsis is the focus of this study. Long wavelength and low-Reynolds number approximations are used in the mathematical modelling. Axial ...
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< p>Theoretical investigation of Ohmic heating (Joule heating) and radiation on MHD Jeffery fluid model with porous material along the tapered channel with peristalsis is the focus of this study. Long wavelength and low-Reynolds number approximations are used in the mathematical modelling. Axial rate, pressure gradient, temperature, and heat transfer coefficient rate expressions are calculated. Plotting diagrams were used to analyse the impact of physical parameters on flow characteristics, which were then addressed in depth. It’s worth noting that raising the gravitational parameter, Jeffery fluid parameter, Hartmann number and Porosity parameter raises the fluid’s velocity. It''s worth mentioning that as the Ohmic heating (Jeffery fluid) parameter and porosity parameter increases, the axial pressure gradient drops, and the temperature of the fluid rises. The rate of heat transfer coefficient rises with an increase in the Radiation parameter, Heat generator parameter and Jeffery fluid parameter. Mathematica software is employed to seek out numerical results.
Research Paper
Robotics
Mohammad Mohammadi; Reza Dehghani; Ali Reza Ahmadi
Abstract
In this paper, a quadrotor with two manipulators constrained on a straight path is modeled and a robust adaptive controller is proposed for it. Adding two manipulators to quadrotor increases its capabilities and applications in industry. Here, these two manipulators are used to place the robot on a constraint ...
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In this paper, a quadrotor with two manipulators constrained on a straight path is modeled and a robust adaptive controller is proposed for it. Adding two manipulators to quadrotor increases its capabilities and applications in industry. Here, these two manipulators are used to place the robot on a constraint path so that the quadrotor can perform monitoring operations more accurately, because the under-actuated quadrotor becomes over-actuated by these constrained manipulators and one can use this feature to accurately control the position of the robot. Reduced form of motion equations are derived for the constrained quadrotor and based on this a robust adaptive controller is proposed. The nonlinear terms in the dynamic model are approximated by basic functions with constant weights and adaptive laws are designed by projection operator. Stability analysis is performed based on the Lyapunov theory. Evaluation of the presented controller is done by some numerical simulations. The simulation results showed that the robot tracks the reference path with bounded error in spite of dynamic uncertainties and wind force and satisfies the considered constraints.
Research Paper
Automation
Ali Mirmohammad Sadeghi; Abdollah Amirkhani; Behrooz Mashadi
Abstract
Recognizing a driver’s braking intensity plays a pivotal role in the development of modern driver assistance and energy management systems; and therefore, it is especially important to autonomous and electric vehicles. This paper aims at developing a system for recognizing a driver’s braking ...
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Recognizing a driver’s braking intensity plays a pivotal role in the development of modern driver assistance and energy management systems; and therefore, it is especially important to autonomous and electric vehicles. This paper aims at developing a system for recognizing a driver’s braking intensity based on the pressure produced in the brake master cylinder. In this regard, a model-based, synthetic data generation concept is used to generate the training dataset. This technique involves two closed-loop controlled models: an upper-level longitudinal vehicle dynamics model, and a lower-level brake hydraulic, dynamic model. The adaptive particularly tunable fuzzy particle swarm optimization algorithm is recruited to solve the optimal K-means clustering problem and to determine the best number of clusters and centroids into which the brake pressure data are to be divided. The obtained results reveal that the brake pressure data for a vehicle traveling the new European driving cycle can be best partitioned into two clusters. A driver’s braking intensity may, therefore, be clustered as moderate or intensive. With the ability to automatically recognize a driver’s pedal feel, the system developed in this research could be implemented in intelligent driver assistance systems as well as in electric vehicles equipped with intelligent, electromechanical brake boosters.
Research Paper
Hydraulic and Pneumatic Systems
Amir Saidani; Ali Fourar; Fawaz Massouh
Abstract
< p>The paper investigates temperature effect on water hammer in an isothermal pressurized copper pipe rig, for single and two phase flow. The study concerns pressure wave’s intensity, celerity and attenuation. Also, the cavities volume created during low pressure periods is inspected. The mathematical ...
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< p>The paper investigates temperature effect on water hammer in an isothermal pressurized copper pipe rig, for single and two phase flow. The study concerns pressure wave’s intensity, celerity and attenuation. Also, the cavities volume created during low pressure periods is inspected. The mathematical model of hyperbolic equations is described by the dynamic and continuity equations, which have been transformed by the characteristics method (MOC) into ordinary differential equations. Water hammer solver was built considering two different models of cavitation and column separation, the discrete vapor cavity model (DVCM) and the discrete gas cavity model (DGCM). In addition of the quasi-steady friction model, two unsteady friction models were incorporated into the code, the convolution based model proposed by Vardy & Brown and the instantaneous acceleration model proposed by Brunone. The simulations concern temperature range within 4°C to 95°C. Although the single and the two phase water hammer don’t behave with the same manner, the results obtained with the different models, show a significant influence of the temperature.
Research Paper
Heat and Mass Transfer
Sreenivasulu Pandikunta; Barinepalle Malleswari; POORNIMA T T; N Bhaskar Reddy
Abstract
This study emphasis on the upshots of non-linear radiation and electrical resistance heating on a three dimensional Jeffrey dissipating nanoflow in view of convective surface conditions. The initial set of nonlinear dimensional boundary layer equation are transformed into a system of ordinary differential ...
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This study emphasis on the upshots of non-linear radiation and electrical resistance heating on a three dimensional Jeffrey dissipating nanoflow in view of convective surface conditions. The initial set of nonlinear dimensional boundary layer equation are transformed into a system of ordinary differential equations with suitable similarity variables and then This study emphasis on the upshots of non-linear radiation and electrical resistance heating on a three dimensional Jeffrey dissipating nanoflow in view of convective surface conditions. The initial set of nonlinear dimensional boundary layer equation are transformed into a system of ordinary differential equations with suitable similarity variables and then solved by shooting method using Mathematica software. For various representative quantities, the behavior of the momentum, energy and species diffusion along with engineering quantities near the surface are figured for different estimations of the fluid properties. The examination of present outcomes has been made with the existing work which is good agreed. This study helps in understanding the heat transfer rate is predominant in the non-linear radiation compared to linear radiation. Jeffrey fluid model has the capacity of describing the stress relaxation property, which usually viscous fluid lags and this is exhibited clearly in the study. Shear stress descends as the fluid pertinent parameter ascends.
Research Paper
Computational Fluid Dynamics (CFD)
Mithilesh K Sahu; Moughbul Basha Shaik
Abstract
The new and advance technologies for higher performance and lower maintenance are required to operate the gas turbines at higher operating temperatures. Higher turbine inlet temperature results in higher blade metal temperatures. These variations in temperatures of the blade material must be limited ...
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The new and advance technologies for higher performance and lower maintenance are required to operate the gas turbines at higher operating temperatures. Higher turbine inlet temperature results in higher blade metal temperatures. These variations in temperatures of the blade material must be limited such that the blades have a sufficient life span. To make blade material temperature within the limits the coolant air is bled from the compressor to protect the outer surface of the turbine blade from the hot gases. The purpose of the work is to investigate the cooling performance of blade with leading edge cooling holes. The numerical simulation approach using ANSYS Fluent has been considered. The analysis is performed by taking different hole geometries namely cylindrical (model 1) and tapered (model 2) on the leading edge of the turbine blade for different blowing ratios. The analysis also compares the cooling effectiveness of the blade for two different coolants namely air and nitrogen. Result shows, for highest effectiveness hole (E3 hole), the Model 1 and Model 2 comparison suggest that Model 1 has 1.2% more cooling effectiveness for air as coolant. For E3 hole comparison of Model 1 between two coolants show that film cooling effectiveness of air gives 0.6% more film cooling effectiveness compared to nitrogen. The article concludes that the presented work helps researchers and blade manufacturers to select the correct hole geometry, coolant type, and determine the best blowing ratio to improve the film cooling efficiency of gas turbine blades with leading edge holes.
Research Paper
Composite Materials
Aidin Ghaznavi; Mohammad Shariyat
Abstract
Studying the behavior of sandwich panels is very important due to their widespread use in different industries. Therefore, over the past decades, various theories have been proposed to study the behavior of these panels. In this paper a higher order global-local theory with 3D equilibrium-based corrections ...
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Studying the behavior of sandwich panels is very important due to their widespread use in different industries. Therefore, over the past decades, various theories have been proposed to study the behavior of these panels. In this paper a higher order global-local theory with 3D equilibrium-based corrections is presented to study behavior of thick and thin sandwich plate with flexible and auxetic core. In addition to correcting the results with 3D elasticity equations, another important advantage of the presented theory is the ability to consider the transverse core deformation of the sandwich panels. It should be mentioned that to study the behavior of thick sandwich panels, especially with soft core, the existence of this feature is very necessary and has a great effect on the accuracy of the obtained results. Comparison of the obtained results with those existing in valid references showed that the formulation of the provided finite element had a very good accuracy even for thick and thin sandwich plates. Finally, the effect of different material and geometrical parameters on the behavior of sandwich plates are carefully investigated using the presented theory.
Research Paper
Biomechanics
Diana Martins; Rui Couto; Elza M M Fonseca; Ana Rita Carreiras
Abstract
This work presents a numerical approach to predict the influence of material stiffness in a dental implant using different thread profile shapes, always with a constant number of threads, thread width and thread pitch. Dental implant affects bone tissue, in response to various mechanical stimuli where ...
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This work presents a numerical approach to predict the influence of material stiffness in a dental implant using different thread profile shapes, always with a constant number of threads, thread width and thread pitch. Dental implant affects bone tissue, in response to various mechanical stimuli where the biomechanical behavior plays a significant role in the study of stresses and strains calculation. In this work, four different thread profile shapes were considered (Model1 - Plateau typeA, Model2 - Plateau typeB, Model3 - Triangular, Model4 - Rectangular) with two different inner diameters equal to 4 and 6 mm, using three different implant materials (titanium, an iso-elastic titanium and zirconium alloys). Two dimensional computational axisymmetric models of a bone-implant were constructed using the finite element method. This study presents numerical results about the mechanical stimuli on dental implant according to the chosen material and profile shape. The main contribution of this work is giving additional information about the stability and implant loosening with the application on surgical techniques in dental science.
Review paper
Welding
Satish S Chinchanikar; Vaibhav S Gaikwad
Abstract
Researchers worked on many facets of joining of similar/dissimilar aluminum alloys using different joining techniques and came up with their own recommendations. Friction Stir Welding (FSW) is widely preferred for joining aluminum alloys being an economical alternative to produce high-quality welds. ...
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Researchers worked on many facets of joining of similar/dissimilar aluminum alloys using different joining techniques and came up with their own recommendations. Friction Stir Welding (FSW) is widely preferred for joining aluminum alloys being an economical alternative to produce high-quality welds. However, obtaining high strength welded joints without the detrimental and visible effects still needs attention considering the effect of hybrid FSW techniques, tool material, and geometry, process parameters (tool rotation, welding speed, and plunge depth), and post welding treatments. This study presents state of the art with the authors' own inferences on the evaluation of FSW performances in terms of joint tensile strength, fatigue strength, corrosion resistance, residual stresses, microstructure, and microhardness. This study also presents attempts made by the researchers on modeling and parametric optimization of FSW to finding scope for application of advanced optimization techniques and development of predictive models for mechanical properties of welded joints. This study emphasizes more studies required on the comparative evaluation of FSW performance with the application of ultrasonic frequency combinedly or individually on advancing and retreating sides of plates.
Research Paper
Composite Materials
Meisam Shakouri; Hessam Sarvahed; H.M. Navazi
Abstract
Pressure vessels are used in a variety of applications in many engineering applications. The thin walled cylinders with torispherical heads have been widely used as pressure vessels in engineering applications. In this paper, the free vibration behavior of carbon fiber reinforced composite cylinders ...
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Pressure vessels are used in a variety of applications in many engineering applications. The thin walled cylinders with torispherical heads have been widely used as pressure vessels in engineering applications. In this paper, the free vibration behavior of carbon fiber reinforced composite cylinders ended with torispherical heads with various boundary conditions is investigated. The shape of a torispherical head is consists of a sphere of large radius and a much smaller minor radius at the knuckle. The numerical calculation with finite element method is obtained and the results were compared with the experimental data to confirm the accuracy of the numerical solution. The acceptable accordance between experimental and numerical results leads to use of numerical model instead of expensive experimental tests. In addition, the effects of the thickness of torispherical head and cylindrical section and the lengths of cylinder and torispherical head on vibrational behavior of the structure are studied.
Research Paper
Computational Fluid Dynamics (CFD)
Sajad Rezazadeh; Mohammad Raad; Mohammadreza Mataji Amirrud; Davod Abbasinejad
Abstract
A numerical simulation of laminar fluid flow and heat transfer over built-in cylinders in a channel is presented. Effects of cylinders that located in a rectangular channel with constant wall temperature on flow and heat trans-fer have been investigated by the drag coefficient on cylinders wall, skin-friction ...
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A numerical simulation of laminar fluid flow and heat transfer over built-in cylinders in a channel is presented. Effects of cylinders that located in a rectangular channel with constant wall temperature on flow and heat trans-fer have been investigated by the drag coefficient on cylinders wall, skin-friction factor on channel wall, Strouhal number, pumping factor, Nusselt number, and Performance Index (PI) factor, which denotes the heat trans-fer in terms of the pressure drop. Results are validated by the most reliable published works in literature. Effects of Reynolds number and blockage ratio (β) for the equilateral triangular cylinder for 120≤Re≤180 and 0.15≤β≤0.55 on flow and heat transfer is investigated with more details. Results indicated that by increasing Re for constant blockage ratio, the drag coefficient, Strouhal number, and Nusselt number increase, but the skin-friction coefficient, pumping factor, and PI factor decrease subse-quently. Additionally, with increase in blockage ratio at constant Re, the drag coefficient, skin-friction coefficient, pumping factor, and Strouhal number grow up, but Nusselt number diminishes and PI factor has an op-timum range. Furthermore, results reveal that variation in blockage ratio has more significant effects on the flow and heat transfer than variation in Reynolds number.
Research Paper
Vibration
Mellel Nacim; Ouali Mohammed; dougdag mourad; Mohammedi Brahim
Abstract
This paper presents an extended cross modal strain energy change method to estimate the severity of damage associated with limited modal data in beam-like structures. This method takes in account the correlation between the analytical modal data and the measured incomplete modal data. A procedure was ...
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This paper presents an extended cross modal strain energy change method to estimate the severity of damage associated with limited modal data in beam-like structures. This method takes in account the correlation between the analytical modal data and the measured incomplete modal data. A procedure was proposed and the analytical elemental stiffness of the damaged element after it is localized is included in quantification of the measured single damage extent. A three-dimensional numerical beam model with different damage cases is used to simulate the CMSE method application and to getting the bending displacements of the damaged element. An experimental modal analysis on a cantilever beam subjected to a controlled crack levels was carried out to demonstrate the effectiveness of the extended CMSE method. The severity magnitude of the damage was predicted within an acceptable error range through the using validation process. Analysis results demonstrate that the presented damage method effectively quantifies single damage severity in beam like structure and can be applied in engineering practice.
Research Paper
Manufacturing Processes
Faiz Fawzi Mustafa; Sadoon Radi Daham
Abstract
Surface layer in many engineering applications is strengthened by ceramic grains where the main parts have higher structure toughness of than the original material. This paper presents the effect of four process parameters that have taken into consideration using Taguchi technique based on L9 orthogonal ...
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Surface layer in many engineering applications is strengthened by ceramic grains where the main parts have higher structure toughness of than the original material. This paper presents the effect of four process parameters that have taken into consideration using Taguchi technique based on L9 orthogonal array. These parameters are;1) transverse speed, 2) type of nano-powders, 3) rotational speed, and 4) groove’s depth friction stir welding T-joints aluminum alloy 6061-T6. This work combines between welding T-joint sections and creating MMNCs in welding region simultaneously.The predicted optimum parameters and their percentage of contribution were estimated, utilizing the analysis of variance and signal to noise ratio techniques, depending on tensile test in skin and stringers direction, and hardness test of the joint. Optical microscope and scanning electron microscope (SEM) analysis were used to verify the microstructure and dispersion of nano-powders in welding joint. The best ultimate tensile stress (UTSskin) was equal to (177MPa) for the skin welded part, were obtained at the optimal conditions of 1550rpm rotational speed, 15mm/min transverse speed, Al2O3 type of powder and 1mm groove’s depth. SEM micrographic for metal matrix nanocomposite of all nine experiments revealed that the nano-particles are irregular dispersed in nugget zone due to one pass. The rotational speeds of 960rpm, the transverse speed of 15mm/min, type of powder TiO2, and groove’s depth of 1.5mm, give the greatest hardness value of 80HV in nugget zone. Analysis of variance showed that the groove’s depth is the most significant parameter in this investigation.
Research Paper
Mir elyad Vakhshouri; Burhan Çuhadaroğlu
Abstract
< p>The effects of uniform injection and suction through the surfaces of a perforated square cylinder on the vortex shedding, heat transfer and some aerodynamic parameters have been investigated numerically. The finite-volume method has been used for solving the Navier-Stokes equations for incompressible, ...
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< p>The effects of uniform injection and suction through the surfaces of a perforated square cylinder on the vortex shedding, heat transfer and some aerodynamic parameters have been investigated numerically. The finite-volume method has been used for solving the Navier-Stokes equations for incompressible, turbulent near-wake flow (Re=21400) with the k-ɛ turbulence model equations. To find the optimum conditions, the effects of injection and suction through the front surface (case Ⅰ), the rear surface (case Ⅱ), top-bottom surfaces (case Ⅲ) and all surfaces (case Ⅳ) with various injection/suction coefficient Γ are studied. The results reveal that parameters such as pressure and drag coefficients and Nusselt number are influenced drastically in some cases as well as flow field parameters. For instance, the maximum reduction of the drag coefficient occurs at case Ⅳ while the maximum increase and reduction of Nu number occur at (|Γ|)=0.025 for all cases about 46% and 32%, 61% and 63%, 92% and 60% and 180% and 115% for cases Ⅰ, Ⅱ, Ⅲ and Ⅳ respectively.
Research Paper
Mechanics of Materials
Sidda Reddy Bathini; . Ch. Ravi Kiran; Vijaya Kumar Reddy K
Abstract
The present paper considers the devise and development of a novel theory to examine the flexure analysis of exponentially graded plates exposed to thermal and mechanical loads. The properties such as Elastic moduli and thermal moduli are assumed to vary exponentially along the thickness by keeping the ...
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The present paper considers the devise and development of a novel theory to examine the flexure analysis of exponentially graded plates exposed to thermal and mechanical loads. The properties such as Elastic moduli and thermal moduli are assumed to vary exponentially along the thickness by keeping the poisons ratio as constant. This theory fulfils the nullity conditions on the upper side and lower side of the exponentially graded plates for transverse shear stress. The Hamilton’s principle has been used to derive the equation of motion. The present theory numerical results are assessed with three-dimensional elasticity solutions and the results of other authors available in the literature. The influence of thermo mechanical loads and thickness ratios and aspect ratios on the bending response of exponentially graded plates are studied in detail. The analytical formulations and solutions presented herein could provide engineers with the potential for the design and development of exponentially graded plates for advanced engineering applications
Research Paper
Impact Mechanics
Farshid Kholoosi; Saman Jafari; Mahdi Karimi
Abstract
In this study, the crush behavior and energy absorption of various thin-walled structures under quasi-static loading are investigated. Some experimental data from similar work was used for validation of a simulated model. Some samples were designed and considered with different combined geometries. It ...
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In this study, the crush behavior and energy absorption of various thin-walled structures under quasi-static loading are investigated. Some experimental data from similar work was used for validation of a simulated model. Some samples were designed and considered with different combined geometries. It was found from simulated model that the most ability of specific energy absorption and crush force efficiency are related to the circle-square sample. For the circle-square sample, the analytic equations for calculating the mean crush force are obtained. The mean crush force result was compared with the result of simulations, showing a good agreement. The multi-objective optimization process for the circle-square structure was performed using non-dominated sorting genetic algorithms for two statuses. The purpose of optimization is to increase the specific energy absorption and to decrease the peak crushing force which causes the increase of crush force efficiency amount. The amount of specific energy absorption in the second status compared to the first status was improved by 17% and the amount of crush force efficiency was improved by 12% after optimization process.
Research Paper
Composite Materials
nabard habibi; yasaman ahmadi
Abstract
Water storage tanks are amongst the essential infrastructures, and the study of their natural frequencies plays a pivotal role in predicting and detecting dynamic behavior. Therefore, it helps to the uninterrupted operation of an industrial plant and the use of tank water in emergencies. This paper has ...
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Water storage tanks are amongst the essential infrastructures, and the study of their natural frequencies plays a pivotal role in predicting and detecting dynamic behavior. Therefore, it helps to the uninterrupted operation of an industrial plant and the use of tank water in emergencies. This paper has studied the influence of different shell materials including steel, aluminum, and laminated composites with three types of different fiber orientations, on the natural frequencies of thin-walled aboveground water storage tanks that have pinned boundary conditions at the base. Models investigated in this paper, either the roof is without an internal support structure or else a group of columns and radial beams are used for supporting it. These huge tanks had the height to diameter ratio 0.4, and a water surface at 90% of the height of the tank's cylinder. The thicknesses of the cylindrical shells are tapered. The tanks without internal support included the vibrations that affect the cylinder mode shapes or the roof mode shapes or simultaneously both the cylinder and roof mode shapes. On the other hand, the mode shapes of the tanks with internal support affect predominantly only the cylinder. Among the studied tanks, the third type of composite tanks had the highest rigidity, and the first type of composite tanks had the lowest rigidity. The natural frequencies related to the first modes of vibrations for cylinder and roof shells with a wide range of circumferential wave numbers (n) and an axial half-wave (m) are studied.
Research Paper
Machining
Pawan Kumar; Meenu Gupta; Vineet Kunar
Abstract
The present research attempts to analyze the surface topography of WEDMed Inconel 825 with respect to surface crack density (SCDi) and recast layer thickness (RCLt). Formation of cracks, recast layer and heat-affected zone are the major issues in determining the final performance of WEDM machined sample. ...
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The present research attempts to analyze the surface topography of WEDMed Inconel 825 with respect to surface crack density (SCDi) and recast layer thickness (RCLt). Formation of cracks, recast layer and heat-affected zone are the major issues in determining the final performance of WEDM machined sample. In this study, WEDM characteristics viz. pulse on time (Ton), pulse off time (Toff), gap voltage (SV), peak current (IP), wire tension (WT) and wire feed (WF) are optimized for response SCDi and RCLt by response surface methodology. The outcome manifested that the topography of the machined surface becomes more rough at increased value of Ton, IP and SV. RSM emerged as a great tool in the development of a predicted model based on desirability approach and finding optimal parametric combination which results in reduced SCDi and RCLt. At optimum combination of process parameters i.e. 109 machine unit Ton, 36 machine unit Toff, 54 V SV, 120A IP, 9 machine unit WT and 7 m/min WF, the values obtained for SCDi and RCLt were 0.00160 μm/μm2 and 20.991μm respectively with an error of less than 5%.
Research Paper
Fluid Mechanics
Mohammad Reza Aligoodarz; Mohsen Dalvandi; Abdollah Mehrpanahi
Abstract
The centrifugal slurry pump is the most common slurry flow pump used in mining industries. The pump head and efficiency are affected by the size, concentration, and density of solid particle when these pumps are applied for the control of slurries. Because the suspended solids in the liquid could not ...
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The centrifugal slurry pump is the most common slurry flow pump used in mining industries. The pump head and efficiency are affected by the size, concentration, and density of solid particle when these pumps are applied for the control of slurries. Because the suspended solids in the liquid could not well absorb, store, and transmit pressure energy, they cause quite different changes in efficiency and performance curve shape. This study was conducted to investigate the variations of the mentioned factors at different flow rates using a numerical simulation of the centrifugal slurry pump. For this purpose, the 3D turbulent flow was solved by applying Reynolds-Averaged Navier-Stokes (RANS) equations using the Shear Stress Transfer (SST) turbulence model based on Eulerian-Eulerian for 45% to 120% flow rates in CFX software. The accuracy of the numerical solution was investigated by comparing the characteristic curves resulting from the numerical solution with experimental data. The obtained results show a satisfactory fitting among the calculated values from the numerical analysis and experimental data to predict pressure and velocity distribution and global performance. Moreover, by simulating the effect of different parameters of the slurry flow, their effect on the characteristic curves of the slurry pump was compared. These results reveal that the numerical solution can efficiently predict the variation trend of the slurry flow parameters.
Research Paper
Nondestructive Testing
Nageswara Rao Boggarapu; Shyam Prasad Kodali
Abstract
Engineering materials and structures have crack-like defects leading to premature failures. Usage of fracture mechanics to assess the structural integrity requires knowledge on the type, location, shape, size, and orientation of the flaws. Tomographic reconstruction is one of the commonly used nondestructive ...
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Engineering materials and structures have crack-like defects leading to premature failures. Usage of fracture mechanics to assess the structural integrity requires knowledge on the type, location, shape, size, and orientation of the flaws. Tomographic reconstruction is one of the commonly used nondestructive testing methods for flaw characterization. The cross sectional image of the object being tested is obtained through the application of various reconstruction methods that are categorized as either analytical methods or iterative methods. In this work an iterative algorithm that works on the principles of genetic algorithms is developed and used for the reconstruction. The results of simulation studies on the tomographic reconstructions using genetic algorithms for the identification of defects in isotropic materials are discussed in the paper. The solution methodology based on use of genetic algorithms is applied to reconstruct the cross sections of test specimens with different flaw characteristics. Simulated time-of-flight data of ultrasound rays transmitted through the specimen under investigation is used as input to the algorithm. The time-of-flight data is simulated neglecting the bending of ultrasound rays and assuming straight ray paths. Numerical studies performed on several specimens with flaws of known materials but unknown location, size and shape are presented. The number of ultrasonic transmitters and receivers needed for complete scanning of the specimen’s cross section is analyzed and presented. The findings of parametric analysis and sensitivity analysis in order to choose appropriate range of algorithm parameters for performance quality and robustness of the algorithm are presented. Performance of present algorithm with noisy projection data is also discussed.
Research Paper
Damage Mechanics
Vinh Van Nguyen; Trung Ngoc Nguyen; Chi Thuy Nguyen
Abstract
Information about the dynamic loading of a steel structure is important for its static design as well as for an assessment of its fatigue life. In the case of a hydraulic static-pile-pressing machine, these loads are mainly caused by vibrations and load sway, which occurs as a result of the slewing motion ...
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Information about the dynamic loading of a steel structure is important for its static design as well as for an assessment of its fatigue life. In the case of a hydraulic static-pile-pressing machine, these loads are mainly caused by vibrations and load sway, which occurs as a result of the slewing motion of the boom around the vertical axis and from the radial movement of the load’s suspension point. This paper presents a study of the dynamics of a hydraulic static-pile-pressing machine during the process of lifting and slewing a pile using a mounted crane. A six -degree-of-freedom non-linear spatial-dynamic model is employed and a non-linear mathematical model of the machine was formulated. To confirm the mathematical model, a comparison between the measured results and simulation results using the mathematical model shows that the mathematical model is reliable. These results can be used to optimise machine design based on calculations of its dynamics, fatigue, life expectancy and stability from a dynamic point of view.
Research Paper
Heat and Mass Transfer
Shaik Ibrahim; Kanna Suneetha; G.V Ramana Reddy; P Vijaya Kumar
Abstract
Due to their position in various industrial applications, convective fluid flow structure is intricate and enticing to investigate. Here the flow has been made by considering multitudinous apropos parameters like induced magnetic factor, heat source and viscous dissipation effects for the mixed convective ...
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Due to their position in various industrial applications, convective fluid flow structure is intricate and enticing to investigate. Here the flow has been made by considering multitudinous apropos parameters like induced magnetic factor, heat source and viscous dissipation effects for the mixed convective chemically radiative fluid from a vertical surface. The frame work of mathematical pattern is conferred with in the circumstances of a system of ordinary differential equations under felicitous legislation.The governed mathematical statement is handled analytically by perturbation strategy. Diagrams and numerical values of the profiles are delineated with apropos parameters. Our sketches illustrate that the induced magnetic field is perceived to be downward with intensification in magnetic parameter. Temperature profile is accelerated by rising thermal radiation and concentration distribution is decelerated by enhancing the chemical reaction and Schmidt number. Propelled by the precursory research, the intrusion here is to scrutinize the repercussion of induced magnetic factor on viscous stream because of vertical surface.
Research Paper
mohamed Elmasry
Abstract
The Tube flange is typically performed using welding, forging method, both of which cost time and effort. In this work, a metal spinning process to form tube flange was proposed. A flange-forming tool was developed based on the outer tube diameter to form the flange. It consists of three components namely ...
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The Tube flange is typically performed using welding, forging method, both of which cost time and effort. In this work, a metal spinning process to form tube flange was proposed. A flange-forming tool was developed based on the outer tube diameter to form the flange. It consists of three components namely collet, mandrill and roller. An experimental study was carried out to form the flange of lead tubes. Several flanged specimens were conducted at different working conditions. These working conditions are rotating speed (rpm), feed rate (mm/rev), and wall tube thickness (mm). The effects of working conditions on the flanging loads were investigated. An experimental analysis was carried out to illustrate the effect of the working conditions on the characteristics of the tube flange. The analysis showed that these working conditions have a clear influence on wall thickness, surface hardness, and flanging loads. A theoretical analysis to model the flange forming loads (axial, radial and tangential) was present. A comparison between analytical calculated and experimental measured loads was discussed. This comparison indicates a good agreement between the deducted forces analytically, and that measured experimentally.
Research Paper
Abdulnaser Mohammed Alshoaibi; omar Yasin
Abstract
This paper proposes a combination of FRANC2D/L (2D crack growth simulation program) and ANSYS mechanical program (3D structural analysis for fracture mechanic analysis. The comparisons between the two software were performed for different case studies for stress intensity factors (SIFs) as well as crack ...
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This paper proposes a combination of FRANC2D/L (2D crack growth simulation program) and ANSYS mechanical program (3D structural analysis for fracture mechanic analysis. The comparisons between the two software were performed for different case studies for stress intensity factors (SIFs) as well as crack growth trajectory. Crack growth was numerically simulated by a step-by-step 3D and 2D finite element method. The SIFs were calculated by using the displacement correlation technique. The procedure consists of computing SIFs, the crack growth path, stresses, and strain distributions via an incremental analysis of the crack extension, considering two and three-dimensional analysis. The finite element analysis for fatigue crack growth was performed for both software based on Paris's law as well as the crack orientation was determined using maximum circumferential stress theory. The simulation results obtained in this study using finite element method provide a good agreement with experimental results for all the case studies reviewed.
Research Paper
Stress Analysis
Mohammad Zadshakoyan; Saman Khalilpourazary; Seyed hamed Hoseini
Abstract
In recent decades, the industrial applications of refined grained pure copper and its alloys have been expanded. The properties such as high strength, high density and low deformability make these alloy more attractive. Hence, investigating the fracture mechanism of refined grained copper is of great ...
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In recent decades, the industrial applications of refined grained pure copper and its alloys have been expanded. The properties such as high strength, high density and low deformability make these alloy more attractive. Hence, investigating the fracture mechanism of refined grained copper is of great significance. In this study, the fracture analysis of copper was investigated using the equal channel angular pressing process. Experimental results on metal alloys have demonstrated that stress state should be incorporated in the constitutive equations. Therefore, the fracture process was analyzed here by focusing on its relationship with the Lode angel variable. To prepare the ECAPed specimens, a die set was manufactured and tensile strength tests were carried out on dog-bone and notched flat plate specimens up to fracture. In addition, the mean value of grain sizes of the copper specimens were evaluated. The results demonstrate that the grain refining process profoundly enhances the load carrying capacity of copper specimens. Moreover, the dog-bone tensile tests clearly show that the peak value of the strain hardening in refined grained copper occurs up to two passes and after two passes the strain hardening drops. Furthermore, the results reveal that the Lode angel variable have a significant influence on the failure of the refined grained copper specimens.
Research Paper
Manufacturing Processes
dastagiri mabbu -; srinivasa rao p; Madar valli p
Abstract
Electro Discharge Machining (EDM) is incredibly recognizable machining for ticklishness profiles in "difficult to machine" materials. In EDM, the material ejection of the cathode is cultivated through exact controlled electric pulse (the flash), which changes the metals of two terminals into dissolve ...
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Electro Discharge Machining (EDM) is incredibly recognizable machining for ticklishness profiles in "difficult to machine" materials. In EDM, the material ejection of the cathode is cultivated through exact controlled electric pulse (the flash), which changes the metals of two terminals into dissolve and vaporize, and because of the breakdown of the dielectric medium. The most commonly used dielectric media are kerosene, paraffin, glycerin, transformer oil, EDM oil .all these are derived from petroleum. these dielectric media undergo pyrolysis and carbon soot formation is deposited on work electrode, and sometimes carbon precipitates into work. To overcome these effects vegetable oils are tried as alternate dielectric media. Pongamia Pinnetta is abundantly available in most of the countries, it's cheaper and non-edible. Pongamia Pinnata (PP) oil is extracting from plant seeds, and that is blended with EDM oil and several experimentations are done to find the suitability. Operational variables with respect to input and output parameters are identified. some of these are best EWR, MRR, TWR, and SR with applied current (I), pulse on time (Ton), and pulse off time (Toff) are which are picked as the input process factors, because for industrial application many machinists are choosing these three are the input parameters and other is constant and pick under specific requirements only. After successful completion of this experimentations, Pongamia Pinnata oil blends are fit for the industrial application using TECHNIQUE OF ORDER PREFERANCING WITH SIMILAR TO IDEAL SOLUTION [TOPSIS], It is observed that no carbon soot formation in the work component with PP oil as the dielectric.
Research Paper
Fatigue
Liela Abbasiniyan; Seyed hamed Hoseini; Shirko faroughi
Abstract
In this paper, the crack propagation and branching in the pre-cracked and notched samples have been modeled using nonlocal peridynamic theory. The bond-based peridynamic model has been numerically implemented which make it possible to simulate the various features of dynamic brittle fracture such as ...
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In this paper, the crack propagation and branching in the pre-cracked and notched samples have been modeled using nonlocal peridynamic theory. The bond-based peridynamic model has been numerically implemented which make it possible to simulate the various features of dynamic brittle fracture such as crack propagation, asymmetries of crack paths and successive branching. The fracture simulation of thin plates made of a brittle material with different crack and notch patterns has been considered. The molecular dynamics open-source free LAMMPS code has been updated to implement the peridynamic theory based modeling tool for two-dimensional numerical analysis. The simulations show that, the simulations time significantly decreases which is the core and distracting deficiency of the peridynamic method. Moreover, the simulated results demonstrate the capability of peridynamic theory to precisely predict the crack propagation paths as well as crack branching during dynamic fracture process. The good agreement between simulation and experiments is achieved.
Research Paper
Stress Analysis
Sidda Reddy Bathini; Vijaya Vumar Reddy K
Abstract
This paper presents closed-form formulations of higher order shear deformation theory (HSDT) to analyse the functionally graded plates (FGPs) acted upon a thermo-mechanical load for simply supported (SS) conditions. This theory assumes nullity conditions for transverse stress on bottom and top face of ...
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This paper presents closed-form formulations of higher order shear deformation theory (HSDT) to analyse the functionally graded plates (FGPs) acted upon a thermo-mechanical load for simply supported (SS) conditions. This theory assumes nullity conditions for transverse stress on bottom and top face of the FGPs. Moreover, considers the influence of both stresses and strains in the axial and transversal direction. In these improvements an accurate parabolic variation is assumed in the thickness direction for transverse shear strains. Therefore, this theory omits the use of correction factor for accurately estimating the shear stress. The physical properties of the FGPs are considered to change along the thickness using a power law. The equilibrium relations and constriants on all edges are attained by considering the virtual work. Numerical evaluations are attained based on Navier’s approach. The exactness and consistency of the developed theory are ascertained with numerical results for deflections and stresses of SS FGPs and it is deemed that numerical solutions for thermo-mechanical load will utilize as a reference in the future.
Research Paper
Internal Combustion Engine
upendra Rajak; Prerana Nashine; Tikendra Nath Verma
Abstract
The unvarying condition diesel engines used for commercial applications, transportation and industries also lead to the crisis of petroleum fuel diminution and ecological squalor caused by due to exhaust gases. Therefore, in this paper optimize the use of MSB in naturally aspirated, direct injection ...
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The unvarying condition diesel engines used for commercial applications, transportation and industries also lead to the crisis of petroleum fuel diminution and ecological squalor caused by due to exhaust gases. Therefore, in this paper optimize the use of MSB in naturally aspirated, direct injection diesel engines, parameters of pure diesel (D100), 80% diesel + 20% microalgae spirulina (B20), 60% diesel + 40% microalgae spirulina (B40) and pure microalgae spirulina biodiesel (B100) were investigated at various fuel injection pressures (FIP) of 18 to 26 MPa and stationary injection timings (23.5° b TDC). The result shows that optimum effect can be obtained in 22 MPa FIP, with B20 bio-diesel without compromising the performance against diesel. B20 blend presented lesser NOX and smoke emissions by 13.7% and 22.2% respectively with no significant change in engine performance when compared to diesel at full load operating condition. The simulation and experiment results are verified at the same operating conditions.
Research Paper
Fluid Mechanics
A hassanvand; Mojtaba Saei Moghaddam; M. Barzegar Gerdroodbary; Y Amini
Abstract
Findings the solutions for heat and mass transfer problems is significant due to their applications in the science and engineering. In this study, Adomian decomposition method (ADM) is chosen as a robust analytical method for investigation of heat and mass transfer characteristics in a viscous fluid ...
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Findings the solutions for heat and mass transfer problems is significant due to their applications in the science and engineering. In this study, Adomian decomposition method (ADM) is chosen as a robust analytical method for investigation of heat and mass transfer characteristics in a viscous fluid which is squeezed between parallel plates. In order to ensure the validation of results, the obtained results of ADM method are compared with the numerical (Runge-Kutta method) results and reasonable agreement was observed. These comparisons confirm that Adomian decomposition method is a powerful and reliable approach for solving this problem. Then, diverse governing parameters namely; the squeeze number, Prandtl number, Eckert number, Schmidt number and the chemical reaction parameter are comprehensively studied. Our findings reveal that Sherwood number rises as Schmidt number and chemical reaction parameter increases while it declines with growths of the squeeze number. Likewise, it can be found that Nusselt number enhances with rise of Prandtl number and Eckert number and it decreases when the squeeze number increases.
Research Paper
Optimization
ehsanolah Assareh; Iman poultangari; Afshin ghanbarzadeh
Abstract
A common method utilized in wind turbines is pitch angle control whereby via varying the angle of wind turbine blades around their own axis, power generated at high speeds of wind is held around maximum amount and is kept away from the severe mechanical stress on wind turbine. In current study, in order ...
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A common method utilized in wind turbines is pitch angle control whereby via varying the angle of wind turbine blades around their own axis, power generated at high speeds of wind is held around maximum amount and is kept away from the severe mechanical stress on wind turbine. In current study, in order to control pitch angle, a control method based on using PI controller is suggested. Therefore, gains of the PI controller are regulated through combining the Firefly evolutionary algorithm and MLP neural network in such a way that the controller at its output sends a suitable controlling signal to the pitch actuator to set the pitch angle and so by varying the blades pitch angle suitably at high speeds of wind, the produced generator power remains around its nominal value. A wind turbine 5MW made by NREL (National Renewable Energy Laboratory) has been utilized based on FAST software code to simulate and analyze the results. The simulation results show that proposed method has a good performance.
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