eng
Islamic Azad University Majlesi Branch
ADMT Journal
2252-0406
2383-4447
2018-09-27
11
3
1
9
668286
Original Article
Investigating the Performance of Coated Carbide Insert in Hard Steel Helical Milling
Navid Molla Ramezani
navidramezani87@yahoo.com
1
Behnam Davoodi
bdavoodi@iust.ac.ir
2
Mojtaba Rezaee Hajideh
mrhagideh68@gmail.com
3
School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran
Department of Mechanical Engineering, University of Tehran, Iran
Helical milling is an alternative hole-making machining process which presents several advantages when compared to conventional drilling. In the helical milling process, the tool proceeds a helical path while rotates around its own axis. Due to its flexible kinematics, low cutting forces, tool wear, and improved borehole quality may be achieved. In this study, a new helical milling process to create holes in hardened steel with a hardness of HRC 52 was used. Carbide inserts with PVD TiN coating were applied. Input parameters including cutting speed and feed rate were considered in 4 and 2 levels, respectively. In order to increase the reliability of the results, experiments were repeated 4 times and the total of 32 tests were performed. Other cutting parameters, such as axial and radial depth of cut were constant. Machining process was performed in dry state and without any lubricant. Output characteristics were tool wear, surface roughness, cutting force, machining time and material removal rate. Tool wear, surface roughness and forces, were measured by tool maker microscopy, roughness tester and dynamometer, respectively. The results showed that increasing the cutting speed on this type of hardened steel, decreases the surface roughness, machining forces and machining time. However, increasing the cutting speed and the feed rate enhances the tool wear and material removal rate considerably. Cutting speed and Feed rate of 50 m/min and 0.05 mm/tooth, offered the best mechanical properties of the Machining.
http://admt.iaumajlesi.ac.ir/article_668286_c7a0cedf221b8b90a5cb831687c2071b.pdf
Coated Carbide Tool
Hard Steel
Helical Milling
High Performance Machining
eng
Islamic Azad University Majlesi Branch
ADMT Journal
2252-0406
2383-4447
2018-09-01
11
3
11
24
668252
Original Article
Nonlinear Vibration Analysis of FG Nano-Beams in Thermal Environment and Resting on Nonlinear Foundation based on Nonlocal and Strain-Inertia Gradient Theory
Ebrahim Mahmoudpour
e.mahmoudpour@iaub.ac.ir
1
Department of Mechanical Engineering,
Islamic Azad University,Borujerd,Iran
In present research, nonlinear vibration of functionally graded nano-beams subjected to uniform temperature rise and resting on nonlinear foundation is comprehensively studied. The elastic center can be defined to remove stretching and bending couplings caused by the FG material variation. The small-size effect, playing essential role in the dynamical behavior of nano-beams, is considered here applying strain-inertia gradient and non-local elasticity theory. The governing partial differential equations have been derived based on the Euler-Bernoulli beam theory utilizing the von Karman strain-displacement relations. Subsequently, using the Galerkin method, the governing equations is reduced to a nonlinear ordinary differential equation. The closed form analytical solution of the nonlinear natural frequency is then established using the homotopy analysis method. <br /> Finally, the effects of different parameters such as length, nonlinear elastic foundation parameter, thermal loading, non-local parameter and gradient parameters are comprehensively investigated on the FG nano-beams vibration using homotopy analysis method. As the main results, it is observed that by increasing the non-local parameter, the frequency ratio for strain-inertia gradient theory has increasing trend while it has decreasing trend for non-local elasticity theory. Also, the nonlinear natural frequencies obtained using strain-inertia gradient theory are greater than the results of non-local elasticity and classical theory.
http://admt.iaumajlesi.ac.ir/article_668252_912b198b0cd00bbb60097fce7a034583.pdf
FG Nano-beam
Homotopy Analysis Method
Nonlinear Foundation
Strain-Inertia Gradient Theory
eng
Islamic Azad University Majlesi Branch
ADMT Journal
2252-0406
2383-4447
2018-09-10
11
3
25
34
668284
Original Article
Geometrical Effects of Duct on the Entropy Generation in the Laminar Forced Convection Separated Flow
Nasrin Aminzadeh
aminizadehn@gmail.com
1
Shima Sotoodehnia
shima.sotoodehnia@yahoo.com
2
Meysam Atashafrooz
m.atashafrooz@sirjantech.ac.ir
3
Department of Mechanical Engineering,
Sirjan University of Technology, Sirjan, Iran
Sirjan Branch. Islamic Azad University, Sirjan, Iran.
Department of Mechanical Engineering,
Sirjan University of Technology, Sirjan, Iran
In this research paper, irreversibility analysis of laminar forced convection flow in a duct with variable cross-section are numerically studied. Two-dimensional Cartesian coordinate system is used to solve the set of governing equations and also the blocked-off method is considered for simulation of the inclined surfaces. To obtain the velocity and temperature fields, the basic equations are numerically solved using the finite volume method and SIMPLE algorithm. To determine the flow irreversibility, the entropy generation number is calculated according to the thermodynamic second law. The geometrical effects of duct on the distributions of streamlines, friction coefficient, Nusselt number, entropy generation, and Bejan number are presented with details. The results show that the duct heights and inclination angle of surfaces have great effects on the flow irreversibility and the hydrodynamics and thermal behaviours. Also, comparison of the present numerical results with the available data published in the open literature shows an excellent consistency.
http://admt.iaumajlesi.ac.ir/article_668284_2e87c1888814ff6a94d8f12af9e2980d.pdf
Blocked-Off Method
Convection Heat Transfer
Entropy Generation
Flow Irreversibility
Variable Cross-Section
eng
Islamic Azad University Majlesi Branch
ADMT Journal
2252-0406
2383-4447
2018-09-10
11
3
35
44
668287
Original Article
Sensitivity Analysis for Optimal Design of Multibody Systems with Clearance Joint
Saeed Ebrahimi
ebrahimi@yazd.ac.ir
1
Esmaeil Salahshoor
esalahshoor@stu.yazd.ac.ir
2
Saeed Nouri
saeed_mech_engineering@yahoo.com
3
Department of Mechanical Engineering, Yazd University, Iran
Department of Mechanical Engineering, Yazd University, Iran
Department of Mechanical Engineering, Yazd University, Iran
This paper deals with the sensitivity analysis and optimization of system parameters for a classical slider-crank mechanism as a multibody system which includes a clearance between the joints of coupler and slider. Due to the nonlinearity involved in the dynamics of clearance joints, the base reaction force, exerted on the base from the crank, changes roughly and does not vary as smooth as the case of the mechanism with ideal joint. Variation of the base reaction force can be a measure of the undesired vibrations induced due to the effect of clearance joint. After deriving the equations of motion and modeling the clearance, the direct differentiation method is used to conduct a local sensitivity analysis to assess the sensitivity measure of the base reaction force on some kinematic and contact parameters. The results show that the reaction force is more sensitive to the variation of link lengths and link masses compared to the variation of contact surface characteristics such as Young’s modulus, restitution coefficient and contact generalized stiffness in most parts of the motion cycle. On the other hand, the sensitivity of the base reaction force to the clearance size is very higher than its sensitivity to the above-mentioned kinematic and contact properties. Finally, based on the results of the sensitivity analysis, an optimization procedure is used to reduce the amount of the maximum base reaction force by choosing the optimized link lengths.
http://admt.iaumajlesi.ac.ir/article_668287_5446f464b1826c95b0e03d8ed1371b54.pdf
Clearance Joint
Direct Differentiation
Momentum Exchange Approach
Optimization
Sensitivity analysis
eng
Islamic Azad University Majlesi Branch
ADMT Journal
2252-0406
2383-4447
2018-09-01
11
3
45
53
668248
Original Article
Evaluating the Effect of Operating Conditions on Temperature Variation Rate of Inner Walls and Inside Inflated Air of Pneumatic Tires
Moslem Namjoo
m.namjoo@shirazu.ac.ir
1
Hossein Golbakhshi
golbakhshi@ujiroft.ac.ir
2
Farhad Khoshnam
f_khoshnam@ujiroft.ac.ir
3
Ahmad Soleimani
a.soleimani@ujiroft.ac.ir
4
Department of Mechanical Engineering of Biosystems,
Faculty of Agricultural, University of Jiroft, 78671-61167, Iran.
Department of Mechanical Engineering,
Faculty of Engineering, University of Jiroft
Department of Mechanical Engineering of Biosystems,
Faculty of Agricultural, University of Jiroft, 78671-61167, Iran.
Department of Mechanical Engineering, Faculty of Engineering, University of Jiroft, 78671-61167, Iran.
For rolling pneumatic tires, the thermal induced effects are mainly resulted from visco-elastic behaviour of rubber parts and dissipation of stores strain energy during the cyclic deformations. It is noted that the operating conditions crucially contribute to the rubber hysteresis effect and temperature development in a rolling tire. In current study, an elaborated 3D FE model is worked up for simulating the certain inflation pressure, loading and velocity conditions for a specified radial tire. Special emphasis is given to transient temperature distribution of interior walls and tire cavities as critical zones. Compared with the experimental tests, the current study gives satisfactory results for time rate of change in temperature of tire walls and inside inflated air.
http://admt.iaumajlesi.ac.ir/article_668248_4663f5e79013075816a2a7078c5de427.pdf
Finite Element Method
Interior Temperature
Rolling Tire
Transient Thermal Analysis
eng
Islamic Azad University Majlesi Branch
ADMT Journal
2252-0406
2383-4447
2018-09-01
11
3
55
61
668288
Original Article
Thermal Optimization of an Array of Needle-Shaped using Constructal Theory
Maryam Hoseinzadeh
m72.9843@gmail.com
1
Afshin Ahmadi Nadooshan
ahmadi@eng.sku.ac.ir
2
Morteza Bayareh
m.bayareh@eng.sku.ac.ir
3
Department of Mechanical Engineering, Shahrekord University, Iran
Department of Mechanical Engineering, Shahrekord University, Iran
Department of Mechanical Engineering, Shahrekord University, Iran
In the present paper, the constructal theory is employed to determine the optimal configuration of three rows of needle-shaped fins. The heat transfer across the fins is due to laminar forced convection. Second order upwind scheme is used for discretization of the diffusion terms of governing equations. The pressure–velocity coupling is performed using the SIMPLE algorithm. The heat transfer is optimized subject to constant fin volume. The effect of Reynolds number and thermal conductivity on the optimal configuration is investigated. The results obtained from the present simulations are in good agreement with the numerical results. The results show that pin–fins flow structure leads to the best performance when the pin–fin diameters and heights are non-uniform. At Re = 100 and 200, the optimal value of is 1.3. It is revealed that at Re = 50, the optimal value for is approximately 1.1. The results demonstrate that heat transfer rate is an increasing function of the Reynolds number.
http://admt.iaumajlesi.ac.ir/article_668288_31f9aa01f080aa722230e14333bef431.pdf
Constructal Theory
Forced Convection
Needle-Shaped Fins
Optimization
Reynolds Number
eng
Islamic Azad University Majlesi Branch
ADMT Journal
2252-0406
2383-4447
2018-09-01
11
3
63
73
668282
Original Article
Investigating Cooling Effect with Compound Angle on the Combustion Chamber Wall Temperature
Mohamad Reza Nazari
nazarireza1369@gmail.com
1
Behrooz Shahriari
shahriari@mut-es.ac.ir
2
Farhad Sebghatollahi
farhadsebghatollahy@gmail.com
3
Department of Mechanical and Aerospace Engineering, Malek Ashtar University of Technology, shiraz, Iran
Department of Mechanical and Aerospace Engineering, Malek Ashtar University of Technology, 84145-115, Isfahan, Iran.
Department of Mechanical and Aerospace Engineering, Malek Ashtar University of Technology, 84145-115, Isfahan, Iran.
Increasing the temperature of the turbine entrance gases increases the efficiency of the gas turbine cycle. Under these conditions, the combustion chamber wall temperature also increases, while there is no high temperature resistance alloy fitted with air motors. Therefore, it is necessary to use cooling methods to reduce the wall temperature. In this study, the cooling effect with compound angles investigated on the combustion chamber wall temperature. The three-dimensional combustion chamber k-ɛ is modelled under the conditions of the input speed and the turbulence model in the ANSYS Fluent software. Inlet air is injected from the cooled holes to the mainstream with compound angle, where the cooling flow angle is constant with the 30° horizontally, and the lateral angle changes from Beta =0 up to Beta=60 degrees. The combustion chamber has two flat planes and two sloping plates, in which the arrangement of cooling holes is different. The results show that this method better distributes the cooling air on the wall surface and covers the space between the cooling holes, especially on flat plates. With this method, the number of cooling holes and the amount of air used to cooling can be reduced.
http://admt.iaumajlesi.ac.ir/article_668282_9c24b218984adb2431d8e76329421401.pdf
Combustion Chamber
Compound Angle
Film Cooling
Wall Temperature
eng
Islamic Azad University Majlesi Branch
ADMT Journal
2252-0406
2383-4447
2018-09-01
11
3
75
82
668289
Original Article
Pareto Optimum Design of Heat Exchangers based on the Imperialist Competitive Algorithm: A Case Study
Mohammadjavad Mahmoodabadi
mahmoodabadi@sirjantech.ac.ir
1
Soodeh Zarnegar
soodehz506@gmail.com
2
Department of Mechanical Engineering, Sirjan University of Technology, Sirjan, Iran
Department of Mechanical Engineering, Sirjan University of Technology, Sirjan, Iran
In this paper, the multi-objective optimum design of shell and tube heat exchangers is investigated. A thermal modelling of an industrial shell and tube heat exchanger is performed using an -NTU method for estimating the shell side heat transfer coefficient and pressure drop. The efficiency and total cost (includes the capital investment for the equipment and operating cost) are two important parameters in the design of heat exchangers. The fixed parameters and the ranges of the design variables are obtained from a shell and tube recovery heat exchanger in Barez tire production factory located in Kerman city, Iran. The Imperialist Competitive Algorithm (ICA) is used to find the optimal design parameters to achieve the maximum thermal efficiency and minimum consumption cost as the objective functions. The tube inside and outside diameters, tube length and the number of tubes are considered as four design variables. Furthermore, the effects of changing the values of the design variable on the objective functions are independently investigated. At the end, the obtained Pareto front and the related design variables and their corresponding objective functions are presented.
http://admt.iaumajlesi.ac.ir/article_668289_222dd244a5021e7a35b60c4456f92b8b.pdf
Imperialist Competitive Algorithm
Multi-Objective Optimization
Shell
Tube Heat Exchangers
eng
Islamic Azad University Majlesi Branch
ADMT Journal
2252-0406
2383-4447
2018-09-01
11
3
83
91
668250
Original Article
Thermal-hydraulic Analysis of Helical Coil Steam Generator of The Multi-Application Small Light Water Reactor (MASLWR) Test Loop Using Drift Flux Model
Mansour Talebi
mansour_talebi@yahoo.com
1
Valiyolah Ghazanfari
ghazanfari@yahoo.com
2
Nuclear Science & Technology Research Institute, Iran
Nuclear Science & Technology Research Institute, Iran
The Multi-Application Small Light Water Reactor (MASLWR) test loophas been built as a proof of concept for SMRs that is scaled down in size and has electric heater rods instead of a nuclear core. In this paper with using Drift-Flux Model (DFM), the thermal-hydraulic analysis of helical steam generator in MASLWR under steady-state conditions is simulated. This simulation is performed using the finite volume method. To ensure the accuracy and stability of solutions, User Defined Function (UDF) is written in C programming language. Distributions of velocities, local void fractions, temperature and pressure in the steam generator are calculated in different heights. To validate this simulation,the calculated primary side and secondary bulk fluid temperature are compared with experimental data. The experimental data have been provided by series of measurements of parameters of heat-transfer agent at Oregon State University. The calculated data are in good agreement with measured data and consequently the accuracy of this simulation is satisfied. Accuracy of the prediction shows that it is possible to use the DFM for thermal-hydraulic analysis in advanced models in nuclear power plant and other industries.
http://admt.iaumajlesi.ac.ir/article_668250_70cbb0ba4318d08fc8eff7833c48c7cd.pdf
Drift Flux Model
Helical Coil Steam Generator
MASLWR Reactor
Thermal–Hydraulic
eng
Islamic Azad University Majlesi Branch
ADMT Journal
2252-0406
2383-4447
2018-09-01
11
3
93
99
668285
Original Article
Dynamic Modelling and Control of a Dielectric Elastomer Actuator with Two Degrees of Freedom
Yaser Hesari
yhesary2006@gmail.com
1
Shahram Etemadi Haghighi
setemadi@gmail.com
2
Department of Mechanical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
Department of Mechanical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
Dielectric elastomer actuators are capable of creating multi degrees of freedom in a single joint. In this paper, a double-cone dielectric elastomer actuator is assumed as a planar joint with two degrees of freedom. Because of theoretical complexities, mathematical formulation of dynamic equations is too complicated. To obtain the dynamic equations of motion, at first, experimental charts are used. At this stage forms of relations between displacements, voltages, forces and moments are proposed, and coefficients are optimized to keep the difference between experimental and estimated charts in minimum. Then dynamic equations of motion are derived based on Newton-Euler method, and state-space form of equations of the joint are obtained. As a second objective, joint stabilization around working point is considered. To stabilize the joint against external loads, or initial dislocations, a regulator controller is designed. The joint is over actuated. So using constraint equations, control rule is extracted and simulated. Simulations show successful performance around the working point.
http://admt.iaumajlesi.ac.ir/article_668285_eb6aeaa60b0e6f7953551c947a45a27c.pdf
Dielectric elastomer actuator
Electro active cone membrane actuator
Lyapunov controller
eng
Islamic Azad University Majlesi Branch
ADMT Journal
2252-0406
2383-4447
2018-09-10
11
3
101
108
668290
Original Article
Optimal Swing up of Double Inverted Pendulum using Indirect Method
Maral Salehi
maralsalehi@semnan.ac.ir
1
Amin Nikoobin
anikoobin@semnan.ac.ir
2
Ebrahim Shahab
ebrahimshhb@yahoo.com
3
Faculty of Mathematics, Statistics and computer Science, Semnan University, Iran
Robotics and Control Lab, Faculty of Mechanical Engineering, Semnan University, Iran
Robotics and Control Lab, Faculty of Mechanical Engineering, Semnan University, Iran
In this paper, optimal swing up of a double inverted pendulum (DIP) with two underactuated degrees of freedom (DOFs) is solved using the indirect solution of optimal control problem. Unlike the direct method that leads to an approximate solution, the proposed indirect method results in an exact solution of the optimal control problem, but suffers from its limited convergence domain which makes it difficult to solve. In order to overcome this problem, an inversion-based method is used to obtain the required initial solution for the indirect method. In the proposed methodology, dynamic equations are derived for a general inverted pendulum using Euler-Lagrange formulation. Then the necessary optimality conditions are derived for a DIP on the cart using the Pontryagin’s maximum principle (PMP). The obtained equations establish a two-point boundary value problem (TPBVP) which solution results in optimal trajectories of the cart and pendulums. In order to demonstrate the applicability of the presented method, a simulation study is performed for a DIP. The simulation results confirm the superiority of the proposed method in terms of reduced effort.
http://admt.iaumajlesi.ac.ir/article_668290_3040ba0d45a450f12b0be63ec45cb4da.pdf
Boundary Value Problem
Inverted Pendulum
Optimal Swing up
Indirect Method