IFC
text
article
2017
per
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
0
0
http://mme.modares.ac.ir/article_16799_f8211c33248017d7ba8146d1da66966a.pdf
Calculation of diffusion coefficients in a normal tissue and tumor using the LevenbergMarquardt method
Pedram
Mirchi
دانشکده مکانیک خواجه نصیرالدین طوسی
author
Masoud
Zia Basharhagh
دانشیار، مهندسی مکانیک، دانشگاه صنعتی خواجه نصیرالدین طوسی ، تهران
author
Majid
Soltani
استادیار، مهندسی مکانیک، دانشگاه صنعتی خواجه نصیرالدین طوسی ، تهران
author
text
article
2017
per
In this paper, the diffusion coefficient in a normal tissue and tumor are to be estimated by the method of inverse problems. At the beginning, distribution of drug (with the assumption of uniform and isentropic diffusion coefficient) in the tissue is considered as the direct problem. In the direct problem, the governing equation is the convection–diffusion, which is the generalized form of fick’s law. Here, a source and a sink are defined; the source as the rate of solute transport per unit volume from blood vessels into the interstitial space and the sink as the rate of solute transport per unit volume from the interstitial space into lymph vessels are added to this equation. To solve the direct problem, the finite difference method has been considered. Additionally, the diffusion coefficient of a normal tissue and tumor will be approximated by parameter estimation method of LevenbergMarquardt. This method is based on minimizing the sum of squared errors which in the present study, considered error is the difference of the estimated concentration and the concentration measured by medical images (simulated numerically). Finally, the results obtained by LevenbergMarquardt method have provided an acceptable estimation of diffusion coefficient in normal tissue and tumor.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
1
8
http://mme.modares.ac.ir/article_16482_a9b8fcd45ff936ace6f42dd6e41010b7.pdf
Investigation of spontaneous curvature and membrane initial configuration on shape evolution of twocomponent vesicle
Mohammad Mahdi
Sahebifard
Department of Mechanical Engineering, Isfahan University of Technology
author
Alireza
Shahidi
دانشکده مهندسی مکانیک، دانشگاه صنعتی اصفهان
author
Saeed
ZiaeiRad
دانشکده مهندسی مکانیک، دانشگاه صنعتی اصفهان
author
text
article
2017
per
This article aims to study the effect of membrane initial configuration and the membrane spontaneous curvature (local asymmetry of layers) on the shape transformation of lipid bilayer vesicles. Since the evolutionary models are considered as a generalization to the equilibrium methods, the used model is developed based on the dynamic equilibrium between the membrane bending potential and the environmental fluid friction in each domain of twophase vesicle. The effect of membrane inertia on the dynamics of the system is ignored. Key parameters are the size of each phase and different combinations of protein distribution as the local spontaneous curvature. Assumed initial conditions are simple shapes such as dumbbell, biconcave and oblate that free vesicles are usually visible in these shapes. Previously published experimental observations are used to evaluate the numerical results. Some situations of homogeneous and multiphase vesicles and red blood cells under the influence of the spontaneous curvature induction mechanisms (for example the composition of the membranes, membrane proteins such as albumin, environmental solution concentration changes) are simulated and the results presented in details. The possibility of the membrane deformation and the relation of membrane phenomena with the primary form and various curvature distributions are discussed.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
9
16
http://mme.modares.ac.ir/article_16477_68285018cd90b1c144e474d2838fc9e7.pdf
The Assessment of Window Blinds effect on Conserving Energy Consumption of Office Building in Tehran
Masoome
Haghani
Art University of Tehran
author
Behrouz
Kari
Member of the Scientific Board  Head of Energy &amp; Environmental Design Department
author
Rima
Fayaz
هیات علمی دانشگاه هنر تهران
author
text
article
2017
per
Windows, as elements connecting built and natural environment, play an important role in providing internal comfort. During winter, solar heat gain through windows reduces heating demand, heating load and energy consumption of the building. On the other hand, it increases cooling load in summer. Hence, using blinds is common in office buildings to control solar radiation. Although using blinds prevents from entering part of the solar radiation, simultaneously, it improves comfort conditions for the employees. It should be mentioned that an appropriate control of blinds, regarding changes in external and internal environmental conditions, will lead to a decrease of energy consumption and discomfort caused by direct solar radiation. In this paper, the use of blinds on windows is simulated for cardinal orientations and different blind angles and positions; finally, the total thermal load of the space and the amount of glare is studied. According to the results, blinds have a significant impact on spaces total load, as well as reduction of interior glare compared to the reference case with no blinds.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
17
28
http://mme.modares.ac.ir/article_16479_dce0eaf98bf3401b3d5127692bf17dcb.pdf
Effect of magnetic field on natural convection heat transfer of nanofluid in wavy cavity with nonuniform temperature distribution
Alireza
Shahriari
دانشگاه زابل
author
text
article
2017
per
In the present paper, natural convection heat transfer of CuOwater nanofluid subjected to a uniform magnetic ﬁeld within an enclosed cavity considering of Brownian motion is studied by adopting the lattice Boltzmann Model. The left wavy wall is heated sinusoidal, while the right flat wall is maintained at the constant temperature of Tc. The top and the bottom horizontal walls are smooth and insulated against heat and mass. The variation of density is slight thus hydrodynamics and thermal ﬁelds equation are coupled using the Boussinesq approximation. The density and energy distribution are both solved by D2Q9 model. In this paper, the inﬂuence of pertinent parameters such as solid volume fraction of nanoparticles, Rayleigh number, Hartmann number and wavywall geometry parameters on ﬂow and heat transfer fields are investigated. Results show that the heat transfer increases with the increment of Rayleigh number and nanoparticles volume fraction, but it decreases by the increment of the Hartmann number. The enhancement of magnetic ﬁeld augments or plummets the effect produced by the presence of nanoparticles at different Rayleigh numbers. In addition, it is shown that for a fixed Rayleigh number and Hartmann number, the heat transfer performance depends on tuning the wavysurface geometry parameters. The greatest effect of nanoparticles is observed by considering the role of Brownian motion. This study can, provide useful insight for enhancing the convection heat transfer performance within enclosed cavities with wavywall surfaces and sinusoidal temperature distribution under influence of magnetic field.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
29
40
http://mme.modares.ac.ir/article_16481_1cbed5f7bac7510e1c2edef747c1eea5.pdf
Numerical Analyses of the Vortical Flow over the Cranked Kite Wing in Ground Proximity
Mohammad Javad
Bazrgar
کارشناس ارشد
author
Mojtaba
Dehghan Menshadi
دانشیار دانشگاه صنعتی مالک اشتر اصفهان
author
text
article
2017
per
In during takeoff and landing phases, flow structures and aerodynamics forces differ from the unbounded flow field. Computational fluid dynamics were used to study the flow field of a cranked kite wing with the focus on studying vortices treatment. Different Angles of attack and heights at free stream equal to 70 m/s were investigated at Mach number 0.2. Qcriteria shows that in ground effect, vortices treatment is at angles of attack 2° similar to 0° and angle of attack 8° similar to angles 4° and 6°.According to the topology of pressure gradient vectors at the angle of attack 2°, the center of all vortices in ground effect is fixed approximately. Axial residual vorticity, axial velocity and induced suction of all vortices increase and isosurfaces of Qcriteria become thicker. At the angle of attack 8° with height decreasing, axial residual vorticity of the primary vortex and the wing kink location vortex increase and decrease respectively. Also, the kink location vortex approach to the primary vortex and it takes away from the wing surface. At the angle of attack 8°, the coherent structure of vortex between leading edge and the kink location vortex breakdown in ground effect and recirculation bubble form on the wing surface. With height decreasing, the most drag and the lift coefficients increment occur on the lower surface.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
41
51
http://mme.modares.ac.ir/article_16484_36231995e9d2561ac2f4dcd9e2985e28.pdf
Experimental investigation of the effect of temperature in extrusion process of ECAPed nanostructured Titanium
Mohammad
Eftekhari
دانشگاه تهران
author
Ghader
Faraji
استادیار دانشگاه تهران
author
Omid
Shapoorgan
دانشگاه تهران
author
Majid
Baniassadi
دانشگاه تهران
author
text
article
2017
per
Todays, numerous researchers have focused on proposing severe plastic deformation (SPD) methods due to the superior mechanical and physical properties of achieved ultrafine grain material. In all SPD methods a large strain is implied without any substantial dimensional change of work piece to generate UFG and even nanograin (NG) materials. Equal Channel Angular Pressing (ECAP) is one of the most successful techniques for industrial applications. Using long and thin rod is limited in ECAP process. In the present study, a combined process composed of ECAP and Extrusion processes is used on Titanium of grade 2. Titanium is extensively used in aviation and other industries because of high strength to weight value. Using combined process leads to produce high length and thin nanostructured rod. The main goal of this process is evaluation of the temperature in Extrusion process on nanostructures Titanium rods. At first, Titanium rods were processed to 4 passes by ECAP process at 400°C Then they were processed by Extrusion process in 5 different temperatures included 300, 350, 400, 450 and 500°C. The result showed that the best mechanical properties were achieved for the specimen was extruded at 300°C. Strength and hardness were severely improved. Also, the microstructure was really homogenous and refine. The mechanical properties of titanium grade 2 after combined process were equivalent to titanium grade 5 which is used in medical applications and it is expensive.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
52
60
http://mme.modares.ac.ir/article_16486_742af9f93a6dd1588782566e4693ea8a.pdf
Application of CVN and 3point bending in determination of critical fracture toughness of 46E2 and 60E1 rails
Ahmad Reza
Ghasemi
دانشیار / دانشکده مهندسی مکانیک/ دانشگاه کاشان
author
Mohammad Ali
Moazam
دانشجوی دکتری
author
Mohammad
Honarpisheh
عضو هیات علمی
author
text
article
2017
per
Measurement of fracture toughness is one of the quality control parameter in rail manufacturing process. Fracture toughness value is needed for designing the rail lines, analysis of defects and other common prevalent works in mechanical engineering. The goal of this research is to introduce a relation for measuring fracture toughness of rail materials with grade R260 by Charpy Vnotch number. At first the fracture toughness of rail material has been determined by 3point bending technique according to ASTM E399 in ambient temperature. The fracture energies have been measured by Charpy impact test and it has been illustrated that fracture energies have no significant change in the tests temperature limit. Relations between the chemical analysis and mechanical properties have been studied and compared with results of the other researcher. Uniaxial tension test, analysis of chemical composite, metallography and hardness test have been carried out to better study of the process. Finally a relation to connect the Charpy Vnotch number and fracture toughness has been introduced and the fracture toughness of the rails material over the impact test temperature limit has been calculated. Good agreement between calculated results and result of 3pint bending test indicate appropriate accuracy of the introduced equation.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
61
66
http://mme.modares.ac.ir/article_16485_d9e47baa0edec49c679fa22d0ad76290.pdf
Modeling, optimal path planning and tracking control of a cable driven redundant parallel robot
Masoud
Ghanbari
دانشگاه صنعتی خواجه نصیرالدین طوسی
author
Mohamadreza
Moosavi
دانشگاه صنعتی خواجه نصیرالدین طوسی
author
Seyed Aliakbar
Moosavian
دانشگاه صنعتی خواجه نصیرالدین طوسی
author
Payam
Zarafshan
University of Tehran
author
text
article
2017
per
In this paper, dynamic modeling, optimal path planning and control scheme on a redundant parallel cable robot is presented. Path planning in parallel robots necessitates the consideration of robot’s kinematics to discern the singularities in the workspace. Also, dynamics analysis is required to consider actuation constraints. To this end, kinematics and dynamics of cable driven redundant parallel robot is derived. In this modeling, cables are assumed to be rigid with negligible mass and hence, tension and sagging along the cable are neglected. Next, a samplingbased algorithm upon rapidlyexploring random tree is developed to increase the convergence rate. In this scheme, distance, epochs and safety are considered as optimization constraints. To evaluate the performance of the proposed algorithm in collision avoidance, a number of obstacles have been considered too. Tracking of the planned path has been handled using a feedforward controller in the presence of obstacles. Regarding the redundancy feature of robot, a redundancy resolution scheme is considered for optimal force distribution. Path planning and control algorithms are implemented on the RoboCab (ARAS Lab.) and experimental results reveal the efficiency of the proposed schemes.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
67
77
http://mme.modares.ac.ir/article_16488_a2684ccd2b371892adb4460331badb0f.pdf
Investigation of the effective parameters on the mechanical and structural properties of aluminum wire sample fabricated by friction stir extrusion
Kamin
Tahmasbi
Department of Mechanical Engineering, Semnan University
author
Masoud
Mahmoodi
Assistant prof. Mechanical Engineering Department, Semnan Uni.
author
text
article
2017
per
Friction stir extrusion (FSE) is a process based on the heat generated by friction between die and materials in which a sample is produced through consolidation and extrusion of precursor materials such as metal chips. In this paper, the wire samples produced by friction extrusion of aluminum alloy AA7022 chips are investigated. The samples were extruded at different rotational speeds and extrusion forces, and impacts of these two parameters were studied. At first, structural properties of samples were studied using optical microscopy and scanning electron microscopy (SEM). The result showed that the samples produced at higher rotational speeds and lower forces had a far better surface quality and lower surface crack were seen on them. On the other hand, the temperature of process and grain size were increased with rise of rotational speed. The SEM micrographs showed that by changing rotational speed and extrusion force, the amount of adhesion and sintering between aluminum particles change and by optimizing these parameters can decrease wire’s internal defects and pits. In the following, to study mechanical properties, micro hardness and compression tests were used. The values of hardness and yield stress of samples were decreased with increasing rotational speed and increasing the extrusion force to a certain extent caused increase in yield stress of material.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
78
84
http://mme.modares.ac.ir/article_16489_2dee2b53ce15d7bf1e613dccbcadc6f1.pdf
A numerical investigation of Nusselt number and friction coefficient in an arctype Stirling engine heater
Hassan
Farzi
دانشجوی کارشناسی ارشد/دانشگاه خواجه نصیرالدین طوسی
author
Ali
Keshavarz Valian
دانشیار دانشگاه خواجه نصیر الدین طوسی
author
Alireza
Batooei
دانشجوی دکترا/دانشگاه صنعتی خواجه نصیرالدین طوسی
author
text
article
2017
per
The usages of stirling engine in many industry such as aerospace, submarines and combined heat and power systems, requires more and detailed analysis in such engines. This type of engine is an external combustion which may use almost any type of fuel. In this article the Nusselt number and friction coefficient of a Stirling engine heat exchanger is investigated numerically. The geometry of this heat exchanger is an arc shape pipe with reciprocating flow. Various parameters such as angular frequencies, type of fluids, working gas pressures, flow regime and heater geometry impact on the Nusselt number and friction coefficient of the heater were investigated. By increasing the angular frequency and the working gas pressure the Nusselt number increases but the friction coefficient decreases. The influences of different working fluids indicated that the Carbon dioxide has the highest Nusselt number. The results also show that the friction coefficient is highly dependent on the flow regime. The comparison between the two different geometry type heaters show that the arctype geometry led to higher Nusselt number. The friction coefficients of both geometries are almost similar to each other at high frequencies.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
85
91
http://mme.modares.ac.ir/article_16490_54bd2d797cb7d5bcf45d029052dbf282.pdf
Investigation of turbulent slot impinging jet using laser doppler anemometry method – Experimental research and error analysis
Mahmood
Charmiyan
دانشجوی دکتری
author
Ahmad Reza
Azimian
هیات علمی
author
Ebrahim
Shirani
هیات علمی
author
Fathi
Aloui
iهیات علمی
author
text
article
2017
per
In this paper, the results obtained from experimental measurements of average and turbulence quantities of a turbulent rectangular impinging jet hitting a fixed wall is reported using the laser doppler anemometry (LDA) method. The nozzle to plate distance is 10 times the nozzle width, and the tests are repeated for three different Reynolds numbers, namely Re=3000, 6000 and 9000. The aim of the current research was to investigate and comparise of flow in different Re and also to determine the two effective experimental errors on average velocities, namely data sampling and residence time in measurement volume. The results reveal that the previous stated correlation for prediction of the number of data required for ensuring independence of the average flow variables on the number of the sampled data is not sufficient by itself, and depending on the turbulence intensity of the flow, this correlation could become ineffective. Further, in the present study, the residence time is used for calculation of average velocities, and the results are compared with those obtained by particle image velocimetry (PIV) method. The comparison shows good agreement between the results from LDA and PIV when considering effect of residence time within the avaraging equations in the former method. The results show that the behavior and quantity of the dimensionless average velocities for various Reynolds numbers are identical at most cross sections of the flow domain while the dimensionless turbulent stresses have different quantities at different values of the Reynolds number.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
92
100
http://mme.modares.ac.ir/article_16501_bba43bd289871d7b93d0d8ea1d4911b5.pdf
The Mechanical interferencefree workspace of the planar parallel robots using geometric approach
Zolfa
Anvari
کارشناس، مهندسی رباتیک، دانشگاه صنعتی همدان، همدان، ایران
author
Payam
VarshoviJaghargh
استادیار، گروه مهندسی رباتیک، دانشگاه صنعتی همدان، همدان، ایران
author
Mehdi
Tale Masouleh
استادیار، دانشکده برق و کامپیوتر، آزمایشگاه تعامل انسان و ربات، دانشگاه تهران، تهران، ایران
author
text
article
2017
per
In spite of several advantages of parallel robots, they generally have limited workspace. Therefore, it is of paramount importance to obtain the workspace by considering the mechanical interference. In this paper, the mechanical interference in planar parallel mechanisms, including interference between links and, collision between links and obstacles and between endeffector and obstacles, are investigated using geometrical reasoning. For this purpose, a new geometric method is proposed for collision detection in the workspace of planar parallel mechanisms based on the lines segment intersection. In this method, the configurations of the planar parallel robot are obtained in the entire workspace. Then, the interference of links with each other and obstacles, which are respectively modeled by line segment and polygon, are determined. Finally, the collisionfree workspace of the parallel robot is obtained for a specified orientation of the moving platform. Moreover, in this paper, an index is presented which can be used for examining the workspace by considering mechanical interference. The foregoing index provides some insight into obtaining a wellconditioned workspace. For the sake of validation, this method is implemented on two planar parallel robots, namely as 3RRR and 3PRR, for different working modes. The obtained results reveal that the ratio of the practical workspace to the theoretical workspace is decreased upon increasing the orientation of the endeffector for both clockwise and counterclockwise directions. Furthermore, due to differences in the number of the moving links, the mechanical interferencefree workspace of 3RRR parallel robot is usually more limited than 3PRR parallel robot.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
101
110
http://mme.modares.ac.ir/article_16483_d0d0cab76b31460d231028e42769e67a.pdf
Reliability based topology optimization for maximizing stiffness and frequency simultaneously
Hamed
Mohammadzadeh
دانشگاه فردوسی مشهد
author
Mohammad Hossein
Abolbashari
دانشگاه فردوسی مشهد
author
text
article
2017
per
Reliability based Topology optimization (RBTO) is a process of determining of optimal design satisfying uncertainties of design variables. Sometimes frequency optimization might produce a design with low stiffness or stiffness optimization might lead to a design with low frequency. In this paper, the multiobjective optimization for both stiffness and frequencies isare presented. This article presents (RBTO) using bidirectional evolutionary structural optimization (BESO) with an improved filter scheme. A multiobjective topology optimization technique is implemented to simultaneously considering the stiffness and natural frequency. In order to compute reliability index the first order reliability method (FORM) and standard response surface method (SRSM) for generating limit state function is employed. To increase the efficiency of the solution process the reliability estimates areis coupled with the topology optimization process. Topology optimization is formulated as volume minimization problem with probabilistic displacement and frequency constraints. Young’s module, density, and external load are considered as uncertain variables. The topologies are obtained by (RBTO) are compared with that obtained by deterministic topology optimization (DTO). Results show that (RBTO) using (BESO) method is capable of the multiobjective optimization problem for stiffness and frequency effectively.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
111
116
http://mme.modares.ac.ir/article_16492_7876d83fc1d2c90be95051a9d566d67a.pdf
Combined radiativeconvective inverse design problem in a 2D channel filled with radiating gases
Mohammad
Omidpanah
دانشگاه شهید باهنر کرمان/دانشکده فنی و مهندسی
author
Seyed Abdolreza
Ganjalikhan Nasab
عضو هیئت علمی
author
text
article
2017
per
In this paper, an inverse analysis of combined radiation and convection heat transfer in a 2D rectangular duct is presented. The working fluid is a mixture of air including CO2 and H2O as two radiating gases. The purpose is to verify the effects of gas mole fractions on the solution of inverse design problem in which the conjugate gradient method is used to find the temperature distribution over the heater surface to satisfy the prescribed temperature and heat flux distributions over the design surface. The radiating gas is considered to be a gray participating medium with absorption, emission and isotropic scattering. The Planck mean absorption coefficient is calculated and used in radiative calculations. The discrete ordinates method is used to solve the radiative transfer equation. An attempt is made to determine the temperature distributions over the heater surface while the enclosure is filled with different mole fractions of CO2 and H2O. The effects of other parameters such as radiation conduction parameter on the solution of inverse problem is examined.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
117
124
http://mme.modares.ac.ir/article_16502_862309dbcb0c949a39b2e7f4100d1abb.pdf
Numerical simulation of thermal effects of continuous wave laser on living tissue with blood perfusion
Seyed Mohammad Ebrahim
Shah Amirian
دانشگاه تحصیلات تکمیلی صنعتی و فناوری پیشرفته
author
Khosro
Lari
دانشگاه تحصیلات تکمیلی صنعتی و فناوری پیشرفته
author
Hossein
Amiri
دانشگاه تحصیلات تکمیلی صنعتی و فناوری پیشرفته
author
text
article
2017
per
In the present work, the thermal effects of a CW laser on skin tissues with blood perfusion are simulated. For this purpose, a onedimensional medium is considered that is exposed to the laser beams from one side and the other side is at the constant temperature (37℃) because of being touched by other parts of the body. The laser beams are considered to be collimated and perpendicular to the surface of the tissue. The skin tissue is a strong anisotropic scattering medium and is assumed to be gray with black walls. Also, the blood perfusion is considered in the bioheat transfer equation of the skin tissue. The governing equations of this problem are radiative heat transfer coupled with conductive heat transfer that the discrete ordinates method, finite volume method and scaling method is used to solve the radiative transfer equation, the energy equation and to model the anisotropic scattering of the tissue, respectively. Validation of the model is performed by comparison with the other related works. Then, the effects of different optical and physical parameters of tissue such as conductionradiation parameter, scattering albedo, extinction coefficient, blood perfusion and the effects of laser power on the time of temperature increase of the tissue and thermal penetration depth are studied. It should be mentioned that the results of the present study show valuable guidance for understanding the coupled light and bioheat transport in tissues in therapy, surgery and diagnostic tasks.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
125
133
http://mme.modares.ac.ir/article_16503_b7b23ba2ed85109971ff5a32e6a78bbc.pdf
Nonlinear vibrations and stability analysis of a micro rotating shaft by considering the modified couple stress theory and micro inertia effect
Seyed Ali
Ghasabi
دانشجوی کارشناسی ارشد/ دانشگاه تربیت دبیر شهید رجایی
author
Majid
Shahgholi
استادیار/ دانشگاه تربیت دبیر شهید رجایی
author
Mohammad Reza
Arbab Tafti
استادیار/ دانشگاه تربیت دبیر شهید رجایی
author
text
article
2017
per
In this paper stability analysis of a nonlinear micro rotating shaft near the primary resonances by considering the modified couple stress theory and micro inertia effect is investigated. The geometric nonlinearities due to classical and nonclassical theory (the modified couple stress theory) are considered. Using Hamilton principle, the nonlinear equations of motion are obtained. In order to solve the equations of motion the multiple scales method are used and an analytical expression is presented for forward and backward frequencies which can be seen the effects of modified couple stress theory and micro inertia effect. The frequency response curves, amplitude versus damping coefficient, amplitude versus total eccentricities, etc. are reported. It is seen that due to the modified couple stress theory and micro inertia effect the amplitude of the system is decreased and the loci of bifurcation points is changed. Symmetrical microshaft in the presence of classical theory and without micro inertia effects becomes completely stable in the least damping coefficient and asymmetrical microshaft in the presence of classical theory and without micro inertia effects becomes completely stable in the most damping coefficient. Symmetrical microshaft in the presence of modified couple stress theory and with micro inertia effects becomes completely stable in the least total eccentricity and asymmetrical microshaft in the presence of classical theory and without micro inertia effects becomes completely stable in the most total eccentricity. So, considering the smallscale effects due to strain and velocity gradients for analysis of the system is mandatory.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
134
142
http://mme.modares.ac.ir/article_16504_05629bb6b530f9aec73857eba2a37961.pdf
Finite element simulation of selective laser melting process for fabrication of a sample part under various support conditions
Mehdi
Eynbeygui
Sharif University of Technology
author
Javad
Shahbazi karami
Shahid Rajaee Teacher Training University
author
Jamal
Arghavani
هیات علمی/ دانشگاه صنعتی شریف
author
text
article
2017
per
Additive manufacturing methods and/or 3D printing have become increasingly popular with a particular emphasis on methods used for metallic materials. Selective Laser Melting (SLM) process is one of the additive manufacturing methods for production of metallic parts. The method was developed in particular to process metal parts that need to be more than 99 percent dense. In this method, according to a predefined pattern, the top surface of the powder layer is scanned by the laser and a local (selective) melt pool is produced in the place of the laser spot which results in a fully dense layer after solidification. In this study, a semicoupled thermomechanical simulation of SLM process is carried out in ABAQUS finite element software. In order to simulate the moving heat flux and update material properties from the powder to the dense solid, the ability of the software for employing userdefined subroutines is employed. Investigation of the residual stress distribution and distortion of a part built using SLM process are the main objectives of this simulation. Results which are presented for two different mechanical boundary conditions show that when the bottom face of the layer is clamped, the top face of the built layer deforms in a concave shape, while the lateral faces of the layer have simplysupported boundary conditions and the bottom face of the layer is free, the part is warped.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
143
153
http://mme.modares.ac.ir/article_16505_628265f21f5ad4c8ca923d40ce2fb0ea.pdf
Effect of MicroChannel Wall Thickness and Diameter on Inlet Gas Temperature and Velocity under the Influence of Thermal Creeping
Behrooz
Behroozi
K. N. Toosi University of Technology
author
Majid
Ghasemi
استاد  دانشگاه صنعتی خواجه نصیرالدین طوسی
author
text
article
2017
per
With the development of micromechanical systems, human became interested in concentrating on the smallscale impact on the flow and heat transfer in microchannels. A microchannel is required for a gas sensor to guide the gas flow. Reducing the size of channel has lead the scientist to concentrate on microsensor. Metal oxide gas microsensors are used to detect gases such as O3, SO2, CO2, NO, NH3, CH4 and etc. Metal oxide gas microsensors are small in size, low cost in fabrication and consume little power. The purpose of the current study is to numerically investigate the microchannel wall thickness and diameter on gas inlet temperature under the influence of thermal creeping. The governing nonlinear differential equations, mass, momentum, energy, and species, are coupled and solved by a commercial code. The channel is assumed to be two dimensional. Since the Knudsen number is between 0.01 and 0.1, the slip boundary condition, Maxwell equation, is utilized. The result shows that as wall thickness increases the gas inlet temperature increases and temperature difference between gas inlet and outlet decreases. On the other hand as channel diameter decreases the gas inlet temperature increases.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
154
160
http://mme.modares.ac.ir/article_16506_330b7a55bf0b8971aa6406fe271dbf67.pdf
The investigation of the effects of Dimension’s and Mold’s Temperature on Bistability of PVC/Glass Fiber composites
Yusef
Oftadeh
دانشگاه تربیت مدرس
author
Mohammad
Golzar
دانشیار دانشگاه تربیت مدرس
author
text
article
2017
per
Nowadays, study on the bistable composites due to the using of them in morphing structure has become more and more important. Unidirectional composites have different thermal expansion coefficients in longitudinal and transverse directions. This difference in thermal expansion coefficient is caused the composites to bend like bimetals due to the raise in temperature and bistable composites are derived. In this research, in order to study effects of fabrication method the squareshaped bistable composites laminates with asymmetric layers were prepared and investigated. Different kinds of bistable composite laminates were fabricated by thermoplastic PVC and glass fibers and the effects of composites laminate's dimensions and mold's temperature were investigated. The maximum height of the bistable composite laminate is selected as the output of experiments. The results derived from ANOVA analysis showed that the dimensions of the laminates has the highest effects on bistability height and the effects of mold temperature are very low. It was also determined that with the larger dimensions of composite laminates and lower mold's temperature, the heights of bistability were higher. Also, these bistable composite laminate were simulated in ABAQUS and the simulation results were compared with the experimental results. The results indicated that simulation method anticipated the higher bistability height rather than the experimental results and the difference between these results are less than 10% in all specimens.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
161
167
http://mme.modares.ac.ir/article_16527_4822a7c0daa07a89e0bcf0f7ff0d4bc5.pdf
Numerical Modelling of Water Entrance into a Wet Tank Using a Modified Wave Propagation Algorithm
Sadegh
Moodi
M.Sc Student in Water Resources Engineering and Management/ University of Sistan and Baluchestan
author
Hossein
Mahdizadeh
Faculty member of Birjand University
author
Mehdi
Azhdary Moghaddam
Faculty member of Sistan and Baluchestan University
author
text
article
2017
per
Accurate investigation of physical phenomena is one of the important challenges in engineering fields. The present study is about a wet tank which entrance of water is investigated in three cases. When the water wave moves into a tank, complex flow regimes are created. This complexity is mainly associated with different flow mechanisms during the entrance of water and propagation of waves at the bottom bed that should be modelled by means of NavierStokes equations with freesurface capability and in 3D phase. Due to complexity and time consuming of NavierStokes equations modelling, Shallow water equations are used with the assumption of hydrostatic pressure. First case is about efflux over a wet bed. Second, water influx from the middle top is investigated and then influx from top edges is modelled. A dimensionless number is introduced for each case based on water velocity, gap length and drop height which shows acceptable domain for appropriate compatibility between results. Finally, results of numerical modelling are compared with NavierStokes solutions which are obtained from STARCD software. Results show admissible compatibility with each other based on observations and inspections.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
168
176
http://mme.modares.ac.ir/article_16528_1373d2413b1402494dd609e11c1348fc.pdf
Numerical modeling of air bubbles entrainment in liquid slug body at Horizaontal duct
Mostafa
Zeynalabedini
دانشجوی دکترا
author
Mohamadreza
Ansari

author
text
article
2017
per
Analysis of air bubbles entrainment in liquid slug body is one of the most important and complicated phenomena during slug flow regime. In the present attempt, a method is proposed for slug modeling to consider the air bubble entrainment into slug liquid body. The effect of consequencies and their impact on slug behaviour to predict more accurate correlations for slug parameters are estimated and calculated. This method considers a twofluid single pressure model, combined with population balance model for equal bubble diameter series and solves using volume of fluid. In this regard based on slug and hydraulic jump similarity, a correlation for air bubble entrainment rate and its mechanism selected. This correlation developed in the form of a user defined function code and coupled with other models in FLUENT solver to calculate slug flow. Finally the result of this numerical modeling is validated with the result of other numerical and experimental results where exist in the related literature. The result is consist of the slug flow profile, entrained air bubble profile and their diameter distribution, vortex at slug front, pressure distribution during slugging, slug mixture velocity, turbullent model parameters and etc.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
177
187
http://mme.modares.ac.ir/article_16533_77a89d48c068de5a9659fa396af4bad0.pdf
Investigating the nonlinear behavior and stability analysis of the automatic ball balancer by the multiple scales method
Mousa
Rezaee
Professor  University of Tabriz
author
Leila
Ghorbanpour
دانشجوی کارشناسی ارشد/ دانشگاه تبریز
author
text
article
2017
per
Unbalance in rotating machines causes malfunction of the system operation and it may leads to its failure. Therefore, the sources for imbalance should be investigated, identified, and measured to solve the mentioned challenges. Rotating unbalance appears when the geometric and the inertia axes of the rotor do not coincide, and as a result this causes self excited vibrations. One of the methods to control and reduce the unbalances is utilizing automatic ball balancer (ABB). In previous studies, the stability and the dynamic behavior of ABB have been mostly investigated by using numerical methods, and the perturbation methods are applied only for stability analysis. Because of the advantages of the analytical methods in studying the dynamics of the systems, in the present study, for the first time the dynamic behavior as well as the stability of a rotor equipped with an ABB is analyzed by the multiple scales method. To this end, nonlinear equations of the systems are derived using the Lagrange’s equations and firstly, the multiple scales method is applied to investigate the stability of system and then the response of the system is achieved considering one and two terms of approximation. The results demonstrate that the stability analysis using the multiple scales method and the first method of Lyapanov lead to the same results. Moreover, the responses obtained by the multiple scales method and the mostly used numerical method, RungKotta technique, are in a good agreement.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
188
198
http://mme.modares.ac.ir/article_16543_94fffb9c8bb2858d18ae96a269360d0b.pdf
Design and numerical analysis of Mach 3.0 inlet
Eman
Bandar Saheby
دانشگاه هوافضای نانجینگ ، نانجینگ چین
author
Ghader
Olyaei
دانشکده مهندسی هوافضا  دانشگاه صنعتی شریف
author
Azadeh
Kebriaee
دانشگاه صنعتی شریف، دانشکده هوافضا
author
text
article
2017
per
Planar inlet concepts play an important role in the design of supersonic propulsion systems. The inlet reduces the speed of supersonic flow by the oblique shock wave or an array of oblique shock waves and a final normal shock provides the subsonic flow after the throat of the diffuser. In this paper, a design method of Mach 3.0 supersonic multiramp inlet is explained, the geometry is designed and simulated by the numerical solver. Designing the inlets for the high supersonic Mach range, between 3 and 5 is very challenging because of the viscosity interactions and the related effects on the propulsive efficiency. The considered inlet in this study is a mixed system which provides the required compression by the combination of the three external ramps and a subsonic diffuser. A computational code calculated the optimum dimensions numerically and a second order CFD solver has simulated the inlet operations by the accuracy of 10E05. In addition to aerodynamic performance, Advantages and problems of such a combination, development of boundary layer and its interactions with the normal shock and performance of bleeding mechanism are simulated and studied. Finally, this paper presents compact details of design, simulation and viscosity effect of mixed compression surface.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
199
208
http://mme.modares.ac.ir/article_16534_b47d6b6d8fbea2eec76b4d946b3faab3.pdf
Gliding parachute platform design optimization with performance & stability Constraints
Mehran
Nosratolahi
دانشگاه صنعتی مالک اشتر
author
Mohammad
Adib Ghapanvary
دانشگاه مالک اشتر
author
text
article
2017
per
In this paper conceptual design and optimization of gliding parachute configuration are discussed. To this end, a design cycle is planned for conceptual design procedure and an optimizationbased design approach are established to provide an integrated design algorithm for gliding parachute platforms. The optimization problem is formulated with a cost minimization approach which is constrained by static stability and safe landing velocity as design criteria. The parachute configuration is defined with minimum required parameters and aerodynamics, stability and performance characteristics are provided based on a semianalytical approach. Hence, a computational software is incorporated with theoretical approximations to provide the required disciplinary data flow in the design cycle.The significant design parameters are verified by available wind tunnel test data.Optimization problem is solved using genetic algorithm method whereas constraints are handled by penalty function approach.Trim points are obtained like an allatonce approach through a simultaneous analysis and design algorithm. Finally, as a case study,optimized configuration is achieved for a real gliding parachute. Results show a fair estimation of parachute characteristics along with the reduction in manufacturing cost for new configuration up to 25%.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
209
216
http://mme.modares.ac.ir/article_16544_4cb63234f2648da9787685e5fe9c095e.pdf
Friction stir vibration welding and study about the effects of its parameters on microstructure and mechanical properties of Al5052 joint
Sajad
Fouladi
دانشگاه کاشان
author
Mahmoud
Abbasi
دانشگاه کاشان
author
Mohammad
Givi
دانشگاه کاشان
author
text
article
2017
per
Friction stir welding (FSW) is a solidstate joining process that leads to several advantages over fusion welding methods as problems associated with cooling from the liquid phase are avoided. In the current research, a new method is presented to improve the microstructure and mechanical properties of joint obtained using FSW. In this method, the joining workpieces are vibrated during FSW. The joining workpieces are fixed on fixture in a butt position and the fixture is vibrated mechanically normal to weld line through camshaft mechanism. The new method is described as friction stir vibration welding (FSVW) process. Microstructure and mechanical properties of welded specimens using FSW and FSVW processes are compared. The results show that weld region grain size of FSV welded specimen is lower than that in specimen welded by FSW for about 30% and the ultimate tensile strength of joint obtained using the former process is higher than that relating to the latter one for about 12%. This is attributed to more generation of dislocations and correspondingly enhanced dynamic recrystallization as vibration is applied. The results also indicate that the weld region grain size of FSV welded specimen increases and mechanical properties of joint decrease as tool rotation speed increases and traverse speed decreases. This is related to temperature increase during FSVW. It is concluded that FSVW is a proper candidate for FSW and its application is recommended for industries.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
217
224
http://mme.modares.ac.ir/article_16545_4c76c0e0b674c63424f8fe05ea43776d.pdf
Total site cogeneration and desalination system integration assessment using Rcurve
Mohsen
Salimi
دانشگاه خواجه نصیرالدین طوسی
author
Majid
Amidpour
استاد دانشگاه خواجه نصیرالدین طوسی
author
text
article
2017
per
In this study, the integration of multieffect desalination (MED) system with cogeneration of heat and power system has been considered. Lowpressure steam in two case studies has been utilized as the motive steam of MED system. Rcurve is a powerful tool that can be used to identify fuel utilization amount in different operation points of the cogeneration system. Rcurve explains utility system operation improvement procedure without capital cost. By deploying and development of the Rcurve concept, the freshwater demand of the total site and total annual cost of the site have been evaluated. These curves can be used as a tool to improve the operation and economic parameters in every operating point of cogeneration system and present comprehensive view about the improvement of utility system operation condition at each operating point. For the first time, Rcurve has been used to identify the impact of cogeneration system integration with a thermal desalination system on the cogeneration system operating point. The performance of the cogeneration system can be either enhanced or impaired by integration of desalination system. As demonstrated in a case study, integration of 2.2 MW MED system can either provide 52.765 MW energy saving or deprive 30.257 MW fuel energy based on the operating state of the cogeneration system before and after integration.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
225
236
http://mme.modares.ac.ir/article_16546_ddc02a7372ceb6a7fd18a5d809e34e97.pdf
Dynamic Modeling and Experimental Evaluation of the Power Loss of a Rotating System with the Angular Misalignment and Unbalancing Faults
Saeed
Ebrahimi
دانشیار گروه مهندسی مکانیک دانشگاه یزد
author
Mohammad Hadi
Ghodsi
دانشگاه یزد
author
Mansoor
Rafeeyan
دانشگاه یزد
author
text
article
2017
per
The problem of power loss in rotating machinery subjected to the angular misalignment and unbalancing faults are of great importance in relevant industries. Therefore, in this study, evaluation of the power loss and bearing forces of a typical couplingdiskshaft system with angular misalignment and unbalancing faults is conducted using a novel approach based on the multibody dynamics. In this concern, the flexible coupling is modeled by linear and torsional springdamper elements. After introducing the model, the kinematic constraints as well as the general form of EulerLagrange equations of motion are expressed. Then, the generalized forces are derived in detail. The equations of motion are then solved numerically by the 5th order RungeKutta method to evaluate the system power loss. In addition, the effect of angular misalignment and unbalancing faults on the disk displacements as well as the bearing forces are discussed. In the next part of this study, the theoretical results of the power loss are verified experimentally on a faulty simulator system. For measuring the power consumption, a digital power analyzer is used. The results of this research highlight clearly how the power loss is affected by increasing the amount of the system rotational velocity, the angle of misalignment, and the unbalance mass.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
237
246
http://mme.modares.ac.ir/article_16567_c4bb53a0a2b4cd8285cc3a05c58f6b4f.pdf
Analysis of effective parameters of auxetic composite structure made with multilayer orthogonal reinforcement by finite element method
Mohsen
Safikhani Nasim
دانشگاه حکیم سبزواری
author
Ehsan
Etemadi
hakim sabzevari university
author
text
article
2017
per
In this paper, the behavior of a new type of auxetic composite (composite with negative Poisson’s ratio) consisted of polyester fibers and ABS tubes as reinforcement as well as polyurethane foam as matrix was investigated by finite element method. Furthermore, the effect of negative Poisson’s ratio and mechanical properties of auxetic composite under quasistatic pressure were analyzed and the results were compared with the published experimental works. Good agreements were found between the results. Considering stressstrain diagram, it is concluded that this type of composite can operate as a damping material due to the specific properties such as high shear strength, indentation strength toughness. So, the foresaid properties make them a great choice with high potential application in various industries. Also, the ways to get the effective parameters to achieve more negative Poisson’s ratio were investigated. The parameters include the foam density as well as material, diameter and distances between ABS tubes. The results show that with decreasing foam density and decreasing distances between ABS tubes, the negative Poisson’s ratio increases at first to reach the critical value and then decreases.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
247
254
http://mme.modares.ac.ir/article_16568_92796ee08c41379d046c9c9f98522c17.pdf
Topology, shape and size optimization of 3 D tensegrity structures with specified number of members under external loads
Nastran
Gheisarieh
دانشجوی کارشناسی ارشد
author
Ali Asghar
Atai
دانشیار دانشگاه تهران
author
Masoud
Shariat Panahi
عضو هیئت علمی دانشکده مهندسی مکانیک دانشگاه تهران
author
text
article
2017
per
“Tensegrity” refers to a class of discrete structures with two force members (bars and cables) wherein bars only take tensile loads and cables only take compressive loads. The pre stressed members are interconnected so as to form a self equilibrium structure. Compared to a truss supporting the same external loading, a tensegrity structure has fewer members and could weigh less. Determining the stable topology (member connectivities), form (node coordinates) and size (cross sectional areas of members) of a tensegrity structure for weight minimization is a challenging task, as the governing equations are nonlinear and the conventional matrix analysis methods cannot be used. This article addresses the weight minimization of a class one tensegrity structure with a given number of bars and cables, anchored at certain nodes and supporting given load(s) at certain node(s). Member connectivities and their cross sectional areas and force densities are taken as design variables, whereas the members’ strength and buckling requirements and maximum nodal displacements constitute the constraints, along with the coordinates of the floating nodes to make the structure symmetric. Constraints are evaluated through the nonlinear shape design of the self equilibrium structure and the linear analysis of the loaded structure, assuming small displacements. Using a novel approach, optimization is simultaneously performed in multiple promising areas of the solution space, resulting in multiple, optimum solutions. The diversity of the solutions is demonstrated by applying the proposed approach to a number of structural design problem.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
255
266
http://mme.modares.ac.ir/article_16569_5e8563e84d9b0bacea9ca6470ce42a80.pdf
Development of CoarseGraining Methods for Modeling of Silicon Nanostructures
Hossein
Nejat Pishkenari
استادیار دانشگاه صنعتی شریف
author
Pourya
Delafrouz
دانشجوی دانشگاه شریف
author
text
article
2017
per
With the rapid progress of nanotechnology, application of nanoscale materials has been extensively increased. Due to increase of surface effects at small sizes, the classical theories are not capable of modeling nanoscale systems. On the other hand, more accurate methods at small sizes are based on the quantum and atomistic models which are too time consuming, and hence using these methods is limited to very small sizes for a short period of time. In this research coarsegraining models for accelerating molecular dynamics simulations for the analysis of silicon structures are proposed. In this technique, after assigning a proper map between beads of the coarsegrained model and atoms of the main structure, the system parameters are modified in a scheme that the original model and the coarsegrained models have the same physical properties. By using various static and dynamic simulations and evaluating the size effect, the accuracy and speed of the proposed model is examined. The error of this CG model for investigating the Young modulus, longitudinal and transversal vibration is less than 5 percent, while it is about 8 times faster than AA model.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
267
276
http://mme.modares.ac.ir/article_16570_af9de5e4bffba149939890ba516623eb.pdf
Numerical evaluation of engine performance and emission characteristics of rapeseed oil and its blends in diesel engines
Mohammad
Saeedan
دانشجوی کارشناسی ارشد دانشکده مهندسی مکانیک دانشگاه صنعتی شریف
author
Mohammad Hassan
Saeedi
مدیر قطب علمی تبدیل انرژی/ استاد دانشگاه صنعتی شریف
author
Hamid Reza
Fajri
کارشناس واحد احتراق شرکت تحقیقات موتور ایرانخودرو
author
text
article
2017
per
In this study, a numerical investigation of using Rapeseed Oil in National Diesel Engine has been developed and validated against the experimental data. By using validated model, the effect of injection timing, exhaust gas recirculation and initial pressure on performance and emissions of this engine with three different range of using diesel and biodiesel fuels have been investigated. Biodiesel fuel has two significant characteristics, existing Oxygen Atom in its structure and low lower heating value comparing diesel fuel. The results show by increasing biodiesel fuel, better combustion process has been achieved and consequently, increasing in thermal efficiency and reducing carbon monoxide emission have been observed. Because of different characteristics of biodiesel fuel, increasing and decreasing in the amount of this fuel can effect differently on engine power and producing nitrogen oxide emission.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
277
284
http://mme.modares.ac.ir/article_16571_d8f1024bafda13845cc65b9fe3fb1953.pdf
An experimental and simulation study of flow balance in multicavity plastic injection molds
Mehdi
Sadeghi
دانشکده مهندسی مکانیکدانشگاه صنعتی نوشیروانی بابل
author
Abbas
Zolfaghari
هیات علمی دانشگاه صنعتی بابل
author
Hamid
Baseri
هیات علمی دانشگاه صنعتی نوشیروانی بابل
author
text
article
2017
per
The main concern in designing of multicavity molds is flow balance between cavities. Any departure in flow balancing of the cavities can resulte difficulties in processing and quality of injected parts. In this paper, flow balance in a twocavity plastic injection mold with different sizes (or called familycavity mold) was investigated. Moldflow software was implemented to predict the filling phase through the cavities. Diameters of runners related to each cavity were adjusted to attain a balanced flow. Evaluating the flow balance was conducted by injection molding as shortshot and measuring the weight of each cavity. A high density polyethylene (HDPE) was applied as plastic material in this research. Good agreement was observed between experimental and simulation results. Moreover, in this paper one of the runners could be resized while injection molding via an insert located in the mold. The effect of flow balance on the tensile properties of the injection molded specimens was investigated. The results indicated that the parts obtained from the balanced mold exhibit a higher tensile strength and elongation at break up to 14% and 18%, respectively. The dimensions of injected parts were measured. It was found that there are not any differences between the shrinkage of specimens obtained by balanced and unbalanced mold.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
285
289
http://mme.modares.ac.ir/article_16572_1966f3a919f3228a2d43152055d86c88.pdf
Robust control of antilock braking system using optimized fast terminal sliding mode controller
Hamidreza
Moghaddam
Department of Electrical, Biomedical and Mechatronics Engineering, Islamic Azad University, Qazvin Branch
author
Hamed
Mojallali
دانشیار دانشگاه گیلان
author
text
article
2017
per
The antilock braking system is one of the main factors to make safety in designing vehicles. The brake pressure control and desired slip tracking through severe braking cause safety in vehicles. Because of uncertainty in parameters and sever nonlinear factors, robust controller designing is suitable for this system. In this paper the types of sliding mode controller have been used to achieve a vehicle desired slip and its stop. Sliding surface and terminal attractions will be analyzed in all of the designed controllers. Also a new structure with high terminal attraction have been for the fast terminal sliding mode controller (FTSMC). The proposed method has reduced tracking error as well. In this paper, the performance of this controller is compared with normal terminal sliding mode controller and fast terminal sliding mode. Also all design parameters are determined to decrease error ratio using particle swarm optimization (PSO) algorithm. This method is suitable for solving complex optimized solution based on certain cost function. Simulation results with using MATLAB software, present better performance of the suggested controller in comparison with normal and fast terminal sliding mode controller.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
290
298
http://mme.modares.ac.ir/article_16575_74211d08bc52722cce643c7c1f2e5a50.pdf
Study of electrohydraulic forming process by using experimental observations and numerical simulation with ALE method
Mehdi
Zohoor
University Faculty Member
KNT University of Technology
author
Seyed Meysam
Mousavi
دانشجوی دکترای دانشکده مهندسی مکانیک دانشگاه صنعتی خواجه نصیرالدین طوسی
author
Amin
Ashrafi Tafreshi
دانشجوی دکترای دانشکده مهندسی مکانیک دانشگاه صنعتی خواجه نصیرالدین طوسی
author
text
article
2017
per
Electrohydraulic forming (EHF) is a high velocity sheet metal forming process in which two or more electrodes are positioned in a water ﬁlled chamber and a highvoltage discharge between the electrodes generates a highpressure to form the sheet. In this study extensive experimental tests were carried out to investigate the effect of different parameters (such as discharge energy, stand off distance and electrodes gap) on the maximum drawing depth and implicit on shock wave maximal pressure in electrohydraulic free forming. EHF is a complex phenomenon and experimental work alone is not sufﬁcient to properly understand this process. To explain different aspects of the problem, Arbitrary Lagrangian Eulerian (ALE) formulations coupled with ﬂuid–structure interaction (FSI) algorithms that are available in the advanced ﬁnite element code LSDYNA were used to the numerical simulation. In order to model the effect of the electrical discharge, two different approaches were implemented; explosive equivalent mass and energy leak. In the first approach, According to the similarity between explosion and electrical discharge in the water, electrical discharge energy was converted to equivalent TNT mass. In the second approach electrodes gap is replaced by a plasma channel and electrical discharge energy was leaked to it in a short amount of time which makes the channel expand and generate shock waves propagating toward the workpiece .Finally, it was found a good correlation between the experimental and simulation results.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
299
306
http://mme.modares.ac.ir/article_16573_16d60f15288a5fe435649656e727d00e.pdf
Numerical simulation of micro/nano magnetic particles movement in bloodstream considering interaction of particles
Hesam
Ami ahmadi
دانشجو، آزمایشگاه تحقیقاتی بیومکاترونیک و مهندسی شناختی، مهندسی مکانیک، دانشگاه علم و صنعت ایران
author
Borhan
Beigzadeh
استادیار، آزمایشگاه تحقیقاتی بیومکاترونیک و مهندسی شناختی، مهندسی مکانیک، دانشگاه علم و صنعت ایران
author
text
article
2017
per
Controlling the path of drugs movement is one of the processes that can effectively help to treat a variety of diseases. For example, in chemotherapy, small fraction of drug is delivered to the cancer cells and other amounts cause destruction of healthy tissues of body, as a result, before destruction of tumors, the body will be destroyed. Hence we cannot remove tumors from body completely. If we are able to control the path of drugs, we could remove tumors with the least injury. One of the ways through which we can control the movement of the drugs is MDT. In this project, we inspect movement of magnetic particles in the blood and their interactions with consideration of constant magnetic field gradient. After governing its equations and presenting a good model for the forces between particles we simulate these processes in the fluent software. The model we used here is a vein with 8 mm diameter. The simulation was done over 8 cm length of the vein, and from the moment of injection. The base fluid is blood which is considered noneNewtonian fluid. Distribution of magnetic particles in the base fluid has been governed by multiphase approach. The simulation results show that residence time of drug in the presence of magnetic field, increases which in turn increases the possibility of drug absorption.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
307
314
http://mme.modares.ac.ir/article_16574_9d74e760e326460cb41e87fbacf3d550.pdf
The hybrid unscented /H∞ Kalman filter in state estimation of nonlinear problems
Mojtaba
Masoumnezhad
دانشکده شهید چمران دانشگاه فنی و حرفه ای
author
Mohammad
Tehrani
دانشجوی دکتری، مهندسی مکانیک، پردیس دانشگاهی، دانشگاه گیلان، رشت
author
Nader
Narimanzadeh
استاد، مهندسی مکانیک، دانشگاه گیلان، رشت
author
text
article
2017
per
The early success in the 1960s of the Kalman filter in aerospace applications led to attempts to apply it to more common industrial applications in the 1970s. However, these attempts quickly made it clear that a serious mismatch existed between the underlying assumptions of Kalman filters and industrial state estimation problems. Accurate system models and statistical nature of the noise processes are not as readily available for industrial problems. In this paper, a novel method of combining two nonlinear unscented Kalman filter and "H" _∞ unscented Kalman filter is presented so that the results are a compromise between in addition of more reliability compared to that of two other filters. One characteristic of this filter is no need to linearize of the nonlinear problems and gives more suitable results than other two filters with nonGaussian noise. Investigations show, when in a part of estimating the UKF is best and in the other part the UHF, the hybrid filter can give better results with present a compromise estimation. The variance analysis indicated that the filter is robust to statistical noise nature and a proper response can be found by changing its variable. Validation of results is performed by simulation of two nonlinear problems, free falling and inverted pendulum in mechanical engineering.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
315
321
http://mme.modares.ac.ir/article_16576_f3d44741459308d66971aa2f1448bd13.pdf
Influence of pre strain shape memory alloy wire on impact properties of smart fibers metal composite
Armin
Ramezani Parsa
دانشگاه صنعتی خواجه نصیرالدین طوسی
author
Reza
Esalmi Farsani
دانشگاه صنعتی خواجه نصیرالدین طوسی
author
text
article
2017
per
The fiber metal laminate composites a new generation of hybrid composites that have high strength to weight ratio. Good mechanical properties combining the properties of metals and fiber composites, led to the widespread use of composites in the industry, especially the aviation industry find. Add shape memory alloy to fiber metal laminate composite, due to super elasticity properties of alloy, makes the alloy formed during the impact hysteresis loop, will attract a lot of energy and impact properties of the fiber metal laminate composites increased. In this study, effects of different strains of nickeltitanium shape memory alloy wire high temperature, experimental in this type of composites against low speed impact using the impact falling, investigated. In metal part of fiber metal laminate composites, 2024T3 aluminum alloy sheet and in composite part of glass fibers and epoxy resin is used. 6 wires with the pre strains 1, 2 and 3% in order to wrapping in the fibers metal laminate composites, was used. Increase the impact resistance of such composites by increasing pre strain as well as the energy absorbed by the shape memory alloy when impact, the results of this research was.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
322
330
http://mme.modares.ac.ir/article_16604_0f7ce9cdbb8e92ba14c0c5e8b4f00092.pdf
Investigation of nonNewtonian fluid mixing in combined electroosmotic/pressure driven flows inside nonhomogeneous microchannel with rectangular obstacles
Alireza
Qaderi
دانشجوی کارشناسی ارشد / دانشگاه رازی
author
Jafar
Jamaati
هیات علمی / دانشگاه رازی
author
Masoud
Rahimi
هیات علمی / دانشگاه رازی
author
text
article
2017
per
In this article, mixing in the combined electroosmotic/pressure driven flows of nonNewtonian fluid in a microchannel with rectangular obstacles and nonhomogeneous ζpotential has been studied numerically. The nonNewtonian behavior of the fluid is considered for the flow field using power law rule. Also, the nonlinear PoissonBoltzmann equation is used to model the distribution of ions across the channel and the electric potential. Numerical solutions of coupled equations of momentum, electric field and concentration field are performed by means of finite element method. In this study, the effects of various parameters such as pressure gradient, rheological behavior of the fluid and the geometrical and physical parameters of obstacles on the mixing quality are investigated. The results indicate that applying adverse pressure gradient to the flow, the dilatant behavior of the fluid, as well as the height of barriers, are highly effective in the enhancement of the mixing quality within the microchannel. It is found that for microchannels with heterogeneous ζpotential, increasing the length of obstacles significantly increases the mixing efficiency while for the microchannels with homogeneous ζpotential, barrier length has a slight effect on mixing efficiency.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
331
340
http://mme.modares.ac.ir/article_16577_6368fa6242127df25a587770284be263.pdf
A Similarity Solution of the MHD Fluid over a Stretching Sheet: A Qualitative Investigation of the Surface with Constant Suction in Cooling Process
Esmail
Lakzian
Assistant Professor of Mechanical Engineering,
Hakim Sabzevari University
author
Maryam
Forozan
دانشگاه حکیم سبزواری
author
text
article
2017
per
In present study, the entropy analysis for laminar MHD flow over a stretching sheet with variable heat flux in presence of heat source and constant suction is done. The flow is influenced by uniform transverse magnetic field. The PDE governing differential equations including continuity, momentum, and energy are reduced to ODE ones by similarity solution. Then, the ODEs are solved by applying the 4thorder RungeKutta method. To validate, the result of this study and the published result are compared and the agreement is achieved. Bejan number is used as a design criterion parameter for a qualitative study about the cooling. The effects of suction parameter, heat source parameter, magnetic parameter, Prandtl number and heat flux parameter on dimensionless velocity and temperature, dimensionless entropy generation and Bejan number are shown in several plots. The results show that with increasing Prandtl number, suction, heat source parameter, magnetic parameters and parameters related to heat flux, the Bejan number is decreased, decreased, increased, decreased and decreased, respectively. The results of this research can be used for the increasing of the cooling in the surface in the coating.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
341
348
http://mme.modares.ac.ir/article_16578_96ee646cf33554cb44a5512d7b2d31f0.pdf
Evaluation of the slug twophase flow parameters in a horizontal twodimensional duct
Mostafa
Zeynalabedini
دانشجوی دوره دکتری
author
Mohamadreza
Ansari

author
text
article
2017
per
Slug flow is one the most complicated flow regime in industrial process that is seen for wide range of fluid flow. However, there are always some differences between experimental and numerical results obtained for slug flow. Proceeding the perivious attempt on the selection of the best turbulent model for numerical simulation, the slug flow is simulated numerically in two dimension by applying implicit VOF method and kε RNG turbulent model. To extract the slug flow parameters accurately FLUENT solver is used. The differences of the obtained results with and without turbulent model during slugging is also presented. To overcome this complicated flow behavior, a new user defined function code is developed. This UDF computes and predict slug parameters from FLUENT solver result without increasing the computational cost. The important slug parametrs are presented which are: liquid slug body velocity, liquid film velocity, slug front and tail velocity, slug center position and length, slug front and tail positions, pressure difference across slug, wall shear stress, slug mixture velocity, slug initiation time and position from the duct inlet. These parameters are analyzed and discused in details after that they had been validated
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
349
358
http://mme.modares.ac.ir/article_16579_b89eca5f92c72ed2baebc47fcdcafd99.pdf
Effects of various parameters on dynamic stall behavior and aerodynamic coefficients of a NACA0012 airfoil
Gholamreza
Abdizadeh
malek ashtar university of technology
author
Hamid
Ahmadvand
malek ashtar university of technology
author
Mohammad Mehdi
Jafari
MalekAshtar University of Technology
author
text
article
2017
per
Dynamic stal behavour of a NACA0012 airfoil undergoing pitching motion has been studied by a numerical approach. The turbulence intensity, oscillation frequency and amplitude and the Reynolds number were found to be the major contributors in dynamic stall. The flowfield structure and the associated vortices for this airfoil as well as the impact of the oscillation frequency on aerodynamic efficiency were also studied. The simulations were two dimensinal and the kω SST turbulence model were utilized for the present analysis. The results show that increasing the oscillation frequency and amplitude and the turbulence intensity, postpones the dynamic stall to higher angles of attack. Furthermore, as increasing the Reynolds number, both the lift coefficient and the width of the associated hysteresis loop decrease. The airfoil aerodynamic efficiency variation with oscillation frequncy has been shown to have a maximum point for all angles of attack considered. The flowfield structure revealed that the main cause of the dynamic stall is a series of low pressure vortices formed at the leading edge which shed into downstream and separate from the surface. A secondary vortex will then appear and increases the lift coefficient dramatically. The present simulation results are in a good agreement whith those found in the literature.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
359
368
http://mme.modares.ac.ir/article_16603_855c8c6c05a5b93f9e58b69684da76cd.pdf
Investigating courtyard and its design parameters for thermal performance and comfort in Tehran climate
Seyyed Mohammad Reza
Maleki
Master student, Department Of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran.
author
Behrooz
Mohammad Kari
Energy, Acoustic & Light Department Of Road, Housing & Urban Development Research Center(BHRC), Tehran, Iran
author
Mehdi
Maerefat
Department Of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran
author
text
article
2017
per
Courtyard has been recognized as one of main elements in the Iranian culture, architecture and building design. According to its microclimate effect in improving thermal performance of building, courtyard has been considered as a considerable subject for many researches. This paper investigates the courtyard’s design parameters and geometric configurations in predesign states for improving thermal performance and comfort. For achieving this point, in this research the influence of courtyard orientation, horizontal dimensions and other parameters related to geometry have been evaluated. Due to microclimate effect of courtyard on parameters related to thermal comfort, three main geometric layouts such as closed, semiclosed and open geometry have been investigated and compared by CFD simulations in ENVImet software. The thermal comfort parameters are also investigated through comparing mean PMV in all simulations cases, using Fanger’s extended model. The results showed that thermal performance of closed shaped courtyard is better than other layouts. Also the comparison of results related to different aspect ratios (length to width ratios), put into evidence that thermal performance improves as the aspect ratio gets close to 1. That means as the courtyard shape encloses to square, the thermal performance improves and the mean air temperature in the investigated microclimates declines. To determine best configuration for Tehran’s climate, the results showed northsouth orientation of building and increase of the height of the courtyard, are the two most appropriate considerations that will directly improve the thermal performance and comfort, specifically in closed and semiclosed layout.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
369
380
http://mme.modares.ac.ir/article_16605_fc19503dd47ad53ce6366bdb0312acfd.pdf
Vibroacoustic analysis of tire and rim finite element model coupled with fluid acoustic cavity
Amir
Karimyan
دانشجوی کارشناسی ارشد، مهندسی خودرو، دانشگاه علم و صنعت ایران، تهران
author
Salman
EbrahimiNejad Rafsanjani
Head of Vehicle Dynamic Systems Department, School of Automotive Engineering, Iran University of Science and Technology
author
text
article
2017
per
Vehicle vibration and noise characteristics play a major role in ride comfort. Noise of tire in contact with the road is one of the main sources of noise in passenger cars, caused by the rolling of tire on uneven surfaces. Excitation imports through tread structure to fluid cavity and noise and vibrations transmission to the rims is of particular importance. In this paper, vibration analysis of coupled acoustic model of tire, rim and fluid acoustic cavity is performed. For this purpose, a coupled numerical finite element model is used. First, tire modeling has been addressed, taking into account the tread and two side walls and steel wheel rim. Then modal analysis has been performed to identify the structural and acoustic resonance frequencies and mode shapes. Then, using the harmonic environment coupled with static and modal analyses, acoustically coupled models of tire, rim and cavity are used to calculate the acoustic pressure of the fluid cavity, and sound pressure level, and the harmonic frequency response of the wheel hub system including the forces of wheel hub is discussed. According to the presented model, the parameters affecting tire noise levels are discussed.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
381
392
http://mme.modares.ac.ir/article_16606_937d93eb7acfbdd729c4e64eb0c03fd3.pdf
Static analysis of transversely anisotropic laminates using improved zigzag theory subjected to sinusoidal load
Mehran
Ghalami Choobar
دانشجوی دکتری
تربیت مدرس
author
Gholam Hossein
Lighat
عضو هیٍئت علمی دانشکدهی مهندسی مکانیک
author
Mojtaba
Sedighi
عضو هیئت علمی دانشکدهی مهندسی مکانیک
author
Hamed
Ahmadi
عضو هیئت علمی دانشکده مهندسی مکانیک
author
text
article
2017
per
In this paper, static analysis of transversely anisotropic laminate is investigated using improved zigzag theory. Variation of inplane displacement is assumed to be sinusoidal while transverse displacement is assumed to remains constant through the thickness. This piecewise continuous sinusoidal function satisfies transverse shear stresses continuity in interfaces. The Hamilton principle is utilized to derive governing equations and related boundary conditions. The Naviertype solution is presented for simplysupported boundary conditions. The theory has the same unknown variable field as Euler Bernoulli beam although it predicts stresses high accurately. The validity of solutions is confirmed by comparing present model results with that of reported in the literature. Numerical results are given to study the influences the transverse anisotropy on displacement, strain and stress fields through the thickness. The piecewise continuous sinusoidal function offers more accurate transverse stress distribution in comparison with the piecewise polynomial function. The present theory provide more slightly accurate stress field through the thickness compared to high order shear deformation theory, which in turn is more accurate than EulerBernouli theory. The results shows the continuity of normal strain through thickness predicted by EulerBernouli theory has not physical basis. Furthermore, the improved zigzag theory is capable of capturing precise stress field through the thickness in transversely anisotropic laminate
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
393
398
http://mme.modares.ac.ir/article_16607_c07f6de5f3b9ea97585d2e1f117459dc.pdf
Investigation of Dynamic Heel Height Effect of Shoe on Joints of Lower Body during Walking
Ali
Mokhtarian
Member of faculty of mechanical engineering department of Islamic Azad university, Khomeinishahr
author
Mohammad Taghi
Karimi
عضو هیأت علمی دانشکده توانبخشی دانشگاه علوم پزشکی شیراز
author
Azam
Karimi
فارغ التحصیل کارشناسی ارشد مهندسی مکانیک گرایش طراحی کاریردی دانشگاه اسلامی آزاد واحد خمینی شهر
author
text
article
2017
per
The aim of this research is to dynamically investigate the effect of highheel shoes on the amount of internal forces and torques produced in the lower body joints (hip, knee, and ankle joints) during walking. To do so, the gait analysis of the subject, in two states of walking barefoot and with highheel shoes, has been conducted in a Musculoskeletal Research Center and then the required kinematic data including rotation matrices, angular velocity and angular acceleration of lower legs using kinematic analysis of legs have been derived. Also, the ground reaction forces have been measured using a force plate installed in the lab and by presenting a 3D dynamic model of lower legs and solving the inverse dynamic problem of model, forces and moments of the joints for two above modes during stance phase of a gait cycle have been calculated. Based on obtained results from investigation of dynamic effect of highheel shoes during walking, variations of internal joint forces have not been salient. However, internal joint moments in state of gait with highheel shoes respect to barefoot walking, have been had considerable increase. According to the results, longterm wear of highheel shoes can lead to damage of lower body joints, especially the knee joint, as well as driving muscles of these joints.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
399
409
http://mme.modares.ac.ir/article_16608_9800207287be2340ff09db39a6395f6c.pdf
Cladding of Carbon Steel with Aluminum Stainless Layer Using Friction Stir Welding Method
Ali
Zohrehvand
دانشجوی کارشناسی ارشد، دانشکده مهندسی مکانیک، پردیس دانشکدههای فنی، دانشگاه تهران، تهران
author
Mohammadreza
Farahani
Assistant Professor,School of Mechanical Engineering, College of Engineering, University of Tehran
author
text
article
2017
per
Cladding on metallic products is really applicable in industries e.g. aerospace, automotive and oil. One layer cladding on metallic specimens could improve mechanical, thermal and corrosion resistance properties by far. Nowadays carbon steels have the highest share of metallic materials among different industries. One layer cladding on this type of steels with the aim of enhancing the corrosion resistance could decrease the price of them when they put into use in different conditions. In this study, for the first time, cladding of the carbon steel by 6061T6 Al alloy via Friction Stir carried out successfully. In order to control on cladding, the effect of different rotational speeds and traverse speeds on mechanical properties and structure of cladded layer was inspected. Results of shear test showed that by increasing the traverse speed the shear strength of the cladded layer increases due to add material into the joint area uniformly. By decreasing the rotational speed and increasing the traverse speed, the generated heat from friction decreases and prevents overstirring in joint area and as a result the shear strength of the joint will increase.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
410
418
http://mme.modares.ac.ir/article_16615_6c6f3142a254a841cb7177bec8166502.pdf
Numerical simulation of free convection around a stationary cylinder with constant heat flux and different diagonal locations using IBLBM
Javad
Rahman Nezhad
دانشجوی دکتری/ دانشگاه بیرجند
author
Seyed Ali
Mirbozorgi
birjand uni
author
text
article
2017
per
In this paper, a new immersed boundarylattice Boltzmann method (IBLBM) is developed to simulate heat transfer problems with constant heat flux boundary condition. In this method, the noslip boundary condition is enforced via implicit velocity correction method and the constant heat flux boundary condition is implied considering the difference between the desired heat flux and the estimated one. The velocity correction represented as a forcing term is added to Boltzmann equation and for temperature correction, a heat source/sink term is introduced to energy equation. Elimination of sophisticated grid generation process, simplicity and effectiveness while keeping the accuracy, are the main advantages of the proposed method. Using the developed method, natural convection around a hot circular cylinder with constant heat flux in an enclosure with cold walls has been simulated at Rayleigh numbers of 103–106. Moreover, effects of diagonal position of cylinder on the flow and heat transfer patterns and local Nusselt number distribution on the surface of cylinder and walls of enclosure have been investigated. The obtained results show that the location of maximum local Nusset number is extremely depended on the diagonal position of the cylinder. According to the results of this simulation, it can be said that the present method is able to imply accurately the constant heat flux boundary condition.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
419
430
http://mme.modares.ac.ir/article_16609_5718f07f8c63491437eb4785e9db01d5.pdf
Numerical Investigation of Lateral jet interaction effects on aerodynamic behavior of a supersonic projectile
Mohammad
Bozorgian
Malek Ashtar University of Technology
author
Mustafa Hadi
Dolabi
Malek Ashtar University of Technology
author
Abbas
Tarabi
استادیار/دانشگاه صنعتی مالک اشتر
author
text
article
2017
per
Lateral jet control systems are being considered as attractive alternatives to conventional control systems in recent years. In present study which is divided in two parts, the effects of lateral jet interaction with supersonic cross flow on aerodynamic behavior of a standard projectile at zero angle of attack has been studied. In the first part, results of the effects of parameters such as jet location, Mach number and nozzle type on pressure coefficient, drag coefficient, drag force and pressure distribution on the fins is presented and analyzed. In the second part, longitudinal static and dynamic stability coefficients of the projectile in presence of lateral jet has been achieved and evaluated according to the mentioned parameters. According to the results, jet location is the most effective parameter. In the first part, the pressure distribution on the fins is much dependent on jet location. Effect of Mach number on pressure coefficient, drag force and drag coefficient is also significant. Besides change of the pressure distribution on the fins comes more into sight at the final locations by variation of Mach number. In the second part, lateral jet effect leads to decreasing longitudinal static stability. Increasing the Mach number is also results in decreasing longitudinal dynamic stability and jet displacement make nonlinear behavior over pitch damping moment coefficient, therefore choosing proper jet location is depend on desired parameters of designer. According to the results, effect of nozzle type has been insignificant for all cases.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
431
442
http://mme.modares.ac.ir/article_16610_0b47b306c38dd0fb5ce436e89ee2694a.pdf
Investigation of the effect of control unit on disruption to fault detection of vehicle active suspension system with hydraulic actuator
Mahdi
Shahab
دانشجوی دکتری دانشگاه فردوسی
author
Majid
Moavenian
هیات علمی دانشگاه فردوسی  گروه مکانیک
author
text
article
2017
per
Design of fault detection and diagnosis systems (FDDS), although extending the control strategies, they are challenged by controller interferences in fault diagnosis. In this study, in order to improve performance and accuracy of FDDS in the fault detection process, considering influential parameters and the level of corresponding interferences is investigated. To achieve this enterprise, a powerful method in fault pattern recognition of industrial plants based on dynamic behavior and dynamic model by using soft computing is designed and tested on simulated suspension system of a vehicle. The suspension system is one the parts, most affecting reliability and safety of the vehicle. For investigating the level of interference caused by the control unite, the simulations of both passive and active (equipped with hydraulic actuator) suspension systems are utilized in association with the control unite. The results of tests under variable circumstances (using random values) demonstrate that the presence of control unite, strict the FDDS process and reduces the robustness of the system against disturbances and noise. Considering the way in which the control unite affects the process, application of suggested solutions in this research, have a considerable impact on amendment of the adverse effects. Fault detection program which is provided by Matlab software benefits special possibilities to investigate and define the effect of controlling unite and can be considered as a useful device to facilitate and precipitate conduction of tests in different stages of the research.
Modares Mechanical Engineering
Tarbiat Modares University
10275940
17
v.
4
no.
2017
443
452
http://mme.modares.ac.ir/article_16611_0f376b9a2f938b444313f822a1cae31c.pdf