Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
1
2
2014
10
01
Analytical bending solution of fully clamped orthotropic rectangular plates resting on elastic foundations by the finite integral transform method
52
58
EN
Ali Mohammad
Moniri Bidgoli
Faculty of Mechanical Engineering, College of Engineering, University of Tehran, iran
a.m.moniribidgoli@gmail.com
Ali Reza
Daneshmehr
Faculty of Mechanical Engineering, College of Engineering, University of Tehran, iran
daneshmehr@ut.ac.ir
Reza
Kolahchi
Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran
r.kolahchi@gmail.com
10.22055/jacm.2014.10742
This study presents exact bending solution of fully clamped orthotropic rectangular plates subjected to arbitrary loads resting on elastic foundations, based on the finite integral transform method. In this method, it is not necessary to determine the deformation function because the basic governing equations of the classical plate theory for orthotropic plates have been used. A detailed parametric study is conducted to elucidate the influences of stiffness of elastic medium, plate length, flexural rigidities and distributed transverse load on the deflections. The applicability of the method is extensive since it can solve any plates with different loadings. Numerical results are presented to demonstrate the validity and accuracy of the approach, as it is totally in agreement with the other studies.
analytical solution,Finite integral transform method,Foundation plate,Orthotropic rectangular plate
http://jacm.scu.ac.ir/article_10742.html
http://jacm.scu.ac.ir/article_10742_bc489c50fbfe2c088c456d7d64466462.pdf
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
1
2
2014
10
01
Solution of strongly nonlinear oscillator problem arising in Plasma Physics with Newton Harmonic Balance Method
59
66
EN
Mohammad
Mehdi
Mashinchi Joubari
Dept. of Mechanical Engineering, Babol University of Technology, Babol, Iran
mmmjouybari@gmail.com
Mohammad Hadi
Pashaei
Assistant Professor, Department of Mechanical Engineering, Babol University of Technology, , Babol, Iran
mpashaei@nit.ac.ir
Hamid
Javaniyan Jouybari
Department of Mechanical Engineering, Babol University of Technology, Semnan, Iran
hamidjavaniyan@gmail.com
10.22055/jacm.2014.10756
In this paper, Newton Harmonic Balance Method (NHBM) is applied to obtain the analytical solution for an electron beam injected into a plasma tube where the magnetic field is cylindrical and increases towards the axis in inverse proportion to the radius. Periodic solution is analytically verified and consequently the relation between the Natural Frequency and the amplitude is obtained in an analytical form. A comparison of the period of the oscillation and obtained solution with the exact result illustrates that the NHBM is a powerful and efficient tool for solving nonlinear vibration equations.
Electron beam,Frequency–Amplitude Relation,Plasma Physics,Newton Harmonic Balance Method
http://jacm.scu.ac.ir/article_10756.html
http://jacm.scu.ac.ir/article_10756_6f8b8c1cfe3c9151b95c25e04eb9ac5c.pdf
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
1
2
2014
10
01
Design of an Adaptive-Neural Network Attitude Controller of a Satellite using Reaction Wheels
67
73
EN
Abbas
Ajorkar
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran
ajorkar@aut.ac.ir
Alireza
Fazlyab
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran
afazlyab@aut.ac.ir
Farhad
Fani saberi
Space Science and Technology Institute, Amirkabir University of Technology, Tehran, Iran
f.sabery@aut.ac.ir
Mansour
Kabganian
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran
kabgan@aut.ac.ir
10.22055/jacm.2014.10757
In this paper, an adaptive attitude control algorithm is developed based on neural network for a satellite using four reaction wheels in a tetrahedron configuration. Then, an attitude control based on feedback linearization control is designed and uncertainties in the moment of inertia matrix and disturbances torque have been considered. In order to eliminate the effect of these uncertainties, a multilayer neural network with back-propagation law is designed. In this structure, the parameters of the moment of inertia matrix and external disturbances are estimated and used in feedback linearization control law. Finally, the performance of the designed attitude controller is investigated by several simulations.
Attitude Control,Adaptive-neural network control,Satellite,Reaction wheel
http://jacm.scu.ac.ir/article_10757.html
http://jacm.scu.ac.ir/article_10757_7f8e8e7b0d99e47d0538a0e83ddeabc0.pdf
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
1
2
2014
10
01
Numerical Investigation on Slot air Jet impingement Heat Transfer between Horizontal Concentric Circular Cylinders
74
82
EN
Arash
Azimi
Department of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University, Tehran
azimi.arash84@gmail.com
Mehdi
Ashjaee
Department of Mechanical Engineering, University of Tehran
ashjaee@ut.ac.ir
Morteza
Khayat
Department of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University, Tehran
mkhayat@srbiau.ac.ir
10.22055/jacm.2014.10758
A numerical study has been carried out for slot air jet impingement cooling of horizontal concentric circular cylinders. The slot air jet is situated at the symmetry line of a horizontal cylinder along the gravity vector and impinges on the bottom of the outer cylinder which is designated as θ=0°. The outer cylinder is partially opened at the top with a width of W=30mm and is kept at constant temperature T= 62°C. The inner cylinder which is a part of the slot jet structure is chosen to be insulated. The effects of jet Reynolds number in the range of 100≤ Rej ≤1000 and the ratio of spacing between nozzle and outer cylinder surface to the jet width for H=4.2 and H=12.5 on the local and average Nusselt numbers are examined. In the numerical study, FLUENT CFD package is used and validated by comparing the results with the experimental data at the same Reynolds number. It is observed that the maximum Nusselt number occurs at the stagnation point at (θ=0°) and the local heat transfer coefficient decreases on the circumference of the cylinder with increase of θ as a result of thermal boundary layer thickness growth. Also, results show that the local and average heat transfer coefficients are raised by increasing the jet Reynolds number and by decreasing the nozzle-to-surface spacing.
heat transfer,Impingement cooling,Slot-jet,Concentric cylinders
http://jacm.scu.ac.ir/article_10758.html
http://jacm.scu.ac.ir/article_10758_c979b74cd4593bab37a0b3a9bedfc33d.pdf
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
1
2
2014
10
01
Investigation the effects of injection pressure and compressibility and nozzle entry in diesel injector nozzle’s flow
83
94
EN
Seyed mohammadjavad
Zeidi
Shahid Rajaee Teacher Training University (SRTTU) Lavizan, Tehran, Iran
mohammadjavad 333 @gmail.com
Miralam
Mahdi
0000-0003-4396-0039
Shahid Rajaee Teacher Training University (SRTTU) Lavizan, Tehran, Iran
m.mahdi@sru.ac.ir
10.22055/jacm.2014.10766
Investigating nozzle’s orifice flow is challenging both experimentally and theoretically. This paper focuses on simulating flow inside diesel injector nozzle via Ansys fluent v15. Validation is performed with experimental results from Winkhofler et al (2001). Several important parameters such as mass flow rate, velocity profiles and pressure profiles are used for this validation. Results include the effects of contraction inside nozzle’s orifice, effect of compressibility; effect of injection pressures and several orifice entries are also simulated in this study. To consider the effect of compressibility, a user defined function used in this simulation. The Cavitation model which is used in this simulation is Singhal et al. (2002) cavitation model. Presto discretization method is used for Pressure equation and second upwind discretization method is used for Momentum equation. Converging Singhal et al. cavitation model is very challenging and it needs several efforts and simulations.
Two phase flow,Mass flow rate,Nozzle entry,cavitation,Singhal
http://jacm.scu.ac.ir/article_10766.html
http://jacm.scu.ac.ir/article_10766_97cf0f69af67df7708e41045c937e6b5.pdf
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
1
2
2014
10
01
Optimizing Hydro Power Turbines in Order to Secure the Passage of Fishes in Khuzestan province
95
102
EN
Moona
Mohammadi
Master of Science at Mechanical Engineering, Khuzestan Water & Power Authority, Ahvaz, Iran
moona_mohammadi@yahoo.com
Ali Reza
Mohammadi
Master of Science at Mechanical Engineering, Turbine Machine M.E. Company, Ahvaz, Iran
aalirezamohammadi@gmail.com
Mohammad Reza
Mohammadi
Master of Science at Mechanical Engineering, National Iranian Gas Company, Boshehr, Iran
mhrz_mohammadi@yahoo.com.au
10.22055/jacm.2014.10755
Nowadays, it is important to consider environmental issues, as ecological problems and their severe effects are intensifying in Iran, particularly in Khuzestan province. The environmental effects of hydroelectric plants are highly regarded due to their significant impact on an extensive area. Lack of safe path for fish passing through the turbines is one of these damages. In order to deal with these challenges, researchers are trying to optimize hydro power turbines. In this optimization, old runners were replaced. Meanwhile, conditions of fish passing through the turbines and fish survival have been improved. Considering the existence of six hydroelectric power plants in Khuzestan province, it would be possible to conduct optimization or constructing studies with a fish-friendly approach for the safe passage of fishes to slightly reduce the extent of environmental damages.
hydro power turbine,fish-friendly turbine,optimization of hydro power turbine
http://jacm.scu.ac.ir/article_10755.html
http://jacm.scu.ac.ir/article_10755_93c421cc49733e4fa342ad1724636d38.pdf
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
1
2
2014
09
05
An investigation the effects of geometric tolerances on the natural frequencies of rotating shafts
103
111
EN
Ali Akbar
Ansarifard
Amirkabir University of Technology
ali.ansarifard@yahoo.com
Abdolrahman
Jaamialahmadi
Ferdowsi University of Mashhad
jaami-a@um.ac.ir
10.22055/jacm.2014.10767
This paper examines the effects of geometric tolerances on the natural frequencies of rotating shafts. In order to model the tolerances, a code is written in MATLAB 2013 that produces deviated points. Deviated points are controlled by different geometric tolerances, including cylindricity, total run-out and coaxiality tolerances. Final surfaces and models passing through the points are created using SolidWorks 2013 and finally modal analysis is carried out with FE software. It is observed whenever the natural frequency is higher or the geometric tolerances are greater, natural frequencies of the real and ideal shafts are more distant. Also, the difference percentage between ideal and real frequencies is investigated. The results show that the percentage value is approximately constant for every mode shapes.
Geometric tolerance,Natural frequency,critical rotational speed,rotating shafts,modal analysis
http://jacm.scu.ac.ir/article_10767.html
http://jacm.scu.ac.ir/article_10767_2796b988223057e4b253771d39b47f67.pdf