eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2014-10-01
1
2
52
58
10.22055/jacm.2014.10742
10742
مقاله پژوهشی
Analytical bending solution of fully clamped orthotropic rectangular plates resting on elastic foundations by the finite integral transform method
Ali Mohammad Moniri Bidgoli
a.m.moniribidgoli@gmail.com
1
Ali Reza Daneshmehr
daneshmehr@ut.ac.ir
2
Reza Kolahchi
r.kolahchi@gmail.com
3
Faculty of Mechanical Engineering, College of Engineering, University of Tehran, iran
Faculty of Mechanical Engineering, College of Engineering, University of Tehran, iran
Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran
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.
http://jacm.scu.ac.ir/article_10742_bc489c50fbfe2c088c456d7d64466462.pdf
Analytical solution
Finite integral transform method
Foundation plate
Orthotropic rectangular plate
eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2014-10-01
1
2
59
66
10.22055/jacm.2014.10756
10756
مقاله پژوهشی
Solution of strongly nonlinear oscillator problem arising in Plasma Physics with Newton Harmonic Balance Method
Mohammad Mashinchi Joubari
mmmjouybari@gmail.com
1
Mohammad Hadi Pashaei
mpashaei@nit.ac.ir
2
Hamid Javaniyan Jouybari
hamidjavaniyan@gmail.com
3
Dept. of Mechanical Engineering, Babol University of Technology, Babol, Iran
Assistant Professor, Department of Mechanical Engineering, Babol University of Technology, , Babol, Iran
Department of Mechanical Engineering, Babol University of Technology, Semnan, Iran
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.
http://jacm.scu.ac.ir/article_10756_6f8b8c1cfe3c9151b95c25e04eb9ac5c.pdf
Electron beam
Frequency–Amplitude Relation
Plasma Physics
Newton Harmonic Balance Method
eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2014-10-01
1
2
67
73
10.22055/jacm.2014.10757
10757
مقاله پژوهشی
Design of an Adaptive-Neural Network Attitude Controller of a Satellite using Reaction Wheels
Abbas Ajorkar
ajorkar@aut.ac.ir
1
Alireza Fazlyab
afazlyab@aut.ac.ir
2
Farhad Fani saberi
f.sabery@aut.ac.ir
3
Mansour Kabganian
kabgan@aut.ac.ir
4
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran
Space Science and Technology Institute, Amirkabir University of Technology, Tehran, Iran
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran
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.
http://jacm.scu.ac.ir/article_10757_7f8e8e7b0d99e47d0538a0e83ddeabc0.pdf
Attitude Control
Adaptive-neural network control
Satellite
Reaction wheel
eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2014-10-01
1
2
74
82
10.22055/jacm.2014.10758
10758
مقاله پژوهشی
Numerical Investigation on Slot air Jet impingement Heat Transfer between Horizontal Concentric Circular Cylinders
Arash Azimi
azimi.arash84@gmail.com
1
Mehdi Ashjaee
ashjaee@ut.ac.ir
2
Morteza Khayat
mkhayat@srbiau.ac.ir
3
Department of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University, Tehran
Department of Mechanical Engineering, University of Tehran
Department of Mechanical and Aerospace Engineering, Science and Research Branch, Islamic Azad University, Tehran
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≤ Re<sub>j </sub>≤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.
http://jacm.scu.ac.ir/article_10758_c979b74cd4593bab37a0b3a9bedfc33d.pdf
heat transfer
Impingement cooling
Slot-jet
Concentric cylinders
eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2014-10-01
1
2
83
94
10.22055/jacm.2014.10766
10766
مقاله پژوهشی
Investigation the effects of injection pressure and compressibility and nozzle entry in diesel injector nozzle’s flow
Seyed mohammadjavad Zeidi
mohammadjavad 333 @gmail.com
1
Miralam Mahdi
m.mahdi@sru.ac.ir
2
Shahid Rajaee Teacher Training University (SRTTU) Lavizan, Tehran, Iran
Shahid Rajaee Teacher Training University (SRTTU) Lavizan, Tehran, Iran
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.
http://jacm.scu.ac.ir/article_10766_97cf0f69af67df7708e41045c937e6b5.pdf
Two phase flow
Mass flow rate
Nozzle entry
Cavitation
Singhal
eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2014-10-01
1
2
95
102
10.22055/jacm.2014.10755
10755
مقاله کوتاه
Optimizing Hydro Power Turbines in Order to Secure the Passage of Fishes in Khuzestan province
Moona Mohammadi
moona_mohammadi@yahoo.com
1
Ali Reza Mohammadi
aalirezamohammadi@gmail.com
2
Mohammad Reza Mohammadi
mhrz_mohammadi@yahoo.com.au
3
Master of Science at Mechanical Engineering, Khuzestan Water & Power Authority, Ahvaz, Iran
Master of Science at Mechanical Engineering, Turbine Machine M.E. Company, Ahvaz, Iran
Master of Science at Mechanical Engineering, National Iranian Gas Company, Boshehr, Iran
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.
http://jacm.scu.ac.ir/article_10755_93c421cc49733e4fa342ad1724636d38.pdf
hydro power turbine
fish-friendly turbine
optimization of hydro power turbine
eng
Shahid Chamran University of Ahvaz
Journal of Applied and Computational Mechanics
2383-4536
2383-4536
2014-09-05
1
2
103
111
10.22055/jacm.2014.10767
10767
مقاله کوتاه
An investigation the effects of geometric tolerances on the natural frequencies of rotating shafts
Ali Akbar Ansarifard
ali.ansarifard@yahoo.com
1
Abdolrahman Jaamialahmadi
jaami-a@um.ac.ir
2
Amirkabir University of Technology
Ferdowsi University of Mashhad
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.
http://jacm.scu.ac.ir/article_10767_2796b988223057e4b253771d39b47f67.pdf
Geometric tolerance
Natural frequency
critical rotational speed
rotating shafts
modal analysis