فهرست مطالب

نشریه بین المللی مهندسی صنایع و مدیریت تولید
سال نوزدهم شماره 3 (1387)

ویژه مهندسی مکانیک
114 صفحه،
تاریخ انتشار: 1387/10/20
تعداد عناوین: 11

فارسی
English

انتخاب همه

Study of pulsatile blood flow dynamic in stenosed vessels

S.M.R. Modares Razzavi, S.H. Seyedein, P. Bashi Shahabi Page 1

In this paper pulsatile laminar blood flow in an axisymmetric stenosed tube is simulated by the Non-Newtonian Power law model. Effect of stenosis, for severe condition of 75% reduction of local area was considered and the flow patterns for three Womersley numbers were studied. The results show that there is a fundamental difference in the flow pattern at. This difference is related to second co-rotating vortex which is observed downstream of stenosis at. The propagation of disturbance that leads to formation of this vortex is shown by wall shear stress surface at. Examining three flow patterns shows that the time that primary vortex forms on the distal face of stenosis is delayed with increasing Womersley number.

Abstract View Paper Original: Persian
TWO-DIMENSIONAL TEMPERATURE FIELD IN HOLLOW CYLINDER OF FINITE LENGTH WITH A PERIODIC EXTERNAL BOUNDARY CONDITION

Gh.A. Atefi, R. Ebrahimi Page 13

An exact study on temperature field in a hollow cylinder of finite length which is influenced by a surrounding with harmonic boundary condition is presented. To simulate an idealized situation, it is supposed that the cylinder is homogeneous and isotropic with physical properties independent of temperature and time. Here we impose a harmonic boundary condition on the external surface of the finite cylinder using Fourier analysis. The classical method of separation of variables and Duhamel’s theory is used to calculate the temperature field under periodic boundary condition. Numerical results reve the key effects of frequency of the surrounding temperature, Biot number and shell thickness on the amplitude ratio and phase difference of the cylinder temperature. The presented solution can lead to a better understanding of temperature behavior under harmonic boundary conditions. A limited case is considered and fair agreement with an available solution is obtained.

Abstract View Paper Original: Persian
LOCAL ACTIVE CONTROL OF VIBRATIONS OF A RECTANGULAR PLATE USING PIEZOELECTRIC PATCHES

M. Sharifnia, M. Rafieian Page 27

Active control vibrations of an arbitrary point of a simply supported rectangular plate is presented in this paper. The governing differential equation of plate with attached piezoelectric sensor/actuator patches, whose effects of mass and stiffness are included by the local functions, is solved at first. The response of the plate is computed using the first nine natural modes. Then, piezoelectric patches are attached about the point based on a special arrangement and possibility of vibration reduction of the local area of the plate without reducing the global vibration of the plate is discussed. Numerical examples with four and nine patches are discussed to contrast the present method. The results show the superiority of the present approach.

Abstract View Paper Original: Persian
LOCAL ORTHOGONAL COORDINATE SYSTEM FOR MODELING 2D CRACKS IN EXTENDED FINITE ELEMENT METHOD

A. Pourkamali Anaraki, M. Mirzaee Page 37

The extended finite element method (X-FEM) is a numerical method for modeling discontinuties, such as cracks, within the standard finite element framework. In X-FEM, special functions are added to the finite element approximation. For crack modeling in linear elasticity, appropriate functions are used for modeling discontinuties along the crack length and simulating the singularity in the crack tip element. As a result, the degrees of freedom (D.O.F.) for the nodes arround the crack tip and the crack length are increased, the so-called node-enrichment scheme. This virtual crack modeling, which is mesh independent, avoids the usage of refined mesh and singular elements arround the crack tip, and does not require remeshing during crack growth simulation. In this paper the principles of the X-FEM are described. A new method, based on the local orthogonal coordinate system, is proposed for the node-enrichment scheme. The development of a special-purpose computer code for modeling 2D cracks using the X-FEM and the new method is presented. The code and the new method are verified through the analyses of different standard cracked geometries.

Abstract View Paper Original: Persian
THE EFFECT OF EHD PHENOMENON ON CONTROL OF THE LAMINAR BOUNDARY LAYER ON CYLINDER BY TWO WIRE ELECTRODE AND TWO PLATE ELECTRODE FLASH MOUNTED ON THE CYLINDER SURFACE

Gholamreza Tathiri*, Esmaeel Esmaeelzadeh Page 51

One of the ways, to control of the drag forces applying to the circular cylinder in the air flow, is control of the generated boundary layer around the cylinder, and one of the new and effective ways for control of the boundary layer, is using high voltage electrostatic field in fluid flow. In these conditions, because of the coupled relations between electric field and momentum equations, the problem is complicated and discussed as electro-hydro-dynamic or EHD. For this purpose, the equation of conservation and momentum for flow field and conservation for electric density and Poisson's for electric field are solved with numerical and finite element method. In this research we used two wire and two plate electrode for generation electric field. By use of the results, we observed that the effect of electric field on fluid flow field is widely dependent on geometry of the electrodes and the intensity of the electric field. But in fact, by applying these forces, particles momentum and the velocity of them is increased. It was shown that increasing in Reynolds number, decrease these effects.

Abstract View Paper Original: Persian
ACTIVE CONTROL OF VIBRATIONS OF A RECTANGULAR PLATE USING FOURIER SERIES AND LAPLACE TRANSFORM

Mehdi Sharifnia, Mansour Rafeeyan Page 73

In this research, active control of vibrations of a simply supported rectangular plate is investigated by a new method. At first, differential equation of motion of a plate with piezoelectric patches is developed by means of classical plate theory in order to apply in this method, and a local function is used for applying the mass and stiffness effects. Then, natural frequencies and modeshapes of the plate with patches are obtained using Fourier series. A PID controller is designed and closed loop poles are calculated. Forced response of the system and mode shapes will be calculated using Laplace transform. The effect of PID on active control of plate is investigated simply for the first time. Some examples are presented to illustrate the validity of this method.

Abstract View Paper Original: Persian

علمی مصوب

توقف انتشار

نشریه بین المللی مهندسی صنایع و مدیریت تولید

International Journal of Industrial Engineering & Production Management

فصلنامه فنی مهندسی

آخرین شماره | آرشیو

ISSN: 2008-4870

انتشار این نشریه متوقف شده‌است.

صاحب امتیاز:

دانشگاه علم و صنعت ایران

مدیر مسئول:

دکتر تورج محمدی

سردبیر:

دکتر محمد سعیدی مهرآباد

تلفن نشریه: ۰۲۱-۷۷۲۰۹۰۷۱

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فهرست مطالب

نشریه بین المللی مهندسی صنایع و مدیریت تولید سال نوزدهم شماره 3 (1387)

نشریه بین المللی مهندسی صنایع و مدیریت تولید

International Journal of Industrial Engineering & Production Management

نشریه بین المللی مهندسی صنایع و مدیریت تولید
سال نوزدهم شماره 3 (1387)