فهرست مطالب

Iranian Journal of Mechanical Engineering Transactions of ISME
Volume:14 Issue: 1, Mar 2013

  • تاریخ انتشار: 1392/05/20
  • تعداد عناوین: 6
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  • Instruction for the Preparation of Camera-Ready Papers
    Pages 1-4
  • S. Gh. Moshir Stekhareh*, A. R. Mostofizadeh, N. Fouladi, A. Soleymani Pages 5-16
    An internal ballistics model has been developed for performance prediction of a solid propellant rocket motor. In this model a 1-D unsteady Euler equation with source terms is considered. The flow is assumed as a non-reacting mixture of perfect gases with space and time varying thermo physical properties. The governing equations in the combustion chamber are solved numerically by using the Steger and Warming flux vector splitting scheme. After validation of results by experimental data, the effect of grain geometrical variables and solid propellant characteristics are studied on performance characteristics of a standard internal burning cylindrical grain. These parameters include of negative /positive erosive burning, propellant characteristics, port to throat area ratio and initial temperature of the propellant. The results of developed model show that, propellant characteristics are dominant factors which affect performance characteristics. When erosive burning rate are considered, the 1-D internal ballistic analysis have good agreement with experimental data.
    Keywords: Ballistic, Solid Rocket motor, Unsteady, Euler, Grain
  • R. Bagheri, M. Ayatollahi*, O. Rahmani Pages 17-32
    The problem of several finite moving cracks in a functionally graded material is solved by dislocation technique under the condition of anti-plane deformation. By using the Fourier transform the stress fields are obtained for a functionally graded strip containing a screw dislocation. The stress components reveal the familiar Cauchy singularity at the location of dislocation. The solution is employed to derive integral equations for a strip weakened by several moving cracks. Numerical examples are provided to show the effects of material properties, the crack length and the speed of the crack propagating upon the stress intensity factor and strain energy density factor.
    Keywords: Crack propagation, Non, homogeneous orthotropic material, Dynamic stress intensity factor, Strain energy density factor
  • Y.Yassi* Pages 33-47
    Waterwheels are the oldest types of hydraulic machines. These turbines are of relatively simple design, large diameter, low rotational speed and high torques. But applying them as micro hydros of high speed and small diameter is yet to be explored. A micro hydro waterwheel of one meter diameter was designed and manufactured at the Iranian Researc†h Organization for Science and Technology (IROST) as a part of a joint research program between IROST and the Iranian Ministry of Power. The model turbine was then tested. Test results as standard turbine curves are also presented in this article. According to the results it was concluded that micro hydro waterwheels can operate efficiently at sites with high flow velocity.
    Keywords: Micro hydro turbine, waterwheel, high speed turbine, micro waterwheel, high speed waterwheel
  • A.Ghaffari *, A.R. Khodayari, S. Salehinia, M. Nouri, Khajavi, M.R. Arbab Tafti Pages 48-71
    The control of car following is essential due to its safety and its operational efficiency. For this purpose, this paper builds a model of car following behavior based on ARMAX structure from a real traffic dataset and design a Model Predictive Control (MPC) system. Based on the relative distance and relative acceleration of each instant, the MPC predicts the future behavior of the leader vehicle and according to this behavior, the acceleration of the follower vehicle is controlled. Validation of the presented controller is done by comparing the behavior of the controller with the human drivers. Results show that the MPC controller has a behavior much safer than that of real drivers and it can provide a pleasant trip for passengers.
    Keywords: ARMAX identification, model predictive control (MPC), Intelligent Transportation Systems, car following behavior, modeling, control
  • R. Amrollahipour *, M. Kadkhodaei, P. Kameli Pages 72-84
    Magnetic shape memory properties of Ni-Mn-Ga single crystals were characterized by measurement of stress-induced martensite reorientation under constant magnetic fields. Also magnetic field-induced strain as a function of the applied magnetic field under different constant compressive stress levels has been investigated. All the experiments were performed at room temperature in which the sample is in its martensite phase. Compressive stress and magnetic field were applied perpendicular to each other, and strain was measured along the compressive load axis. Magnetoelasticity, martensite reorientation, shape memory effect, and pseudoelasticity were observed throughout the experiments. Moreover, twinning stress and blocking stress were obtained.
    Keywords: Ni, Mn, Ga, Ferromagnetic shape memory alloy, Magnetic field, induced strain, Magnetic shape memory effect, Martensite reorientation