NONLINEAR POST-BUCKLING ANALYSIS OF ISOTROPIC PLATES BY USING FINITE STRIP METHODS

Seyyed Amir Mahdi Ghannadpour; H.R. Ovesy; M. Nassirnia

Volume 8, Issue 1 , March 2011, , Pages 11-19

Abstract
  ABSTRACT This paper presents the theoretical developments of two finite strip methods (i.e. semi-analytical and full-analytical) for the post-buckling analysis of isotropic plates. In the semi-analytical finite strip approach, all the displacements are postulated by the appropriate shape functions while ...  Read More

Aerospace Science and Technology
Improving the Reliability of GPS and GLONASS Navigation Solution in Urban Canyons using a Tuned Kalman Filter

Ali Khavari; S. Mohammad Reza Moosavi; Amir Tabatabaee; Hadi Shahriyar Shahhosseini

Volume 12, Issue 2 , October 2019, , Pages 11-18

Abstract
  Abstract: Urban canyon is categorized as hard environment for positioning of a dynamic vehicle due to low number and also bad configuration of in-view satellites. In this paper, a tuning procedure is proposed to adjust the important factors in Kalman Filter (KF) using Genetic Algorithm (GA). The authors ...  Read More

Aerospace Science and Technology
Model Reference Adaptive Control Using a New Adaptation Law Based on Power-Series Quadratic Lyapunov Functions for the Single Degree of Freedom Wing Rock Phenomenon

Jafar Roshanian; Ehsan Rahimzade

Volume 14, Issue 1 , June 2021, , Pages 11-29

https://doi.org/10.22034/jast.2021.132822

Abstract
  In this research, new adaptation law for updating parameters of the model reference adaptive control and the model reference adaptive control with feedback integrators for a specific class of nonlinear systems with additive parametric uncertainty are presented. The innovation presented in this paper ...  Read More

Aerospace Science and Technology
Guidelines on Conceptual and Preliminary Design of Hypersonic Waveriders with Different Number of Inlet Ramps

Mohammadreza Varshavi; Sahar Noori

Volume 17, Issue 1 , June 2024, , Pages 11-22

https://doi.org/10.22034/jast.2023.400869.1155

Abstract
  Air-breathing hypersonic flight is presumed by many of the savants in the field of aeronautical engineering as the last boundary of aerial vehicle design to be pushed back. An auspicious design configuration for the prospective hypersonic transport vehicles of the future is a “Waverider,” ...  Read More

Three Dimensional Stability Analysis of a Liquid Propellant Combustor

Mohammad Farshchi

Volume 4, Issue 2 , June 2007, , Pages 13-22

Abstract
  A theoretical study analyzing three-dimensional combustion acoustic instabilities in a liquid propellant rocket engine combustor has been conducted. A linear theory based on Crocco’s pressure sensitive time lag model is used. To apply this theory the combustor is divided into two main components, including ...  Read More

Maximum Allowable Dynamic Load of Flexible 2-Link Mobile Manipulators Using Finite Element Approach
Volume 4, Issue 3 , September 2007, , Pages 13-24

Abstract
  In this paper a general formulation for finding the maximum allowable dynamic load (MADL) of flexible link mobile manipulators is presented. The main constraints used for the algorithm presented are the actuator torque capacity and the limited error bound for the end-effector during motion on the given ...  Read More

Compressional Stability Behavior of Composite Plates with Multiple Through-the-Width Delaminations

H.R. Ovesy

Volume 5, Issue 1 , March 2008, , Pages 13-22

Abstract
  In this paper, the compressive behavior of composite laminates with multiple through-the-width delaminations is investigated analytically. The analytical method is based on the CLPT theory and its formulation is developed on the basis of the Rayleigh-Ritz approximation technique to analyze the buckling ...  Read More

A FAST MESH-FREE GALERKIN METHOD FOR THE ANALYSIS OF STEADY-STATE HEAT TRANSFER

S. Forouzan-sepehr; Soheil Dr. Mohammadi

Volume 6, Issue 1 , March 2009, , Pages 13-23

Abstract
  The element-free Galerkin method is employed for two-dimensional analysis of steady-state heat transfer. The unknown response of the system, i.e. temperature is approximated using the moving least squares technique. Numerical integration of governing simultaneous system of equations is performed by Gauss ...  Read More

A Parametric Study for Vibration Analysis of Composite Cylindrical Shell Resting under Elastic Foundation: Analytical and Numerical Methods

M. Noorabadi; N. Namdaran; M. Rahnama; Jafar Eskandari Jam

Volume 11, Issue 2 , October 2017, , Pages 13-22

Abstract
  The aim of this study is to investigatethe effective parameters on vibrations of circular cylindrical shells with fixed rotary speed andresting elastic foundation by means of analytical and finite element numerical simulation. First, the governing equations are derived using the theory of Donnell, considering ...  Read More

Aerospace Science and Technology
Designing the Nonlinear Guidance Law Adaptable to Initial Deviations for the Vertical Landing of the Booster

Morteza Sharafi; Nasser Rahbar; Ali Moharrampour; Abdorreza Kashaninia

Volume 15, Issue 1 , June 2022, , Pages 14-25

https://doi.org/10.22034/jast.2022.327899.1113

Abstract
  This study proposes a new non-linear guidance law for a Falcon 9 missile booster landing's terminal phase using a non-linear vectorized high expansion method. For this purpose, At first, the dynamic modeling of the landing problem is presented, assuming mass, gravity, and density are variables. Then, ...  Read More

An Experimental Investigation of the Effects of Canard Position on the Aerodynamic Forces of a Fighter Type Configuration Model

M. Manshadi; A. Sharafi; M.H. Soltani

Volume 9, Issue 2 , September 2012, , Pages 15-24

Abstract
  An extensive experimental investigation is conducted to study the effect of canard position relative to the fuselage reference line on the aerodynamic forces of a fighter type configuration model. Aerodynamic forces at different flight conditions are measured in a subsonic wind tunnel. The wing and the ...  Read More

Aerospace Science and Technology
Post-buckling response of thin composite plates under end-shortening strain using Chebyshev techniques

S. Amir M. Ghannadpour; M. Barekati

Volume 12, Issue 1 , March 2019, , Pages 15-26

Abstract
  In this paper, a method based on Chebyshev polynomials is developed for examination of geometrically nonlinear behaviour of thin rectangular composite laminated plates under end-shortening strain. Different boundary conditions and lay-up configurations are investigated and classical laminated plate theory ...  Read More

Aerospace Science and Technology
A Method for Selection of Optimum Solidity in Design of a Tandem Compressor Blade Row

Hamzeh Eshraghi

Volume 16, Issue 1 , June 2023, , Pages 16-30

https://doi.org/10.22034/jast.2023.365224.1133

Abstract
  In the current article, using results of previous researches, a guideline has been developed to select a proper value for solidity of a tandem blade row in an axial flow compressor stage. Next, using this guideline, a highly loaded tandem compressor stage has been designed. To verify the selected solidity ...  Read More

Numerical Simulation of Flow Past Oscillating Airfoil Using Oscillation of Flow Boundary Condition

Hamid Parhizkar

Volume 3, Issue 1 , March 2006, , Pages 17-21

Abstract
  The present study is devoted to an approximate modeling for numerical simulation of flows past oscillating airfoils. In this study, it is shown that the harmonic oscillating objects can be studied by simple numerical codes that are not able to solve moving grids. Instead of using moving grid for the ...  Read More

Aerospace Science and Technology
Numerical study of flow visualization and thermal performance for pulsating heat pipes

Sam Mohamad Hassan Pouryoussefi; Sohrab Gholamhosein Pouryoussefi

Volume 15, Issue 2 , October 2022, , Pages 17-24

https://doi.org/10.22034/jast.2022.346070.1119

Abstract
  Importance of study of pulsating heat pipes (PHPs) behavior and limitations in conducting experimental studies, the necessity of numerical simulations is getting critical in this area. In present work, numerical simulations are carried out for pulsating heat pipes. Thermal performance of closed loop ...  Read More

Aerospace Science and Technology
The Success of the Hybrid Genetic and Particle Swarm Algorithm for a Return Spacecraft from the Atmosphere with an Optimal Trajectory Design Approach to Reduce Aerodynamic Heat Transfer

Alireza Ekrami Kivaj; Alireza Novinzadeh; farshad pazooki; Ali Mahmoodi

Volume 16, Issue 2 , October 2023, , Pages 17-32

https://doi.org/10.22034/jast.2023.375858.1138

Abstract
  This study aims to investigate the spacecraft returning from the atmosphere. Due to high speed, prolonged flight duration, and numerical sensitivity, returning from the atmosphere is regarded as one of the more challenging tasks in route design. Our suborbital system is subjected to a substantial thermal ...  Read More

Numerical Simulation of Separation Bubble on Elliptic Cylinders Using Three-equation k-? Turbulence Model

Reza Dr. Taghavi

Volume 5, Issue 2 , June 2008, , Pages 57-66

Abstract
  Occurrence of laminar separation bubbles on solid walls of an elliptic cylinder has been simulated using a recently developed transitional model for boundary layer flows. Computational method is based on the solution of the Reynolds averaged Navier-Stokes (RANS) equations and the eddy-viscosity concept. ...  Read More

EXPERIMENTAL INVESTIGATION OF EFFECTS OF WALL POROSITY AND SUCTION ON THE FLOW QUALITY IN A TRANSONIC WIND TUNNEL

Kaveh Amiri; Mohammad Reza Dr. Soltani; H. Haghiri; Mahmood Mani

Volume 6, Issue 2 , June 2009, , Pages 63-70

Abstract
  A trisonic wind tunnel has been modified to improve its flow quality when operating at transonic speeds through perforated walls and side suctions. The usefulness of such a perforated wall, already known, is reduction of the blockage effect as well as the shock elimination. Two types of perforated walls ...  Read More

Numerical Simulation of Scaling Effect on Bubble Dynamics in a Turbulent Flow around a Hydrofoil

Mehrzad Shams; Reza Ebrahimi

Volume 3, Issue 2 , June 2006, , Pages 67-75

Abstract
  A Lagrangian-Eulerian numerical scheme for the investigation of bubble motion in turbulent flow is developed. The flow is analyzed in the Eulerian reference frame while the bubble motion is simulated in the Lagrangian one. Finite volume scheme is used, and SIMPLEC algorithm is utilized for the pressure ...  Read More

Process Improvement of Experimental Measurements Using D-optimal Models

Farid Shahmiri; Mahsa Baghban Salehi

Volume 8, Issue 2 , September 2011, , Pages 77-86

Abstract
  In this paper, the application of D-optimal models, as an alternative to response surface models (RS models) for design of experiment (DOE) was examined. Two D-optimal models for tilt-rotors in the wind tunnel experiment, as a form of quadratic functions, were generated based on a chosen optimality criterion. ...  Read More

Design of Nonlinear Robust Controller and Observer for Control of a Flexible Spacecraft

maryam malekzadeh; Abolqasem Naghash; H.Ali Talebi

Volume 7, Issue 2 , September 2010, , Pages 81-91

Abstract
  Two robust nonlinear controllers along with a nonlinear observer have been developed in this study to control a 1D nonlinear flexible spacecraft. The first controller is based on dynamic inversion, while the second one is composed of dynamic inversion and µ-synthesis controllers. The extension of dynamic ...  Read More

Gravity-Compensated Robust Control for Micro-Macro Space Manipulators During a Rest to Rest Maneuver

Mohammad J. Sadigh; Ali Salehi

Volume 5, Issue 3 , July 2008, , Pages 107-113

Abstract
  Many space applications require robotic manipulators which have large workspace and are capable of precise motion. Micro-macro manipulators are considered as the best solution to this demand. Such systems consist of a long flexible arm and a short rigid arm. Kinematic redundancy and presence of unactuated ...  Read More

In-Trim Flight Investigations of a Conceptual Fluidic Thrust-Vectored Unmanned Tail-Sitter Aircraft

fariborz saghafi

Volume 3, Issue 3 , September 2006, , Pages 125-133

Abstract
  The feasibility of using a stand alone Fluidic Thrust-Vectoring (FTV) system for the purpose of longitudinal trim of an unmanned aerial vehicle is the focus of the research presented in this paper. Since the fluidic thrust vectoring requires high pressure secondary air to deflect the engine exhaust gases, ...  Read More

Modeling and Simulation Research on Dynamics of Missiles with Deflectable Nose Control

G. Yuan

Volume 5, Issue 4 , December 2008, , Pages 161-166

Abstract
  The dynamic characteristics of deflectable nose missiles with rotary single-channel control were investigated in this paper. Firstly, the effective angle of attack, effective angle of sideslip and quasi-body coordinates were introduced based on the spin characteristics of the missile’s body. Secondly, ...  Read More