Sharif Digital Repository

Simulation is perhaps the most cost-effective tool to evaluate the operation of a system under design. A flexible, easy to extend, fully object-oriented, and multilayered simulator for interconnection networks can be a very useful tool for multicomputer designers and researchers. It is so desirable to attach newly designed components to the existing models and to exploit detailed results. This paper presents XMulator, an object-oriented listener-based simulation environment for evaluating multicomputer interconnection networks. The simulator involves a toolbox of various network topologies, routing algorithms, switching techniques, and flexible router models. This work introduces a... 

The simulation and experimental results obtained from stretching test of a commercial sheet of AA1200 aluminum alloy were compared and evaluated. Uniaxial tensile tests were carried out to obtain the required input parameters for simulation. Finite element analysis of the forming process was carried out using Abaqus/Explicit by considering von Mises and Hill-1948 yield criteria. Simulation results including punch force and strain distribution were compared and validated with the experimental results. The results reveal that using anisotropic yield criteria for simulation has a better match in both cases with the experiments  

The robots that can move on rough terrains are very important especially in Rescue operation, exploration, etc. In this research, a mechanism is introduced for a ring-like robot with a flexible body. This robot is moved by arms which are placed radially and have Reciprocating motion in this direction. By controlling the contraction and the extension of the arms which contact lhe ground, the robot will be forced to move which is called rolling-creeping motion. The robot is stable in stationary state.; also the maximum angle which it can be stable is determined. Considering the speed of contracted arm is the input parameter, the speed of the extended arm for locomotion of the robot has been... 

This paper outlines the effectiveness of the ultrasonic machining of alumina in terms of tool wear rate of the tool used and the material removal rate of work piece produced. The optimum combination of various input factors as type of abrasive slurry, their size and concentration, power and feed rate, in the machining of alumina has been determined by applying the Taguchi technique, also analysis is used to choose the best shape for horn. The study shows that among input parameters, power has the highest effect on MRR (material removal rate). Effects of grit size and feed rate on TWR (tool wear rate) also investigated  

In this paper, Virtual Cathode Oscillator as a microwave generator is studied concentrating on the nonlinear behavior of the microwave-plasma interaction that introduces chaos to the output voltage and power of the generator. It is shown that periodic oscillations of the electron beam strictly depend on the two most critical characteristics of the VCO, the input maximum voltage and the cathode radius. The chaos caused by the critical values of these two parameters, could restrict the maximum possible values of the input parameters, reducing the overall maximum output values. The effects of these two parameters are studied trough PIC-code simulations. The simulation results were used to... 

Despite the numerous researches in Stress Corrosion Cracking (SCC) risk of austenitic stainless steels in aqueous chloride solution, no formulation or reliable method for prediction of time to failure as a result of SCC has yet been defined. In this paper, the capability of artificial neural network for estimation of the time to failure for SCC of 304 stainless steel in aqueous chloride solution together with sensitivity analysis has been expressed. The output results showed that artificial neural network can predict the time to failure for about 74% of the variance of SCC experimental data. Furthermore, the sensitivity analysis also demonstrated the effects of input parameters (Temperature,... 

To have a complete model of a thunniform Fish-Robot, models of both body and tail are required. The dynamic model of the body is developed according to the parameters of a thunniform Fish-Robot built in MIT University, while, as the main part of this paper, the dynamic model of the tail is developed using fuzzy logic. Using experimental data and table look-up scheme, a fuzzy black box is introduced that gives the value of thrust force generated for any value of the Fish-Robot's input parameters: frequency of tail oscillation, amplitude of tail oscillation and speed of the Fish-Robot. In the second part, a trajectory fuzzy controller is designed for the Fish-Robot. The output of trajectory... 

In this study, neural network models have been used to predict the mechanical behaviors of mouse embryos. In addition, sensitivity analysis has been carried out to investigate the influence of the significance of input parameters on the mechanical behavior of mouse embryos. In order to reach these purposes two neural network models have been implemented. Experimental data earlier deduced-by [Flückiger, M. (2004). Cell Membrane Mechanical Modeling for Microrobotic Cell Manipulation. Diploma Thesis, ETHZ Swiss Federal Institute of Technology, Zurich, WS03/04]-were collected to obtain training and test data for the neural network. The results of these investigations show that the correlation... 

Intelligent deep-drawing is an instrumental research field in sheet metal forming. A set of 28 different experimental data have been employed in this paper, investigating the roles of die radius, punch radius, friction coefficients and drawing ratios for axisymmetric workpieces deep drawing. This paper focuses an evolutionary neural network, specifically, error back propagation in collaboration with genetic algorithm. The neural network encompasses a number of different functional nodes defined through the established principles. The input parameters, i.e., punch radii, die radii, friction coefficients and drawing ratios are set to the network; thereafter, the material outputs at two... 

To have a complete model of a thunniform Fish-Robot, models of both body and tail are required. The dynamic model of the body is developed according to the parameters of a thunniform Fish-Robot built in MIT University, while, as the main part of this paper, the dynamic model of the tail is developed using fuzzy logic. Using experimental data and table look-up scheme, a fuzzy black box is introduced that gives the value of thrust force generated for any value of the Fish-Robot's input parameters: frequency of tail oscillation, amplitude of tail oscillation and speed of the Fish-Robot. In the second part, a trajectory fuzzy controller is designed for the Fish-Robot. The output of trajectory... 

An artificial neural network to predict the fatigue life, residual stress and Almen intensity of shot peened alloy Ti6Al4V ELI was developed. To minimize the prediction error, a feed forward model was used and the neural network was trained with back-propagation learning Algorithm. The results of this investigation show that a neural network with one hidden layer and five neurons in this layer will give the best performance. With this structure the network approaches to the desired error in the least time. Furthermore, it was concluded that there is a good agreement between the experimental data, the predicted values and the well-trained neural network. Therefore, the neural network has a... 

The objective of this research is geometrical optimization of half toroidal Continuously Variable Transmission (CVT) in order to achieve high power transmission efficiency. The dynamic analysis of CVT is implemented and contact between the disk and the roller is modeled viaelastohydrodynamic (EHL) lubrication principles. Computer model is created using geometrical, thermal and kinetic parameters to determine the efficiency of CVT. Results are compared by other models to confirm the model validity. Geometrical parameters are obtained by means of Particle Swarm Optimization (PSO) algorithm, while the optimization objective is to maximize the power transmission efficiency. Optimization was... 

The purpose of this paper is to model the detailed effects of interactions that take place between components of un-bonded flexible risers, and to study the three-dimensional motion responses of risers when subjected to axial loads, bending moments, and internal and external pressures. A constitutive law for un-bonded flexible risers is proposed and a procedure for the identification of the related input parameters is developed using a multi-scale approach. A generalized finite element structural model based on the Euler-Bernoulli beam theory is developed in which the constitutive law is embedded. The beam theory is enhanced by the addition of suitable pressure terms to the generalized...