Sharif Digital Repository

This project focuses on the design of fuel drop tanks for airplanes that add minimal drag and positive lift to the flying object. This will obviously effect the stability and dynamic performance of the airplane. To reduce adverse dynamic effects the tank was divided to several segment with a special emptying sequence. The add-on tank has to have no interference with the object existing systems and require minimum structural changes in the object. Several designs were proposed and the one gaining highest marks was selected. The flow field and the dynamic behavior of combined vehicle and drop tanks were studied using FE simulations. The result shows that adding a drop tank with optimized... 

In This project the most important phenomena for design of Vibration Isolation Module is investigated and modeled. These isolators are used in mooring Arrays. One of the most important problems in design of these isolators is lacking of suitable information in resources. Vortex Induced Vibration in Towed Cable and Flutter of Drogue are the most important source of vibrations. They are modeled and frequency band for a typical Sonar Array is calculated. Then by investigating of Normal and Tangantional Vibration in towed cables, it was found that normal vibration is damped, so the Isolators must be damped transactional vibrations. Before final design, for better understanding of the problems... 

Fog computing environment consists of several devices which distribute across an arbitrary topology. Each of these devices is capable of carrying out a designated computation simultaneously with other devices. One of the common ways of describing a computation is through the usage of workflows. Workflow is a flexible and formal way of modeling tasks and their requirements for execution. A workflow is essentially a DAG. Therefore, it can model the data dependency between tasks quite accurately. The complex structure of a workflow in conjunction with the homogenous nature of devices in a fog environment makes it difficult to find a resource management algorithm to minimize execution time, used... 

The main objective of this project is to take the first step in designing torsional vibration damper (TVD) for engines in Iran. To this end a complete dynamic model of a 4 cylinder internal combustion engine comprising of all reciprocating parts plus the crankshaft was developed using Bond Graph method. Real firing data of the engine was used as input to the system and output torque to gearbox shaft as the output. The system equations in two cases, with TVD and without TVD were derived. MATLAB software was used to solve these equations in finding the quality of performance of the torsional vibration damper. Dynamic properties of crankshaft and designed TVD were obtained using finite element... 

Cancer can be defined as a stochastic phenomenon. Thus, the tumor growth can be defined as a stochastic process. A Cancer tumor can be analyzed by its geometric shape. Furthermore, computing fractal dimension of shapes is a useful technique to analyze chaosity and complexity of shapes. This approach can be used to compare results from laboratory with simulated results of a mathematical model. A stochastic model of tumor growth will be presented. And some geometrical properties will be analyzed through computer simulation of the model  

The effects of combined task demands on the way muscles are recruited to balance external loads during posture and movement is of great importance in quantitative analysis of upper arm function. Pain and disability of shoulder joint is becoming more important as population spends more often interacting with computers in seated position and carrying repetitive tasks using upper extremities. Shoulder joint that is more dependent on the muscles for its normal function than other joints such as hip due to its small articular surface and large range motion has been used here to study its coordination during isometric exertions. Since, the numbers of tasks that could be performed are enormous. In... 

In this research, acoustic field around an underwater vessel generated by different sources is studied. Hull vibration due to harmonic forces from rotating machinery inside the vessel, flow induced noise due to flow around the hull, and propeller generated noise were considered. Finite Element Method (FEM) was used to determine hull vibration due to mechanical excitations by internal machinery. A 3-D boundary element computer code was then developed to solve Helmholtz equation in the surrounding water by which Acoustic field around the vessel was then obtained. To calculate flow induced noise and propeller noise, Navier-Stocks equations with LES turbulent model was solved around the vessel... 

This research concentrates on active and passive control of vibrations from a dieselgenerator set. A comprehensive study of the system is performed to design a system to provide minimum vibration transmission from a mid size generator set (300 kw) in a wide frequency range around operating point. The control system consists of two stages, a passive part with mode separation feature and an active part inserting control force by inertial actuators on the intermediate mass. Independence of the performances of passive and active parts of control system and low energy consumption of the active system can be considered as the main advantaged of this system. To evaluate the controller design, a DOF... 

The goal of this research is design and manufacturing of a device for fatigue test and 3D crack propagation in spur gear roots. Clearly it should be able to test gear in oscillated bending load and control the amplitude and period of loading. Designed setup in this project using a electro hydraulic actuator can do it up to 50 KN and 10 Hz in amplitude and frequency and a PLC controls it during the test time. System can load gears symmetric or anti symmetric and simulate the effect of shaft misalignments, bearing damage and gear production tolerances on the gear loading. System completely designed, built and tested during this project and using experimental data, its performance was... 

Using clean and renewable energy as driving force for vehicles is becoming more and more important because of rising fuel prices and also environmental concerns. Using solar and wind power for direct use in vehicles seems impractical with today’s technology. Compressed air can serve as an intermediate medium to store energy and utilize it for running vehicles. The main purpose of this research was to conceptually design an air driven vehicle with acceptable performance in a city for everyday life. After a brief history, at first step advantages and disadvantages of using air as driving force of vehicle is studied. This study was carried out in different categories including cost, capability... 

Communication Buoys are devices that facilitate radio communication between underwater ships and surface stations. In this research such device is thoroughly designed for a submersible application. The system comprises of buoy, connection cable, buoy cavity, cable passage, winch and other supporting and safety subsystems. Buoy and cable system was analyzed in a general form and their stable states were determined for different ship maneuvers, sea streams, and wave conditions. Based on this, optimum buoy geometry and cable length were found for the defined application and other subsystems were detail designed. To evaluate the design, some of the system components were manufactured and... 

Advancements in solar powered systems bring about the possibility for today’s transportation systems to be operated and driven by such a clean and renewable source of energy. The challenging point of this combination is to draw high power levels from such a low power density source of energy. As a result, employing an efficient power storage and management system becomes inventible. The subjects of this research are to design a grid connected system and evaluate its performance and feasibility in a real application (Tehran- Mehrshahr surface train – Tehran 5th Metro Line). The task includes sixteen pairs of DC transmission lines which are powered by CIGS solar module technology and four... 

Cars with high center of gravity, such as SUV-Sport Utility Vehicles- have high tendency to roll over in high speeds and rapid maneuvers. An idea formerly proposed is to use a high speed rotating disc like a gyroscope on the onset of the rollover to exert a high stabilizing moment on the vehicle, and consequently prevent rollovers. Also using two counter rotating discs with opposite nutation will prevent interference with the car other degrees of freedom. To reduce the interference of the spinning discs with the vehicle dynamics, the discs are to be brought to speed by the action of a high accelerating mechanism during the rollover process(similar to the action of an airbag). This project... 

There are two ways for quality control testing of power transmission systems in various industries. A method of testing the specific positions of power transmission, and final testing (Automotive road tests), respectively. In various stages of design, manufacturing and quality control components, power transmission systems, require detailed information on the performance of parts. It's a special place for each transmission experiment designed and manufactured. Gearbox as an important component of the transmission of this issue is no exception. Magnetic gearbox has a new generation of power transmission systems in the last decade of the optimization is presented. In recent years, several... 

Regarding the price of industrial turbo machines, testing the rotating elements of them is always an important issue. One of the companies of the aviation industry decided to design and fabricate a spin tester device to check the quality of new rotating parts before installing them on gas turbines. A team has worked on this project for more than a one year. The present thesis is on designing the drive system of the spin tester. The drive system was chosen to be an air motor. This thesis concentrates on the design procedure of this air motor. The designed system is capable of providing enough power to accelerate the disks to the test speed in the appropriate time. The disk geometry, test... 

The present research intends to design a controller for modular reconfigurable manipulator robots. Manipulators are made up of several links and joints. By attachment of links and joints in different ways, one may make a variety of robot configurations in modular reconfigurable manipulators.
To meet modularity and reconfiguration needs, hybrid control architecture was selected which contains a central supervisory section and distributed controllers located on individual modules. Central supervisory section specifies the trajectory of the robot and other control tasks like position control, speed control and etc. are performed by distributed controllers. In hybrid architecture, dynamic... 

Nowadays, Gas turbines are developing more than before and one of the most important components of these turbines improving continuously is their combustor. In the recent years strict standards for controlling the amount of pollutants releasing from aero engines have been established and these standards are moving towards limiting these pollutants. Hence one of the most important criteria of combustor design is keeping its emissions at a lowest possible amount. In this study, at first an algorithm for combustor design has been calculated and then by means of this algorithm the combustor of CF6-80E1A4 engine is designed again. The amount of the produced emissions of the designed combustor has... 

In this thesis, overall design of a multi-purpose vehicle for transportation, repair and cleaning missions in hydro power station water ways during overhaul is presented. Design process is divided into several parts. The main challenges of the project and customer requirements are discussed first. A brief review of electric vehicles history is presented. The conceptual design including initial dimensional calculations, energy analysis and component selection are described in subsequent sections. Finally the structural and dynamic analysis of chassis and suspension system are carried out. To avoid pollution and life hazards to workers, a battery and electric motor drive system is utilized.... 

Motion simulators have been highly sought after by the growth of the aerospace industry. In the meantime, the Stewart mechanism, or the so-called Hexapads, is a robot that, in addition to being used in machining tools, is mainly used to simulate the flight. The Stewart-Gaph mechanism was created and introduced in 1954 and 1965, and since then dynamics and control have been widely addressed in the mechanical engineering literature. The robot is considering the project to test parts and equipment installed in marine vessels under sea movements and waves. Therefore, according to information obtained through relevant organs, the purpose of this project is to design and implement a hexapad... 

Recent studies show a great number of micro hydro power potentials all over Iran. They have the capability to generate electricity for shops, residential areas, agricultural communities, and recreational tourism centers. In order to cover the micro hydro power potentials of the country, Sharif University of Technology and Iran Water and Power Resources Development Corporation decided to conduct a project to design and fabricate three types of micro hydropower for the first time in Iran. The potentials with low head and high discharge are located beside rivers and are appropriate places to install axial micro hydro turbine. In this project we tried to prototype an axial micro hydro turbine...