, M.Sc. Thesis Sharif University of Technology Farshid, Saman (Author) ; Adib Nazari, Saeed (Supervisor)

Abstract

First stage blades tempreture in the turbine rotor section for the advanced turbines has increased up to 1100oc. The blades should be under mentioned condition for the long times up to 70000 hours and accordingly creep happens. Fatigue–creep interaction is the main reason for the failures of many engineering components under high temperature and cyclic loading. In this thesis, a model for the life prediction of fatigue–creep interaction which was developed by other investigators has been modified to predict fatigue–creep interaction on the nickel-based superalloys. In this model, the law of energy conservation and the momentum conservation principle are used to describe the process of...

Molecular dynamics simulation of manipulation of metallic nanoclusters on double-layer substrates [electronic resource]

, Article Physica E: Low-dimensional Systems and Nanostructures ; 2010, Vol. 42, No. 9, pp. 2364-2374 Mahboobi, H. (Hanif) ; Meghdari, Ali ; Jalili, Nader ; Amiri, Farshid ; Sharif University of Technology

Abstract

Molecular dynamics simulations are carried out to investigate the manipulation of metallic clusters on double-layer surfaces. The system parts are made of transition metals. The conditions which are subjected to change in the tests are material combinations for cluster, main substrate and lubricant layer (adlayer). In addition to qualitative observations, two criteria which represent the particle deformation and substrate abrasion are utilized as evaluation tools and are computed for each case. Obtaining this sort of knowledge is highly beneficial for further experiments in order to be able to plan the conditions and routines, which guarantee better success in the manipulation process

Robust shape control of two SMA actuators attached to a flexible beam based on DK iteration

, Article International Conference on Control, Automation and Systems ; 2012 , Pages 316-321 ; 15987833 (ISSN) ; 9781467322478 (ISBN) Alambeigi, F ; Zamani, A ; Vossoughi, G ; Zakerzadeh, M. R ; Sharif University of Technology

2012

Abstract

There has been great demand for shape memory alloy (SMA) wires as actuators for shape control of flexible structures. The experimental setup of this study consists of a flexible beam actuated by two active SMA actuators. The input applied to the SMA actuator in this setup is electrical current while the output is the strain or position. To control strain of the actuator, the SMA wire is heated resistively in order to reach the desired temperature calculated by inverse of the phenomenological model. In heating the SMA wire resistively, the controllable quantity is the heat input to the wire via an applied current. In controller design, changes of physical properties of SMA wires and the...

Bilateral Control of a Laparoscopic Tele-Surgical Workstation with Haptic Feedback

, M.Sc. Thesis Sharif University of Technology Alambeigi, Farshid (Author) ; Vossoughi, Gholamreza (Supervisor) ; Farahmand, Farzam (Supervisor)

Abstract

Laparoscopic surgery which is categorized under Minimal Invasive Surgery, has many advantages over conventional open surgery. Despite the beneficial effect of this method on patients, surgeons suffer difficulties in utilizing the method. Robotic surgery has been constituted as the answer to remove the difficulties yet retain the advantages.
In the so-called robotic surgery, the tool is handed to a robotic arm, i.e., the slave robot, which is installed and positioned at the bed side. The surgeon sits before a comfortable console and uses a joystick-like robot, i.e., the master robot, to manipulate the slave robot. The vision is also provided by a robotic camera holder and shown in a...

A comparison of performance of artificial intelligence methods in prediction of dry sliding wear behavior

, Article International Journal of Advanced Manufacturing Technology ; Volume 84, Issue 9-12 , 2016 , Pages 1981-1994 ; 02683768 (ISSN) Alambeigi, F ; Khadem, S. M ; Khorsand, H ; Mirza Seied Hasan, E ; Sharif University of Technology

Springer-Verlag London Ltd 2016

Abstract

Developing a computational model for studying tribological performance is essential for computing accurate life cycle of various materials. Caused by the existence of complicated and nonlinear interactions between material surfaces, exact modeling of wear behavior is very difficult. Artificial intelligence (AI) can be used in distinguishing similar patterns in experimental data and predictive modeling of a certain material’s wear behavior. In this paper, artificial neural networks (ANNs) approach, adaptive neural-based fuzzy inference system (ANFIS) technique, and fuzzy clustering method (FCM) are used to develop a simple, accurate, and applicable model for predicting the wear behavior of...

Planar molecular dynamics simulation of Au clusters in pushing process

, Article International Journal of Nanomanufacturing ; Vol.5, No.3/4 , 2010 , pp.288-296 Mahboobi, S. H ; Meghdari, A. (Ali) ; Jalili, N. (Nader) ; Amiri, F. (Farshid) ; Sharif University of Technology

2010

Abstract

Based on the fact that the manipulation of fine nanoclusters calls for more precise modelling, the aim of this paper is to conduct an atomistic investigation for interaction analysis of particle-substrate system for pushing and positioning purposes. In the present research, 2D molecular dynamics simulations have been used to investigate such behaviours. Performing the planar simulations can provide a fairly acceptable qualitative tool for our purpose while the computation time is reduced extremely in comparison to 3D simulations. To perform this study, Nose-Hoover dynamics and Sutton-Chen interatomic potential will be used to investigate the behaviour of the aforementioned system. Pushing of...

Molecular dynamics simulation of manipulation of metallic nanoclusters on stepped surfaces

, Article Central European Journal of Physics ; Volume 9, Issue 2 , 2011 , pp 454-465 ; 1644-3608 Mahboobi, S. H ; Meghdari, A. (Ali) ; Jalili, N. (Nader) ; Amiri, F. (Farshid) ; Sharif University of Technology

2011

Abstract

Molecular dynamics simulations are carried out to investigate the manipulation of metallic clusters on stepped surfaces. Five surface forms are considered in the simulations. The system parts are made of pure transition metals and Sutton-Chen many-body potential is used as interatomic potential. The conditions which are subjected to change in the tests include: materials used for particles and substrate, and surface step conditions. In addition to qualitative observations, two criteria which represent the particle deformation and substrate abrasion are utilized as evaluation tools and are computed for each case. Simulation results show the effect of the aforementioned working conditions on...