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The Course of Martin Heidegger’s Notion of Science in His Early Thought,Based on Works Preceding Being and Time
, M.Sc. Thesis Sharif University of Technology ; Sefidkhosh, Meysam (Supervisor)
Abstract
In this research, first of all, the main question of Heidegger and his epoch is investigated. If we read Heidegger along the tradition of German philosophy, then it is perceived that the problem of science is the most central subject matter standing against Heidegger. My question is this: how Heidegger reaches to this existential phenomenological view about science. Regarding that, by giving a coherent narration about a crucial problem called 'the crisis of science', in the first chapter I gave a short view to philosophies preceding Heidegger, some important of which is Dilthey's philosophy of life, phenomenology of Husserl, and south-west school of neo-Kantianism. The second chapter...
A failure control method for smart composite morphing airfoil by piezoelectric actuator
, Article Transactions of the Canadian Society for Mechanical Engineering ; Volume 35, Issue 3 , 2011 , Pages 369-381 ; 03158977 (ISSN) ; Zabihollah, A ; Sharif University of Technology
2011
Abstract
In this paper, a nonlinear Finite Element (FE) approach based on the layerwise displacement theory is utilized to obtain the interlaminar stresses due to buckling phenomena in unsymmetric laminated smart composite morphing structure. An On/Off control strategy is designed to control the snap-through phenomena. Due to cycling nature of applied load on morphing, these structures are vulnerable to failure due to fatigue. A failure control mechanism utilizing a piezoelectric actuator is developed to control the failure
A semi-active SMA-MRF structural stability element for seismic control in marine structures
, Article Applied Ocean Research ; Volume 100 , 2020 ; Zabihollah, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The stability and integrity of structures under indeterminant external loadings, particularly earthquakes, is a vital issue for the design and safe operation of marine and offshore structures. Over the past decades, many structural control systems, such as viscous-based systems, have been developed and embedded in marine and offshore structures, particularly oil platforms to maintain the stability and mitigate the seismic hazards. Rapid improvement in intelligent materials, including shape memory alloys (SMAs) and Magnetorheological fluid (MRF), have led to the design and development of efficient structural control elements. The present work aims to establish a framework for the structural...
A study of pre-straining shape memory alloy (SMA)-based control elements subject to large-amplitude cyclic loads
, Article Ships and Offshore Structures ; 2020 ; Zabihollah, A ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
Dynamic environmental loads, such as winds and waves, make the stability of offshore structures at high risk, requiring reliable yet efficient control elements to ensure the stability of such structures under lateral loads. Among the variety of control elements that have been developed to enhance the stability of a structure, shape memory alloy (SMA)-based control elements are promising as they are low-cost, easy to embed into the main control element, and do not need an external power supply. However, cyclic loads may highly influence the performance and functionality of SMA-based elements. The present work investigates the effects of pre-straining SMA components in energy dissipation...
Failure and Buckling Control of Smart Morphing Composite using Nonlinear Finite Element Method
, M.Sc. Thesis Sharif University of Technology ; Zabihollah, Abolghasem (Supervisor)
Abstract
Structures that change shapes are often called morphing structures. Smart morphing composites refer to the morphing structures that can detect the change in conditions and, through a control mechanism, command the actuators to maintain the stability and/or perform a new task. The present report provides a framework on the eld of smart morphing composite structures. The emphasis on this work is on, particularly, multi-stable composite structures with capability to detect the new conditions and adapt themselves to properly respond to them. Due to cycling nature of applied load on morphing, these structures are vulnerable to failure due to fatigue. A failure control mechanism utilizing a...
Buckling control of morphing composite airfoil structure using multi-stable laminate by piezoelectric sensors/actuators
, Article Proceedings of SPIE - The International Society for Optical Engineering, 7 March 2011 through 9 March 2011, San Diego, CA ; Volume 7978 , 2011 ; 0277786X (ISSN) ; 9780819485403 (ISBN) ; Zabihollah, A ; Azizi, A ; Sharif University of Technology
2011
Abstract
In the present work, an unsymmetric laminated plate with surface bonded piezoelectric sensors, and actuators has been considered. Piezoelectric sensor were used to monitor the load and deformation bifurcation occurs. Monitoring the shape and load of a morphing structure is essential to ascertain that the structure is properly deployed and it is not loaded excessively, thus, preventing structural to failure. A piezoceramic actuator is used to provide activation load and to force the structure to change its stability state from one to another. A non-linear finite element model based on the layerwise displacement theory considering the electro-mechanical coupling effects of piezoelectric...
Explaining Moral Role of Artifacts With Regards to Value Laden Theory of Technology
, M.Sc. Thesis Sharif University of Technology ; Sefidkhosh, Meysam (Supervisor) ; Taghavi, Mostafa (Supervisor)
Abstract
In this thesis we review different approaches to the theory of value laden technology and realize that there are at least two major ideas about this. Some philosophers believe that technology is not a mere instrument and has a value laden nature. In contrast some others count technology as something neutral which contains no social or moral value. After explaining this ideas, in the second chapter we examine different models which explain the relation between technology and moral and social values and show how this values can contribute in design and use of technologies. In chapter three we talk about different methods used to steer technology in a desirable way which is in accordance with...
Vibration monitoring of wind turbine blade using fiber bragg grating
, Article Wind Engineering ; Volume 34, Issue 6 , 2010 , Pages 721-731 ; 0309524X (ISSN) ; Zabihollah, A ; Zareie, S ; Sharif University of Technology
2010
Abstract
Rapid growth in generating power from wind turbines led to application of long laminated composite blades. However, as the length of blades increases, the risk of failure due to excessive vibration increases. Therefore, a reliable wind power generator requires an efficient and accurate, yet economical structural health monitoring system to detect vibration and apply a reliable control to prevent from unpredicted failure. This paper presents an optimal, low cost and continuous vibration monitoring system for laminated composite blades using Fiber Bragg Grating (FBG). Utilizing a layerwise displacement theory, the Finite Element (FEM) model has been developed for the wind turbine blade. The...
Optimization of Forging Processes with Concurrent Approach
, M.Sc. Thesis Sharif University of Technology ; Hosseini Kord Khyli, Ali (Supervisor)
Abstract
With the increasing complexity of manufacturing processes and the interrelations between the different phases, the possibility of a phase being affected by a preselected desing variable is very high. In that case, the influence of a desing variable not only on the part performance of but also on the feasibility and efficiency of its manufacturing should be considered. Concurrent engineering approaches should then be adopted to take the control of such complicated relations among the subprocesses. In this thesis a concurrent design optimization methodology was proposed to minimize the cost of a cold forged manufacturing process using the design parameters as optimization variables. An...
On the Topological Entropy of Geodesic Flows
, M.Sc. Thesis Sharif University of Technology ; Razvan, Mohammad Reza (Supervisor) ; Nassiri, Meysam (Supervisor)
Abstract
Let M be a connected, compact, Riemannian manifold. Geodesic flow is a flow on the unit tangent bundle of M . This flow can be studied in dynamics prespective. for example entropy or complexity of the geodesic flow. in this thesis we will follow methods of entropy estimation or computing for geodesic flow. we will follow the method of anthony manning and Ricardo Mañe for proving such result. Maning present two results linking the topological entropy of the geodesic flow on M. we expalin how he find exponential growth rate volume of balls in universal cover as a lower bound for topologycal entropy. another theorem , Mañe represent the equlity between exponential growth rate of avrage of...
Classification of Partial Hyperbolic Diffeomorphisms on 3-manifolds
, M.Sc. Thesis Sharif University of Technology ; Safdari, Mohammad (Supervisor) ; Nassiri, Meysam (Supervisor)
Abstract
In this dissertation, we will study partially hyperbolic diffeomorphisms. First, we are going to introduce partially hyperbolic diffeomorphisms and construct some examples. One of the important questions in the study of partially hyperbolic diffeomorphisms is their classification problem, which provides a deeper understanding of manifolds and also of partially hyperbolic diffeomorphisms themselves. We will go through this problem by examining Hammerlindl, Potrie’s [1]’s work. They have proved that a partially hyperbolic diffeomorphism on a 3-manifold with a virtually solvable fundamental group, that has no periodic torus tangent to contraction-center or expansion-center, is dynamically...
Finding an unknown object by using piezeoelectric material: A finite element approach
, Article 2nd International Conference on Environmental and Computer Science, ICECS 2009, 28 December 2009 through 30 December 2009, Dubai ; 2009 , Pages 156-160 ; 9780769539379 (ISBN) ; Durali, L ; Zareie, S ; Parvari Rad, F ; Sharif University of Technology
IEEE
2009
Abstract
This paper presents a method to determine material of an unknown sample object. The main objective of this study is to design a database for specifying material of an object. We produce the database for different materials which is subjected to different forces. For this purpose we use a Polyvinidilene Fluoride (PVDF) sensor which is a piezoelectric material. Also we study the effect of changing place of sensor on our study. The detailed design was performed using finite element method analysis. Furthermore, if we have an object which we do not know its material by use of this database we can find out what this object is and how much its Yanoung's modules is. This study will be suitable for...
Control of vibration suppression of a smart beam by pizoelectric elements
, Article 2nd International Conference on Environmental and Computer Science, ICECS 2009, 28 December 2009 through 30 December 2009, Dubai ; 2009 , Pages 165-169 ; 9780769539379 (ISBN) ; Durali, L ; Rad, F. P ; Zareie, S ; Sharif University of Technology
2009
Abstract
Vibration control is an essential problem in different structure. Smart material can make a structure smart, adaptive and self-controlling so they are effective in active vibration control. Piezoelectric elements can be used as sensors and actuators in flexible structures for sensing and actuating purposes. In this paper we use PZT elements as sensors and actuator to control the vibration of a cantilever beam. Also we study the effect of different types of controller on vibration. © 2009 IEEE
Strictly Toral Dynamics
, M.Sc. Thesis Sharif University of Technology ; Esfahanizadeh, Mostafa (Supervisor) ; Nassiri, Meysam (Supervisor)
Abstract
This dissertation deals with nonwandering (e.g. area-preserving) homeomorphisms of the torus which are homotopic to the identity and strictly toral, in the sense that they exhibit dynamical properties that are not present in homeomorphisms of the annulus or the plane. This includes all homeomorphisms which have a rotation set with nonempty interior. There are two types of points: inessential and essential. It is known that the set of inessential points Ine(f ) is a disjoint union of periodic topological disks ("elliptic islands"), while the set of essential points Ess(f ) is an essential continuum, with typically rich dynamics ("the chaotic region"). One of the key results in this context is...
Effect of shape memory alloy-magnetorheological fluid-based structural control system on the marine structure using nonlinear time-history analysis
, Article Applied Ocean Research ; Volume 91 , 2019 ; 01411187 (ISSN) ; Alam, M. S ; Seethaler, R. J ; Zabihollah, A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Marine structures, as key elements in the global energy network, constantly are subjected to harsh environmental loading conditions. Therefore, reliable yet efficient structural control mechanisms are required to ensure their safe functionality and structural stability. In the present work, a novel hybrid structural control element for marine structures has been designed in which the superelasticity effect of shape memory alloy (SMA) and damping controllability of magnetorheological fluid (MRF), as smart materials, have been combined. The novel system does not require huge external energy for activation and in addition, the system has the ability to be tuned for variable loading conditions....
Stability control of a novel frame integrated with an SMA-MRF control system for marine structural applications based on the frequency analysis
, Article Applied Ocean Research ; Volume 97 , 2020 ; Alam, M. S ; Seethaler, R. J ; Zabihollah, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Structural integrity and ensuring the stability of steel frame structures, including marine and coastal structures, are the main challenges for designers in civil infrastructures, particularly in oil platforms, subjected to tough periodic and non-periodic environmental loading conditions. Variable loadings with different amplitudes and frequencies may lead to the stability of steel structures loss. In order to keep the stability of the steel structures and prevent possible damages, reliable yet efficient structural control systems are in demand. Conventional structural control systems need significant activation energy and/or in-depth users knowledge to be effective. Most recently, smart...
A novel shape memory alloy-based element for structural stability control in offshore structures under cyclic loading
, Article Ships and Offshore Structures ; Volume 15, Issue 8 , 2020 , Pages 844-851 ; Alam, M. S ; Seethaler, R. J ; Zabihollah, A ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
Wind and ocean waves highly influence the performance and functionality of structures, requiring an efficient control element. The structural behavior of one of the most recent structural control elements, namely shape memory alloys (SMA)-based control element, under cyclic loadings of oceans waves, has been investigated. Shape memory alloys are one of the attractive smart materials with the ability to return to the initial shape after experiencing large deformation. Experimental tests have been conducted to study the effects of cyclic loads on several specimens of the SMA wires. The SMA wires are being used in the SMA-based structural control system to dissipate the energy of external...
Recent advances in the applications of shape memory alloys in civil infrastructures: A review
, Article Structures ; Volume 27 , 2020 , Pages 1535-1550 ; Issa, A. S ; Seethaler, R. J ; Zabihollah, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Shape Memory Alloys (SMAs) are a new generation of smart materials with the capability of recovering their predefined shape after experiencing a large strain. This is mainly due to the shape memory effects and the superelasticity of SMA. These properties make SMA an excellent alternative to be used in passive, semi-active, and active control systems in civil engineering applications. This paper presents a comprehensive review of the recent developments in the applications of SMA in civil infrastructures, including, steel, concrete, and timber structures. This review reveals the significance of SMA in civil infrastructures particularly, the enhancement of structural behavior and energy...
Design, validation, and application of a hybrid shape memory alloy-magnetorheological fluid-based core bracing system under tension and compression
, Article Structures ; Volume 35 , 2022 , Pages 1151-1161 ; 23520124 (ISSN) ; Hamidia, M ; Zabihollah, A ; Ahmad, R ; Dolatshahi, K. M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Civil infrastructures are vulnerable to catastrophic failures when exceeding the limit loading, requiring a reliable structural control mechanism, such as bracing systems, to enhance the integrity and stability of the structure. Bracing systems improve the performance of the structures by increasing the stiffness/strength of structures, the damping coefficient, and/or the energy absorption capacity. However, the functionality of these bracing systems is not controllable and may be altered after strong seismic events. Recently, the smart bracing systems based on multifunctional materials, particularly the shape memory alloy (SMA) and the magnetorheological fluid (MRF) have been developed. The...
Comparison of corrosion behavior between fusion cladded and explosive cladded Inconel 625/plain carbon steel bimetal plates
, Article Materials and Design ; Volume 43 , January , 2013 , Pages 467-474 ; 02641275 (ISSN) ; Akbari Mousavi, S. A. A ; Madani Sani, F ; Sharif University of Technology
2013
Abstract
One of the main concerns in cladding Inconel 625 superalloy on desired substrates is deterioration of corrosion resistance due to cladding process. The present study aims to compare the effect of fusion cladding and explosive cladding procedures on corrosion behavior of Inconel 625 cladding on plain carbon steel as substrate. Also, an attempt has been made to investigate the role of load ratio and numbers of fusion layers in corrosion behavior of explosive and fusion cladding Inconel 625 respectively. In all cases, the cyclic polarization as an electrochemical method has been applied to assess the corrosion behavior. According to the obtained results, both cladding methods aggravate the...