An efficient tabu search algorithm for the single row facility location problem [electronic resource]

, Article European Journal Of Operational Research ; Vol. 205, No. 1, pp. 98-105 Samarghandi, H. (Hamed) ; Eshghi, Kourosh ; Sharif University of Technology

Abstract

The general goal of the facility layout problem is to arrange a given number of facilities to minimize the total cost associated with the known or projected interactions between them. One of the special classes of the facility layout problem is the Single Row Facility Layout Problem (SRFLP), which consists of finding an optimal linear placement of rectangular facilities with varying dimensions on a straight line. This paper first presents and proves a theorem to find the optimal solution of a special case of SRFLP. The results obtained by this theorem prove to be very useful in reducing the computational efforts when a new algorithm based on tabu search for the SRFLP is proposed in this...

Sensitivity analysis of matching pennies game [electronic resource]

, Article Mathematical and Computer Modelling ; Volume 51, Issues 5–6, March 2010, Pages 722–735 Yarmand, H. (Hamed) ; Eshghi, Kourosh ; Sharif University of Technology

Abstract

In this paper, we have discussed the results of sensitivity analysis in a payoff matrix of the Matching Pennies game. After representing the game as a LP model, the sensitivity analysis of the elements of the payoff matrix is presented. The game value and the optimal strategies for different values of parameters are determined and compared

, M.Sc. Thesis Sharif University of Technology (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

FGM sheets with component or grain size gradient in their thickness direction provide mechanical and physical gradient properties through ND direction. FGMs are fabricated by various methods including centrifugal casting, powder metallurgy, PVD and CVD,all of which suffer from some shortcomings such as porosity of the products, low rate and high cost of production and restrictions on mass production. In this study, 2 and 4 layered Al matrix FGM sheets containing SiC and Al2O3 powders were fabricated by laminating method of Accumulative Roll Bonding(ARB). Two approaches of stacking were chosen as accumulative coupled roll bonding (ACRB) and (ASRB) for initial roll bonding and subsequent...

Hot workability of a high carbon high chromium tool steel

, Article Materials and Design ; Volume 46 , 2013 , Pages 654-659 ; 02641275 (ISSN) Akbarzadeh, A ; Naghdy, S ; Sharif University of Technology

2013

Abstract

In this work, hot tension tests were conducted on as cast and wrought samples of a high carbon high chromium tool steel to study the hot workability under the rolling conditions. The flow curves illustrate the classical shape of dynamic recrystallization (DRX). It is observed that broken carbide nets in the wrought samples result in lower deformation activation energy 398. kJ/mol in comparison to the as cast samples 432. kJ/mol. Necking strains were calculated using the inflection point of the work-hardening (θ) vs. stress curves. Wrought samples show higher hot ductility and lower maximum stress than the as cast ones. It is shown that lower activation energy of deformation and lower stress...

Sensitivity analysis of torque transmission efficiency of a half-toroidal CVT

, Article 2006 SAE World Congress, Detroit, MI, 3 April 2006 through 6 April 2006 ; 2006 ; 01487191 (ISSN) Akbarzadeh, S ; Zohoor, H ; Sharif University of Technology

SAE International 2006

Abstract

In this research a computer model based on elasto hydrodynamic fluid film lubrication is developed in order to calculate the torque transmission efficiency of a half-toroidal CVT variator. Validation of this model is verified by comparing the experimental and the model results. Sensitivity of torque transmission efficiency to eleven parameters is investigated. These parameters are: dimensionless roller curvature, aspect ratio, half cone angle, fluid viscosity index, pressure constant for Roelands model, input rotational velocity, absolute viscosity at atmospheric pressure, Young modulus of disks and power rollers, Poisson ratio of disks and power rollers, number of power rollers and variator...

Optimizing the geometry of a half-toroidal CVT

, Article Powertrain and Fluid Systems Conference and Exhibition, San Antonio, TX, 24 October 2005 through 27 October 2005 ; 2005 ; 01487191 (ISSN) Akbarzadeh, S ; Zohoor, H ; Sharif University of Technology

SAE International 2005

Abstract

In this research a model is developed which calculates the torque transmission efficiency of a half-toroidal CVT as a function of variator geometry, gear ratio and input torque. The different criteria which are considered to be important in a half toroidal CVT performance are torque transmission efficiency, variator weight, roller fatigue life and bearing torque loss. Variation of geometrical characteristics such as roller curvature, number of power rollers, aspect ratio and half cone angle affect these criteria in different ways. Therefore, in order to find the optimal quantity for each geometrical parameter an optimization problem should be developed. The objective function of this...

Deposition of Ceramic Nanoparticles on Aluminum Sheet by Air Gun Spraying for ARB Processing of Nanocomposite Sheets

, M.Sc. Thesis Sharif University of Technology Keramat, Ehsan (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

Particle reinforced aluminum matrix composites have considerable attraction in automotive and aerospace industries due to their special properties as light weight, high ratio of strength/density, improved elastic modulus, low coefficient of thermal expansion and high wear and corrosion resistance. Among the production processes of metal matrix composites, accumulative roll bonding process has particular importance due to producing ultrafine grained composite sheets. However, uncontrolled and undesired agglomeration of particles is the main problem in producing these composites. In this research, the Al2O3 and SiC nanoparticles were electrostatically stabilized against agglomeration by...

Hot Workability of a Free-cutting Steel with Severe Sulfur Segregation During Continuous Casting

, M.Sc. Thesis Sharif University of Technology Naghdy, Soroosh (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

Splitting in ingot cast structures and transverse cracks in continuous cast structures are the main problems of hot rolling of low carbon resulfurized free-cutting (LCRF) steels. Presence of high volume fraction of manganese sulfide inclusions in cast structure increases the risk of alligatoring in hot rolling. Because of high sulfur content of these steels and probability of formation of low melting point phases, minimum level of manganese and maximum level of copper and tin is necessary. Morphology of manganese sulfide is another important factor in hot forming of these steels, which can be controlled by level of deoxidation in steel making. In fact, MnS2 is present in fully killed...

Evaluation the Effect of Thermo-Mechanical Parameters on Microstructure and Texture of Electrical Steel for Improving Magnetic Permeability

, M.Sc. Thesis Sharif University of Technology Ahmadian, Peyman (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

Dependence of some magnetic properties such as core loss and permeability on temper rolling was studied in this thesis. It is shown that with a proper temper rolling sharper textures are obtained in the electrical steel and the magnetic properties in the longitudinal and traverse directions are improved. By texture analysis, it is shown that because of temper rolling, shear strain on the surface of the sheet is the main factor for abnormal grain growth and shear texture formation on the surface. The result of formation of this texture is enhancement of the {100} intensity and reduction of the {111} intensity, leading to the improvement of the permeability. Temper rolling is always...

Design and Manufactur, Medical Stent at Stainless Steel 316L

, M.Sc. Thesis Sharif University of Technology Moghtada, Abdolmajid (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

Due to increased mortality from Coronary Heart Disease, it is important to work on ways to treat this disease. An effective method of treatment on this disease is the coronary stent implantation. There are nearly two decades passed since implanting the first heart stent. The main objective of this research is design and manufacturing of the medical stents of stainless steel 316 L. Stent materials should have excellent corrosion resistance and biocompatibility. Various materials such as stainless steel 316 L, platinum alloys, niobium alloys, cobalt alloys are used for manufacturing the stents. In this project, at the first stage seam tube was prodected with laser welding of a tube with...

Bonding Feasibility, Mechanical Properties and Formability of Three-layered St/AZ31/St Composites Fabricated by Roll Bonding

, M.Sc. Thesis Sharif University of Technology Abedi, Reza (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

New materials as hybrid materials or laminate composites, due to combination of many properties, can be used in many industries. The aim of this research is bonding of three-layered St/AZ31/St composite by roll-bonding process. The roll-bonding process was performed at three preheating temperatures, 340, 400 and 450 ⁰C, with thickness reduction of 30 to 68% and different thicknesses of intermediate layer (AZ31). In order to improve the bonding strength, the as-rolled specimens were annealed at constant temperature of 375 ⁰C. For evaluation of bond strength and investigating the formation of a diffusion layer, the results of peel test and microscopic images were studied. Tensile specimens...

Using ARB Process for Metal Matrix Foam and Composite Production

, M.Sc. Thesis Sharif University of Technology Khalkhali, Mohammad (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

Metal matrix composites (MMC) and metal foams (MF) have been the topic of numerous researches during the last decades. The appropriate mechanical and physical properties of these materials make them useful in various industries. In this research, a unique approach is introduced for producing MMCs and MFs in which accumulative roll bonding (ARB) is employed in order to achieve a homogeneous distribution of ceramic particles in the metal matrix. Also, foamed structures can be made by subjecting Al/TiH2 composite to an appropriate annealing heat treatment where TiH2 particles decompose to hydrogen and titanium. In this work, the effect of number of ARB cycles on the size and distribution of...

Using FSP Method to Create Composite and Surface Foam with Distribution Gradient of Particles and Porosity as FGM and Study of Physical and Mechanical Properties

, M.Sc. Thesis Sharif University of Technology Karimi, Mahdi (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

Nowadays, the tendency to use Al/SiC composites with FGM structure has increased in the automotive and aerospace industries, because in this type of composite, the properties can be gradually changed in the direction of thickness. For example, one composite surface is used as a wear-resistant or high-temperature-resistant coating, and the other surface can be welded, has high thermal conductivity, or has a good toughness. In recent years, methods have been used to make surface composites, most of which are in the molten state and at high temperatures. In this case, the reactions between the compounds can not be easily controlled and the possibility of the formation of undesirable or...

Effects of Rolling Process on Mechanical Properties and Formability of Reinforced Polymeric Matrix with Stainless Steel Mesh as Cladding Composite Sheet

, M.Sc. Thesis Sharif University of Technology Aminoon, Mohadeseh (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

In this study, the mechanical properties of composite sheet polymer matrix reinforced with steel mesh were investigated. This bonding was carried out by rolling of a three layers of steel mesh in between two composite polymer sheets. Then, the effective parameters of process; Sample maintenance temperature inside the furnace, reduction during rolling, rolling speed, rolling direction and Number of rolling passes were investigated to determine the optimized processing conditions. In this way, adding mesh to the polymeric matrix improves the strength and polymer / polymer bond in the sandwich structure. Placing the mesh in the sandwich structure converts the brittle behavior of the polymeric...

Experimental Investigation of Formability and Mechanical Properties of Composites Manufactured by Direct Roll Bonding

, M.Sc. Thesis Sharif University of Technology Maleki, Payam (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

In this study, the ST14 low carbon steel sheet was used as a skin layer in the construction of three-layer laminates. The use of this steel was due to its high mechanical properties and excellent formability. A thermoplastic polyurethane sheet was also used as the core layer. The selection criteria of this polymer were no need for adhesive (for bonding metal to polymer) as well as proper mechanical properties (elongation and strength) and physical (density). The perfect process for manufacturing three-layer laminates is the roll bonding process. To manufacturing a laminate with the desired properties of the designer, the rolling parameters (rolling speed and thickness reduction) must be...

Effect of Geometric Distortion on the Flow Field and Performance of an Axisymmetric Supersonic Inlet

, M.Sc. Thesis Sharif University of Technology Akbarzadeh, Hossein (Author) ; Farahani, Mohammad (Supervisor)

Abstract

Inlets must decelerate the air with lowest loss and drag together with a given pressure and Mach number with best quality and uniformity to the engine. This is done based on flight Mach number, by an arrangement of shock waves and surfaces gradient in the inlet. Any distortion in the flow field and the inlet geometry parameters may disrupt such arrangement and influence on the inlet performance, in addition, under critical conditions, it might affect the stability of the intakes. Any distortion in the flow field and the inlet geometry parameters may disrupt such arrangement and influence on the inlet performance, in addition, under critical conditions, it might affect the stability of the...

Fabrication and Investigation of the Microscopic Structure and Mechanical Properties of Zx00 Magnesium Alloy by Applying the Multi-Directional Forging Process on Extruded and Homogenized Samples

, M.Sc. Thesis Sharif University of Technology Dehghan, Ali (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

Magnesium and its alloys have gained significant attention in medical applications due to their good biocompatibility. However, their widespread use has been limited by some inherent drawbacks, such as poor mechanical properties. The ZX00 magnesium alloy has been used in medical applications, including implants, due to its slow degradation rate and good ossification. However, this alloy lacks sufficient strength and ductility. The severe plastic deformation method can create an ultrafine grain structure and improve mechanical properties. In this study, to improve the mechanical properties and create an ultrafine grain structure, the multi-directional forging process was performed on...

Microstructural Study, Anisotropic Behavior, and Mechanical Properties of AA3104 Aluminum Sheets for Beverage Can Manufacturing in the Deep Drawing Process

, M.Sc. Thesis Sharif University of Technology Khezri, Iman (Author) ; Akbarzadeh, Abbas (Supervisor)

Abstract

Aluminum alloys, due to their high strength-to-weight ratio and excellent corrosion resistance, are considered as an alternative to steel sheets in various industries. The high demand for aluminum alloys in this competitive market forces aluminum sheet manufacturers to thoroughly analyze their production processes in terms of both cost and final material properties, aiming to improve quality and reduce production costs through innovation. One of the most important applications of aluminum alloys is in beverage can manufacturing, where aluminum alloy 3104 is commonly used. These cans are primarily produced using the deep drawing method. The microstructure and texture anisotropy play a key...

Parametric study and computation of seismic performance factors of braced shear panels

, Article Scientia Iranica ; Volume 23, Issue 2 , 2016 , Pages 460-474 ; 10263098 (ISSN) Hamed, A ; Mofid, M ; Sharif University of Technology

Sharif University of Technology 2016

Abstract

By locating a steel shear panel on the intersection point of the X-braces, concentrically or eccentrically braced shear panel (CBFSP or EBFSP) is formed. In this paper, to perform parametric study, 1-story CBFSP and EBFSP models with span length greater or less than height are considered. Using linear static analyses, the effects of size and location of the shear panel on the lateral stiffness of the frame with respect to the moment resisting frame with the same member sections are investigated. Next, for 1- And 3-story models, maximum displacement, along with base shear, and the ratio between the dissipated energy and input energy are examined under 4 ground motion records. Behavior of the...

Assessment of Seismic Retrofit Policies for Buildings

, M.Sc. Thesis Sharif University of Technology Movahedi, Ali (Author) ; Kashani, Hamed (Supervisor)

Abstract

Occurrence of natural disasters such as earthquake could seriously damage most buildings especially those with insufficient resistance located in urban worn-out textures. In order to reduce unpleasant consequences of an earthquake, appropriate policies need to be considered to persuade the beneficiaries to follow retrofitting standards in the process of planning, designing, and construction of buildings. These policies shall be implemented through institutions in arbitrary or obligatory forms, by encouragement or penalty mechanisms. In order to consider these policies, first of all we need to identify the beneficiaries and their particulars. By studying and considering subjects discussed in...