Volume 2, Issue 3, June 2011

Finite-Element Modeling of Manual Metal Arc Welding (MMAW) Process

Ali. Moarrefzadeh

Department of Mechanical Engineering, Mahshahr Branch
Islamic Azad University , Mahshahr , Iran

Abstract– Manual Metal Arc Welding is a process where an arc is struck between a flux-coated consumables electrode and the work piece. The arc and the weld pool are both shielded by gases generated by the flux coating of the electrode. In this paper, the Manual Metal Arc Welding is studied and Carbon Steel temperature field is gained in this process. The thermal effect of Manual Metal Arc that specially depends on the electrical arc, electrode type and temperature field of it in workpiece, is the main key of analysis and optimization of this process, from which the main goal of this paper has been defined. Numerical simulation of welding process in SIMPELC method and by ANSYS software for gaining the temperature field of carbon steel, the effect of parameter variation on temperature field and process optimization for different cases of electrode done.

Keywords—Finite-Element, MMAW, FSI, SIMPLEC, ANSYS Temperature Field and Carbon Steel

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Application of AHP in Measuring and Comparing Quality of Manufacturing Industries

Mohit Singh, Dr. I.A. Khan, and Dr. Sandeep Grover

Department of Mechanical Engineering, Faculty of Engineering & Technology, Jamia Millia Islamia, New Delhi, India
Department of Mechanical Engineering, YMCA University of Science & Technology, Faridabad (HR), India.

Abstract– Quality has become a prerequisite for success in global market. Urge for quality and excellence is not new. Customers have always desired quality goods. For the last two decades organizations have been anticipating profitability, quality and customer satisfaction through various techniques. Quality has become a strategic priority for business around the world because of its proven significance for achieving and maintaining competitive advantage. With the organizations spending resources for adoption and implementation of Quality, it becomes necessary to assess their performance. The present work provides a methodology for comparison and selection of industries based on their Quality performance using Analytic hierarchy Process (AHP). The AHP model covers broad areas of quality, commitment and satisfaction. The model considers criteria of human resource; material, machine & methodology; Planning the organization, Organizational culture; Supplier and customer; and Inspection strategies. The different quality level at system and subsystem levels are identified and prioritized based on literature and body of knowledge at different levels using pairwise comparison thus assigning them global weightage. To find out the Local weightage and rating of the factors a survey has been conducted in around 146 manufacturing Industries. The present methodology is dynamic in nature and takes into consideration Quality factors along with their predefined weightage before arriving at a selection.

Keywords—AHP, Critical Factors, Quality and Pairwise Comparison

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Compromising Price and Security in the Short-Term Planning of Modern Power Systems

Mohammad Sadegh Javadi, Bahram Noshad and Shahla Keyvan

Department of Electrical Engineering, Science and Research Branch, Islamic Azad University, Fars, Iran
Department of Electrical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
Department of Foreign Language, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran

Abstract– One of the most challenging problems for operator in power system, in both regulated and deregulated environment is security in operation. With using regulated structure, separating various sectors to generation, transmission, and distribution, system operators are seeking for more benefit. Each entity has offered its desired prices to the power market. Independent system operator who is responsible for maintaining security interacts directly with market operator. Considering modern power and competitive system in which demands including price parameter are issued by consumer, the compromising between security and price should be considered. This article tends to accomplish this approach.

Keywords—Competitive Market, Social Welfare, Bender Decomposition, Prevention and Modification Approach

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Soliton Transmission Capacity of Vertical Cavity Surface Emitting Laser Degradation under Thermal Irradiated Fields

Abd El-Naser A. Mohamed, Nabil A. Ayad, Ahmed Nabih Zaki Rashed and Hazem M. El-Hageen

Electronics and Electrical Communication Engineering Department, Faculty Electronic Engineering, Menouf, 32951, Egypt
Atomic Energy Authority, P.O. Box 29, Naser City, Cairo, Egypt

Abstract– This paper has presented the performance of the VCSELs in thermo-irradiated has been modeled, investigated and deeply parametrically analyzed over wide range of the affecting parameters. As well as we have processed soliton transmission capacity of VCSELs based different materials (silica-doped, Aluminum Gallium Arsenide (AlGaAs), and polymer) in thermo-irradiated field effects. Both the ambient temperature and irradiation dose as well as the spectral wavelength possess serve reduction effects on the transmission characteristics (dispersion, and bandwidth) and consequently the transmitted bit rates and products. Useful semi-emperical relations have been cast. Thermo-irradiated penalties were computed and fitted as nonlinear relationships of useful impact in the design model for the device. Analysis of laser characteristics after irradiation showed that the main effect of radiation damage is an increase in bulk recombination that increases loss within the laser cavity. The device performance degradation is proportional to the fluence. The fluence rate is also relevant for degradation in electron irradiation. Low fluence rate leads to larger degradation compared to those associated with high fluence rate resulting from heat impact in bulk. The radiation damage of neutron is larger than irradiation damage of electron, which is caused by the difference in mass and the possibility of nuclear collision for the formation of lattice defects.

Keywords—VCSELs, Radiation Hardness Assurance, Reliability, Soliton Transmission and Neutrons Irradiation

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Using FEM and CFD for Engine Turbine Blades to Localize Critical Areas for Non Destructive Inspections

M. Saqib Hameed and Irfan A. Manarvi

Department of Mechanical Engineering, HITEC University, Taxila, Pakistan

Abstract– Damage to turbine blades is of critical importance in military aircraft engines. Irregular movements of throttle settings are a mandatory requirement for the pilots to perform various air combat maneuvers in military aircraft. It leads to excessive stresses on engine turbine blades in various flight regimes. The turbine blades are inspected exhaustively using non destructive inspection techniques during the engine overhaul process. A variety of non destructive inspections inspection methods like dye penetrant, eddy currents, magnetic particle testing and radiographic inspections etc are used consuming a large number of man machine hours increasing the cost of inspections. Still the possibilities of missing out internally damaged area due to micro cracks may also exist. Present research was focused on using Finite element methods (FEM) and/or Computational Fluid dynamics (CFD) to predict the location of possible damaged areas on turbine blades. These results could then be used as reference for carrying out non destructive inspections. In this manner the number of blades inspected by per unit time could be substantially increased leading to savings in inspection cost, lesser repair time and more focused fault isolation in the blades.

Keywords—Non Destructive Inspections, Finite Element Modeling, Computational Fluid Dynamics, HP and Turbine Inlet Temperature

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Improvement Power Plant Efficiency with Condenser Pressure

Amir Vosough, Alireza Falahat, Sadegh Vosough , Hasan Nasr Esfehani, Azam Behjat and Roya Naseri Rad

Young Researchers club, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
Department of Mechanics, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
Department of Mechanics, Shushtar Branch, Islamic Azad University, Shushtar, Iran

Abstract– In this study, the energy and exergy analysis of an ideal Rankin cycle with reheat is presented. The primary objectives of this paper are to analyze the system components separately and to identify and quantify the sites having largest energy and exergy losses at cycle. In addition, the effect of varying the condenser pressure on this analysis will also be presented. The performance of the plant was estimated by a component-wise modeling and a detailed break-up of energy and exergy losses for the considered plant has been presented. Energy losses mainly occurred in the condenser where 2126KW is lost to the environment while nothing was lost from the boiler system because it assumed adiabatic. The percentage ratio of the exergy destruction to the total exergy destruction was found to be maximum in the boiler system 86.27% and then condenser and stack gas 13.73%. In addition, the calculated thermal efficiency was 38.39 % while the exergy efficiency of the power cycle was 45.85%. The boiler is the major source of irreversibilities. For improvement the power plant efficiency the effect condenser pressure has been studied.

Keywords—Ideal Rankine Cycle, Energy Analysis, Exergy Analyses and Condenser Pressure

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