School of Mechanical and Industrial Engineering

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Biodiesel Production Optimization and Quality Assessment Using Jatropha Curcas Oil And Ethanol Alcohol
(Addis Ababa University, 2001) Demissie, Biniyam; Alemu, Demiss (PhD)
Concern over high transportation fuel costs, trade deficits, depleting resources, energy security, and mounting evidence of global climate change has led to re-investigation of fossil fuel alternatives. For this reason Ethiopian Ministry of Water and Energy has started promoting bio-energy as a means to transform the nation’s abundant renewable biomass resources into cost competitive, high power biofuels and products. Biodiesel offers one renewable fuel option that can be produced from non edible vegetable oil sources. Fortunately Ethiopia has many opportunities for biodiesel production. The country´s favorable climatic condition for the cultivation of non edible vegetable oil bearing plants and the abundance of ethanol alcohol produced from the byproduct of local sugar factories gave the country a great advantage in producing biodiesel and get a little relief from petroleum related problems. However, the effort made to introduce the technology and take the most out of it is so low to force policy makers and encourage local and foreign businessmen towards the production of biodiesel using local resources. Therefore this research tries to fill this gap. The main purpose of this research is therefore to develop a biodiesel production technique from Jatropha oil (Jatropha curcas Linnaeus) and a locally produced ethanol alcohol. Special attention was paid to the optimization of base-catalyzed transesterification for converting fatty acid ethyl ester (FAEE). The crude Jatropha oil used in the transesterification contained 5.01 mg KOH/g of acid and after neutralization it was possible to bring down the acid value to 1.35 mg KOH/g. Inorder to determine the optimum condition for tranestefication of Jatopha oil using ethanol and caustic soda as input, 16 experiments varyings ethanol-to-oil molar ratio (6:-9:1) and reaction temperature (55, 65, 70, and 78 oC). Reaction time, mixing intensity, and catalyst concentration was fixed to 3 hrs, 600 rpm, and 1.5 % by weight of the oil respectively. The optimum conditions found for transesterification were an ethanol-to-oil molar ratio of 9:1 and a reaction temperature of 70 0C. At the optimum condition obtained a FAEE conversion of 80 % v/v was achieved. The resulting Jatropha biodiesel has, a density of 0.86 g/ml, viscosity of 4.13 mm2/s, acid value of 0.71 mg KOH/g, and flash point of 173 0C satisfing ASTM D6751-02 and EN 14214 biodiesel standards. The production proces developed in this work will be used in production of a small scale plant withh capcity of 300 liter per day.
A Decision Support System on Equipment Replacement
(Addis Ababa University, 2002-06) Tecleab, Sium; Roy, R.N. (PhD)
Project Management Approach to The Establishment of Computer Assembly Plant in Ethiopia
(Addis Ababa University, 2002-06) Arefaine, Fessehatsion; Roy, R.N. (PhD)
The creation of the computer and the advancement in communication systems has led to the emergence of a new era called the information age. In the new era information is rapidly becoming the world's most valuable resources. The central part of the information technology (IT) is nothing but the computer. Due to its paramount importance the personal computer (PC) has become a part of day-to-day existence of people all over the world. As a result, the computer industry today is a trillion-dollar market. In order to narrow down the gap between the developed and developing nations, countries like Ethiopia should work hard to improve the level of their information and communication technology (ICT). These days it is realized that ICT is a proven tool that one must be equipped with in the fight against poverty and in the effort to secure sustainable economic development. ICT may be composed of four elements: computer hardware, software, communication equipment and know-how. The availability of PCs at cheaper prices and preferred designs would obviously enhance the development of ICT. It is seen that the demand for PCs in Ethiopia is increasing from time to time. But, the supply so far is from imports, with an expenditure of considerable sum of hard currency. In this regard, this thesis research attempts to analyze the feasibility of building a PC assembly plant in Ethiopia applying modern project management techniques. The research applies the method of trend analysis as well as market-buildup methods to estimate the xii present and future demand of PCs in Ethiopia. Make or buy decision analysis is carried out to indicate which components to make in-house and which ones to import form outside sources. The technology, organization and implementation plans are studied at the required depth. Finally, the financial viability of the project is analyzed with the help of appropriate software.
Marketing Decision Support System (Mdss) Case Studies on Aspsc & Mobil Oil East Africa Limited
(Addis Ababa University, 2004-06) Abebe, Abiy; Kitaw, Daniel (PhD))
Many marketing decisions are made in complex environments where numerous variables are affecting the decision outcomes. Faced with these difficulties, marketing executives seek decision aid tools like Marketing Decision Support System (MDSS). It is a tool to utilize relevant information from business environment and return it in to basis for making actions. Most of the international enterprises use this MDSS to improve the effectiveness of their decision making process. However, several of the domestic companies shy away from the use of decision support tools. The good examples of such companies are: Akaki Spare Parts and Hand Tools S. Co. and Mobil Oil East Africa Limited. The main intention of this thesis is to prepare tools that assist these two companies’ marketing decision makers in carrying out their tasks. To be successful, the companies’ current working systems are analyzed in detail with reference to the surveyed literatures. Then, selected decision problems are formulated using appropriate modeling techniques. Finally, computer programs that match with the diagnosed situations have developed by using visual basic computer programming language and its database by access computer programming language. The proposed MDSS works for four decision types, two from ASPSC and two from Mobil. It can be further implemented to other decision types with slight modifications.
Model Development for Improving the Performance of Projects A Case Study on Ethiopian Roads Authority(Era)
(Addis Ababa University, 2004-06) Talargie, Abrham; Kitaw, Daniel (PhD))
Productivity Improvement in Ethiopian Leather Industry Through Efficient Maintenance Managenet
(Addis Ababa University, 2004-06) Teklemariam, Misikir; Teklemariam, Misikir; Kitaw, Daniel (PhD)); Kitaw, Daniel (PhD))
Increasing global competition has made many business leaders and policy makers turn their attention to such critical issues as productivity and quality. Productivity improvement should be a concern of every industry regardless of the type of production, economic or political system. The definition of productivity, the ratio of output value to input value, remains the same for every sector. Productivity can either be improved through increasing the output value by increasing the quality or quantity of products, or through decreasing the input value by utilizing the resources effectively & efficiently. Efficient maintenance management is one way of improving the productivity through capital resources of the company. The paper examines how proper maintenance management improves the productivity of leather industries. Leather industry, as it is one of the potential economic sectors, it should be given proper attention for sustainable development of the country. Thus, the purpose of this paper is to propose improvement areas in maintenance activities of Ethiopian leather industries to improve their productivity by analyzing the problems associated with it.
Developing Project Performance Evaluation Model to Minimize Project Delay Based on Some Ongoing Industrial Projects
(Addis Ababa University, 2004-06) Geremew, Sisay; Roy., R.N. (PhD)
Delays and cost overruns are the rule rather than the exception in most industrial projects, and project management suffers from numerous problems of costing and scheduling. Cost overruns of 50 to 100% are common. Projects are often delayed to the point where the market conditions for which they were designed have changed. Many projects suffer from the "90% syndrome" in which a project is thought to be 90% complete for half the total time required. There is consensus among researchers and industry experts that one of the principal barriers to promote improvement in industrial projects is the lack of appropriate performance measurement. For continuous improvement to occur it is necessary to have performance measures which check and monitor performance, to verify changes and the effect of improvement actions, to understand the variability of the processes, and in general, it is a necessary to have objective information available in order to make effective decisions. The main body of this thesis is divided in to three major parts. The first part is a general literature review about the fundamentals and the process of project management, in which case the historical background of project management and the different functions of management (planning, organizing, monitoring and control) from the project stand point are revised. The second part of the thesis is all about data collection, analysis and presentation. In this case the different techniques of data collection are used to collect data and information some facts about Ethiopia on xi project performance evaluation criteria and the data is analyzed from different perspectives for presentation. In the last part of the thesis which is about the developing a general project performance evaluation model, three general project management models are discussed. Based on these general project management models and the data and information obtained from different parts of the country, a model is developed for performance evaluation. Finally a set of recommended model implementation steps and a general conclusion about the overall project performance evaluation is given.
Development of Production Planning and Control (Ppc) System of Job Order Companies in Ethiopia A Case Study on Akaki Spare Parts and Hand Tools Share Company (Aspsc)
(Addis Ababa University, 2004-06) Bawoke, Mezgebu; Kitaw, Daniel (PhD))
Planning system of any profit oriented company determines its survival. Whether a company is service giving or production type, the first thing expected from it is setting its objective properly. The process of setting objectives and their courses of action is planning. Manufacturing companies plan their production and formulate mechanisms of production controlling to be profitable and survive in the market. Production planning and control (PPC) is the process of deciding what to produce in advance, setting exact route of each item, fixing the starting and finishing date for each item, and following up the progress of products according to the order. PPC of job order companies is more complicated than that of non-job order companies. In this thesis work, PPC systems of some selected Ethiopian job order companies are analyzed. The PPC system of Akaki Spare Parts and Hand Tools Share Company, it problems and possible solution to the problems have been discussed in detail. Finally flowchart type of model which helps minimize the PPC related problems of ASPSC is developed. The model is developed after performing the following activities. 1. Visiting ASPSC and collecting all necessary data from it. 2. Visiting job order companies found in and outside Addis Ababa. 3. Visiting major customers of ASPSC. Data which are obtained from job order companies are used to compare the PPC system of ASPSC with other job order companies. Data which are collected from major customers are used as feedbacks to identify shortcomings of the PPC system of the company. Key words: PPC, Job Order Company, Forecasting, Aggregate Production Planning, Material Requirement Planning.
Computer Modeling and Simulation of Coal fired Cogeneration Power Plant
(Addis Ababa University, 2004-07) Tamirat, Yohannes; Alemu, Demiss (PhD)
This thesis describes a power plant simulator which has been developed using MATLAB code. The basis of the power plant modeled here is the design data of Coal-Phosphate Fertilizer Complex Project (COFCOP), and the type of boiler and turbine are taken as selected by the project. Therefore, the boiler modeled here is a circulating fluidized bed coal combustor type, and the turbine is an extraction condensing type at heat to power ratio. Conservation equations and characteristic curves are used to model each component of the power plant. From these mathematical model equations, the component modules are developed using MATLAB code. Output parameters are obtained from input data to the component modules. Simulation of systems, subsystems and components are accomplished using the Newton-Raphson technique. The total system of the power plant is simulated by a program called powerplant_main. In this program there are four basic solvers. These are: the turbine solver, the boiler solver, the water flow solver and the steam flow solver. Each solver has its own residue generator function and Jacobean generator function. The Gaussian elimination function is called by any solver during simulation. The power plant in COFCOP is still in design stage, and it cannot be used for program verification in this paper. Hence, a hypothetical power plant data is taken and the output of the simulation closely approximates the real case.
Thermal Stresses and Creep Analysis of Boiler Tubes
(Addis Ababa University, 2004-09) Taye, Chanyalew; Bazezew, Alem (PhD)
An analysis is developed for the calculation of creep deformation of an axisymmetric boiler tube subjected to axisymmetric load. The stresses and the permanent strains at a particular time and at the steady state condition, resulting from loading of the tube under constant internal pressure and elevated temperature were evaluated when accounts is taken to the secondary creep characteristics of a given material. In this thesis first the formulation of an analytical theory of creep for tubes according to the Bailey creep theory [41] was discussed. Bailey theory was proposed for an idealized homogeneous material loaded uniaxially. The theory takes into account the initial elastic strain, the transient creep strain, and the minimum creep rate strain. Next, more general solution by finite element method are presented and discussed for a class of problems in which no prior analytical solution may exists; like the cases of cracked and/or pitted boiler tubes. The method of solution is an extension of the direct stiffness method. The body is replaced by a system of discrete triangular cross-section ring elements interconnected along circumferential nodal circles. The equations of equilibrium for the body are derived from the principle of minimum potential energy. The creep behavior of the body is formulated in terms of creep laws in current use. Starting with the elastic solution of the problem, creep strains are treated as initial strains to determine the new stress distributions at the end of time interval. The procedure is repeated until either the final time is reached or until the stress distribution is not changed i.e. when a steady stated condition is reached. Calculated results according to arbitrarily selected boiler tube data are shown at the end.
Experimental Analysis of Drying of Agricultural Product
(Addis Ababa University, 2004-09) Hagos, Berhane; Assefa, Abebayehu (PhD)
An experimental system set up has been developed to investigate the drying rate of the selected material, the drying air temperature and relative humidity and moisture content profiles developed with the food materials during forced convective air drying. The moisture content profile was determined by employing the technique of oven drying method. Embedded thermocouples were used to sense temperature at different locations, and the embedded digital relative humidity measuring instruments were used to sense the relative humidity and recording the values manually at different locations of the drying chamber. A data logger and a computer front end were implemented for data acquisition. Temperature, relative humidity, moisture and drying rate profiles are presented as function of the drying time. All profiles described the drying phenomena inside each trays of the drying chamber. The close relations of overall drying rate and profiles of moisture content, drying air temperature and relative humidity are discussed. Finally correlations are formulated from the experimental data to relate the drying parameters; drying air temperature, relative humidity, velocity, initial moisture content of material to be dried and drying time that predict the moisture content on wet basis.
Transint Analysis of Cooling Load of a Single Zone Building
(Addis Ababa University, 2004-10) Fantu, Korbaga; Alemu, Demiss (PhD)
Cooling load calculation is the major work performed in the air-conditioning system design. This should be performed as accurately as possible to reduce over design or under design of the system. Some of the factors that influence results of cooling load are heat gain through wall and glass, infiltration of atmospheric air, ventilation, appliances load, and occupancy. The objective of this thesis is to develop a user-friendly program that can easily calculate space-cooling load of a single zone system taking some of the basic inputs like latitude, longitude time zone, building materials and other metrological data of the location. This thesis uses finite difference method for computation of transient heat conduction through the wall and roof. Implicit finite difference method is chosen for its stability.. To make the developed program more friendly, number of commonly used construction materials with their thermal properties are inbuilt in the program. Infiltration effect in the total cooling load is also discussed in detail. Various experimental data and graphs are used for determining the infiltration rate. Heat gain through window is calculated by taking solar heat gain coefficients (SHGC) of the various combinations of glass used. Various types of glass and glass combination with their thermal properties are also inbuilt in the program. The components of heat gain are finally categorized under convective and radiant portion. The convective portions are taken as cooling load. The radiant portions are changed to viii cooling load by multiplying them with radiant time factors. Beside the project uses number of assumptions proposed by ASHRAE for its calculation of heat gain and cooling load. All the above-mentioned influencing factors of cooling load calculation are dealt in-depth in the thesis in chapter 3 4 5 and 6. The results found are verified with results found in other literatures. Finally cooling load of an actual building in Gode is computed using the developed program.
A Petri net Approach to Bottling Line Modeling and Performance Analysis: A Case Study on Meta Abo Brewery Share Company
(Addis Ababa University, 2004-10) Lakew, Mesfin; Alemu, Demiss (PhD)
Increasing global competition has made many business leaders and policy makers turn their attention to such critical issues as productivity and quality. Businesses seek new approaches to production processes and manufacturing techniques and explore new boundaries of technology. One of the frequently prescribed remedies for the problem of decreased productivity and declining quality is the automation of factories. To achieve strategic benefits of automation in line with improved quality, greater flexibility, and cost reduction, firms must carefully manage the implementation of their techniques. In the light of the above, because of capital intensive and complex nature of automated manufacturing system (AMS), the design and operation of these systems require modeling and analysis in order to select the optimal design alternative and operational policy. Besides, errors in the modeling process can substantially contribute to the development time and cost. Therefore, special attention should be paid to the correctness of the models that are used at all planning levels. Petri nets as a graphical and mathematical tool provide a uniform environment for modeling, formal analysis and design of manufacturing systems. This study therefore, focuses on both traditional analysis of manufacturing system after setting key performance factors and the application of Petri nets in modeling and analysis of an AMS. It also includes a comprehensive review of xvi Petri nets and manufacturing system in view of Petri nets application domain. ith the view to give more emphasis in the practical and realistic industrial application of Petri nets, particularly in modeling and analysis of AMS, a case study on an existing manufacturing firm was carried. In this regard, Meta Abo Brewery S. Co (MABSCo) is believed to serve as a model. Above all, the success of Petri nets and related technologies can be greatly achieved only when more industrial engineers and designers use them together with other techniques in system development and operation. The author, being an industrial engineer, develop the sample model attributed to the bottling line of MABSCo through a careful study of relevant literatures, systematic data collection, and after systematic survey of the plant, particularly the bottling line. Further research in the future that includes other classes of Petri nets is also proposed to make the study more complete.
Design of Energy Efficient Buildings for Hot Areas of Ethiopia With Respect to Air Conditioning
(Addis Ababa University, 2004-10) W/abzgi, Teklay; Alemu, Demiss (PhD)
This thesis is intended to identify the design improvements of buildings that can be made for the hot region of Ethiopia. A detail literature survey is done on design improvements and those that can be most suitable and economical are suggested. A case study of two different buildings in Gode (one of the hottest area in Ethiopia) was conducted using building energy simulation software to quantify the energy saving from some of the design improvement measures such as using insulation in roof or ceiling and in walls, window glazing and shadings, and orientation. The simulation result verifies that using 75mm insulation in roof or ceilings give a better saving and most economical when the building has small glazing area with respect to the wall size and lower internal cooling load. And when the building has large glazing area using either internal or external window shading is the best way to reduce the annual energy cost of the building and 50mm roof insulation is most economical. In addition to the above results the relation between insulation and different conditions of cooling load in a building is verified. This result shows that when internal load and solar load through window are dominating insulation can have a negative impact to cooling load.
Aspects of Lean and Agile Manufacturing Systems and Their Appropriatness in Ethiopia
(Addis Ababa University, 2004-10) Zehrudin, Idris; Roy, R.N. (PhD)
The thesis deals with the principles of Lean and Agile Manufacturing Systems and their appropriateness in Ethiopian context. Inflexible mass-production methods that produce voluminous of standardized products were inadequate for demands of increased variety. In pursuit of greater flexibility and elimination of manufacturing wastes, Lean Production System has been developed. More recently, demand for further responsiveness to the everchanging customer demand and turbulent business environment, led to a formulation of Agile Manufacturing concept with the intention of greater adaptability. Thus, it is necessary to study their vital principles and adopt the appropriate system to improve the competitive capability of industries. Using available literatures, Internet, industry survey and analyzing the gathered pertinent information, the thesis reviewed the main principles of lean production system. Taking authentic pilot cases, enhanced value stream map is generated and lean Manufacturing Cell for cutlery production is designed. The fundamental principles of agile manufacturing system and then, the comparison of the two systems are also discussed. Finally the suitability of these systems in Ethiopia context is analyzed. It is found that Lean Manufacturing is a collection of technical and operational systems focused on productivity improvements with limited resources (44). LPS focuses on minimizing manufacturing wastes, continuously improving methods, utilizing flexible production system to produce variety of defect-free goods. Agile manufacturing (AM), on iii the other hand, is a comprehensive manufacturing system focused on thriving in unpredictable business environment. AM focuses on enriching customers, reorganizing production system for greater flexibility, cooperation to enhance market responsiveness and increased use of Information technology. The comparison between these systems shows a difference in viewpoint and perhaps strategy with regard to change, but not in method or approach. Cases on the implementation of Lean techniques indicate that industries can enhance competitiveness by adapting Lean. The survey revealed that Industries are experiencing forces that lead to more responsiveness. More over, it is found that most industries believe that the Lean Production is more appealing in current Ethiopian Industries Situation.
Quality Management System in Ethiopian Food Procssing Industries A Case Study at D.H. Geda P.L.C. & Elfora Agro-Industries
(Addis Ababa University, 2004-11) Tsegaye, Ezra; Kitaw, Daniel (PhD))
Like most industries in Ethiopia, the food processing industries are suffering from quality related problems. These problems include poor performance of products in the export market, low quality and insufficient raw material supply, low product confidence due to lack of quality assurance systems and increased pressure from high quality and competitive products in the local market. The proposed solution is to implement a properly developed Quality Management System (QMS) in the industry. Based on the assessment of two cases in the food processing industries (D.H.GEDA & ELFORA Agro-Industries) and other information, seven main components and three minor elements have been identified for this QMS. The first deals with the role of managers and owners, which includes leadership, decision-making and organization related to quality. Quality issues related to raw material and inputs are addressed in the supplier-relationship. Quality design is where customer based products are developed. Quality improvement is the general approach that must be adopted to improve processes and product. Quality control activities are carried out to minimize defect during processing. Quality assurance deals with meeting internationally recognized system to assure product/process quality. To improve the QMS quality review and audits are used. Although they are partially discussed in the main components, elements such as quality manuals, cost of quality, and customers need more focus. This QMS can alleviate a considerable proportion of problems in the industry. As the food processing industry dominates the manufacturing industry, such exertion will have tremendous impact on the overall performance of the economy.
Computer-Aided Dynamic Force Analysis of Four-Bar Planar Mechanisms
(Addis Ababa University, 2004-11) Metiku, Robel; Bazezew, Alem (PhD)
The four-bar linkage is the most basic chain of pin-connected links that allows relative motion between links. Although a simple mechanism, the four-bar linkage mechanism is very versatile and used in thousands of applications. The main themes of this thesis are the modeling, computer-aided dynamic force analysis and simulation of four-bar planar mechanisms composed of rigid bodies and massless force and torque producing elements. Motions of the rigid bodies are predicted by numerically integrating Differential-Algebraic Equations (DAEs) developed from principles of mechanics by using the Newton-Euler’s approach. The computer program used for solving the equations developed in the analysis problem and that integrates the differential equations is Matlab.
Implementation of Just-in-Time Production System In Automotiive Manufacturiing Company of Ethiiopiia and Addiis Ababa Bottle & Glass Factory
(Addis Ababa University, 2004-11) Garoma, Temesgen; ROY, R.N. (PhD)
Traditionally, a manufacturing business competes on price, variety, and after service. Now, these conditions are merely prerequisites. Few businesses exist today without offering this requirement, and the key competitive factor has become speed. Major businesses have been trying to adopt new business initiatives in order to stay alive in the new competitive market place, and there is no question that the elimination of waste is an essential ingredient for survival in today's manufacturing world. Companies must strive to create high quality, and low cost products that can get to the customers in the shortest time possible. Just-in-time production system is one of these initiatives that focus on cost reduction by eliminating non-value added activities. The tools and techniques of JIT have been widely used in both discrete and process industry starting with the introduction of the original Toyota production system. This thesis addresses the implementation of Just-in-Time production system with focus on AMCE and AABGF. The goal of this research is to investigate how JIT can be implemented in these companies. This thesis attempts to introduce JIT from its conception, and many collaborative JIT concepts, components, elements, and tools that are used for the elimination of wastes are addressed. To develop the implementation model first the status of the companies were investigated and then the problems are identified and x formulated. The JIT implementation guidelines developed by APICS and others have been seen to develop the line implementation model of JIT for the companies. It has been seen that only a hybrid (Push-Pull) JIT systems is applicable to both companies. In the implementation model developed, Value stream mapping was used as a tool. The companies can use it to identify various types of waste in the value stream of the company and try to take steps to eliminate them. Finally the conclusions and recommendations are provided for the thesis.
Simulation of Modern Steam Power Plant
(Addis Ababa University, 2005-06) Hailu, Alemayehu; Assefa, Abebayehu (PhD)
The thesis describes a steam power plant simulator which has been developed using the MATLAB code. The simulation is important to study the behavior of the steam power plant system by means of a model, and the results obtained allow us to consider many different design possibilities as well as varieties operating conditions. Therefore, different designs may be evaluated so that an acceptable design can be chosen and safe levels may be established for the operating conditions. These results are also used for optimization of the plant. The basic considerations in the development of a mathematical model are first presented in the thesis, followed by a discussion of simulation of a steam power plant. Conservation equations and characteristic curves are used to model the component of the steam power plant. From these mathematical model equations, the component modules are developed using MATLAB code. Output parameters are obtained from input data to the component modules. The STEAM_POWER_PLANT_SIMULATION program is used to simulate the power plant system. In the program there are two main solvers. These are: the turbine-heater solver and boiler solver. The turbine-heater solver consists of the turbine and feed water heaters including the pumps and the condenser. The boiler solver has its own residue generator function and Jacobean generator function and then Newton-Raphson technique is used to solve a set of nonlinear algebraic equations.
Effect Of Incompressibility in The Analysis of Metal Forming Using Finite Element Method
(Addis Ababa University, 2005-09) Ahmed Nurye; Tamrat Tesfaye (PhD)
Metal forming is one of the most common metal manufacturing processes used, which is noted for its minimum waste and dimensional precision, and usually improves the mechanical properties of the formed part. Metal forming process is a process that causes changes in the shape of solid metal particles via plastic (permanent) deformations. Hence, knowledge of metallurgy and mechanics combine to provide an insight to its behavior. Its applications are wide in the manufacturing of machinery, automotive, aerospace and other hardware components. The material is modeled as a hyperelastic, viscoplastic solid. A constitutive model with a single scalar variable representing the isotropic resistance to the plastic flow is employed. Many finite elements exhibit the so-called ‘volumetric locking’ in the analysis of incompressible or quasiincompressible problems in metal forming. Nearly incompressible plasticity in metal forming displays severe volume locking problems when low order standard nodal-based displacement methods are used. This means that after deformation each small portion of the medium has the volume as before the deformation. In this thesis a finite element formulation for a frictionless large deformation contact problem in metal forming is presented. It is based on the formulation which introduces the contact constraints via Lagrange multipliers. The stabilized formulation which allows the use of low-order interpolation functions for both displacement and the pressure field is applied to eliminate volumetric locking effects and to circumvent numerical instabilities. Starting from the variational formulation of the constitutive and the kinematic problems, the linearization of the principle of virtual work relation, the contact potential energy, and finally the matrix formulation of the method is derived. To improve the convergence property of the method an augmentation step was included. Then the formulation is converted to a computer code written using Matlab. Finally the program is used to solve a benchmark example.

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