Mühendislik Fakültesi / Faculty of Engineering
Permanent URI for this collectionhttps://hdl.handle.net/11727/1401
Browse
13 results
Search Results
Item A Decision Support System for Selection of Net-Shape Primary Manufacturing Processes(2014) Yurdakul, Mustafa; Arslan, Emre; Ic, Yusuf Tansel; Turkbas, O. Selim; https://orcid.org/0000-0001-9274-7467; AGE-3003-2022Developments in the capabilities of the manufacturing processes increased the number of processes that can produce a part within the requirements determined by its design and market research. The increased number of processes and unfamiliarity of manufacturing engineers to many new manufacturing processes forces the researchers to develop systematic process selection tools instead of depending on the accumulated human expertise only. In this paper, a net-shape primary manufacturing process selection decision support system (DSS), which is named PROSEL (PROcess SELection), is developed. The developed selection programme eliminates the unsuitable processes step by step by checking a part's material, annual production quantity, specified shape, thickness and presents the most economical process as the most appropriate net-shape primary process after a final cost analysis. The developed DSS is written in Visual Studio and tested with a great deal of real-life examples. It can be concluded from the tests that the programme provides the same or better primary manufacturing process selection decisions than the practical usage, and it is a very useful support tool for net-shape primary process selections.Item Development of A Multi-Level Performance Measurement Model for Manufacturing Companies Using A Modified Version of the Fuzzy TOPSIS Approach(2018) Yurdakul, Mustafa; Ic, Yusuf Tansel; 0000-0002-1562-5738; 0000-0001-9274-7467; AAA-6966-2021; AGE-3003-2022This paper aims to develop a comprehensive hierarchical performance measurement model. The proposed model not only determines a manufacturing company's overall performance within its industry but also obtains its strengths and weaknesses in critical activities. It lets one to combine a company's performance scores in seventeen critical activities with important industry-specific objectives to obtain a single overall performance score by using a 4-Point Fuzzy Scale and a modified fuzzy version of the Technique for Order Preference by Similarity to Ideal Solution approach. The calculated overall performance scores provide a ranking order among manufacturing companies within their industry. In addition, it also enables each company to compare its performance in critical activities with respect to other companies in its industry. Furthermore, the performance measurement model has the capability to determine what a company should do to improve its performance in critical activities. This paper provides an example to illustrate the application of the proposed model.Item Development of A Decision Support System for Robot Selection(2013) Ic, Yusuf Tansel; Yurdakul, Mustafa; Dengiz, Berna; 0000-0001-9274-7467; 0000-0002-1562-5738; AGE-3003-2022; AAA-6966-2021With the availability of more different robot types and models along with their separate specifications, selecting the most appropriate robot is becoming more difficult and complicated for companies. Furthermore, a common set of robot selection criteria is not available for the decision makers. In this study, a two-phase robot selection decision support system, namely ROBSEL, is developed to help the decision makers in their robot selection decisions. In development of ROBSEL, an independent set of criteria is obtained first and arranged in the Fuzzy Analytical Hierarchy Process (FAHP) decision hierarchy. In the first elimination phase of the decision support system, the user obtains the feasible set of robots by providing limited values for the 15 requirements. ROBSEL, then, uses FAHP decision hierarchy to rank the feasible robots in the second phase. ROBSEL is illustrated and tested and several critical issues in its practical usage are explored in the paper. The applications of ROBSEL show that ROBSEL is a useful, practical and easy to use robot selection tool and improves robot selection decisions in the companies. (C) 2012 Elsevier Ltd. All rights reserved.Item Analysis of the Robustness of the Operational Performance Using a Combined Model of the Design of Experiment and Goal Programming Approaches for a Flexible Manufacturing Cell(2023) Ic, Yusuf Tansel; Yurdakul, Mustafa; Dengiz, Berna; Sasmaz, TurgutA combined model of a 2(k) design of experiment (DOE) and goal programming (GP) approaches is presented to determine optimum levels of input variables and analyze their robustness for a multiobjective performance of a flexible manufacturing cell (FMC) in this study. Two main performance metrics, namely, manufacturing lead time (MLT) and surface roughness (SR), are considered performance outputs for the FMC. Machine sequence, robot speed, tool type, and material type are selected as the four input variables on the input side of the proposed model. The study shows that even with a limited number of experiments, one can determine optimum input levels for the multiobjective performance of the FMC and determine their robustness.Item Development of a Goal Programming Model Based on Response Surface and Analytic Hierarchy Process Approaches for Laser Cutting Process Optimization of St-52 Steel Plates(2022) Yurdakul, Mustafa; Tukel, Taha; Ic, Yusuf TanselThis paper presents an integrated model for optimization of laser cutting process of St-52 steel plates with multiple performance characteristics using Goal Programming (GP), Analytic Hierarchy Process (AHP), and Response Surface Methodology (RSM) approaches. In this study, optimum levels of the laser cutting process input parameters namely, material thickness, cutting speed, laser power, and assist gas pressure are obtained. For optimization purposes, four different surface roughness types of a cut surface, surface hardness, cutting time, and heat-affected zone (HAZ) of the cut surface are considered as performance outputs (responses) in this study. Optimization of multiple performance objectives (responses) requires obtaining regression functions with RSM first, and then weighting the regression functions using the AHP and finally combining the multiple functions into a single overall goal within a GP model and solving the model to optimize the laser cutting process. The study clearly shows that the presented optimization model is flexible enough to optimize the laser cutting process for various scenarios and conflicting priorities.Item Analysis of the manufacturing flexibility parameters with effective performance metrics: a new interactive approach based on modified TOPSIS-Taguchi method(2022) Ic, Yusuf Tansel; Sasmaz, Turgut; Yurdakul, Mustafa; Dengiz, Berna; 0000-0001-9274-7467; AGE-3003-2022Flexibility is one of the most important strategy parameters to achieve a long-term successful performance for a manufacturing company. Studies in the literature aim to operate a manufacturing system at optimum levels of flexibility parameters under its own manufacturing environment. This study aims to present an interactive analysis framework based on TOPSIS and Taguchi parameter design principles for investigating the effects of different levels of flexibility parameters on the performance of a flexible manufacturing cell (FMC). The main performance metric used in this study is manufacturing lead time. Other important metrics to evaluate quality control and inspection policies are also investigated in this study. To conclude, a combined model of an interactive approach based on TOPSIS and Taguchi methods are used to assess the effectiveness of the flexibility parameters for a FMC.Item Development and comparison of airplane fuselage panel assembly system alternatives using axiomatic design principles and simulation methodology(2022) Celek, Osman Emre; Yurdakul, Mustafa; Ic, Yusuf Tansel; 0000-0001-9274-7467; AGE-3003-2022This paper presents a combined usage of axiomatic design principles and simulation in developing and comparison of alternative assembly systems for airplane fuselage panels. In the application, four assembly system alternatives are obtained with axiomatic design methodology; and their performance results are obtained using simulation. The simulation results are made available for system designers to see each alternative's capabilities and make a comparison among the alternatives. The application of the proposed combined application of axiomatic design principles and simulation provides a reference guide for system designers to apply in designing other assembly systems' design.Item Risk-based inspection planning for internal surface defected oil pipelines exposed to fatigue(2022) Sozen, Levent; Yurdakul, Mustafa; Ic, Yusuf TanselThe pipelines should be inspected periodically to minimize the probability of failure. The timing of these periodic inspections can be determined by a risk assessment that considers the probability of failure of the pipeline and the potential undesirable effects of the chemical transferred. These are referred to as risk-based inspection methods in the literature. We evaluate pipelines with internal surface defects and under the effect of variable pressure in this study. Internal surface defects were considered production-related, and there is a lack of studies in the literature examining such kinds of defects. These defects generate the concentration of stress on the pipeline section. The reliability variation of the pipeline depends on some factors, namely, surface defect ge-ometry, the pipe section geometry, and the mechanical properties of the pipe. Fatigue is accepted as the crucial damage mechanism. The cause of variable load is considered as the number of operations. As a result of the study, the probability of fatigue failure for pipelines with internal surface defects was evaluated. Then, a new approach was proposed for risk-based inspection planning of the pipelines. As a case study, the probability of fatigue failure on a fuel pipeline established between a refinery and an oil terminal operating in Turkey was calculated. Also, we tried to determine the most appropriate inspection time. The data used in the planning phase was collected from a measurement process performed on the pipeline using PIG (Pipe Inspection Gauge). Finite element analysis was used to calculate stress concentration factors. Finally, we used the Monte Carlo simulation method to obtain the probability of failure.Item Development of a New Support Mechanism to Calculate Feed-in Tariffs for Electricity Generation from Renewable Energy Sources in Turkey(2019) Yurdakul, Mustafa; Ic, Yusuf Tansel; 0000-0001-9274-7467; AGE-3003-2022Turkish government agencies support capital investments in electricity generation from renewable energy sources. When making support decisions related with renewable electrical energy sources, the government agencies should consider various issues such as renewability, cleanliness, origin of the source, supply security, cost per kilowatt hour (kWh), and total electricity generation capacity. The tariff mechanism being used in Turkey provides constant rates per kWh of electricity generated from renewable energy sources. The levels of the rates are determined to stimulate renewable energy sources' usage. In this paper, instead of a constant rate, a feed-in tariff is calculated for each individual electricity generation project using renewable energy source and its level is increased according to the source's desirability with respect to other renewable energy sources. Various criteria are taken into account in determination of electrical energy sources' desirability. Furthermore, a combination of two multi-criteria decision-making (MCDM) approaches (the fuzzy versions of the analytic hierarchy process (AHP) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)) is used in obtaining a ranking among alternative renewable electrical energy sources. The developed support model's applicability is illustrated in this paper. The new model developed in this paper has many key benefits. For example, for an individual renewable electrical energy project, final cost per kWh can be calculated and multiplied by new Support Constant to calculate feed-in tariff purchase price per kWh. In another key benefit of the developed model, only local instead of state-wide renewable electrical energy projects can be compared within the AHP-TOPSIS decision hierarchy.Item Development of a new trapezoidal fuzzy AHP-TOPSIS hybrid approach for manufacturing firm performance measurement(2021) Ic, Yusuf Tansel; Yurdakul, Mustafa; 0000-0001-9274-7467; AGE-3003-2022This study develops a multi-level hierarchical performance measurement model to measure a manufacturing firm's overall performance score by grading its success levels in critical operations and combining them. Linking overall performance score to local grades of a manufacturing firm in critical operations requires placement of manufacturing goals in the performance measurement model. The relative importance scores of the components at any level in the multi-level performance measurement model with respect to each component belonging to the immediately above level are determined using the fuzzy analytic hierarchy process (FAHP) method. The relative importance scores of the components are combined with success grades in seventeen pre-determined critical operations to obtain overall performance scores for manufacturing firms using the technique for order preference by similarity to ideal solution (TOPSIS) approach. In this study, scorecards are developed to guide scoring in each critical operation by checking levels of success in terms of practices, infrastructures, investments and actions. The developed performance measurement approach provides a structured decision-making environment with the scorecards and fixed hierarchy. Furthermore, the developed approach is more comprehensive in representing important issues necessary for obtaining realistic overall performance scores. For example, fuzzy numbers take into account vagueness (uncertainties) in the assignment of scores. Another advantage identified by the users is that the developed decision hierarchy can be adapted to new sectors or decision environments by adding new components or removing existing ones using the same overall structure and calculation steps.