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Lotfısadıgh, Bahram
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Name Variants
Lotfisadigh, B.
Lotfısadıgh, Bahram
Bahram, Lotfısadıgh
Lotfisadigh, Bahram
L.,Bahram
B.,Lotfisadigh
L., Bahram
Bahram, Lotfisadigh
B., Lotfisadigh
B.,Lotfısadıgh
Lotfısadıgh,B.
Lotfisadigh,B.
Sadigh, Bahram Lotfi
Lotfısadıgh, Bahram
Bahram, Lotfısadıgh
Lotfisadigh, Bahram
L.,Bahram
B.,Lotfisadigh
L., Bahram
Bahram, Lotfisadigh
B., Lotfisadigh
B.,Lotfısadıgh
Lotfısadıgh,B.
Lotfisadigh,B.
Sadigh, Bahram Lotfi
Job Title
Doktor Öğretim Üyesi
Email Address
bahram.lotfisadigh@atilim.edu.tr
ORCID ID
Scopus Author ID
Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Scholarly Output
10
Articles
6
Citation Count
66
Supervised Theses
3
10 results
Scholarly Output Search Results
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Master Thesis Ultrasonik destekli frezeleme işlemi kullanarak kesilmesi zor malzemelerin işlenebilirliğini artırmaya yönelik deneysel bir araştırma(2019) Namlu, Ramazan Hakkı; Lotfısadıgh, Bahram; Lotfısadıgh, Bahram; Kılıç, Sadık Engin; Mechanical Engineering; Manufacturing EngineeringTi-6Al-4V, yüksek mukavemet/ağırlık oranı, iyi korozyon direnci ve mükemmel kırılma tokluğu gibi eşsiz malzeme özelliklerine sahiptir. Bu nedenle, işlemenin önemli bir süreç olduğu havacılık, tıp ve otomotiv endüstrilerinde yaygın olarak. Bununla birlikte, Ti-6Al-4V'nin işlenmesi aşınma direnci ve düşük ısı iletkenliği nedeniyle oldukça zordur. Ultrasonik destekli işleme, talaşlı imalat uygulamalarında oldukça yeni bir methoddur ve azaltılmış kesme kuvvetleri, arttırılmış yüzey kalitesi ve azaltılmış takım aşınması gibi geleneksel işleme proseslerine göre sayısız avantaja sahiptir. Ek olarak, minimum miktar yağlama (MMY) işlem verimliliğindeki birçok iyileştirme nedeniyle, geleneksel soğutma sistemlerinin yerine kullanılan alternatif bir soğutma türüdür. Kesme kuvvetleri, bir işleme prosesinin kesme performansını ölçen en önemli çıktılardan biridir. İşleme için bir başka önemli çıktı, iş parçasının kalitesi üzerindeki doğrudan etkisi nedeniyle yüzey pürüzlülüğüdür Bununla birlikte, ultrasonik destekli işlemede kesme kuvvetleri ve yüzey pürüzlülüğündeki değişiklikleri minimum miktarda yağlama kullanımı ile karşılaştırmak için çok fazla çalışma yoktur.. Bu çalışmada, Ti-6AL-4V malzemesinin işlenmesi sırasında kesme kuvvetleri ve yüzey pürüzlülüğündeki değişiklikler, MMY kullanılarak Z ekseninde kesici takıma uygulanan ultrasonik titreşimler ile ultrasonik destekli frezeleme kullanılarak araştırılmıştır. Bunun literatürde ilk kez yapıldığı düşünülmektedir. Tezde yapılan deneysel çalışma, MMY soğutmalı ultrasonik destekli frezelemenin, kesme koşulları uygun şekilde seçilirse kesme kuvvetleri ve yüzey kalitesi açısından kesme performansını önemli ölçüde artırabildiğini göstermiştir.Article Citation Count: 6Cutting Force Prediction in Ultrasonic-Assisted Milling of Ti-6al With Different Machining Conditions Using Artificial Neural Network(Cambridge University Press, 2021) Namlu, Ramazan Hakkı; Turhan, Cihan; Lotfısadıgh, Bahram; Kılıç, Sadık Engin; Energy Systems Engineering; Mechanical Engineering; Manufacturing EngineeringTi-6Al-4V alloy has superior material properties such as high strength-to-weight ratio, good corrosion resistance, and excellent fracture toughness. Therefore, it is widely used in aerospace, medical, and automotive industries where machining is an essential process for these industries. However, machining of Ti-6Al-4V is a material with extremely low machinability characteristics; thus, conventional machining methods are not appropriate to machine such materials. Ultrasonic-assisted machining (UAM) is a novel hybrid machining method which has numerous advantages over conventional machining processes. In addition, minimum quantity lubrication (MQL) is an alternative type of metal cutting fluid application that is being used instead of conventional lubrication in machining. One of the parameters which could be used to measure the performance of the machining process is the amount of cutting force. Nevertheless, there is a number of limited studies to compare the changes in cutting forces by using UAM and MQL together which are time-consuming and not cost-effective. Artificial neural network (ANN) is an alternative method that may eliminate the limitations mentioned above by estimating the outputs with the limited number of data. In this study, a model was developed and coded in Python programming environment in order to predict cutting forces using ANN. The results showed that experimental cutting forces were estimated with a successful prediction rate of 0.99 with mean absolute percentage error and mean squared error of 1.85% and 13.1, respectively. Moreover, considering too limited experimental data, ANN provided acceptable results in a cost-and time-effective way. Copyright © The Author(s), 2020. Published by Cambridge University Press.Article Citation Count: 6Predictive Models for Mechanical Properties of Expanded Polystyrene (eps) Geofoam Using Regression Analysis and Artificial Neural Networks(Springer London Ltd, 2022) Akis, E.; Lotfısadıgh, Bahram; Guven, G.; Lotfisadigh, B.; Manufacturing EngineeringInitial elastic modulus and compressive strength are the two most important engineering properties for modeling and design of EPS geofoams, which are extensively used in civil engineering applications such as light-fill material embankments, retaining structures, and slope stabilization. Estimating these properties based on geometric and physical parameters is of great importance. In this study, the compressive strength and modulus of elasticity values are obtained by performing 356 unconfined compression tests on EPS geofoam samples with different shapes (cubic or disc), dimensions, loading rates, and density values. Using these test results, the mechanical properties of the specimens are predicted by linear regression and artificial neural network (ANN) methods. Both methods predicted the initial modulus of elasticity (E-i), 1% strain (sigma(1)), 5% strain (sigma(5)), and 10% strain (sigma(10)) strength values on a satisfactory level with a coefficient of correlation (R-2) values of greater than 0.901. The only exception was in prediction of sigma(1) and E-i in disc-shaped samples by linear regression method where the R-2 value was around 0.558. The results obtained from linear regression and ANN approaches show that ANN slightly outperform linear regression prediction for E-i and sigma(1) properties. The outcomes of the two methods are also compared with results of relevant studies, and it is observed that the calculated values are consistent with the results from the literature.Master Thesis Yazılım Araçları Kullanarak Kablaj Tasarımı ve Maliyetanalizinin Modellenmesi ve Optimizasyonu(2021) Tankut, Mehmet Kemal; Lotfısadıgh, Bahram; Lotfısadıgh, Bahram; Kara, Ali; Manufacturing EngineeringBir kablaj elektriksel gücü, sinyali veya veriyi iki veya daha fazla kaynak arasında ileten kablo ağı veya kablo montajlarına denir. Bir kablaj aynı zamanda, konnektörleri, arkalıkları, iletken telleri, koruyucu kılıfları, branşmanları, metal örgüleri, kablo ceketlerini ve birleştirici kılıfları gibi bazı alt bileşenler içerebilir. Bir kablaj çeşitli materyal ve alt bileşen içerebildiği için gerekli malzemelerin kablaj tasarımı ve imalatı sürecinde belirlenmesi kritiktir. Bu nedenle, uygun bileşenlerin seçimi, standartlar ve veri sayfalarına göz atmak için çok fazla zaman gerektirir. Zaman kayıpları, büyük ölçüde tasarımcıların deneyim düzeyine ve istenilen kablajın karmaşıklığına bağlıdır. Bu araştırmada, kablo demeti tasarımı sırasında zaman kayıplarını azaltmak ve bu arada bileşen seçimlerinde hata riskini azaltmak için yazılım geliştirilmiştir. Bu çalışma, kablaj karmaşıklığı ve tasarımcı tecrübesi göz önünde bulundurularak, kablaj tasarım sürecini geliştirmeye yönelik böyle bir girişimin etkilerini ve sonuçlarını özetlemektedir. Deneysel sonuçlara göre, her tasarımcı için projelerde aylık harcanan zaman hesaplanmış ve bir maliyet modeli geliştirilmiştir. Son olarak, hazırlanan yazılımın katkısı değerlendirilmiş ve sonuçlar, bu yazılımın kablaj tasarım ve geliştirme sürecinde, kablaj karmaşıklığı ve kullanıcı deneyimi ne olursa olsun uygulanmasının faydalı olduğunu göstermektedir.Conference Object Citation Count: 11An Experimental Study on Surface Quality of Al6061-T6 in Ultrasonic Vibration-Assisted Milling With Minimum Quantity Lubrication(Elsevier B.V., 2022) Namlu,R.H.; Namlu, Ramazan Hakkı; Yilmaz,O.D.; Lotfisadigh,B.; Yılmaz, Okan Deniz; Kiliç,S.E.; Lotfısadıgh, Bahram; Mechanical Engineering; Manufacturing EngineeringAl6061-T6 is frequently used in the automotive and aerospace industries, where milling is an essential process, due to its high strength-to-weight ratio. In order to achieve improved surface quality in milling, Ultrasonic Vibration-Assisted Milling (UVAM) has been introduced recently. Besides, Minimum Quantity Lubrication (MQL) is another advanced method to enhance the surface properties of the cutting by improving the coolant performance. However, the effects of simultaneous implementation of UVAM and MQL methods has not yet been studied sufficiently. This paper investigates the effects of applying UVAM in tandem with MQL in cutting of Al6061-T6. The results showed that surface quality enhanced with this combination. © 2022 The Authors.Article Citation Count: 17A Survey of Partner Selection Methodologies for Virtual Enterprises and Development of a Goal Programming-Based Approach(Springer London Ltd, 2016) Nikghadam, Shahrzad; Kılıç, Sadık Engin; Sadigh, Bahram Lotfi; Ozbayoglu, Ahmet Murat; Lotfısadıgh, Bahram; Unver, Hakki Ozgur; Kilic, Sadik Engin; Manufacturing EngineeringA virtual enterprise (VE) is a platform that enables dynamic collaboration among manufacturers and service providers with complementary capabilities in order to enhance their market competitiveness. The performance of a VE as a system depends highly on the performance of its partner enterprises. Hence, choosing an appropriate methodology for evaluating and selecting partners is a crucial step toward creating a successful VE. In this paper, we begin by presenting an extensive review of articles that address the VE partner selection problem. To fill a significant research gap, we develop a new goal programming (GP)-based approach that can be applied in extreme bidding conditions such as tight delivery timelines for large demand volumes. In this technique, fuzzy analytic hierarchy process (F-AHP) is used to determine customer preferences for four main criteria: proposed unit price, on-time delivery reliability, enterprises' past performance, and service quality. These weights are then incorporated into the GP model to evaluate bidders based on customers' preferences and goals. We present a case study in which we implement the F-AHP-GP technique and verify the model's applicability, as it provides a more flexible platform for matching customers' preferences.Article Citation Count: 10An Experimental Investigation on the Effects of Combined Application of Ultrasonic Assisted Milling (uam) and Minimum Quantity Lubrication (mql) on Cutting Forces and Surface Roughness of Ti-6al(Taylor & Francis inc, 2021) Namlu, Ramazan Hakki; Namlu, Ramazan Hakkı; Sadigh, Bahram Lotfi; Kılıç, Sadık Engin; Kilic, Sadik Engin; Lotfısadıgh, Bahram; Mechanical Engineering; Manufacturing EngineeringTi-6Al-4V is widely used in aerospace, medical and defense industries where materials with superior characteristics are needed. However, Ti-6Al-4V is categorized as a difficult-to-cut material, and machining of this alloy is highly challenging. Ultrasonic Assisted Milling (UAM) is a quite recent method to facilitate the machining of difficult-to-cut materials. This method has numerous advantages over the Conventional Milling (CM) method, such as reduced cutting forces and increased surface quality. Besides, Minimum Quantity Lubrication (MQL) is an alternative cooling method to enhance the process efficiency with respect to conventional cooling methods. Cutting force and surface roughness are essential measures to evaluate the cutting performance of a machining process. However, the simultaneous effects of implementing MQL and ultrasonic vibrations in milling operations are not much researched yet. In this study, the combined effects of UAM and MQL on cutting forces and surface roughness during the machining of Ti-6AL-4V are investigated. Results show that the combination of MQL and UAM enhances the cutting forces in rough cutting operations and the surface roughness in both finish and rough cutting operations significantly compared to conventional processes. Consequently, it is concluded that simultaneous implementation of UAM and MQL enhances overall cutting performance in end-milling operation of Ti-6Al-4V.Article Citation Count: 8An Ontology-Based Multi-Agent Virtual Enterprise System (omave): Part 1: Domain Modelling and Rule Management(Taylor & Francis Ltd, 2017) Sadigh, Bahram Lotfi; Lotfısadıgh, Bahram; Unver, Hakki Ozgur; Nikghadam, Shahrzad; Kılıç, Sadık Engin; Dogdu, Erdogan; Ozbayoglu, A. Murat; Kilic, S. Engin; Manufacturing EngineeringNew advancements in computers and information technologies have yielded novel ideas to create more effective virtual collaboration platforms for multiple enterprises. Virtual enterprise (VE) is a collaboration model between multiple independent business partners in a value chain and is particularly suited to small and medium-sized enterprises (SMEs). The most challenging problem in implementing VE systems is ineffcient and inFLexible data storage and management techniques for VE systems. In this research, an ontology-based multi-agent virtual enterprise (OMAVE) system is proposed to help SMEs shift from the classical trend of manufacturing part pieces to producing high-value-added, high-tech, innovative products. OMAVE targets improvement in the FLexibility of VE business processes in order to enhance integration with available enterprise resource planning (ERP) systems. The architecture of OMAVE supports the requisite FLexibility and enhances the reusability of the data and knowledge created in a VE system. In this article, a detailed description of system features along with the rule-based reasoning and decision support capabilities of OMAVE system are presented. To test and verify the functionality and operation of this system, a sample product was manufactured using OMAVE applications and tools with the contribution of three SMEs.Article Citation Count: 8An Ontology-Based Multi-Agent Virtual Enterprise System (omave): Part 2: Partner Selection(Taylor & Francis Ltd, 2017) Sadigh, Bahram Lotfi; Lotfısadıgh, Bahram; Nikghadam, Shahrzad; Ozbayoglu, A. Murat; Kılıç, Sadık Engin; Unver, Hakki Ozgur; Dogdu, Erdogan; Kilic, S. Engin; Manufacturing EngineeringA virtual enterprise (VE) is a collaboration model between multiple business partners in a value chain. The VE model is particularly feasible and appropriate for small- and medium-sized enterprises (SMEs) and industrial parks containing multiple SMEs that have different vertical competencies. The VE consortium's success highly depends on its members. Therefore, it is crucial to select the most appropriate enterprises when forming a VE consortium. In this study, a new multi-agent hybrid partner selection algorithm is developed for application in the development of an ontology-based multi-agent virtual enterprise (OMAVE) system. In this platform, the agent's interactions are supported by agent ontology, which provides concepts, properties and all message formats for the agents. Different types of agents collaborate and compete with each other so that unqualified or inefficient enterprises are eliminated from the enterprise pool. Only the remaining enterprises would be allowed to enter the negotiation process and propose in the bidding. The agent-based auctioning platform is coupled with a fuzzy-AHP-TOPSIS algorithm to evaluate partners based on their proposals and background. Accordingly, the winning enterprise for each task is identified and the whole project can be accomplished by assigning tasks to the responsible partners. To test and verify the functionality of the developed OMAVE system, a sample module using OMAVE applications and tools was manufactured. The last section of this paper presents the results of this case study, which validate the applicability of the proposed technique.Master Thesis Ayrık Üretim Sistemlerinde Kestirimci Bakım için Akıllı Süreç Planlama Uygulaması(2022) Al-humaırı, Elaf Rıyadh Resen; Lotfısadıgh, Bahram; Lotfısadıgh, Bahram; Amınbakhsh, Saman; Manufacturing EngineeringSıkı küresel pazar rekabeti ve sürekli değişen müşteri talepleri, üretim işletmelerini esnek üretim sistemlerine doğru itmektedir. Bu şekilde, süreç planlama ve çizelgeleme adımları üreticiler için gerçekten çok önemlidir. Özellikle hacim ve ürün tipi esnekliği olan esnek atölyelerde bu süreçler daha da kritik hale geliyor. 'Endüstri 4.0' adı verilen yeni bir sanayi devrimi, işletmelerin bu ezici rekabet baskısı ile yüzleşmelerini desteklemek ve süreç planlama ve çizelgeleme süreçlerinin verimliliğini artırmak için bilgisayar ve bilgi teknolojilerini üretim sistemleriyle entegre ederek yeni teknolojik olanaklar getiriyor. Etmen tabanlı sistemler, üretim sistemlerinin sanallaştırılması, siber-fiziksel katmanların oluşturulmasıyla sistem simülasyonu, dijital ikizler ve diğerleri gibi bu teknolojilerden bazıları literatürde çeşitli araştırmalarda çalışılmış ve geliştirilmiş olarak adlandırılabilir. Bu araştırmada, üretim alanının ontolojik modellemesi ve muhakeme kurallarının süreç planlama aşamasına bir çözüm olarak Lekin çizelgeleme programı ile entegre edilerek yeni bir metodoloji önerilmiştir. Bu tezde, önce talaşlı imalat işlemleri için geliştirilen ontoloji etki alanı modeli anlatılmış, daha sonra tasarlanarak eklenen muhakeme kuralları ve SPARQL sorguları detaylı olarak anlatılmıştır. Son olarak, Lekin programı yerleşik sezgisellerinden elde edilen çizelgeleme sonuçları açıklanmıştır.
