Akar, Samet
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Akar, Samet
Akar, S.
Akar, Samet
Akar, Samet
Akar, S.
Akar, Samet
Akar, Samet
Job Title
Doç. Dr.
Email Address
samet.akar@cankaya.edu.tr
Main Affiliation
06.06. Makine Mühendisliği
Makine Mühendisliği
06. Mühendislik Fakültesi
01. Çankaya Üniversitesi
Makine Mühendisliği
06. Mühendislik Fakültesi
01. Çankaya Üniversitesi
Status
Current Staff
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ORCID ID
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WoS Researcher ID
Files
Sustainable Development Goals
15
LIFE ON LAND
0
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14
LIFE BELOW WATER
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4
QUALITY EDUCATION
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16
PEACE, JUSTICE AND STRONG INSTITUTIONS
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7
AFFORDABLE AND CLEAN ENERGY
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10
REDUCED INEQUALITIES
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2
ZERO HUNGER
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11
SUSTAINABLE CITIES AND COMMUNITIES
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9
INDUSTRY, INNOVATION AND INFRASTRUCTURE
6
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6
CLEAN WATER AND SANITATION
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5
GENDER EQUALITY
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17
PARTNERSHIPS FOR THE GOALS
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12
RESPONSIBLE CONSUMPTION AND PRODUCTION
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8
DECENT WORK AND ECONOMIC GROWTH
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3
GOOD HEALTH AND WELL-BEING
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13
CLIMATE ACTION
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This researcher does not have a Scopus ID.
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Scholarly Output
23
Articles
16
Views / Downloads
6/0
Supervised MSc Theses
2
Supervised PhD Theses
1
WoS Citation Count
96
Scopus Citation Count
133
WoS h-index
7
Scopus h-index
7
Patents
0
Projects
0
WoS Citations per Publication
4.17
Scopus Citations per Publication
5.78
Open Access Source
6
Supervised Theses
3
| Journal | Count |
|---|---|
| Journal of Manufacturing Processes | 2 |
| Materials Today Communications | 2 |
| Computer Methods in Biomechanics and Biomedical Engineering | 1 |
| Electro-Micromachining and Microfabrication: Principles and Research Advances | 1 |
| International Conference and Exposition on Mechanical, Material and Manufacturing Technology (ICE3MT) -- OCT 09-10, 2020 -- Hyderabad, INDIA | 1 |
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23 results
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Now showing 1 - 10 of 23
Article A Soft Sensor-Integrated Cell Stretching Device for Precise and Reproducible Mechanotransduction(Royal Soc, 2026) Yildiz, Solen Kumbay; Akar, Samet; Ozturk, Emre; Dincer, Pervin; Uyanik, Ismail; Duz, NiluferMechanical stretch is a fundamental regulator of cell fate, yet in vitro replication remains challenging because conventional stretchers deliver non-uniform strain and ignore batch-to-batch variations in substrate stiffness-so the stress actually experienced by cells varies unpredictably. We introduce the first biaxial cell-stretching platform that couples an embedded soft resistive micro-channel sensor with high-frequency closed-loop control. Real-time deformation read-out (60 Hz) drives a 24 kHz actuator loop to compensate for polydimethylsiloxane (PDMS) moduli spanning an order of magnitude, delivering user-defined triangular or square waveforms (5-20% amplitude; 0.5-10 s period) with less than 2% steady-state error. Closed-loop operation maintains strain-invariant membrane stress within +/- 5%, reducing well-to-well variability threefold compared with open-loop actuation. Biological validation using immortalized human myoblasts exposed to 10% cyclic stretch for 4 h produced a significant upregulation of YAP/TAZ target genes (C-MYC, MYL9, DIAPH1, ANKRD1; p < 0.001), confirming mechanotransductive efficacy. The platform's modular architecture accommodates stiffness-tunable hydrogels and live imaging, offering a reproducible tool for mechanobiology, tissue engineering, disease modelling and personalized mechanotherapy.Doctoral Thesis Bilyalı Rulmanların Superfiniş İşlemesinin Modellenmesi(2025) Aslanbaş, İrem Gül; Akar, SametBilyalı rulman üretimi dövme, tornalama, ısıl işlem, taşlama ve süperfinisaj (SF) işlemlerini içerir. En kritik adım olan süperfinisaj, yüzey pürüzlülüğünü, yük kapasitesini, yorulma direncini, form doğruluğunu, gürültü seviyesini ve aşınma direncini önemli ölçüde etkiler. Ayrıca yağlama tutunmasını artıran mikro dokular oluşturur. İşlem, hidrolik basınç ve pnömatik basınçla tahrik edilen ve kesme sıvısı olarak yağ kullanan salınımlı aşındırıcı bir taş ile dönen bir iş parçası arasında karmaşık bir etkileşimi içerir. İş parçası izlerini önlemek ve talaş kaldırma verimliliğini korumak için uygun aşındırıcı temizlik çok önemlidir. Gürültü seviyesi, rulmanları sınıflandırmak için önemlidir ve sınıflandırılmamış rulmanlar hurdaya çıkar. Yüksek hassasiyetli rulmanların üretimi daha az gürültü ve titreşim seviyesine ihtiyaç duyar. Gürültü seviyesi ile işlemi uzlaştırmak önemli hale gelmiştir. SF işleminin özelliklerini öğrenmek için önce deneysel bir tasarım oluşturuldu. Deney Tasarımı (DOE) yöntemi kullanılarak, süperfinishing (SF) prosedürünün aşınma ve yüzey topografisini nasıl etkilediğini incelemek için kapsamlı bir araştırma yürütüldü. Daha doğru bir yüzey kalitesi elde etmek için ideal işlem parametrelerini belirlemek amacıyla 405 deneysel gözlem yapıldı. Önemli aşınma parametrelerini değerlendirmek için hem aşındırıcı hem de aşınmış yüzeylerin optik ölçümleri dahil olmak üzere bulgular üzerinde çeşitli analizler yapıldı. Yüzey özelliklerinin gürültüyü nasıl etkilediğini daha iyi incelemek için makine öğrenimi algoritmaları kullanıldı. Gürültü seviyeleri ile işlem parametreleri vii arasındaki ilişki regresyon analizi kullanılarak araştırıldı. SF işlem parametrelerine dayalı gürültü seviyelerini tahmin etmek için hem sayısal hem de kategorik verileri işlemek için derin öğrenme algoritmaları kullanıldı. Bu strateji, işleme giderlerini ve gürültülü hurdayı düşürürken doğru ürün çıktılarını sağlamayı amaçladı. Ayrıca, çalışma makine öğrenme araçları kullanılarak, işlem parametrelerinin yatakların gürültü seviyesini belirleyen yüzey özellikleri Ra ve Rz üzerinde bir etkiye sahip olduğunu göstermiştir. Sonucun hurda olmasının etkisi şu şekildedir: 1. Öncelikli taş basıncı 2. Öncelikli salınım hızı 3. Öncelikli iş parçası rpm'si. Ra endüstriyel uygulamalarda daha fazla kullanılmasına rağmen, Rz gürültüyü azaltmada Ra'dan daha etkilidir. Üretim sırasında yüzey pürüzlülüğünden kaynaklanan gürültüyü azaltmaya çalışırken Rz parametresinin işlem değerlerinin incelenmesi gerekir. İşlem boyunca iyi değerler ve hassas bir yüzey elde etmek için hem aşındırıcı hem de aşınmış yüzey kullanılarak aşınma incelenirken SiC aşındırıcı kullanılmalıdır. WA aşındırıcı, işlemin başlangıcında agresif bir yapı gösterir. FA ve SiC aşındırıcı daha kararlı sonuçlar verir. Bu nedenle, bu bilgi esastır ve işlem ve ürün iyileştirme çalışmalarında kullanılmalıdır.Book Part Surface Modification Through Micro-EDM Process(Apple Academic Press, 2024) Perveen, A.; Akar, S.Electro-discharge machining, among other nonconventional machining processes, is known for its capability to machine materials regardless of hardness. In addition toits contactless and zero-force nature of machining, this process is reported to contribute to surface alteration and modification. Literature reveals surface modification through powder mixed EDM; modification through electrode materials, modification through electrical discharge (ED) coating process as some of the imperative surface modificationtechniques that can alter surface microstructure and therefore, enhances its properties such as microhardness, surface finish, wear, and corrosion resistance. This chapter will present a comprehensive discussion on these surface modification practices implemented to improve the functional characteristics of the surface machined by micro-EDM. © 2024 by Apple Academic Press, Inc.Article Citation - Scopus: 5Fused Filament Fabrication in Cad Education: a Closed-Loop Approach(Sage Publications inc, 2025) Totuk, Onat Halis; Selvi, Ozguen; Akar, SametIntegrating low-cost fused filament fabrication 3D printing as a foundation for learning 3D modelling is explored. This method blends traditional computer aided design (CAD) instruction with additive manufacturing possibilities. Experimental results demonstrate increased comprehension speed and reduced learning time. This hands-on approach empowers students by enabling direct engagement with the modelling process. Analogous to reverse engineering, the strategy instructs engineering students from final product to model creation, closing the gap between theory and practice. Incorporating 3D printing bridges this divide, enhancing understanding, creativity and problem-solving. The study underscores technology's influence on learning strategies, aligning with the surge of 3D printing in education. Results link advanced design technology usage to improved student performance, with 3D-printed materials yielding 45% higher grades and 30% faster task completion. This study advocates curricular advancement for design-focused careers through enhanced technology integration and favourable 3D printing model reception.Article Citation - WoS: 11Citation - Scopus: 13Molecular Dynamic Approach To Predict Thermo-Mechanical Properties of Poly(Butylene Terephthalate)/Caco3 Nanocomposites(Elsevier, 2021) Boga, Cem; Akar, Samet; Pashmforoush, Farzad; Seyedzavvar, MirsadeghThermo-mechanical properties of poly(butylene terephthalate) polymer reinforced with carbonate calcium nanoparticles have been investigated using molecular dynamics simulations. Detailed analyses have been conducted on the effects of nanofiller content, at concentration levels of 0-7 wt%, on the mechanical properties of PBT, i.e. Young's modulus, Poisson's ratio and shear modulus. Thermal properties, including thermal conductivity and glass transition temperature, have been determined using Perl scripts developed based on nonequilibrium molecular dynamics and a high temperature annealing procedure, respectively. Experiments have been performed to verify the accuracy of the results of MD simulations. The CaCO3/PBT nanocomposites were synthesized using melt blending and mold injection techniques. The uniaxial tensile test, thermal conductivity, differential scanning calorimetry and x-ray diffraction spectroscopy measurements were conducted to quantify the thermo-mechanical properties of such nanocomposites experimentally. The results showed significant improvements in the mechanical properties by addition of CaCO3 nanoparticles due to strong binding between rigid particles and PBT polymer and high nucleation effects of nanoparticles on the matrix. Thermal conductivity and glass transition temperature of nanocomposites represented a consistent increase with the ratio of CaCO3 nanoparticles up to 5 wt% with an enhancement of 38% and 36% with respect to that of pure PBT, respectively.Master Thesis Farklı Koşullarda Üretilmiş PDMS Malzemelerin Mekanik Davranışlarını Araştırmak(2025) Savaş, Ülviye; Akar, SametBu tez çalışmasında, ana hedef, Polidimetilsiloksan (PDMS) malzemesinin çeşitli üretim koşulları altındaki mekanik davranışını hesaba katan bir malzeme modeli geliştirmektir. PDMS, benzersiz özellikleri nedeniyle mikro üretim ve robotik alanlarında yaygın olarak kullanılmaktadır, ancak PDMS malzemesinin mekanik özelliklerini nlamak, uygulama alanlarının optimize edilmesi için önemlidir. Bu tez çalışması karışım oranı, kürleme süresi ve sıcaklığın PDMS'in mekanik özellikleri üzerindeki etkilerini incelemektedir. Mekanik davranışı anlamak amacıyla, farklı koşullarda hazırlanmış PDMS örnekleri üzerinde çekme testleri yapılacaktır.Article Citation - WoS: 18Citation - Scopus: 23Investigation of Surface Integrity in Laser-Assisted Turning of Aisi 4340 Hardened Steel: Finite Element Simulation With Experimental Verification(Elsevier Sci Ltd, 2022) Sadeghi, Mohammad Hossein; Akar, Samet; Khatir, Farzad AhmadiThis study investigates the laser-assisted turning (LAT) of AISI 4340 hardened steel (similar to 52 HRC). Despite the various advantages of this process for machining hard materials, the issues related to the machined surface integrity remain the most important challenge. The laser heating used in this process substantially affects the surface integrity characteristics of the workpiece and its mechanical properties. Therefore, it is important to understand, predict, and optimize the workpiece's heat effects at various regions. Due to the complexity of the process, experimental investigations alone cannot reveal thorough information of various phenomena involved. Therefore, a reliable finite element model has been developed to predict the effect of various process input parameters on the metallurgical changes of the machined workpieces. Since general-purpose finite element codes cannot predict the phenomena of interest, three user-defined subroutines have been developed to capture surface integrity parameters such as heat-affected zone, hardness variations of the machined surface, and white layer formation. The developed FE model consists of three parts: mechanical model, thermal model, and coupled thermo-mechanical model. The results of the FE models are verified with experimental data, and a good agreement has been observed. The effect of various process parameters on the surface integrity characteristics of the workpiece has been studied in detail. It has been observed that the laser scanning speed, laser power, and undeformed chip thickness have the most significant influence on the metallurgical effects on the workpiece, respectively.Article Citation - WoS: 7Citation - Scopus: 10Combined Use of Ultrasonic-Assisted Drilling and Minimum Quantity Lubrication for Drilling of Niti Shape Memory Alloy(Taylor & Francis inc, 2023) Namlu, Ramazan Hakki; Lotfi, Bahram; Kilic, S. Engin; Yilmaz, Okan Deniz; Akar, SametThe drilling of shape-memory alloys based on nickel-titanium (Nitinol) is challenging due to their unique properties, such as high strength, high hardness and strong work hardening, which results in excessive tool wear and damage to the material. In this study, an attempt has been made to characterize the drillability of Nitinol by investigating the process/cooling interaction. Four different combinations of process/cooling have been studied as conventional drilling with flood cooling (CD-Wet) and with minimum quantity lubrication (CD-MQL), ultrasonic-assisted drilling with flood cooling (UAD-Wet) and with MQL (UAD-MQL). The drill bit wear, drilling forces, chip morphology and drilled hole quality are used as the performance measures. The results show that UAD conditions result in lower feed forces than CD conditions, with a 31.2% reduction in wet and a 15.3% reduction in MQL on average. The lowest feed forces are observed in UAD-Wet conditions due to better coolant penetration in the cutting zone. The UAD-Wet yielded the lowest tool wear, while CD-MQL exhibited the most severe. UAD demonstrated a & SIM;50% lower tool wear in the wet condition than CD and a 38.7% in the MQL condition. UAD is shown to outperform the CD process in terms of drilled-hole accuracy.Article Citation - WoS: 7Citation - Scopus: 7A Study on the Μwire-Edm of Ni55.8ti Shape Memory Superalloy: an Experimental Investigation and a Hybrid Ann/Pso Approach for Optimization(Springer Heidelberg, 2023) Seyedzavvar, Mirsadegh; Boga, Cem; Akar, SametThe unique properties of high hardness, toughness, strain hardening, and development of strain-induced martensite of nickel-titanium superalloys made the micro-wire electro discharge machining (mu wire-EDM) process one of the main practical options to cut such alloys in micro-scale. This paper presents the results of a comprehensive study to address the response variables of Ni55.8Ti superalloy in mu wire-EDM process, including the kerf width (KW), material removal rate (MRR), arithmetic mean surface roughness (R-a) and white layer thickness (WLT). To this aim, the effects of pulse on-time (T-on), pulse off-time (T-off), discharge current (I-d) and servo voltage (SV) as input parameters were investigated using the experiments conducted based on Taguchi L-27 orthogonal array. The results were employed in the analysis of variance (ANOVA) to examine the significance of input parameters and their interactions with the output variables. An optimization approach was adopted based on a hybrid neural network/particle swarm optimization (ANN/PSO) technique. The ANN was employed to achieve the models representing the correlation between the input parameters and output variables of the mu wire-EDM process. The weight and bias factor matrices were obtained by ANN in MATLAB and together with the feed forward/backpropagation model and developed functions based on PSO methodology were used to optimize the input parameters to achieve the minimum quantities of KW, R-a and WLT and the maximum value of MRR, individually and in an accumulative approach. The results represented a maximum accumulative error of nearly 8% that indicated the precision of the developed model and the reliability of the optimization approach. At the optimized level of input parameters obtained through the accumulative optimization approach, the KW, R-a, and WLT remained nearly intact as compared with the levels of responses obtained in the individual optimization approach, while there was a sacrifice in the machining efficiency and reduction in the MRR in the mu wire-EDM process of Nitinol superalloy.Article Selection of Optimum Performance Conditions in the Laser-Assisted Turning of Aisi 4340 Hardened Steel Through the Coupling of Entropy/Mcdm Analysis(Springer Heidelberg, 2024) Khatir, Farzad Ahmadi; Modanloo, Vahid; Abedini, Vahid; Akar, Samet; Ghadikolaee, Hossein TalebiThe laser-assisted turning (LAT) process comprises complicated interactions between cutting process parameters and laser heating. These interactions pose a significant challenge for predicting and optimizing surface integrity, even though it is crucial for the success of the process and its adoption as an alternative industrial process. This research employs multi-criteria decision-making (MCDM) approaches to determine the optimal machining conditions. The entropy method was applied to assign weights to the criteria, and the MOORA and TOPSIS techniques were utilized to rank the alternatives. A combination of various machining parameters, including feed, cutting speed, and depth of cut were assumed to be the alternatives (machining conditions). Moreover, the white layer thickness, microhardness, and surface roughness were considered selection criteria. The results demonstrated that all parameters are effective for surface integrity. On the other hand, the properties of surface integrity were greatly impacted by the laser power and feed. Therefore, the factors that most affected the creation of the white layer were the feed (47.26%) and the laser power (22.10%). The most advantageous process parameters for the LAT of AISI 4340 steel were found to be a cutting speed of 240 m/min, a cutting feed of 0.07 mm/rev, a cutting depth of 0.5 mm, and a laser power of 450 W by the MCDM analysis.
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