Browsing by Author "Esleman, Esmael Adem"

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    Doctoral Thesis
    Deniz Suyu Ortamında Şartlandırılmış Bazalt/karbon/cam/epoksi Hibrit Kompozitlerin Yorulma Özelliklerinin Deneysel Olarakincelenmesi
    (Konya Teknik Üniversitesi, 2022) Esleman, Esmael Adem; Önal, Gürol
    Günümüzde hibrit kompozitler, daha düşük ağırlık ve daha yüksek mukavemet ve rijitlik, daha iyi korozyon ve aşınma direnci, uzun yorulma ömrü gibi çekici özelliklerinden dolayı kritik yapısal parçalar için farklı sektörlerde kullanılmaktadır. Öte yandan, yapısal çökmenin en yaygın nedeni yorulmadır. Yorulma, tekrarlanan yüklemeye maruz kaldığında, malzemenin maksimum mukavemetinin altındaki bileşenlerin ani bir hasardır. Bu tez, tuzlu suyu koşullarının bazalt, karbon ve cam elyaf/epoksi hibrit kompozitlerin çekme, eğilme ve üç noktalı eğilme yorulma özellikleri üzerindeki etkisini incelemektedir. Beş farklı kompozit plaka: Bazalt/Epoksi (BE), Karbon/Epoksi (CE), Cam/Epoksi (GE), Bazalt-Cam/Epoksi (BGE) ve Bazalt-Karbon-Cam/Epoksi (BCGE), Vakum Destekli Reçine Transfer Kalıplama yöntemi (VARTM) kullanılarak üretilmiştir. PST 650 dekupaj testeresi numuneleri ASTM D3039 ve ASTM D7264 standartlarına göre hazırlamak için kullanılmış ve testlerden önce 60 gün, 120 gün ve 180 gün tuzlu suyu çözeltisine daldırılmıştır. Testler 100 KN kapasiteli Instron 8801 çekme/yorulma test cihazı kullanılarak yapılmış ve her kategoriden üç numune test edilerek deneyin tekrarlanabilirliği gözlemlenmiştir. Ayrıca statik ve yorulma üç nokta eğilme testini yapmak için özel bir fikstür tasarlanıp üretilmiştir. Ağırlık kazancı eğrisi, gerilme-BŞD diyagramı, S-N ve rijitlik (stiffness) bozulma eğrileri oluşturulmuştur. Hibritleme ve tuzlu suyu koşullarının çekme, statik eğilme, yorulma ömrü ve eğilme rijitlik kaybı üzerindeki etkileri tartışılmıştır. Sonuçlar tüm kompozit numunelerin çekme ve eğilme özelliklerinin, şartlandırma süresi arttıkça bozulduğunu/azaldığını göstermektedir. Örneğin, BE kompozitlerinin çekme mukavemeti %21,11 oranında düşerken, CE kompozitleri sadece %9,09 oranında azalmıştır. Aynı şekilde, maksimum ve minimum çekme modülü kaybı sırasıyla BE (%17,12) ve BCGE (%8,68) hibrit kompozitlerde görülmektedir. En yüksek eğilme mukavemeti ve modül kaybı sırasıyla BE (%45,59) ve BCGE hibrit kompozitlerde (%11,18) görülmektedir. Bununla birlikte, BGE hibrit kompozitlerinin çekme mukavemeti, bazalt elyafların varlığı sayesinde GE'ye göre gelişme göstermiştir. Yorulma testi sonuçları, tuzlu su çözeltisi içerisinde şartlandırma süresi arttıkça tüm kompozit numunelerin eğilme yorulma özelliklerinin bir bozulma gösterdiğini ortaya koymaktadır.
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    Article
    Citation - WoS: 3
    Citation - Scopus: 4
    Investigation of Fracture Behaviour of Hybrid Composite Materials Under Compact Tension
    (Elsevier, 2025) Esleman, Esmael Adem; Batu, Temesgen; Onal, Gurol; Wu, Qian
    This study examines the fracture behavior of hybrid composite materials by analyzing the relationship between stress intensity factors, crack opening displacement, and critical energy release rates for compact tension specimens. Five types of composite laminates-Basalt/Epoxy (BE), Carbon/Epoxy (CE), Glass/Epoxy (GE), BasaltGlass/Epoxy (BGE), and Basalt-Carbon-Glass/Epoxy (BCGE)-were fabricated using the Vacuum Assisted Resin Transfer Molding (VARTM) method. Compact tension (CT) tests were conducted using a Universal Testing Machine (Instron 8801), recording load and displacement data to calculate fracture toughness and energy release rates. The results revealed that hybrid composites (BGE and BCGE) showed better fracture toughness (29.73 MPa \/ and 30.95 MPa m \/ m , respectively), energy dissipation (220 kJ/m2 and 230 kJ/m2, respectively), and crack resistance than mono-fiber composites (GE). However, the BE composite exhibits the highest toughness (KQ of 37.7 MPa\/) and critical energy release rate (GQ of about 260 kJ/m2) among the mono-fiber composites, m attributed to strong fiber-matrix bonding. The GE composite has the lowest value of critical energy release rate of 150 kJ/m2 and stress intensity factor of 17.02 MPa\/m, Indicating that glass fibers have a lower capability to dissipate energy during crack propagation. The crack propagation behavior differed among the composites, with BE, CE, and GE showing linear crack paths, whereas the hybrid composites exhibited mixed-mode fracture patterns, improving energy dissipation and enhancing crack propagation resistance.
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    Article
    Citation - WoS: 8
    Citation - Scopus: 19
    Optimal Pid and Fuzzy Logic Based Position Controller Design of an Overhead Crane Using the Bees Algorithm
    (SPRINGER INT PUBL AG, 2021) Esleman, Esmael Adem; Önal, Gürol; Kalyoncu, Mete
    Different industrial applications frequently use overhead cranes for moving and lifting huge loads. It applies to civil construction, metallurgical production, rivers, and seaports. The primary purpose of this paper is to control the motion/position of the overhead crane using a PID controller using Genetic Algorithms (GA) and Bee Algorithms (BA) as optimization tools. Moreover, Fuzzy Logic modified PID Controller is applied to obtain better controller parameters. The mathematical model uses an analytical method, and the PID model employs Simulink in MATLAB. The paper presents the PID parameters determination with a different approach. The development of membership functions, fuzzy rules employ the Fuzzy Logic toolbox. Both inputs and outputs use triangular membership functions. The result shows that the optimized value of the PID controller with the Ziegler-Nichols approach is time-consuming and will provide only the initial parameters. However, PID parameters obtained with the optimization method using GA and BA reached the target values. The results obtained with the fuzzy logic controller (0.227% overshoot) show improvement in overshoot than the conventional PID controller (0.271% overshoot).
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    Article
    Citation - WoS: 5
    Citation - Scopus: 5
    Three-Point Bending Fatigue Behavior of Basalt-carbon-glass/Epoxy Hybrid Composites Under Saltwater Environment
    (Wiley, 2023) Esleman, Esmael Adem; Önal, Gürol
    Fatigue is a sudden failure of components below the maximum strength of the material when subjected to repeated loading. This paper studies the fatigue behavior of basalt, carbon, and glass fibers/epoxy hybrid composites under three-point flexural loading and a saltwater environment. Five different composite panels were manufactured using the VARTM. The samples were then immersed in a saltwater solution for 60, 120, and 180 days before conducting the tests. Three-point static and fatigue tests were conducted using UTM as per ASTM D7264-07 and ASTM D7774-12. The S-N and stiffness degradation curves were plotted, and the morphology of the fatigue samples was investigated using SEM. In addition, the ion penetration in the solution was detected with ICP-OES analysis. The result shows that bending fatigue properties of all composite samples show a degradation as the immersion period increases. This might be due to micro-hole formation as the ions move from the sample to the saltwater solution.
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    Article
    Citation - WoS: 3
    Citation - Scopus: 5
    Weight Optimization of Hybrid Composite Laminate Using Learning-Oriented Artificial Algae Algorithm
    (SPRINGER INTERNATIONAL PUBLISHING AG, 2020) Yibre, Abdulkerim Mohammed; Koçer, Barış; Esleman, Esmael Adem; Önal, Gürol
    The optimal design of parameters is vital for the effective use of hybrid composite laminated structures. This is due to a highly dependent property of laminated composite structures strength on its fiber orientation, stacking sequence and the number of ply in each laminate. The main aim of this study is to apply Learning-Oriented Artificial Algae Algorithm for optimization of the weight of rectangular hybrid composite laminated plate subjected to compressive in-plane loading. The design parameters are number of plies and stacking sequence of the laminate. The critical buckling factor is the constraint of the optimization process. The parameters of the hybrid composite plate are optimized using Learning-Oriented Artificial Algae Algorithm with the aim of minimizing weight.The performance of the algorithm was compared with previous studies that employed the GA and ACO algorithms. The Learning-Oriented method is integrated to reduce the number of functions evaluated and in turn reducing computational cost. The results showed that Learning-Oriented Artificial Algae Algorithm outperformed GA and ACO, and hence can be successfully applied in the optimization of laminated composite structures.