Browsing by Author "Karaduman, Alper"
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Item Experimental and numerical fatigue-based design optimisation of clutch diaphragm spring in the automotive industry(Inderscience Enterprises, 2019) Karaduman, Alper; Yıldız, Ali Rıza; Yıldız, Betül Sultan; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; F-7426-2011; AAL-9234-2020; 57190752987; 57094682600; 7102365439In the present study, the fatigue behaviour of a clutch diaphragm spring is investigated experimentally and numerically. Differential evolution optimisation algorithm and response surface methodology are used to define optimal variables of the diaphragm springs under constraints both minimum stress and required clamp load. The required clamp load is checked by the chi-square theorem vs. to target clamp load curve. Ten design variables are considered for creating a design of experiment with two steps, including finger shape optimisation with eight variables, load, and stress optimisation with two variables as the aim of maximum fatigue definition. One hundred seventy-five different designs are analysed numerically. As a result of the optimisation study, the optimum design is provided an endless lifetime subject to the required load, minimum stress, and minimum weight. The optimum design is manufactured and tested experimentally.Publication Investigation of clutch hub strength with various geometries under variable torque conditions(Yildiz Technical Univ, 2020-03-01) Genç, Mehmet Onur; Karaduman, Alper; Aktaşgil, Zübeyir Ramazan; Karamangil, Mehmet İhsan; KARAMANGİL, MEHMET İHSAN; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Otomotiv Mühendisliği Bölümü.; 0000-0001-5965-0313; AAH-8619-2019The clutch is a component that performs the duty of transmitting the torque generated by the internal combustion engines to the powertrain. The hub component on disc assembly is one of the most important components in this transmission process. During operation under torque conditions, a hub is supposed to withstand the radial loads. For this purpose, the structural strength analysis of the hub is of importance. In this study, the hub component of the clutch disc assembly is analyzed to simulate real driving conditions. In this analysis, analytical calculations and finite element calculations were made for different hub structures. By comparing the two calculations, the precision of the design and the reasons of failures were determined. According to FEA results, the maximum principal stress occurs in the contact regions where the pressure is applied. With respect to these results, the damage locations are compared to the parts which have been subjected to real bench test, and cracks/breaks occurred. After the tests, damage analysis was performed for fractures. This study enables the assumptions of the hub resistance under the various dynamic conditions with different hub geometry. Furthermore, this novel study provides the cost and time-saving in terms of the design phase in automotive engineering.Publication Minimization of release bearing load loss in a clutch system for high-speed rotations using the differential evolution algorithm(Walter De Gruyter Gmbh, 2022-11-25) Lekesiz, Hüseyin; YILDIZ, ALİ RIZA; Karaduman, Alper; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi.; F-7426-2011Diaphragm spring is a critical part of a clutch system because it affects the release bearing load characteristics directly and that determines the quality of disengagement. Bearing load provides required clamping for coupling however it may vary significantly during the engagement/disengagement process. A significant drop in bearing load may be experienced especially for high engine velocities for certain bearing displacement due to centrifugal forces occurring on the fingertips of diaphragm springs. The falling in release bearing load is undesirable for comfortable driving and clutch performance. This problem has not been addressed clearly in technical literature. In this study, the diaphragm spring for a C-segment passenger car is optimized using a differential evolutionary algorithm, and an optimized diaphragm was manufactured for testing. The load-bearing characteristics of the optimized diaphragm were compared with those of the currently available diaphragm spring. Loss of bearing load occurring in high-speed rotations was significantly reduced for the optimized diaphragm. Parameters influencing the performance were identified using parameter influence analysis, and a robust disengagement behavior was actualized using the optimization process.Item Shape optimization of clutch cushion disc using differential evolution method(American Society of Mechanical Engineers, 2016) Kartal, Saruhan; Çakmak, Tanyel; Karaduman, Alper; Kaya, Necmettin; Karpat, Fatih; Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü.; 0000-0001-8474-7328; 0000-0002-8297-0777; A-5259-2018; R-4929-2018; 7005013334; 24366799400The clutch is an element which makes a temporary connection between gear box and vehicle engine. It transmits not only engine torque, but also ensures comfort and drivability during slippage. One of the main functions of clutch disc is to transmit the engine torque while absorbing vibrations. It allows a soft gradual reengagement of torque transmission. The cushion disc which is located between two clutch facings has wavy surface, thus it behaves like a spring during engagement and disengagement. The axial elastic stiffness of the. clutch disc is obtained by a cushion disc. The load-deflection curve is obtained by compressing clutch disc between two plates, representing pressure plate and flywheel. The wavy shape of the cushion disc provides progressive stiffness curve of the clutch disc.The cushion disc participates in drivers comfort during engagement of the clutch. The comfort depends on the limits of the progressive stiffness. curve. Outside the limits of this cushion function, the clutch engagement would be harsh and uncomfortable for the driver. Besides, engine torque may not be transmitted during the later service lifetime and the life of the clutch might be decreased. In the case cushion disc has no cushioning function, then the engine might be stopped. Additionally, improper cushioning function causes heat and deform of the pressure plate and it also decreases the transmitted engine torque. Therefore, cushion disc has to have certain cushioning characteristics in order to overcome these problems.In this study, the optimum shape design of cushion disc was performed using an evolutionary optimization algorithm. Differential evolution algorithm was selected as the optimization method because it guarantees the global optimum. Design of experiment method has been employed to construct the response surface that approximates the behavior of the objective function inside a certain design space. Three shape parameters of cushion disc have been selected. The objective of the shape optimization is to find the optimum shape parameters that provide the target stiffness curve. After solving the optimization problem with differential evolution method, optimum shape parameters of cushion disc have been found for two case studies. A Pascal code based differential evolution optimization code was developed for shape optimization and Ansys finite element software was used for calculating stiffness curve of cushion disc.Item Taşıt debriyaj elemanlarının optimizasyonu için yapay zeka algoritması tabanlı bir sistemin geliştirilmesi(Bursa Uludağ Üniversitesi, 2022-06-21) Karaduman, Alper; Yıldız, Ali Rıza; Bursa Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Otomotiv Mühendisliği Anabilim Dalı.; 0000-0001-6723-5136Bu tez çalışmasında taşıt debriyaj elemanlarının dinamik davranışı ve fonksiyonelliği göz önünde bulundurularak taşıt diyaframı ve damperinin tasarım optimizasyonu gerçekleştirilmiştir. Algoritmalarda keşif ve elde edilen bilginin kullanılması arasındaki dengenin ayarlanamaması ve uygun parametre ayarlarının gerçekleştirilememesi yerel optimuma takılma ve erken yakınsama problemine neden olabilir. Bu yüzden algoritmalar içerisindeki seçim mekanizması ve algoritma parametrelerinin ayarlanması önemlidir. Algoritma içerisinde çeşitlilik, bütünü arama ve yerel arama mekanizmalarının bilgiyi kullanma mekanizması ile yüksek performansta çalışması gerekmektedir. Bu amaçla kır kurtlarının sürü içerisindeki sosyal durumları ve çevreye uyum davranışlarından ilham alan Kır Kurdu Optimizasyon (COA) algoritması tabanlı yeni bir algoritma taşıt debriyaj elemanları için geliştirilmiştir. Bu çalışmada kır kurdu optimizasyon algoritmasının çeşitlilik ve arama mekanizmasının iyileştirilmesiyle geliştirilmiş bir algoritma elde edilmiştir. Ortaya çıkan geliştirilmiş algoritmanın kısıtlı ve kısıtsız mühendislik problemleri ile test edilip taşıt debriyaj elemanlarına uygulanarak gerçekliği kanıtlanmıştır. Önerilen algoritmanın test sonuçları, yeni algoritmanın etkinliğini ölçmek için literatürdeki diğer algoritmalara karşı kontrol edilmiştir. Deneysel sonuçlar, yeni algoritmanın kısıtlı ve kısıtsız test fonksiyonları üzerinde önemli ölçüde daha iyi verimliliğe sahip olduğunu göstermektedir. Bu eniyileme çalışması ile taşıt debriyaj elemanları diyafram yayının başlangıçtaki modeline göre belirtilen asgari ayrılma yüküne göre daha dinamik koşullarda daha iyi performans gösteren yeni bir diyafram modeli ortaya konulmuştur. İkinci eniyileme çalışmasında taşıt debriyaj damper elemanının başlangıçtaki modeline göre daha iyi sönümleme karakteristiğine sahip damper modeli elde edilmiştir. Böylece geliştirilen kır kurdu algoritması literatürde ilk olup taşıt debriyaj elemanlarının eniyilenmesinde kullanılmıştır.