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Öğe Advanced Friction-Wear Behavior of Organic Brake Pads Using a Newly Developed System(Taylor & Francis Inc, 2019) Öktem, Hasan; Uygur, İlyasThe objective of this study was to investigate the influence of an advanced performance system on the tribological behavior of brake pad material using a specially designed brake pad tester system following standard SAE J-661. The tribological behavior and friction and wear characteristics of the organic brake pad samples were evaluated. During braking tests, the samples, in contact with a cast iron disk, were studied at different disc speeds, temperatures, and braking cycles under a constant pressure. In order to understand the friction and wear behavior, the unworn surfaces, worn surfaces, and wear debris were characterized by means of scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). Furthermore, the surface characteristics and differences in the wear modes of the brake pad samples were examined. Wear debris was permitted to deform the brake pad surfaces, leading to friction layers and enabling the estimation of the friction behavior of the brake pads. The results showed that the best friction-wear behavior was obtained with lower braking cycles at low speeds and temperature. Thus, the newly developed brake pad tester system proved very effective in evaluating the performance of the brake pad samples. [GRAPHICS] .Öğe Alternatif katkı maddesi olarak kullanılan bor oksitin fren balatasının sürtünme davranışına etkisinin incelenmesi(2019) Akıncıoğlu, Gülşah; Akıncıoğlu, Sıtkı; Uygur, İlyas; Öktem, HasanOtomobillerin frenleme sistemlerinin en önemli parçalarından olan fren balatalarınıniçeriğinde onlarca farklı malzeme bulunmaktadır. Kompozit bir malzeme olan frenbalatasından, iyi bir frenleme performansı, kararlı bir sürtünme katsayısı, yüksekaşınma direnci ve çevre dostu olması beklenmektedir. Özellikle son yıllarda, çevreyezararsız, doğal fren balata malzemesi arayışları hız kazanmıştır. Bu çalışmadadünya rezervlerinin büyük çoğunluğu ülkemizde bulunan bor oksit kullanılarak, frenbalatası numunesi üretilmiştir. Alternatif toz ile üretilen fren balatasının performanstestleri yapılmıştır. Bor oksit katkılı numuneden elde edilen performans test sonuçlarıborun fren balatalarında alternatif toz olarak kullanılabileceğini göstermiştir.Öğe Bor oksit tozunun fren balatalarının tribolojik özelliklerine etkisi(2018) Akıncıoğlu, Gülşah; Akıncıoğlu, Sıtkı; Uygur, İlyas; Öktem, HasanBu çalışmada, Renault Clio otomobilin fren balatası, bor oksit tozu katkısı ile sıcak presleme yöntemiyleüretilerek, bor oksit tozunun balatanın tribolojik özellikleri üzerine etkisi deneysel olarak araştırılmıştır.Son yıllarda çevre dostu malzemelerin kullanılmasının önem kazanmasından dolayı fren balatasınıniçeriğinde bor oksit kullanılmıştır. Ayrıca bu malzemenin seçilmesinde ülke ekonomisine fayda sağlamaktaamaçlanmıştır. Karşılaştırma yapmak için ticari Clio balatası kullanılmıştır. Balata numunelerinin aşınmasürtünme deneyleri Chase tipi cihazda yapılmıştır. Bor oksit katkısının fren balatasının aşınma sürtünmeperformansına etkisi ticari fren balatasının sonuçlarıyla kıyaslanarak incelenmiştir. Sonuçta bor oksitkatkısının sürtünme katsayısına olumlu etki yaptığı gözlenmiştir.Öğe Brake Pad Performance Characteristic Assessment Methods(2021) Akıncıoğlu, Gülşah; Akıncıoğlu, Sıtkı; Öktem, Hasan; Uygur, İlyasAlong with the developing technology, expectations for improved automobile brake pads are also rising. Research on higher performance brake pads is contin-uing at a rapid pace. It is also recognized that in this field, widespread efforts are being made towards the production of brake pads which are economical, envi-ronmentally friendly and do not pose risks to human health. In recent years, non-industrial waste products have also been used as additives in brake pads, thus contributing to local economy. Performance tests have to be carried out so that the brake pads produced with the new compositions can be used. For this reason, the performance tests of the brake pads are important. This study brings a new overview via an investigation of the methods applied in determining their per-formance characteristics.Öğe Design, construction and performance of a novel brake pad friction tester(Elsevier Sci Ltd, 2018) Öktem, Hasan; Uygur, İlyas; Çevik, MuratDetermination of the tribological behavior of brake pads under real environmental conditions is an important and critical task which can significantly impact the automotive industry. Most studies simulate or measure the variants by indirect methods and accept them as true results. The new computer-controlled, interactive brake pad friction tester presented in this study was developed for this purpose. The major components of the machine, which are operated simultaneously, include: a proportional pressure-controlled hydraulics power pack, a mechanical transmission system with electromagnetic clutch, and a brake and automation control with SCADA computer analysis interface. Compared to other friction testing machines, a very important innovation of the newly developed friction tester allows for the testing of the brake pad samples and measuring of the noise level both to be performed with high precision under real conditions. Moreover, this friction tester is capable of determining the friction coefficients; wear behavior, temperature, and life intervals of brake pad samples. This novel brake pad system is relatively cheaper and measures effective friction coefficients more accurately. The uncertainty in measurements for friction coefficient and wear rate was approximately calculated as +/- 0.0135 and +/- 0.170 in all of experiments, respectively. In this study, the machine performance was carried out to evaluate the friction behavior of non-asbestos brake pad samples reinforced with hazelnut shell powder according to the standard brake lining quality control testing procedure (SAE J661).Öğe Determination of Friction-Wear Performance and Properties of Eco-Friendly Brake Pads Reinforced with Hazelnut Shell and Boron Dusts(Springer Heidelberg, 2018) Akıncıoğlu, Gülşah; Öktem, Hasan; Uygur, İlyas; Akıncıoğlu, SıtkıBrake pads are the most important component of an automobile braking system. In recent studies, brake pads have been produced by varying the constituents of existing compositions and by making new formulations with other friction materials. This study evaluated two sets of asbestos-free automotive brake pads produced from boron oxide (6%) and hazelnut shell (7%) dusts and seventeen other components. All ingredients were mixed and pressed to manufacture the sample eco-friendly brake pads in the same shape as commercial Clio pads. Hardness, porosity, compressibility, shear and wear tests were carried out on the samples, and the test results were compared with those of the commercial pad.Öğe DETERMINATION OF THE CUTTING-TOOL PERFORMANCE OF HIGH-ALLOYED WHITE CAST IRON (Ni-Hard 4) USING THE TAGUCHI METHOD(Inst Za Kovinske Materiale I In Tehnologie, 2016) Kır, Durmuş; Öktem, Hasan; Çöl, Mustafa; Koç, Funda Gül; Erzincanlı, FehmiHigh-alloyed white-cast-iron materials are commonly used in the manufacturing industry due to their high wear resistance. The aim of this research is to determine the cutting tool and the optimum cutting conditions required for the metal cutting of these materials. In this study, it is proposed to determine the wear and the tool life utilizing the Taguchi optimization method when hard turning the Ni-Hard 4 material, the alloyed cast iron, with cutting tools produced with powder metallurgy (PM) and to improve the performance of the cutting tools. A series of 18 experiments were conducted on a CNC turning machine, using the cutting process parameters such as the cutting speed, the feed and the depth of cut, based on the Taguchi L-9 orthogonal design of experiments. Uncoated cutting tools were utilized to perform these experiments. PM cutting tools with WC grain sizes of 0.8 mu m and 1.25 mu m were selected for the hard-turning experiments. The flank wear of the cutting tools was examined with SEM. Then, the life of each cutting tool was identified based on the cutting length. The performance of the cutting tools in terms of the wear and the tool life was determined with the Taguchi method based on the obtained data. The results of this study contributed to the hard turning of the Ni-Hard 4 material that is mostly employed in the as-cast condition in the manufacturing industry due to its high hardness. The optimum cutting conditions were determined by means of the Taguchi method.Öğe EVALUATION OF NON-ASBESTOS HIGH PERFORMANCE BRAKE PADS PRODUCED WITH ORGANIC DUSTS(Tanger Ltd, 2015) Öktem, Hasan; Uygur, İlyas; Akıncıoğlu, Gülşah; Kır, Durmuş; Karakaş, HamdiRecently, research-development studies conducted for the production of organic brake pads because of the usage of asbestos in brake pads have negative effects on human health and the environment. This study aims to develop to non-asbestos high performance brake pads. Twenty-four types of different dusts in commercial brake pads have utilized as fillers, reinforcements, binders, abrasives and friction modifiers in mixture of organic brake pads produced. In this study, seventeen of these friction dusts were used to develop to organic brake pads. The 3.5 wt.% and 7 wt.% content of hazelnut and walnut as friction modifier materials were replaced with petrocoke dust eco-friendly. The performance of brake pads was determined by microstructural examinations, oil absorption and dimensional stability, and hardness of brake pads. The results indicated that the brake pads produced with organic dusts such as hazelnut and walnut shells can replaced with petrocoke dust. From this, it can be concluded that new type brake pads of non-asbestos organic-based dusts can be effectively used as a replacement for asbestos and performance in brake pad production.Öğe Evaluation of The Physical Properties of Hazelnut Shell Dust-Added Brake Pad Samples Treated With Cryogenic Process(2019) Akıncıoğlu, Gülşah; Akıncıoğlu, Sıtkı; Öktem, Hasan; Uygur, İlyasAfter understanding that asbestos fibers are harmful to human health; researchers have investigated for alternative and eco-friendly materials. Agricultural products can be an example of these alternative and environmentally friendly materials because they are easily supplied . Thus, in this study, asbestos-free automotive brake pads produced from %7 hazelnut dusts with other seventeen additives. Hazelnut shell is preferred because it is widespread in our country. Cryogenic process applied at -80°C to the brake pads. Before and after cryogenic treatment, the produced brake pads properties such as water absorption, hardness test, porosity and microstructural examinations were investigated. The hardness values of brake pads increases after cryogenic and cyclic-cryogenic process. The highest values obtained for the B-CYC sample.Öğe Evaluation of The Physical Properties of Hazelnut Shell Dust-Added Brake Pad Samples Treated With Cryogenic Process(Gazi Univ, 2019) Akıncıoğlu, Gülşah; Akıncıoğlu, Sıtkı; Öktem, Hasan; Uygur, İlyasAfter understanding that asbestos fibers are harmful to human health; researchers have investigated for alternative and eco-friendly materials. Agricultural products can be an example of these alternative and environmentally friendly materials because they are easily supplied. Thus, in this study, asbestos-free automotive brake pads produced from %7 hazelnut dusts with other seventeen additives. Hazelnut shell is preferred because it is widespread in our country. Cryogenic process applied at -80 degrees C to the brake pads. Before and after cryogenic treatment, the produced brake pads properties such as water absorption, hardness test, porosity and microstructural examinations were investigated. The hardness values of brake pads increases after cryogenic and cyclic-cryogenic process. The highest values obtained for the B-CYC sample.Öğe A nature-inspired optimal design for a ventilated brake disc(Sage Publications Ltd, 2022) Shinde, Dinesh; Öktem, Hasan; Uygur, İlyasBrake discs are critical automobile components that provide the braking effect and ultimately ensure the safety of passengers. Because of intermittent braking operations, brake discs are subjected to fluctuating loads and are provided with ventilation to facilitate cooling. The present study utilized a combination of response surface methodology parametric analysis, finite element analysis, statistical analysis, predictive modeling, and design optimization. Based on the response surface methodology design of experimental runs, ventilated brake discs were modeled considering the critical design parameters, viz., radius of center hole, thickness of inboard and outboard plate, height of vanes, and offset. Using finite element analysis, the brake discs were simulated under actual braking conditions for fatigue life cycles. Thirty-two (32) trial finite element analysis trials were performed. The obtained results were interpreted using ANOVA and an effective predictive model was established. Parametric analysis was performed using plots of response surface methodology and contours to predict the optimal parameter settings. In addition, two nature-inspired optimization techniques, the genetic algorithm and particle swarm optimization, were implemented and the optimal design parameter settings were determined for maximum fatigue life. The genetic algorithm and particle swarm optimization produced 7.67% better results than the parametric analysis, clearly demonstrating that the proposed design techniques exhibited significant performance improvement compared to widely used classical techniques.
