Yazar "Unuvar, Ali" seçeneğine göre listele

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    Investigation of influence of load and velocity on scoring of addendum modified gear tooth profiles
    (PERGAMON-ELSEVIER SCIENCE LTD, 2009) Imrek, Huseyin; Unuvar, Ali
    In general gears are used for power transmission in machines. Scoring is one of the factors that causes gears unusable. Since there are too many factors affecting scoring which have not satisfactorily been explained, researches on this subject are continuing. With the exception of addendum modi. cation, many factors affecting scoring phenomena have been analyzed in detail. Experimental works was performed in a FZG gear test apparatus for this purpose. In the experiments, scoring was investigated by using different speed and load levels with gear pairs having different addendum modi. cations. Amount of wearing and physical situation of pro. le surface were determined and evaluated for each speed and load level. The effect of addendum modi. cation and speed of revolution on scoring, were given in the conclusion according to the test results. (C) 2008 Elsevier Ltd. All rights reserved.
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    A novelty optimization approach for drilling of CFRP nanocomposite laminates
    (SPRINGER LONDON LTD, 2019) Kaybal, Halil Burak; Unuvar, Ali; Koyunbakan, Murat; Avci, Ahmet
    Numerous problems are encountered in drilling of carbon fiber-reinforced polymer composite materials (CFRP) such as delamination, tool wear etc. Delamination has been recognized as a major damage encountered when drilling composite laminates. In the present study, machinability and the effects of cutting speed and feed rate upon thrust force and delamination formation in carbon nano tube (CNT)-added carbon fiber-reinforced plastics (CFRP) and CFRP were investigated. With this purpose, the experiments were planned. The response surface analysis has been carried out to study the main and the interaction effects of the machining parameters. By using the Taguchi method, cutting parameters' degrees of influence were determined. A new multi-objective optimization for the appropriate drilling process of these composite materials was proposed and an analytical optimization technique was applied. Appropriate cutting parameters of thrust force and delamination factor were found and the optimization results showed that the combination of low feed rate with high cutting speed is necessary to minimize delamination in drilling of CFRP.The machinability refers to the relative ease or difficulty under certain cutting conditions. So, it is very important to understand the factors that affect the machinability and to evaluate their effects. Machinability of Epoxy/CF and CNT-Epoxy/CF was investigated. It was aimed to evaluate the machinability of these materials. A new machinability index has been developed in current study. It was found out that machinability of Epoxy/CF is better than CNT-Epoxy/CF.
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    OPTIMIZATION OF PROCESS PARAMETERS IN DRILLING OF SMC COMPOSITES USING TAGUCHI METHOD
    (UNIV OSIJEK, TECH FAC, 2017) Can, Ahmet; Unuvar, Ali
    This paper has presented and discussed machinability in the drilling of SMC ( Sheet Mould Compound) A-Class composite materials using Taguchi's DoE method. The thrust forces, surface roughness and push-out - peel-up delamination behaviour in drilling process for glass fibre reinforced SMC composites have been evaluated. The experimental results and the contribution ratio of parameters on machinability outputs have been statistically analysed by ANOVA. Analysis of variance shows that drill bit angle is the prominent parameter followed by feed rate and cutting speed that contributes towards output responses. Confirmation experiments performed with the optimum parameter condition levels show a reduction in thrust force by 9,8 %, surface roughness by 33,3 %, push-out delamination by 2,5 % and peel-up delamination by 1,38 %. A detailed deformation analysis was investigated for SMC composites. For the empirical modelling of machinability, outputs of SMC composites can be modelled with the quadratic polynomial regression model in a higher range of accuracy.