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    Finite Element Analysis of Thrust Force in Drilling of Al2014 Aluminum Alloy
    (TUBITAK, 2019) Korkmaz, M.E.; Çakiroglu, R.; Yagar, N.; Özmen, R.; Günay, M.
    The purpose of this work is to compare the experimental and simulational results of the thrust force in drilling of the Al2014 aluminum alloy with the uncoated cemented carbide tool. In the experimental study, drilling was performed using cutting parameters (cutting speed and feed rate) at different levels. Numerical analyzes for thrust force were performed using the ThirdWave Advantages simulation program, which is based on the finite element method. With constant feed rates of 0,1, 0,2 and 0,3 mm / rev, the thrust force decreased by 9,1%, 12,8% and 18,6%, respectively, with the cutting speed increased by 35%. At constant cutting speeds of 170, 200 and 230, the thrust force increased by 23,9%, 16,1% and 11%, respectively, by increasing the feed rate from 0,1 to 0,3 mm / rev. It has been determined that the thrust force decreases with increasing the cutting speed and increases with the increasing feed rate. The results of drilling simulation performed by finite element method were similar to experimental results. As a result of the study, it was determined that there was an average difference of 7% between the experimentally measured thrust force and the force values obtained as a result of the simulation. Finally, the applicability of the finite element model was proved. © 2019, TUBITAK. All rights reserved.
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    An investigation on deformation behaviors of energy absorbers for passenger coaches
    (International University of Sarajevo, 2017) Özmen, R.; Günay, M.
    Thin-walled structures is used commonly as energy absorbers at the front and back of the coaches. These parts should be designed to minimize the damage to the vehicle and prevent the passengers from fatality and/or injury by absorbing the collision energy in railway transportation. In this paper, deformation behaviors of tube like structures with truncated cone under the axial impact load were investigated by means of finite element analysis (FEA). The energy absorbers having tube like structures were modelled at the same weight and have three different wall thickness and taper angle. As a result of FEA, the performances of straight and truncated cone type energy absorbers were compared in terms of energy absorption capacities and an optimization study was done to determine the effects of thickness and taper angle on energy absorbing performances of the members. The analysis of variance in 95% confidence level was applied in order to determine the effects of design parameters on total efficiency (TE). Besides, optimum design parameters for TE were determined by using Taguchi optimization methodology. Thickness was found as the most significant parameter on total efficiency with 60.52% percentage contribution ratio according to ANOVA results.