Yazar "Pazarkaya, Ibrahim" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • [ X ]
    Öğe
    Computational fluid dynamics analysis of flowmeters with elliptical gear pairs and evaluation of calculated flow rate by Taguchi method
    (Elsevier Sci Ltd, 2023) Pazarkaya, Ibrahim; Yazar, Mehmet; Ozdemir, Ahmet
    Accurate determination of flowmeters' design and manufacturing parameters ensures that commercially available flowmeters' declared characteristics are reliable. In this study, nine different flow meters with elliptical gear pairs were manufactured at three different a/b ratios, three different modules, and three different tooth numbers, and the Computational Fluid Dynamics (CFD) models were prepared. CFD analysis forms the basis of the study's methodology, which seeks to statistically identify the most appropriate elliptical gear parameters according to the flow meters manufactured and what the most influential parameter that changes the measured flow rate is. As the pressure of the fluid increased, the measured and CFD-calculated flow rates decreased. According to the measured flow rates and CFD analysis results, it was found that the average flow rate change was -0.0102 %, the biggest change was in the flow meter coded Db-03 with 0.0855 % at 3.00 MPa pressure, and the least change was in the flow meter coded Db-02 with 0.0002 % at 4.50 MPa pressure. The CFD models developed for the manufactured flowmeters were suitable for all flowmeters according to the measured and calculated percent flow rate variations. Taguchi L9 analysis revealed that a/b = 1.40, m = 2.50 mm, and z = 40 teeth are the optimal manufacturing parameters for elliptical gear, according to the signal-to-noise ratio based on the largest, best analysis. According to the analysis of variance, the modulus value contributed the most to the calculated flow rate at 65.25%, whereas the a/b ratio contributed the least with 0.96%.
  • [ X ]
    Öğe
    Delamination and thrust force analysis in GLARE: Influence of tool geometry and prediction with machine learning models
    (Sage Publications Ltd, 2024) Ekici, Ergun; Pazarkaya, Ibrahim; Uzun, Gultekin
    The multi-layered (fiber/metal) structure of glass fibre aluminium reinforced epoxy (GLARE) makes it difficult to obtain acceptable damage-free holes that meet aerospace standards. This paper investigated the effects of tool geometry and drilling parameters on reducing delamination damage and uncut fibers at the hole exit surface in drilling GLARE. The hole surfaces were examined by scanning electron microscope (SEM) at various magnifications. In addition, deep neural network (DNN) and long-short-term memory (LSTM) machine learning models were used to predict delamination (Fda), uncut fiber (UCF), and thrust forces using experimental data. No positive contribution of the special geometry tool was observed, while the standard geometry tool was found to be ideal for drilling conditions. Analysis of variance (ANOVA) revealed that feed rate contributed 57.83% to delamination damage, while tool geometry contributed 74.31% and 92.33% for uncut fiber and thrust force, respectively. SEM analysis revealed high deformation zones in the aluminum layers and fiber fracture and separation in the glass fibre reinforced polymer (GFRP) layers. DNN and LSTM models were found to provide accurate predictions with R2 values greater than 95% and 98%, respectively.
  • [ X ]
    Öğe
    Effect of lapping process on axis misalignment and surface roughness in elliptical gear pairs
    (Elsevier Sci Ltd, 2024) Pazarkaya, Ibrahim; Yazar, Mehmet; Karabulut, Sener; Uzun, Gultekin; Ozdemir, Ahmet
    This study aims to investigate the effect of application of the lapping process on the amount of axis misalignment in elliptical spur gears. Using a Taguchi L9 experimental design, nine distinct pairs of elliptical spur gears were manufactured, each featuring three distinct modules (m), number of teeth (z), and ratio of major and minor radius of the pitch ellipse (a/b). Specialized hardware and software were developed to determine inter-axis misalignment in the gear pairs. The hardware measured the misalignment, while the software collected data from a digital indicator, recording changes in inter-axis alignment at different angular positions of the gear pairs. Three diverse parameters were utilized in the lapping processes: rotational speed of 120 rpm, 170 rpm, and 220 rpm; duration of 10 min, 20 min, and 30 min; and mass of 0.5 kg, 1 kg, and 1.5 kg. Axial misalignment of the gear pairs was evaluated both before and after the lapping process. The most significant change in misalignment was observed at 76 mm for gear pairs with parameters m = 2.0, z = 25, a/b = 1.60, while the smallest misalignment change was recorded at 5 mm for gear pairs with parameters a/b = 1.60, m = 1.60, z = 40. After lapping process, the average surface roughness values of all gear pairs improved by an average of 27.64%, and no significant weight loss was noted. The optimal lapping parameters were determined based on post-lapping average surface roughness values, and they were found to be 220 rpm, 10 min, and a 1 kg weight. Although the rotational speed and duration varied, it was observed that a constant 1 kg weight parameter was the optimal lapping weight for all gear modules.