Yazar "Ekici, Ergun" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • Küçük Resim Yok
    Öğe
    Numerical and Statistical Investigation of The Effect of Composite Layer Thickness on Low-Velocity Impact Behaviour in Fibre Metal Laminate Materials
    (Gazi Univ, 2025) Dundar, Mustafa; Uygur, Ilyas; Ekici, Ergun; Tascioglu, Cihat; Gulenc, Behcet
    In the field of aviation, reducing fuel costs by designing lighter vehicles and thus producing more environmentally friendly aircraft is one of the most important issues. This situation has led aircraft manufacturers to search for lighter and more durable materials. For this reason, Fibre Metal Laminate (FML) structures, which are used especially in the aerospace industry due to their superior fatigue and impact resistance properties, attract attention. Carbon fibre reinforced aluminium plates (CARALL), the most unique member of the FML hybrid structure family, has attracted the attention of researchers. In this study, the low-velocity impact behaviour of CARALL FML structures with different composite layer thicknesses at different energy loading (8J-12J-18J) and different impactor types (& Oslash;15 and & Oslash;20) were statistically investigated. CARALL FML structures were modelled in 2/1 arrangement (Al-0 degrees[1]-Al, Al-0 degrees[3]-Al, Al-0 degrees[5]-Al) in LS-DYNA finite element programme. It is observed that the peak load Fmax increases with increasing energy loading. The increase in striker diameter decreased the amount of absorbed energy and increased the rebound.
  • Küçük Resim Yok
    Öğe
    Optimization of low-velocity impact behavior of FML structures at different environmental temperatures using taguchi method and grey relational analysis
    (Sage Publications Ltd, 2025) Dundar, Mustafa; Uygur, Ilyas; Ekici, Ergun
    Carbon fiber-reinforced Aluminum Laminate (CARALL) is a new generation of Fibre Metal Laminate (FML) material. This study investigates the low-velocity impact behavior of CARALL structures at different environmental temperatures (-40 degrees C, 23 degrees C, and 80 degrees C). Two different groups of CARALL composite structures with varying fiber orientations were produced by hot pressing in a 3/2 arrangement: C1 (Al/0 degrees 90 degrees/Al/90 degrees 0 degrees/Al) and C2 (Al/0 degrees 0 degrees/Al/0 degrees 0 degrees/Al). Low-velocity impact tests were conducted at 23 J, 33 J, and 48 J energy levels using a & Oslash;20 mm spherical impactor tip. The area of damage was detected by ultrasonic C-Scan. In addition, analysis of variance (ANOVA) was applied to reveal the influential parameters and their effect levels. After conducting experiments using the Taguchi L18 test set, it was observed that the C2-coded specimen yielded better results in terms of maximum peak load, maximum displacement, and damage area. While the decrease in temperature increased the damage and maximum peak load, the increase in temperature did not cause a significant change in the maximum peak load. The primary damage mechanisms observed in damage investigations were matrix cracks and delamination between composite layers. Although delamination is present between the Al/CFRP layer, it is not significant. According to ANOVA results, impact energy was the most effective parameter for maximum impact force, maximum displacement, and damage area, with contribution rates of 81%, 74%, and 76%, respectively. The optimal experimental conditions (23 degrees C temperature and 23 J impact energy with the C1-coded sample) were determined using grey relational analysis based on principal component analysis.
  • Küçük Resim
    Öğe
    Performance of Multilayer Coated and Cryo-Treated Uncoated Tools in Machining of AISI H13 Tool Steel-Part 1: Tungsten Carbide End Mills
    (Springer, 2021) Cicek, Adem; Kivak, Turgay; Ekici, Ergun; Kara, Fuat; Ucak, Necati
    This paper focused on the performance of tungsten carbide end mills in machining of AISI H13 hot work tool steel under dry and wet conditions. The tool performance was evaluated in terms of resultant cutting force (Fc), average surface roughness (Ra) and tool life. In the milling tests, four categories of end mills were used: untreated (U), cryo-treated (CT), cryo-treated and tempered uncoated (CTT) and TiAlN/TiN multilayer coated (MLC). The tests were performed at four cutting speeds (80, 100, 120, 140 m/min), three feeds (0.08, 0.12, 0.16 mm/rev) and a depth of cut (2 mm). The test results showed that the lowest values of Fc and Ra were obtained with the use of MLC end mills. However, the cryogenic treatment was also effective on decreasing Fc and Ra. In addition, while the CTT end mills provided a slight improvement in tool life under dry conditions, they showed a remarkable improvement of 126.1% in comparison with the untreated ones under wet conditions. Although the CTT end mills exhibited a superior performance to U and CT ones, the MLC end mills were much more resistant to abrasive wear. This study is organized into two parts (WC-Co and HSS) to observe the effects of deep cryogenic treatment on performance of two different tool materials and to compare cryo-treated end mills with multilayer coated ones. This part is related to the cryogenic treatment of tungsten carbide end mills, whereas part two is regarding cryo-treated HSS end mills.
  • Küçük Resim
    Öğe
    Performance of Multilayer Coated and Cryo-treated Uncoated Tools in Machining of AISI H13 Tool Steel-Part 2: HSS End Mills
    (Springer, 2021) Cicek, Adem; Ekici, Ergun; Kivak, Turgay; Kara, Fuat; Ucak, Necati
    This part of the study aimed to investigate the effects of cryogenic treatment applied to uncoated high speed steel (HSS) end mills on cutting forces (Fc), surface roughness (Ra), and tool life. The milling tests were performed at four cutting speeds (40, 50, 60, and 70 m/min), three feeds (0.018, 0.024, and 0.03 mm/rev), and a depth of cut (2 mm) under dry and wet conditions. Three categories of uncoated HSS end mills were used in the tests: conventional heat treated (CHT), cryo-treated (CT), cryo-treated and tempered uncoated (CTT), and TiAlN/TiN multilayer coated (MLC) end mills. The test results showed that the lowest values of Fc and Ra were measured with the use of MLC end mills. However, the cryogenic treatment provided in a reduction in Fc and Ra values. In addition, under wet conditions, the CTT end mills exhibited better performance than the CHT ones by 71.4%. The test results showed while cryogenic treatment is a useful and cheap application in steels, it does not have the ability to compete with coating technology in terms of tool life in milling of hot work tool steel. This paper is organized into two sections. In the first section, cutting performance of cryo-treated and multilayer coated end mills is evaluated. In the second section, performance comparison of cryo-treated WC-Co (Part 1), HSS (Part 2), and MLC end mills in milling of AISI H13 hot work tool steel is presented.