Yazar "Demirel, Yusuf Soner" seçeneğine göre listele

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  • Kapalı Erişim
    Yayın
    Fixture design for high-strength fasteners and the effect of surface clearance on test results
    (Liberty Publishing House, 2026) Demirel, Yusuf Soner; Acar, Ayberk Okan; Tanrıver, Kürşat; Ay, Mustafa; Sinha, Thuna
    In this study, the effects of fixture designs and surface clearance tolerances on test results were investigated for the shear performance of high-strength fasteners, such as 7075-T6 aluminum, which are of critical importance in aerospace assemblies. With reference to ISO 8749 (maximum clearance of 0.15 mm) and NASM 1312-13 (maximum clearance of 0.0125 mm), the performance of compression-type and tension-type fixtures was comparatively evaluated using the Finite Element Method. The analyses were conducted in ANSYS 2025, employing mesh sizes of 0.6 mm for the pin, 0.8 mm for the hole surfaces, and 0.05 mm for the shear region. For fixture material selection, AISI 4140, Toolox 40, and AISI 4340 steels were assessed; AISI 4140 was found to be sufficient to meet the target yield strength criterion of 1.5 times the tensile strength of 7075-T6 aluminum. According to the simulation results, undesired stress levels on the order of 500 MPa were observed on surfaces outside the shear plane in the tension-type fixture. Consequently, the compression-type fixture, which concentrates stresses more effectively on the shear plane, was preferred. To examine the effect of tolerance between the fixture walls, analyses were performed for clearance scenarios of 0.3 mm and 0.025 mm. For these two clearance values, the maximum von Mises stresses were calculated as 641 MPa and 643 MPa, respectively, while the maximum shear stresses were 370.42 MPa and 370.95 MPa. These results, obtained for an 8 × 28 mm pin geometry, indicate that tolerance tightness does not lead to a statistically significant difference in stress outcomes. Consequently, it was concluded that ISO-compliant designs with relatively looser tolerances can be employed to reduce manufacturing costs without compromising test reliability.
  • Küçük Resim
    Yayın
    HL23‐5 ve HL23‐6 7075‐T6 alüminyum HI‐LOK vidalı pinler için çekme ve kesme test fikstürlerinin tasarımı ve sonlu elemanlar analizi
    (Güven Plus Grup Danışmanlık A.Ş. Yayınları, 2025) Demirel, Yusuf Soner; Acar, Ayberk Okan; Tanrıver, Kürşat; Ay, Mustafa
    Öz: Bu çalışmada, havacılık ve savunma uygulamalarında kullanılan HL23-5 ve HL23-6 tipi 7075-T6 alüminyum vidalı pinlerin çekme ve kesme testlerine yönelik özel test fikstürlerinin tasarımı ve sayısal doğrulaması ele alınmıştır. Pinlerin geometrik kısıtları nedeniyle evrensel test makinelerinde doğrudan test edilememesi, fikstür tasarımını zorunlu kılmaktadır. Bu kapsamda geliştirilen fikstürler SolidWorks ortamında modellenmiş; Toolox 33, AISI 304 ve AISI 4140 malzemeleri kullanılarak ANSYS 2025 akademik sürümünde sonlu elemanlar analizleri gerçekleştirilmiştir. Çekme ve kesme yükleme koşullarını kapsayan analizlerde gerilme dağılımları, deformasyonlar ve emniyet katsayıları karşılaştırılmıştır. Elde edilen sonuçlar doğrultusunda, deneysel testler için en uygun fikstür geometrisi ve malzeme seçimi belirlenmiş; çalışmanın küçük çaplı havacılık tipi vidalı pinlerin mekanik karakterizasyonu için güvenilir ve tekrarlanabilir bir test altyapısı sunması hedeflenmiştir.
  • Kapalı Erişim
    Yayın
    Localization of a high strength and vibration resistant fastening element for the defense industry
    (Liberty Academic Publishers, 2026) Demirel, Yusuf Soner; Şentürk, İsmail Hakkı; Tanrıver, Kürşat; Ay, Mustafa; Şahin, Ethem İlhan
    In the modern defense and aerospace industry, maintaining the structural integrity of air platforms and optimizing their operational life cycles are directly dependent on the high-precision domestic production of critical components. The indigenization of strategic parts not only minimizes foreign dependency but also ensures supply chain security against embargo risks and international logistical disruptions. This study comprehensively addresses the localization and technical validation processes of a specialized structural pin, which serves as a primary fastener in aerospace structures, aircraft wings, and missile systems, characterized by high strength and vibration damping capabilities. Within the scope of the research, Al 7075-T6 aluminium alloy, a premium material in aerospace standards known for its superior strength-to-weight ratio, was selected as the raw material. During the manufacturing phase, "Swiss-Type Lathe" (Sliding Headstock) technology was utilized to provide high dimensional stability in tight-tolerance geometries, and samples underwent heat treatment processes in accordance with aerospace norms. The mechanical performances of the manufactured specimens were subjected to static and dynamic tests within the framework of internationally recognized NASM1312 standards. In the design validation phase, non-linear static Finite Element Analysis (FEA) was performed using ANSYS software. In these numerical simulation processes, based on experimental data obtained from physical testing equipment, displacement values of 0.55 mm for tensile analysis and 0.23 mm for double shear analysis were defined as boundary conditions in the system. When the numerical analysis results were compared with the experimental data obtained from production samples, a high-correlation alignment was determined with an acceptable deviation of approximately 5%. The fact that both tensile and double shear strength values exceeded the minimum limits specified by the standards, and that the physical fracture lines perfectly overlapped with the plastic deformation zones in the simulation model, proves the reliable applicability of domestic production in critical defense systems with concrete and scientific data.