5 sonuçlar
Arama Sonuçları
Listeleniyor 1 - 5 / 5
Yayın Tribo-corrosion behavior of electroplating, nitrocarburizing, and QPQ processes on barrel finishing(Walter de Gruyter GmbH, 2023-11-27) Yücel, Aysu Hande; Yılmaz, Alpay; Bakkal, Mustafa; Kuzu, Ali TanerIn this study, the effects of nitrocarburizing, QPQ, and Cr coating on the surface properties of 32CrMoV12-10 gun barrels are discussed. Hardness measurements, pin-on-disc tests, and anodic polarization tests were performed to examine the hardness values, wear resistance, friction coefficient, and corrosion resistance. The hardness of the specimen treated with QPQ was found to be the highest. Comparing the hardness profiles, it was observed that the casing depth of the nitrocarburized sample was shallower than that of the QPQ-treated sample. The pin-on-disc test revealed that the nitrocarburized sample exhibited a high coefficient of friction, while the Cr-coated sample showed the lowest coefficient of friction. Analyzing the Tafel polarization curve, it was determined that the nitrocarburized and QPQ-treated specimens demonstrated similar levels of corrosion resistance. However, it can be noted that the QPQ-treated specimen had a slightly lower corrosion rate.Yayın Neural network steering control algorithm for autonomous ground vehicles having signal time delay(SAGE Publications Ltd, 2024-03) Dinçmen, ErkinAn adaptive neural network–based steering control algorithm is proposed for yaw rate tracking of autonomous ground vehicles with in-vehicle signal time delay. The control system consists of two neural networks: the observer neural network and the controller neural network. The observer neural network adapts itself to the system dynamics during the training phase. Once trained, the observer neural network cooperates with the controller neural network, which constantly adapts itself during the control task. In this way, an adaptive and intelligent control structure is proposed. Through simulation studies, it has been shown that while a proportional-integral-derivative type steering controller fails to perform its control task in case of steering signal delay, the proposed control algorithm manages to adapt itself according to the control problem and achieves reference yaw rate tracking. The robustness of the control algorithm according to the signal delay magnitude has been demonstrated by simulation studies. A rigorous Lyapunov stability analysis of the control algorithm is also presented.Yayın Investigation of residual stresses induced by milling of compacted graphite iron by x-ray diffraction technique(Springer, 2024-04) Kara, Mehmet Emre; Kuzu, Ali Taner; Bakkal, MustafaThis study investigates the relationship between residual stresses, cutting parameters, and machining performance in the milling process of compacted graphite iron (CGI). X-ray diffraction (XRD) analysis is employed to measure residual stresses on the cast and milled surfaces, while cutting force modeling is utilized to calculate the tangential force, power, and active work. The results demonstrate that tensile residual stresses are predominant on the milled surfaces, attributed to the both mechanical and thermal loads generated during milling. By analyzing various cutting conditions, it is observed that lower feeds contribute to reduced plastic deformation, resulting in lower residual stress levels. Additionally, higher cutting speeds lead to higher temperatures, but due to the shorter machining time, heat accumulation is limited, resulting in higher residual stresses, especially at low feeds. At high feeds, residual stresses decreased as the cutting speed increased. The interplay between cutting parameters and residual stresses highlights the need for optimizing cutting conditions to enhance fatigue strength in CGI components. These findings provide valuable insights for process optimization and quality control in the milling of CGI materials.Yayın A new local path planning approach by synthesis of PRM and RRT* algorithms for an autonomous mobile robot(Springer, 2025-02) Göktaş, Anıl Gökhan; Sezer, SemihMany research efforts have been and continue to be carried out to make human life easier through the use of new technologies. The ability to shift labor to non-humans and reduce the workforce demonstrates the scope of innovation. In this investigation, a new approach is proposed to address several shortcomings of the PRM and RRT algorithms used for path planning in mobile robots. The proposed approach differs by building markers around it, avoiding dynamic obstacles and providing a shorter path. Simulation studies of the PRM and RRT* algorithms, along with the Circular Nodes (CN) approach, were conducted in real and virtual environments. Meanwhile, experimental studies for the CN approach were carried out in a real environment, with obstacles. When compared to other methods, the proposed approach has demonstrated an increase in node efficiency by up to five times. Moreover, implementing node points that are approximately 10% of those used in the PRM and RRT* algorithms has resulted in a shorter path. The reduction in the number of nodes and path length leads to a reduction in energy consumption and processing power.Yayın Energy-based characterization of drilling-induced residual stresses in AA7075-T6(Multidisciplinary Digital Publishing Institute (MDPI), 2026-01) Tok, Görkem; Dinçer, Ammar Tarık; Bakkal, Mustafa; Kuzu, Ali TanerThis study examines the influence of drilling parameters on thrust force, torque, active work, and axial residual stress formation in hot-forged and T6-treated AA7075, a critical high-strength aluminum alloy. A full factorial design was applied using three spindle speeds (800, 1000, 1200 rpm) and three feed rates (0.05, 0.10, 0.15 mm/rev). Cutting force and torque signals were measured using a dynamometer, and axial residual stresses were determined by X-ray diffraction at two locations along the hole depth, namely, the hole entrance (Point A) and the hole exit (Point B). The results show that feed rate is the dominant factor influencing drilling mechanics and residual stress formation, whereas spindle speed mainly affects the thermal and frictional conditions governing stress relaxation. A consistent asymmetry was observed between the two measurement locations, with the exit side exhibiting stronger stress relaxation behavior associated with breakthrough mechanics. Finally, the relationship between active work and axial residual stress is discussed using a qualitative, energy-based interpretation, highlighting active work as a physically meaningful indicator for drilling-induced residual stress evolution.
