This study investigates the factors affecting surface integrity during the machining of near-β Ti-5553, a critical material in the aerospace and defense industries. Considering this alloy as a difficult-to-machine material, the turning process was examined by analyzing the effects of cutting speed, feed rate, and cooling strategy (dry, conventional, and 30 MPa/High-Pressure cooling) on cutting force, temperature, surface roughness, and residual stress. The primary novelty of this research lies in its integrated approach: rather than evaluating surface integrity metrics in isolation, it simultaneously models interrelated responses to residual stress, cutting temperature, cutting force, and surface roughness under high-pressure coolant (HPC) conditions. Furthermore, it introduces a robust machine learning framework that uniquely applies data augmentation (Gaussian jittering and interpolation) to overcome the conventional constraints of limited experimental machining data, providing a highly accurate predictive tool. The experimental data were expanded using data augmentation methods (Gaussian jittering and interpolation) and modeled using five different machine learning algorithms (Extra Trees, Random Forest, Gradient Boosting, KNN, and AdaBoost). The results revealed that cooling pressure plays a dominant role, particularly in residual stress (importance score: 0.926) and cutting temperature (0.657). It was observed that high-pressure cooling (HPC) reduces thermal gradients, thereby lowering tensile stresses and improving surface integrity. When algorithm performances were compared, the Extra Trees and Random Forest models achieved the most accurate predictions after hyperparameter optimization. Specifically, the optimized Extra Trees regressor demonstrated exceptional predictive capability for residual stress, achieving an accuracy of 98.47%, a remarkably high coefficient of determination (R² = 0.9997), and a minimal Mean Squared Error (MSE = 6.8289). These quantitative results confirm that the proposed machine learning framework provides a highly reliable and precise tool for controlling surface quality in HPC- assisted machining.

Total kalça protezi tasarımında protez performansı ve kullanım ömrünün artırılmasına yönelik çalışmalar gelişen cerrahi yöntemlerin yanı sıra malzeme ve üretim teknolojileriyle beraber son yıllarda oldukça hız kazanmıştır. Değişen ve gelişen biyomedikal teknolojisine her geçen gün ayak uydurabilen pratik yapısal ve mekanik çözümler günümüz mühendislik biliminin temel sorunlarından biri haline gelmiştir. Bu nedenle bilim insanlarının ilgi odağı, farklı malzemelerden yapılmış yapısal ve mekanik bileşenlerin farklı davranışlarına ilişkin analitik, sayısal ve deneysel çalışmalar olmuştur. Sonlu elemanlar yöntemi yeni protez tasarımlarının dayanım performansları hakkında prototip üretimi ve fiziksel testler yapılmaksızın gerçeğe oldukça yakın önemli bilgiler sağlamaktadır. Sunulan çalışmada kalça protezlerinde yaygın olarak kullanılan Ti-6Al-4V malzemesi kullanılarak ASTM F2996-20 kalça protezi sapı modeli üzerinde sonlu elemanlar yöntemi ile statik analiz yapılarak protezin performansı incelenmiştir. Ayrıca mesh tipi ve eleman boyutunun gerilme ve birim şekil değiştirmeler üzerindeki etkileri nümerik olarak ANSYS 19 paket programı kullanılarak ele alınmıştır. Elde edilen sonuçlardan, eleman boyutunun 1mm’den küçük olması durumunda, gerilme ve birim şekil değiştirmeler üzerinde etkisi olmadığını fakat işlem süresini oldukça arttırarak çözümü ekonomiklikten uzaklaştırdığı görülmüştür.

This study aims to investigate the differences and deviations between theoretical engineering calculations and numerical results obtained from finite element analyses for S235JR steel, which is widely used in structural and mechanical engineering applications. Tensile, torsional, and three-point bending loading conditions were considered. The loading cases were modeled using the finite element software ABAQUS and ANSYS. The numerical results were compared with reference values calculated using classical engineering equations. Because S235JR steel is widely used in engineering designs, examining the consistency between theoretical calculations and numerical results obtained from different software environments is important for both academic research and engineering practice. For this purpose, specimen geometries, material properties, boundary conditions, and loading types were defined identically in both software programs. This approach ensured that the observed differences mainly resulted from solution algorithms and numerical formulations rather than modeling choices. Key parameters that directly affect the analysis results, such as mesh density, element type, and solver selection, were carefully controlled. Stress distributions, deformation behavior, and maximum displacement values were evaluated separately for ABAQUS and ANSYS and compared with theoretical calculations. The results indicate that the deviations between theoretical and numerical outputs vary between approximately 1% and 10%, depending on the type of test. Overall, the numerical results show good agreement with theoretical predictions. However, small but measurable differences were observed due to software-specific numerical approaches. These findings demonstrate that a comparative numerical analysis approach supported by theoretical calculations is effective for validating finite element models and obtaining reliable results in engineering applications.

This study investigates the effect of goat horn powder (GHP) reinforcement on the hardness, microstructure, and mechanical properties of wood-like polyurethane composites. GHP, a keratin-based animal waste, was incorporated into the polyurethane matrix at weight fractions of 5, 10, 15, 20, and 25 wt.%. The mechanical behavior was evaluated through tensile, three-point bending, Charpy impact, and Shore D hardness tests, complemented by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses. Results indicate that GHP significantly enhances impact resistance, with 10 wt.% loading achieving a 140% improvement in impact energy compared to the neat matrix. Tensile stress improved by 12.89% at 5 wt.% loading. However, reinforcement levels exceeding 10–15 wt.% led to a decline in tensile and flexural performance due to particle agglomeration and weak interfacial adhesion. Shore D hardness increased systematically with higher GHP content across all ratios. The study demonstrates that GHP is a functional, sustainable reinforcing element that improves toughness and hardness while supporting environmental waste management.

This study investigates the effects of Shore A hardness, extruder type, and infill ratio on ultimate tensile strength (UTS), elastic modulus (E), and elongation at break (%) in FDM-printed thermoplastic polyurethane (TPU) specimens using a multifactor experimental design, ANOVA, and regression models. Unlike previous studies that often focus on printing parameters or material hardness individually, this work presents a holistic evaluation of how Direct Drive and Bowden Tube extruder systems modify the tensile response across different hardness levels and structural densities. ASTM D638 Type-IV tensile tests indicate that Shore hardness is the most dominant factor governing mechanical performance. Considering extruder configuration, the Direct Drive system outperforms the Bowden setup because its shorter filament path and more stable material flow improve interlayer fusion. Numerically, the strongest mechanical resistance was achieved using the Direct Drive system with 95A hardness and 100% infill, yielding the highest UTS (41.2 MPa) and elastic modulus (43.8 MPa). Conversely, the weakest results occurred with the Bowden Tube system at 70A hardness and 50% infill, resulting in the lowest UTS (22.4 MPa) and elastic modulus (18.7 MPa). Maximum ductility was observed at 70A hardness and 100% infill with the Direct Drive system, reaching 703% elongation at break, while the lowest elongation (285%) was recorded using the Bowden Tube at 95A and 50% infill. Overall, the findings recommend 70A + high infill + Direct Drive for applications requiring flexibility, and 95A + 100% infill for applications demanding high strength.

Ti-5553 (Ti–5Al–5Mo–5V–3Cr) one of the titanium alloys, is a recently developed near beta Titanium alloy, which is frequently used in the aerospace industry such as landing gear. When machining these superalloys, surface integrity can be affected by cutting and cooling conditions. An experimental study was conducted on Ti-5553, also known as beta-like titanium alloy, to understand the role of High Pressure Cooling and Lubrication conditions on surface integrity. In this study, high pressure coolant levels and other machining parameters (cutting speed, feed rate) were chosen as variable factors. These various levels were selected in different values and used in the tests to emphasize the relations of the accepted shear conditions from the effective data in the formation of residual stresses, which is also a parameter of the surface integrity. The results demonstrate the need to prepare coolant pressure levels to improve work surface integrity in such a material. In order to reveal the consistency of the coolant pressure values with other determined cutting parameters and the accuracy of choice, a relationship optimization has been tried to be explained.