Değişken talaş ve helis açılarına sahip dalga formlu parmak frezeler, talaşlı imalat alanında henüz çok yeni ve performansları hakkında çok az bilgi sahibi olunan kesici takımlardır. Bu çalışmada, helisel kesici kenar üzerinde değişken talaş ve helis açıları bulunan dalga formlu parmak frezelerin; çalışma sertleşmesi, yüksek takım aşınması ve yığıntı talaş (BUE) oluşturma eğilimi sebepleriyle işlenmesi zor malzemeler grubunda yer alan, AISI 316L östenitik paslanmaz çelik üzerindeki işleme performansları araştırılmıştır. Bu kapsamda, farklı dalga boylarına (mm) ve dalga genliklerine (µm) (6-550, 8-250, 4-450 ve 8-650) sahip dalga formlu ve standart form olmak üzere beş farklı yekpare karbür kesici takım, deneysel ve istatistiksel yaklaşımlardan oluşan bir çalışma planı çerçevesinde; kesme kuvvetleri, yüzey kalitesi ve takım ömrü kriterleri dikkate alınarak değerlendirilmiştir. Dalga formlu takımlar; kesme kuvvetleri ve yüzey kalitesi açısından, pozitif talaş açılı bölgelerin sağladığı avantajlara rağmen negatif talaş açılı bölgelerdeki işleme olumsuzluklarının baskın gelmesi nedeniyle, bütün işleme şartlarında, standart takıma göre daha yüksek kesme kuvvetleri ve yüzey pürüzlülük değerleri sergilemiştir. Diğer taraftan, daha küçük pozitif ve negatif talaş açılarına (+4°, -2°, -3°) sahip 8-250 ve 8-650 dalga formlu takımlarda, standart takıma göre sırasıyla %17,2 ve %6,9 oranlarında daha düşük takım aşınma değerleri görülmüştür. Sonuç olarak, AISI 316L malzemesinin işlenebilirliğini zorlaştıran yüksek mekanik dayanım ve yüksek çalışma sertleşmesi (pekleşme) özelliklerinin neden olduğu düşük takım ömrü problemi için 8-250 ve 8-650 dalga formlu takımların, kaba talaş (rough) frezeleme işlemlerinde çözüm olabileceği düşünülmüştür.

A comprehensive review of all the related investigations carried on water jet cutting or AWJ (AWJ) cutting is performed. The experimental methods and results used on this subject were examined, defined and compared by the researchers. This research shows that further improvements are possible in the water jet cutting method. In order to reduce the high cost of the empirical technique and increase the time efficiency, it is important to perform computerized Finite Element Analysis (FEA) or Computational Fluid Dynamics (CFD) based AWJ processing. An attempt has been performed to systematically arranged the research investigations conducted on water jet cutting. The studies on the definition of the nozzle failure, calculate using CFD of water jet cutting or AWJ cutting processes, the studies on the parameters influencing water jet cutting are reviewed and the future work for the further improvement of water jet cutting process is highlighted.

Background/Objectives: The medial meniscus is crucial for load transmission and knee stability. Meniscal tears disrupt joint biomechanics, increasing the risk of cartilage degeneration. However, few studies have quantitatively compared how different tear types affect stress and contact mechanics using finite element analysis (FEA). This study aims to analyze stress distributions for various meniscal tear types and develop a predictive model for meniscal stress behavior. This study investigates how stress distributions differ between healthy and torn medial menisci under identical loading conditions. The study examines which meniscal tear type produces the highest stress concentrations. The effects of different tear types on penetration, gap formation, pressure distribution, and sliding distance at the meniscus interface are also analysed. Materials and Methods: The FEA model of the knee joint, including femoral and tibial cartilage and the medial meniscus, was developed. Simulations were conducted for a healthy meniscus and for menisci with radial, horizontal and complex tears. Stress, penetration, gap, pressure, and sliding distance were calculated, and a mathematical model describing their relationships was established. Results: All torn menisci exhibited significantly higher stresses than the healthy meniscus (p < 0.001). Radial tears generated the highest stress concentrations (p < 0.001). Pressure was mainly influenced by meniscal geometry, while the gap remained nearly constant. Penetration increased slightly (p < 0.05). The predictive model demonstrated a strong correlation between meniscal stress and interface parameters (R² > 0.9). In a healthy meniscus, stress distribution is homogeneous (≈26 MPa). Stress concentration increases depending on the tear type: limited in a horizontal tear (≈26.5 MPa), significant in a vertical tear (≈30.8 MPa), and highest in a radial tear (≈40.6 MPa). These results indicate that as the tear progresses, the load-bearing capacity of the meniscus decreases, and stresses concentrate at the tear edges. Conclusions: Meniscal tears, especially radial ones, substantially alter knee biomechanics and elevate tissue stress. These biomechanical insights highlight the importance of early diagnosis and targeted rehabilitation strategies to prevent further cartilage damage and osteoarthritis progression.

This study investigates the biomechanical behavior and corrosion resistance of Ti6Al4V screws coated with hexagonal boron nitride (hBN) and hydroxyapatite (HA) for femoral neck fracture fixation using a triangular configuration under axial loading. Utilizing 3D modeling software (Geomagic Studio and SolidWorks) and numerical analysis with AnsysWorkbench, the screws were designed and analyzed. The study aimed to determine the biomechanical effects and corrosion relationships of Ti6Al4V coated with hBN and HA. Comparative analysis revealed that Ti6Al4V-HA exhibited higher gap (0.036427), penetration (0.0028631), and sliding distance values (0.0024398) compared to Ti6Al4V-hBN (gap: 0.036196, penetration: 0.0028579, sliding distance: 0.0024300), indicating greater reactivity and corrosion potential. Conversely, Ti6Al4V-hBN demonstrated superior corrosion resistance. The findings suggest that hBN-coated Ti6Al4V screws provide improved stability and reduced stress concentration, which are critical for successful fracture fixation. Additionally, hBN coating effectively reduced the corrosion rate of Ti6Al4V in simulated body fluids, enhancing implant longevity and patient safety. However, further in vivo studies are necessary to validate these findings and assess long-term performance and biocompatibility. The study underscores the need to consider multiple factors in implant material selection to gain a comprehensive understanding of corrosion behavior. Overall, this research lays the groundwork for future advancements in orthopedic implant technology and has the potential to improve patient outcomes in fracture management.

The main focus of this study revolves around the problem of vibrations in unmanned aerial vehicles and aims to propose solutions using different designs of vibration dampers. Specifically, the study identifies the sources of vibrations in a Single Rotor Rotary Wing (Monocopter) type UAV. To assess the damping performance of the designed dampers, vibration tests were conducted in a controlled setup. Based on the measurement results obtained at three different speed stages, a particular damper, referred to as G2S2, exhibited the highest damping performance. At the first speed stage, it achieved damping percentages of 66% for the X-axis, 77% for the Y-axis, and 84% for the Z-axis. At the second speed stage, the percentages increased to 81% for the X-axis, 84% for the Y-axis, and 97% for the Z-axis. Finally, at the third speed stage, the damper demonstrated damping percentages of 85% for the X-axis, 84% for the Y-axis, and 98% for the Z-axis. This study successfully developed an experimental setup for measuring vibrations during UAV flight, particularly focusing on unmanned aerial vehicles. Furthermore, among the vibration dampers produced using additive manufacturing techniques, the damper with the highest performance, namely G2S2, was selected. Considering the measurement results, G2S2 emerged as the most effective vibration damper. It is worth mentioning that this damper can also be tested in real flight scenarios in the future, building upon the outcomes achieved through the experimental setup.