Carbon fiber-reinforced polymer (CFRP) laminates are extensively utilized in aerospace and advanced engineering fields because of their outstanding strength-to-weight ratio and superior fatigue durability. However, despite their high in-plane strength and stiffness, CFRP laminates are inherently susceptible to delamination. This weakness stems from the relatively low interlaminar strength of the resin-rich interfaces between layers compared to the much stronger in-plane fiber reinforcement. During mechanical processes such as drilling and punching, out-of-plane stresses and interlaminar shear forces develop, concentrating at these weak interfaces. This study investigates the delamination behavior of CFRP laminates with 3 to 7 plies under drilling and punching, focusing on the effects of ply count and drilling speed. Experimental tests were conducted using an 8 mm punch and drill bit at 2500, 3000, and 3500 rpm, reflecting typical workshop practices for M8 fastener holes. Scanning electron microscopy (SEM) analyses at different magnifications were used to quantify delamination extent. A three-dimensional finite element model was created in ABAQUS/Explicit, integrating the Hashin failure criterion to predict damage initiation within the plies and cohesive surfaces to simulate interlaminar delamination. The analyses show that with proper support, punching can approach the damage levels of drilling for thin CFRP plates, but drilling remains preferable for thicker laminates due to better integrity and tool longevity.

This study provides a comprehensive numerical investigation of altitude-dependent combustion performance and emissions of a commercial aircraft engine, leveraging real engine data to evaluate kerosene-fueled operation across six flight levels: FL300, FL318, FL336, FL354, FL372, and FL390. The combustion chamber geometry was modeled using Siemens NX, simplified in ANSYS SpaceClaim, and meshed with a five-layer inflation strategy to ensure proper boundary layer resolution. A high-quality mesh was achieved, and a mesh independence study was conducted to ensure numerical accuracy. Using the realizable k –ε turbulence model with enhanced wall treatment and an eddy-dissipation approach for turbulence-chemistry interactions, the results show that lower flight levels are associated with higher combustion efficiency, with peak temperatures exceeding 2500 K at FL300. Conversely, higher altitudes demonstrated reduced combustion efficiency and increased unburned fuel fractions, providing insights into the performance and environmental impact of altitude-dependent aircraft operations. These results may assist in optimizing engine design and operational strategies for improved fuel efficiency and reduced environmental impact across varying altitudes.

Integrating maintenance considerations into aircraft design is essential for ensuring both operational efficiency and reliability. One of the key factors in aircraft selection and facilitating maintenance is the accessibility of critical components. This study focuses on the design and enhancement of design-based maintenance access panels during the early stages of conceptual design. The primary goal is to develop a methodology for identifying optimal locations for access panels, thereby minimizing the need for modifications during later design phases. The approach considers various factors, including Mean Time Between Failures (MTBF), maintenance intervals, and accessibility. The research encompasses several phases, such as evaluating maintenance needs, establishing a product lifecycle framework, and implementing Digital Mock-Up (DMU) activities based on Computer Aided Design (CAD) data and product development processes. This methodology fosters collaboration between design and maintenance teams, employing iterative techniques to develop access panels based on advanced DMU and CAD models. The findings of this research underscore the importance of a collaborative approach, the necessity of integrating maintenance considerations early in the design process, and the advantages of using design-based tools to optimize access panel design. Adopting this methodology helps aircraft manufacturers improve maintainability, reduce maintenance costs, and boost efficiency.

Helicopter imaging classification and detection are crucial for autonomous navigation, military operations, search and rescue, and civil aviation management. This study utilized two helicopter image datasets, applying data augmentation techniques such as random resizing, cutting, horizontal rotation, rotation, and color adjustments, along with histogram equalization for contrast enhancement. Twenty-four helicopter classes were trained using GoogleNet and AlexNet architectures, while the YOLOv9c model was employed for object detection. The results revealed that the GoogleNet classification model achieved an 81% F1 score, and AlexNet reached 73%. In contrast, the YOLOv9c model demonstrated an average mean Average Precision (mAP) of 87%. These findings indicate that CNN architectures and YOLO are effective for helicopter image classification and detection, highlighting their potential applications in military, search and rescue, and civil aviation contexts.

This research examines the effect of micro size sodium pentaborate pentahydrate and anhydrate forms on the physicochemical and mechanical properties of filled polypropylene (isotactic homopolimer – Borealis HE125MO) composite matrices. The Sodium pentaborate pentahydrate and anhydrite dried 105°C 1 hour and mixed with micro compounder with polypropylene (with different proportions) and produced test samples with injection molding method. Mechanical properties were measured (tensile strength, modulus of elasticity, ultimate strength, tensile at yield (at room temperature)) along with hardness (charpy impact) test. Increasing filler content lead to an increase mechanical strength of the composite material depends on the percentage quantity of mixture proportion. The observed increase in tensile strength is %4,2 with %1 sodium pentaborate pentahydrate additive. The modulus of elasticity increases with additive quantity and the ultimate strength and strain at yield effected parallel with tensile strength change. With high proportion (%5-%10) of filler content, the mechanical properties decreased but increased the hardness. To understand the physicochemical effects, FTIR test applied on samples and O-H bonds effects and C-C bonds change observed. According to Infrared spectroscopy, the polypropylene had changed 1,56% with sodium pentaborate pentahydrate additive and 2,86% with %1,5 additive of sodium pentaborate anhydrite form. The fingerprint region alterations at FTIR tests and water effect observed. The molecular bonding effects of sodium pentaborate with chain of isotactic homopolimer examined. The nucleating effect of sodium pentaborate in polypropylene is viewed with SEM test. In microstructure, positioning effects of sodium pentaborate particles in chain/fiber structure of polypropylene observed and associated with mechanical properties and physicochemical impacts.