查看更多>>摘要：This paper presents a novel artificial fuzzy heuristic theory specifically designed for nonlinear simulations in the context of aircraft systems. Leveraging the principles of fuzzy logic, the proposed methodology addresses the complexities and uncertainties inherent in nonlinear dynamics of aircraft behavior. By integrating fuzzy inference systems with heuristic optimization techniques, we develop a robust framework that enhances the accuracy and efficiency of simulations. The study begins with a comprehensive review of existing methodologies in aircraft simulation, highlighting their limitations in handling nonlinearities and uncertainties. We then introduce our fuzzy heuristic approach, detailing its architecture and operational mechanisms. Through a series of simulations, we demonstrate the effectiveness of our theory in predicting aircraft performance under various operational scenarios. Results indicate significant improvements in simulation accuracy and computational efficiency compared to traditional methods. The proposed approach not only facilitates better understanding and analysis of aircraft dynamics but also provides a valuable tool for engineers and researchers in the field of aerospace engineering. Future work will explore the integration of this theory with real-time systems and its application in flight control design.
查看更多>>摘要：This paper investigates the power spectral density (PSD) of wind gusts by utilizing data from Low Earth Orbit (LEO) satellites. The wind gust represents one of the most unpredictable phenomena; indeed, its transient nature presents significant challenges in the aircraft design. Aircraft structural components are designed to deal with fatigue loads generated by the turbulent movement of the air, which, due to the ongoing changes of climate, may increase more and more and affect the safety of the aircraft. The effects of gusts on the structural integrity are typically evaluated through power spectral analysis, which provides a realistic representation of the air movement The potential impact of climate change on gust spectra urges to incorporate recent data, and satellites are a valuable resource for this purpose. The analysis is divided into two parts: the first combines power spectral analysis with LEO satellite data to assess PSD of vertical wind gust based on von Karrnan model (PSD_(vk)); the second compares the PSD_(vk) with the PSD assessed via a model, named "agnostic" (PSD_a), which does not rely on a pre-defined equation. The results, focusing on a part of the transatlantic route, show that the proposed approach allows to reveal annual and seasonal fluctuations in gust patterns. The comparison between PSD_(vk) and PSD_a reveals that some differences may occur at high frequencies. These findings highlight the potential of satellite technology to monitor climate change's effects and establish a foundation for further research in this critical area.
查看更多>>摘要：The current work presents a novel cylindrical dielectric resonator (CDR) antenna geometry operating at 28 GHz for fifth-generation wireless communication networks (5G). Because of its high radiating power factor, the used dielectric resonator is regarded as a promising new candidate in the field of antennas. The CDR antenna is made up of a FR4 Epoxy Resin substrate with a relative permittivity of 4.4 and a height of 1.8 mm, to which we added a dielectric resonator with a relative permittivity of 83, a height of 1.5 mm and a radius of 1.34 mm and it fed by a single microstrip line. The designed antenna geometry was simulated and optimized with the electromagnetic solver HFSS, and the results were validated with the CST microwave studio software. The results allowed us to obtain an antenna radiation at the desired frequency of 28 GHz with an interesting return loss value, a good radiation pattern, a high gain, a large bandwidth and a high directivity. As a result, this antenna is suitable for a wide range of wireless satellite applications.
Tamer SaracyakupogluMarziyya F. AghayevaAmdulla O. MekhrabovPari N. Rustamova...
59-75页
查看更多>>摘要：The epoxy resin, reinforced with magnetic nanoparticles, demonstrates superior properties by combining the strengths of both the epoxy resin and the magnetic nanoparticles. Epoxy resin is a traditional and essential thermosetting polymer known for its high tensile strength, Young's modulus, and excellent thermal and electrical properties. Moreover, the magnetic nanoparticle-reinforced epoxy resin exhibits exceptional mechanical properties, particularly regarding microwave shielding, which is crucial for Radar Absorbent Materials (RAMs) and stealth technology. Stealth technology is vital in aerospace and naval technologies, enhancing warfare capabilities. The computational understanding of microwave shielding is essential for the practical applications of RAMs and stealth technologies. However, there has been a significant lack of computational research on the microwave-shielding properties of magnetic nanoparticle-reinforced epoxy resin, a gap that the current study aims to fill. The study delves deeply into the microwave-shielding characteristics of this material, thereby contributing to the field and potentially opening up new avenues for research and application.
查看更多>>摘要：This article investigates the nonlinear forced vibration behavior of a functionally graded carbon nanotube-reinforced composite (FG-CNTRC) rotating annular plate subjected to external excitation forces. First, the governing equations are established based on the first-order shear deformation theory (FSDT) and the Hamiltonian principle. Subsequently, the Galerkin method is utilized to discretize the nonlinear equations. Considering pinned and fixed boundary conditions, the multi-scale method is used to derive analytical solutions. By comparing the results with existing literature, good consistency is achieved, validating the accuracy of the research. Finally, the influences of different parameters on the nonlinear vibration of the annular plate are analyzed. The results indicate that temperature, distribution patterns and volume fraction of CNTs, rotational velocity, and geometric configurations of the plate significantly affect the resonance position. Additionally, the damping coefficient and external load exhibit a pronounced impact on the resonance domain but do not affect the natural frequency. As external excitation varies, periodic motion and chaotic phenomena are observed in the system.
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