Yazar "Friswell, Michael I." seçeneğine göre listele

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    A review of control strategies used for morphing aircraft applications
    (Elsevier Science Inc, 2024) Parancheerivilakkathil, Muhammed S.; Pilakkadan, Jafar S.; Ajaj, Rafic M.; Amoozgar, Mohammadreza; Asadi, Davood; Zweiri, Yahya; Friswell, Michael I.
    This paper reviews the various control algorithms and strategies used for fixed -wing morphing aircraft applications. It is evident from the literature that the development of control algorithms for morphing aircraft technologies focused on three main areas. The first area is related to precise control of the shape of morphing concepts for various flight conditions. The second area is mainly related to the flight dynamics, stability, and control aspects of morphing aircraft. The third area deals mainly with aeroelastic control using morphing concepts either for load alleviation purposes and/or to control the instability boundaries. The design of controllers for morphing aircraft/wings is very challenging due to the large changes that can occur in the structural, aerodynamic, and inertial characteristics. In addition, the type of actuation system and actuation rate/ speed can have a significant effect on the design of such controllers. The aerospace community is in strong need of such a critical review especially as morphing aircraft technologies move from fundamental research at a low Technology Readiness Level (TRL) to real -life applications. This critical review aims to identify research gaps and propose future directions. In this paper, research activities/papers are categorized according to the control strategy used. This ranges from simple Proportional Integral Derivative (PID) controllers at one end to complex robust adaptive controllers and deep learning algorithms at the other end. This includes analytical, computational, and experimental studies. In addition, the various dynamic models used and their fidelities are highlighted and discussed. (c) 2023 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
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    Fundamental frequency optimization of variable stiffness Multi-Region composite panels in Presence of geometrical nonlinearity
    (Academic Press Ltd - Elsevier Science Ltd, 2025) Farsadi, Touraj; Ahmadi, Majid; Jiffri, Shakir; Khodaparast, Hamed Haddad; Kurtaran, Hasan; Friswell, Michael I.; Fichera, Sebastiano
    Multi-region laminate optimization offers a comprehensive approach to enhance aerospace structures, making them efficient, safe, and cost-effective. Similarly, Automated Fiber Placement (AFP) processes optimize toolpaths and fiber deposition, reducing waste, saving time, and improving composite quality. Strategically placing fibers where needed, it boosts structural performance and allows for innovative composite designs. This study, first, focuses on optimizing the Fundamental Natural Frequency (FNF) of composite panels, which feature various Curvilinear Fiber Paths (CFP) mathematically modeled using bilinear interpolation distributed across different regions of the panel with comparisons drawn against the conventional Unidirectional (UD) fiber layup. Secondly, a study is conducted to explore the Fundamental Amplitude-dependent Nonlinear Frequencies (FANF) within the context of the optimized configuration featuring curved fiber layup. The modulation of stiffness in composite laminates is achieved through continuous adjustments of fiber angles, governed by the CFP function. A nonlinear structural model, grounded in the principles of virtual work, is employed for this analysis. The formulation incorporates Green's nonlinear kinematic strain relations to accommodate geometric nonlinearities, and First-order Shear Deformation Theory (FSDT) is applied to extend the analysis to moderately thick cylindrical panels, including transverse shear deformations. The principal aim of this investigation is to evaluate the impact of Variable Stiffness (VS) parameters across multiple regions on the linear and nonlinear free vibration characteristics of the panel. This research examines symmetric eight-layered composite panel incorporating three distinct design regions and two boundary condition sets. The Generalized Differential Quadrature (GDQ) method is employed to solve the nonlinear equations of motion governing these structures. The numerical findings show the impact of fiber angle paths and boundary conditions on the FNF of cylindrical panels.
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    High Aspect Ratio Composite Wings: Geometrically Nonlinear Aeroelasticity, Multi-Disciplinary Design Optimization, Manufacturing, and Experimental Testing
    (Mdpi, 2024) Farsadi, Touraj; Ahmadi, Majid; Sahin, Melin; Khodaparast, Hamed Haddad; Kayran, Altan; Friswell, Michael I.
    In the field of aerospace engineering, the design and manufacturing of high aspect ratio composite wings has become a focal point of innovation and efficiency. These long, slender wings, constructed with advanced materials such as carbon fiber and employing efficient manufacturing methods such as vacuum bagging, hold the promise of significantly lighter aircraft, reduced fuel consumption, and enhanced overall performance. However, to fully realize these benefits, it is imperative to address a multitude of structural and aeroelastic constraints. This research presents a novel aeroelastically tailored Multi-objective, Multi-disciplinary Design Optimization (MMDO) approach that seamlessly integrates numerical optimization techniques to minimize weight and ensure structural integrity. The optimized wing configuration is then manufactured, and a Ground Vibration Test (GVT) and static deflection analysis using the Digital Image Correlation (DIC) system are used to validate and correlate with the numerical model. Within the fully automated in-house Nonlinear Aeroelastic Simulation Software (NAS2) package (version v1.0), the integration of analytical tools offers a robust numerical approach for enhancing aeroelastic and structural performance in the design of composite wings. Nonlinear aeroelastic analyses and tailoring are included, and a population-based stochastic optimization is used to determine the optimum design within NAS2. These analytical tools contribute to a comprehensive and efficient methodology for designing composite wings with improved aeroelastic and structural characteristics. This comprehensive methodology aims to produce composite wings that not only meet rigorous safety and performance standards but also drive cost-efficiency in the aerospace industry. Through this multidisciplinary approach, the authors seek to underscore the pivotal role of tailoring aeroelastic solutions in the advanced design and manufacturing of high aspect ratio composite wings, thereby contributing to the continued evolution of aerospace technology.