1,721,010 research outputs found
Multi‐disciplinary and multi‐objective optimization of an over‐wing‐nacelle aircraft concept
No full textIn this paper a Multi-Disciplinary and Multi-Objective Optimization (MDO-MOO) of a baseline Over-Wing-Nacelle (OWN) concept design is presented. The present study extends previous works, which considered only aerodynamic optimization, to include structural and mission design parameters. The competing objectives of minimum empty weight and minimum fuel weight for a design mission are considered in the multi-objective formulation as well as the single objective problem of minimizing takeoff gross weight, one of many compromises possible for the multi-objective problem. An integrated computational environment has been implemented. High-fidelity analyses for the structural and aeroelastic assessment, together with middle-fidelity analyses for aerodynamic, mission, and performance analyses are performed. A complex multi-disciplinary analysis framework is proposed, in order to account for the interdisciplinary interaction and to provide a consistent computational framework. Optimization results with a Multi Objective Genetic Algorithm (MOGA) show Pareto frontiers accounting for structural, aeroelastic, and mission design constraints. The disciplines coupling is quantified, in terms of constraints, design variables influences, and possible trade-offs among the objectives
Multi-objective optimization for the design of an inconventional sun-powered high-altitude-long-endurance unmanned vehicle
No full textThe use of High Altitude and Long Endurance (HALE) Unmanned Aerial Vehicles (UAVs) is becoming increasingly significant in both military and civil missions
as High-Altitude Pseudo-Satellite (HAPS). Since this class of aircraft is usually powered by solar cells, it typically features unconventional configurations to maximize sun exposed surfaces. In the present paper, a Multidisciplinary Design Optimization (MDO) and a Multi-Objective Optimization (MOO) environment have been developed to provide a computational design tool for modeling and designing these unconventional aircraft in order to achieve as independent objectives the maximization of solar power flux, the maximization of the lift-to-drag ratio, and the minimization of mass. To this purpose, a FEM models generator, capable of managing unconventional geometries, and a solar power estimator, are suitably developed to be integrated within a multi objective optimization loop. The simultaneous use of MDO/MOO approaches, and Design Of Experiment (DOE)
creation and updating principles, enables to efficiently take into account the multiple and contrasting objectives/constraints arising from the different disciplines involved in the design problem. The study is carried out by using two different commercial codes
for multi-objective optimization and for structural and aeroelastic analyses respectively. The use of advanced MDO/MOO approaches revealed to be effective for designing unconventional vehicles
Multi-Disciplinary Optimization for the Conceptual Design of Innovative Aircraft Configurations
No full textMultidisciplinary Optimization for the Conceptual Design of Innovative Aircraft Configurations
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Structural damping models for passive aeroelastic control
No full textAeroelastic qualification requirements are typically met by sizing aircraft to achieve adequate stability margins and keep peak gust responses below specified thresholds. A possible alternative approach is delaying flutter and alleviating gust response by embedding dissipative materials into structural components. This approach requires accurate damping models applicable to the analysis of complex configurations. In this paper, the effect of damping models in the evaluation of flutter boundaries and gust response of an aeroelastic test-bed is studied. In particular, three damping models completely different in frequency are considered to model the presence of skin patches for passive aeroelastic control: viscous damping, hysteretic damping and Biot damping models. In order to make them comparable the three models are tuned in order to dissipate the same amount of power at the flutter frequency by means of the introduction and definition of a generalized loss factor. The damping models are compared by evaluating their effect on flutter suppression and gust load alleviation. Finally, the sensitiveness of the stability and response aeroelastic analyses to the considered damping models are outlined and the obtained results are compared to provide modeling recommendations for passive flutter suppression and gust alleviation studies. The proposed methodology is applicable to any linear material model for which the related complex stiffness can be expressed in the frequency domain meeting the Hilbert restriction
POD approach for unsteady aerodynamic model updating
No full textA method for aerodynamic model updating is proposed in this paper. The approach is based upon a correction of the eigenvalues of the reduced order unsteady aerodynamic matrix through an optimization with objective function defined through the difference in the generalized aerodynamic forces or on the aeroelastic poles. The high fidelity model in reduced order form is obtained by the Proper Orthogonal Decomposition (POD) technique applied to the Computational Fluid Dynamics (CFD) Euler-based formulation. Many of the methods that have been developed in the past years for simpler aeroelastic models that use, for example, doublet-lattice method (DLM) aerodynamics, can be adopted for this purpose as well. However, this model is not able to capture shocks and flow separation in transonic flow. The proposed approach performs the updating of the aerodynamic model by imposing the minimization of a global error between target aerodynamic performances, namely, experimental performances, and an aerodynamic model in reduced order form via POD approach. After a general presentation of the application of the POD method to the linearized Euler equations, the optimization strategy is presented. First a simple test on a 2D wing section with theoretical biased data is performed and then the performances of different optimization strategies are tested on a 3D model updated by Wind Tunnel data
MDO in Preliminary Design of Innovative Configurations Inclusive of Aeroelastic Constraints
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Advanced multidisciplinary design of next-generation green aircraft
No full textThis study presents an advanced Multidisciplinary Design Optimization (MDO) tailored for the design of next-
generation green aircraft, integrating innovative propulsion systems and advanced materials. The MDO is
based on an advanced Class III weight estimation method. Traditional Class I and II methods were inadequate
for contemporary green aircraft, necessitating a sophisticated approach to accommodate new concentrated
masses and materials. The Asymmetric Subspace Optimization (ASO) method was employed to balance
computational loads effectively across disciplines such as aerodynamics, structures, and propulsion systems.
Preliminary results for a hybrid electric/traditional regional aircraft have shown significant performance improve-
ments, including a notable reduction in fuel mass and an increase in lift-to-drag ratio
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