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Constrained aerodynamic optimization of three-dimensional wings driven by Navier-Stokes computations

AIAA JOURNAL 2005年第9期43卷 1946-1957页

作者： Epstein, B Peigin, S Acad Coll Tel Aviv Yaffo Dept Comp Sci IL-64044 Tel Aviv Israel Israel Aircraft Ind Ltd Div Engn IL-70100 Ben Gurion Israel

A robust and efficient approach to the multiobjective constrained design, previously developed by the authors, is extended to optimization of three-dimensional aerodynamic wings. The objective is to minimize the total drag at fixed lift subject to various geometrical and aerodynamical constraints. The approach employs genetic algorithms (GAs) as an optimization tool in combination with a reduced-order-models (ROM) method, based on linked local databases obtained by full Navier-Stokes computations. The work focuses on the following issues: geometrical representation of three-dimensional shapes, handling of sensitive nonlinear constraints such as pitching moment, and the influence of flight conditions on the results of optimization. The method, implemented in the computer code OPTIMAS (optimization of Aerodynamic Shapes), was applied to the problem of multipoint transonic three-dimensional wing optimization with nonlinear constraints. The results include a variety of optimization cases for two wings: a classical test case of ONERA M6 wing and a generic cranked transport-type wing. For the investigated class of problems,, significant aerodynamic gains have been obtained.

关键词： Aerodynamic Characteristics Trailing Edges Aerodynamic Efficiency Supercritical Wings Genetic algorithm Pressure Coefficient Numerical Simulation optimization algorithm Navier Stokes Solver C++ Language

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Mixture optimization of superdetonative ram accelerator using refined response surface method

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JOURNAL OF PROPULSION AND POWER 2005年第6期21卷 1136-1139页

作者： Lee, JW Jeon, KS Byun, YH Lee, C Jeon, YH Konkuk Univ Ctr Adv eSyst Integrat Technol Seoul 143701 South Korea Konkuk Univ Dept Aerosp Engn Seoul 143701 South Korea Seoul Natl Univ Dept Aerosp Engn Seoul 151742 South Korea

The effect of mixture composition on the performance of a ram accelerator by investigating the pressure distribution on the projectile surface and the location of the detonation wave was investigated. The optimum mixture composition that minimized the ram tube length was examined by implementing several optimization techniques. The optimum mixture composition was obtained after seven design iterations by the implementation of gradient-based sequential linear programming, which resulted in the reduction of 19% of the launch tube length. The implementation of refined surface method during the design optimization lead to a global optimum solution with 50% fewer analysis run.

关键词： Superdetonative Ram Accelerator Projectiles Sequential Linear Programming Genetic algorithm Surface Modeling Propellant optimization algorithm Numerical optimization Design of Experiments Shape optimization

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optimization of a secondary power distribution system

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INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS 2005年第2期27卷 131-138页

作者： Safigianni, AS Democritus Univ Thrace Power Syst Lab Dept Elect & Comp Engn GR-67100 Xanthi Greece

This paper presents an algorithm for the technnoeconomical optimization of a secondary power distribution system. The technical constraints, which this algorithm takes into account, are the permissible voltage drop, the conductor thermal capacity, tapering and short-circuit strength and the applied protective earthing. If any of the above constraints is not satisfied, the program implementing the algorithm, proposes alternative, technically acceptable solutions, which concern transformer or conductor replacements or both of them. These solutions ere economically estimated and the most economical one is finally adopted. (C) 2005 Elsevier Ltd. All rights reserved.

关键词： secondary power distribution systems economic functions optimization algorithm

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optimization of a tetrahedral satellite formation

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JOURNAL OF SPACECRAFT AND ROCKETS 2005年第4期42卷 699-710页

作者： Clemente, DC Atkins, EM Univ Maryland College Pk MD 20742 USA

Two fundamental approaches can be applied to satellite-formation mission design: active control, where satellites exert forces with their thrusters to maintain a constant or periodic geometry for all or part of each orbit, and natural, where satellite orbits are designed to naturally assemble a geometry for all or part of each orbit to within a tolerance defined from scientific requirements. An actively controlled formation can be labeled virtual rigid body (VRB) because geometry is precisely maintained as if the satellites were rigidly connected. This work describes a hierarchical optimization method for minimizing mission design computational complexity and applies this method to the design of VRB, natural-orbit, and multi-impulse solutions for a tetrahedron formation applicable to the proposed magnetospheric multiscale mission. Cost is defined in terms of total fuel per second of observation and tetrahedron geometric quality factor. Although both natural-orbit and active solutions are feasible, the active solutions substantially increase average data quality and observation time per orbit at minimum fuel cost, and the multi-impulse solution does not require thruster use during data collection periods.

关键词： Satellite Formation Orbital Period Active Control Orbital Elements Magnetospheric Multiscale Mission Propellant Earth optimization algorithm Formation Flying Mixed Integer Linear Programming

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Computationally efficient analysis and optimization of stiffened thin-walled panels in shear

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JOURNAL OF AIRCRAFT 2005年第3期42卷 743-747页

作者： Viljoen, A Visser, AG Groenwold, AA CSIR Div Mfg & Mat Technol ZA-0001 Pretoria South Africa Univ Pretoria Dept Mech Engn ZA-0002 Pretoria South Africa

The computationally efficient analysis and optimum design of the buckling of stiffened, thin-walled shear panels in aircraft structures is discussed. Namely, the postbuckling behavior of these panels is assessed using the iterative procedure developed by Grisham. This procedure requires only linear finite element analyses, whereas convergence is typically achieved in as few as five iterations. An algorithm developed by (A. E. Grisham, "A Method for Including Post-Buckling of Plate Elements in the Internal Loads Analysis of Any Complex Structure Idealized Using Finite Element Analysis Methods," AIAA Paper 78-515, April 1978) using connect format, is compared with empirical methods of analysis frequently used in aircraft structures and also with a refined, nonlinear quasi-static finite element analysis. It is shown that the procedure proposed by Grisham overcomes some of the conservatism inherent in conventional methods of analysis. In addition, the method is notably less expensive than a complete nonlinear finite element analysis, which makes it attractive for use during initial design iterations, even though global collapse of a structure cannot be predicted. As an illustration of the optimal design of buckled, stiffened thin-walled structures, the Grisham algorithm is combined with a microgenetic algorithm. Important reductions in weight are obtained within relatively few function evaluations.

关键词： Finite Element Analysis Allowable Stress Postbuckling Analysis Aircraft Structures Iterative algorithm Genetic algorithm Structural optimization optimization algorithm Material Properties Structural Members

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Pareto optimal flexible alignment of molecules using a non-dominated sorting genetic algorithm

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CHEMOMETRICS AND INTELLIGENT LABORATORY SYSTEMS 2005年第1-2期77卷 232-237页

作者： Daeyaert, F de Jonge, M Heeres, J Koymans, L Lewi, P van den Broeck, W Vinkers, M MolMo Serv BVBA B-2300 Turnhout Belgium Janssen Pharmaceut NV Ctr Mol Design B-2350 Vosselaar Belgium Tibotec BVBA B-2800 Mechelen Belgium

The use of multi-objective function optimization to superimpose a flexible source molecule onto a rigid target molecule is explored. The objective functions are the SEAL similarity score between the source and target molecules, which has to be maximized, and the conformational strain of the source molecule, which has to be minimized. The optimization algorithm used is an elitist non-dominated sorting genetic algorithm. The algorithm is tested with the superposition of two non-nucleoside HIV-reverse transcriptase inhibitors and the superposition of methotrexate onto dihydrofolate. (c) 2005 Elsevier B.V. All rights reserved.

关键词： optimization algorithm methotrexate dihydrofolate

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Analytical relationships between conflict counts and air-traffic density

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2005年第6期28卷 1150-1156页

作者： Jardin, MR NASA Ames Res Ctr Moffett Field CA 94035 USA

Semi-empirical random variable models of the expected number of air-traffic conflicts as a function of airtraffic density are derived. Model parameters are determined from analysis and simulation of real air-traffic data. These models are applied to simulated air-traffic scenarios to analyze conflict properties in various conflict resolution strategies. It is shown that under free routing conditions (approximated by great-circle routes in zerowind conditions) the expected number of conflicts is well represented by a binomial random variable model. Using this model, it is further demonstrated how conflict resolution can cause a chain reaction, leading to an increased number of conflicts for all aircraft, and how the model can be used to predict the airspace capacity for a given conflict resolution strategy. In a separate study, it is shown that for an iterative horizontal-plane conflict resolution strategy, a random variable model with the geometric distribution closely matches empirical data. This model also predicts the aircraft density at which the airspace becomes saturated. It is shown how analysis of conflicts in the horizontal plane can be scaled and applied to the analysis of conflicts in three-dimensional airspace.

关键词： Special Use Airspace Future Air Traffic Management Concepts Evaluation Tool Flight Altitude ATC Systems Flight Planning optimization algorithm Conflict Detection and Resolution NASA Ames Research Center Monte Carlo Simulation Aircraft to Aircraft

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Estimating the parameters of semiconductor lasers based on weak optical feedback self-mixing interferometry

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IEEE JOURNAL OF QUANTUM ELECTRONICS 2005年第8期41卷 1058-1064页

作者： Xi, JT Yu, YG Chicharo, JF Bosch, T Univ Wollongong Sch Elect Comp & Tleecommun Wollongong NSW 2522 Australia Zhengzhou Univ Coll Informat Engn Dept Elect Engn Zhengzhou 450052 Peoples R China ENSEEIHT LEN7 INPT F-31071 Toulouse France

The paper presents a practical approach for measuring the linewidth enhancement factor a of semiconductor lasers and the optical feedback level factor C in a semiconductor laser with an external cavity. The proposed approach is based on the analysis of the signals observed in an optical feedback self-mixing interferometric system. The parameters ce and C are estimated using a gradient-based optimization algorithm that achieves best data-to-theoretical model match. The effectiveness and accuracy of the method has been confirmed and tested by computer simulations and experiments, which show that the proposed approach is able to estimate alpha and C with an accuracy of 6.7% and 4.63%, respectively.

关键词： linewidth enhancement factor (LEF) optical feedback optimization algorithm self-mixing interferometry semiconductor lasers

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Modified pseudoinverse redistribution methods for redundant controls allocation

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2005年第5期28卷 1076-1079页

作者： Jin, JY Korea Atom Energy Res Inst Nucl Fuel Cycle Remote Technol Lab Taejon 305600 South Korea

Several modified pseudoinverse-redistribution (PIR) methods for redundant control allocation problem for a tailless aircraft are described. The PIR method repeats the process of calculating a pseudoinverse and a control vector by setting the saturated elements of a control vector to their limit values until a solution is obtained or there is no unsaturated element. Bordignon and Bessolo developed a modified method and applied it to the X-35 aircraft's control allocation problem. The modified PIR methods select only one saturated element and sets it to its limit value during the redistribution process as compared to the traditional PIR method where it sets the saturated control elements to their limit values.

关键词： optimization algorithm Short Takeoff and Vertical Landing Singular Value Decomposition Tailless Aircraft Numerical Modeling Aircraft Control Nuclear Fuel Cycle MATLAB

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Use of kriging models to approximate deterministic computer models

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AIAA JOURNAL 2005年第4期43卷 853-863页

作者： Martin, JD Simpson, TW Appl Res Lab State Coll PA 16804 USA Penn State Univ Dept Mech Engn University Pk PA 16802 USA Penn State Univ Dept Nucl Engn University Pk PA 16802 USA Penn State Univ Dept Ind & Mfg Engn University Pk PA 16802 USA

The use of kriging models for approximation and metamodel-based design and optimization has been steadily on the rise in the past decade. The widespread use of kriging models appears to be hampered by 1) computationally efficient algorithms for accurately estimating the model's parameters, 2) an effective method to assess the resulting model's quality, and 3) the lack of guidance in selecting the appropriate form of the kriging model. We attempt to address these issues by comparing 1) maximum likelihood estimation and cross validation parameter estimation methods for selecting a kriging model's parameters given its form and 2) an R-2 of prediction and the corrected Akaike information criterion assessment methods for quantifying the quality of the created kriging model. These methods are demonstrated with six test problems. Finally, different forms of kriging models are examined to determine if more complex forms are more accurate and easier to fit than simple forms of kriging models for approximating computer models.

关键词： Probability Distribution Maximum Likelihood Estimation optimization algorithm Multidisciplinary Design optimization Numerical optimization Nelder Mead Simplex Newton's Method Structural optimization Aerospace Engineering

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