检索结果-内蒙古大学图书馆

Response surface techniques for diffuser shape optimization

AIAA JOURNAL 2000年第9期38卷 1512-1518页

作者： Madsen, JI Shyy, W Haftka, RT Univ Aalborg Inst Engn Mech DK-9220 Aalborg E Denmark Univ Florida Dept Aerosp Engn Mech & Engn Sci Gainesville FL 32611 USA

The design of incompressible diffusers for maximum pressure recovery is used to demonstrate the utility of response surface approximations for design optimization of flow devices. Two examples involving two and five design variables are treated, with the diffuser wall shapes described by polynomials and B-splines. In both erases monotonicity conditions drastically reduce the design space. In this irregularly shaped space, a pool of designs is selected by a D-optimality criterion and analyzed by a finite volume computational fluid dynamics (CFD) code. Quadratic polynomial response surfaces are then fitted to the pressure recovery coefficients. To improve the prediction accuracy, uncertain regressor terms and possible outlier design points are excluded based on statistical tests. A standard optimization algorithm is used to find the optimal diffuser design from the response surface approximations. The optimum diffusers exhibit minimal flow separation and yield similar wall shapes fur the two parameterizations. A main asset of the response surface optimization approach lies in the smoothing of noisy response functions. Therefore, the issue of numerical noise in CFD results based on the use of two different analysis codes is addressed.

关键词： Diffusers Shape optimization Numerical Modeling optimization algorithm Reynolds Averaged Navier Stokes Numerical Simulation Design of Experiments Static Pressure Surface Modeling Regression Analysis

来源：评论

学校读者我要写书评

暂无评论

Mathematical Methods in Defense Analyses 3rd ed.

引用

丛书名： AIAA Education Series

2000年

作者： J.S. Przemieniecki

ISBN: (数字)9781600862137

ISBN: (纸本)9781563473975

This text presents the various mathematical methods used in military operations research in one easy-to-use reference volume. The reader will find the calculations necessary to analyze all aspects of defense operations, from weapon performance to combat modeling. The text is so clearly written and organized that even newcomers to the field will find it useful. Included with the text is an updated version of Defense Analyses Software, a compendium of software subroutines that allow the reader to compute numerical values for functions or tables derived in the text. Each subroutine is provided with a detailed reference to the equation from which it was derived to ensure that its intended application is consistent with the assumptions used in the derivation. The third edition has a new chapter on theater missile defense based on the concept of layered defense with different strategies of allocating defense interceptors against short- or mid-range ballistic missiles. This text is a highly recommended reference for defense analysts, researchers, and professionals entering the field of military operations research.

关键词： Aerodromes Aeronautics Air Forces Aircraft Collision Avoidance Systems Aircraft Operations and Technology Aircraft Radars Aircraft Tracking Aircrafts Airfields algorithms and Data Structures Anti-Ballistic Missile Anti-Submarine Warfare Applied Mathematics Artificial Intelligence Artillery Systems Aviation Aviation Communication Aviation Risk Aviation Safety Ballistic Missile Ballistics Combat Aircraft Communication System Computational Fluid Dynamics Computer Programming and Language Computing and Informatics Computing, Information, and Communication Cruise Missiles Data Science Elementary Algebra Energy Weapons Fluid Dynamics General Physics Guidance, Navigation, and Control Systems Guided Missiles Helicopters Mathematical Analysis Mathematical optimization Military Airbases Military Aircraft Military Aviation Military Science Military Technology Missile Defense Missile Guidance and Control Missile Systems, Dynamics and Technology Missiles Navigational Guidance Nuclear Weapons Numerical Analysis Operating Systems optimization algorithm Projectiles RADAR Rotorcrafts Search algorithm Software Systems Space Weapons Statistical Analysis Surface-to-Air Missile Systems Software Tracking and Positioning Systems Warfare and Military Operations Weapon Systems

来源：评论

学校读者我要写书评

暂无评论

Euler/Navier-Stokes optimization of supersonic wing design eased on evolutionary algorithm

引用

AIAA JOURNAL 1999年第10期37卷 1327-1328页

作者： Oyama, A Obayashi, S Nakahashi, K Nakamura, T Tohoku Univ Dept Aeronaut & Space Engn Nakahashi Lab Sendai Miyagi 9808579 Japan Natl Aerosp Lab Dept Aeronaut & Space Engn Tokyo 1828522 Japan

An evolutionary algorithm (EA) coupled with a Euler/Navier-Stokes code has been applied to supersonic wing shape design. Aerodynamic evaluations are distributed to the processing elements (PE) of the numerical wind tunnel (NWT) to overcome the enormous computational time necessary for the optimization. The design yields both the minimum drag and the minimum volume wave drag in the given design space. The important features of supersonic wing design as compared with conventional transonic wing design are presented.

关键词： Evolutionary algorithm Aerodynamic Design Aerodynamic Performance Wing Root National Aerospace Laboratories optimization algorithm Aeroplane Camber Numerical optimization Spline Interpolation

来源：评论

学校读者我要写书评

暂无评论

Airfoil and wing design through hybrid optimization strategies

引用

AIAA JOURNAL 1999年第5期37卷 634-641页

作者： Vicini, A Quagliarella, D Ctr Italiano Ric Aerospaziali Aerodynam & Prop Dept I-81043 Capua Italy

Real-world design problems need robust and effective system level optimization tools inasmuch as they are ruled by several criteria, most often in multidisciplinary environments. In this work a hybrid optimization algorithm has been obtained by adding a gradient-based technique to the set of operators of a multiobjective genetic algorithm. This makes it possible to increase the computational efficiency of the genetic algorithm while preserving its favorable features of robustness, problem independence, and multiobjective optimization capabilities. Aerodynamic shape design problems, including both airfoil and wing designs, are considered.

关键词： NACA 0012 Genetic algorithm optimization algorithm Aerodynamic Characteristics Aspect Ratio Swept Wing Angle of Attack Sweep Angle Structural Weight Wing Root

来源：评论

学校读者我要写书评

暂无评论

Design optimization of phased-array-fed reflector antennas for mobile communication satellites

引用

JOURNAL OF SPACECRAFT AND ROCKETS 1999年第1期36卷 105-108页

作者： Tokunaga, K Tsunoda, H Shoki, H Okumura, M Adv Space Commun Res Lab On Board Antenna Technol Sect Chiyoda Ku Tokyo 1010032 Japan Toshiba Corp Ctr Res & Dev Commun & Informat Syst Res Labs Saiwai Ku Kawasaki Kanagawa 2108581 Japan Toshiba Corp Komukai Works Saiwai Ku Kawasaki Kanagawa 2108581 Japan

A satellite antenna system for satellite communications requires high gain and effective transmission power use. To satisfy these requirements, we studied a phased-array-fed reflector antenna for multiple beams, particularly the optimization method to design antenna parameters and to determine the array weight distributions for high gain, low side-lobe levels, and efficient amplifier use. The results of our analytical study and experiment model test clarified the electrical performance and verified the optimum design method. We also studied the effects of the weighting error, given to the optimized weighting distribution, which have a significant effect on the antenna performance.

关键词： Reflector Antennas Asia Cellular Satellite Satellites optimization algorithm Power Generation Radiators

来源：评论

学校读者我要写书评

暂无评论

Multiple-spacecraft orbit transfer problem: Weak-booster and strong-booster cases

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1999年第6期22卷 897-904页

作者： Ocampo, CA Rosborough, GW Univ Colorado Dept Aerosp Engn Sci Boulder CO 80309 USA

Primer vector theory, in combination with a parameter optimization algorithm, is used to compute the optimal transfer of n spacecraft from an initial parking orbit to a final operational orbit with the added constraint that all spacecraft an: injected from the parking orbit on one upper-stage booster and that all are required to be spaced along the final orbit according to some prescribed, but otherwise arbitrary, spacing constraint between individual spacecraft. Two particular cases of the problem, known as the weak- and the strong-booster cases, are examined, In the weak-booster case, the booster provides the departure maneuver from parking orbit, but because of a booster propellent constraint, its trajectory does not reach the final orbit, requiring that all spacecraft make at least two maneuvers to complete the transfer. For the strong-booster case, the booster departure maneuver is unconstrained in magnitude, implying that at least one of the spacecraft can complete the transfer with a single maneuver because the transfer trajectory ran reach the final orbit. The solution is formulated for a general force field, and examples are given for a three-spacecraft constellation transfer in the restricted three-body problem force-field model.

关键词： Spacecraft Maneuvers Propellant optimization algorithm Constellations Spacecraft Orbits Earth Lambert's Problem Satellite Constellations Propulsion System Right Ascension

来源：评论

学校读者我要写书评

暂无评论

Aeroelastic tailoring of composite structures

引用

JOURNAL OF AIRCRAFT 1999年第6期36卷 1041-1047页

作者： Eastep, FE Tischler, VA Venkayya, VB Khot, NS Univ Dayton Dept Mech & Aerosp Engn Dayton OH 45469 USA USAF Res Lab Air Vehicle Directorate Struct Div Wright Patterson AFB OH 45433 USA

A wing-design optimization study is conducted on a composite wing. The objective is to evaluate the effect of the composite layup orientation on the optimized weight while satisfying constraints on strength, roll-reversal velocity, and flutter velocity. The wing optimization studies are presented with the composite layups oriented at 5-deg increments up to +/-20 deg from the midspar of the wing. The multidisciplinary optimization system, ASTROS, was used in the design study. This study, although not conclusive, indicates that optimal designs when subjected to multiple structural constraints are relatively insensitive to the orientation of the laminate layup.

关键词： Composite Structures Control Surfaces Stiffness Matrices Center of Pressure Freestream Velocity Angle of Attack Structural Analysis Aspect Ratio optimization algorithm Sensitivity Analysis

来源：评论

学校读者我要写书评

暂无评论

Optimal configuration of multiple-focused ultrasound transducers for external hyperthermia

引用

MEDICAL PHYSICS 1999年第9期26卷 2007-2016页

作者： Lin, WL Chen, YY Lin, SY Yen, JY Shieh, MJ Kuo, TS Natl Taiwan Univ Inst Biomed Engn Taipei 10764 Taiwan Natl Taiwan Univ Dept Elect Engn Taipei 10764 Taiwan Natl Taiwan Univ Dept Mech Engn Taipei 10764 Taiwan

External ultrasound hyperthermia is considered to be a very flexible modality for heating deep-seated tumors owing to its penetration and focusing ability, However, using this flexibility requires that many complicated, interacting decisions be made to obtain optimal treatment. This paper presents the feasibility of arranging multiple-focused ultrasound transducers to produce an appropriate heating pattern for a specific treatment, based on the optimal scan parameters obtained from an optimization algorithm. The variable scan parameters of the heating system optimized are the transducer tilt and rotation angles, focal depth, scan radius, and output acoustical power. After obtaining the optimal scan parameters, multiple transducers are systematically arranged according to these scan parameters. Three-dimensional ultrasound power deposition and temperature distribution for a specific treatment are calculated for this multiple ultrasound transducer system. A more uniform temperature distribution in the treatment region for a large, highly perfused tumor can be achieved by scanning the system with respect to the central scan axis and/or swinging the transducers inwards and outwards. The maximum heating depth of focused ultrasound transducers used in this heating system is also studied. Simulation results demonstrate that the optimal arrangement of this multiple-focused ultrasound transducer system is highly promising for heating deep, large, and highly perfused tumors. (C) 1999 American Association of Physicists in Medicine. [S0094-2405(99)02109-4].

关键词： external hyperthermia multiple-focused ultrasound transducer system optimal configuration optimization algorithm

来源：评论

学校读者我要写书评

暂无评论

Multiple rigid-body reorientation using relative motion with constrained final system configuration

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1999年第3期22卷 441-446页

作者： Rubenstein, DS Melton, RG Charles Stark Draper Lab Inc Guidance Navigat & Control Directorate Cambridge MA 02139 USA Penn State Univ Dept Aerosp Engn University Pk PA 16802 USA

Moveable appendages in multibody spacecraft can augment or replace the attitude control actuators. In this work, motions of the movable bodies relative to the main body are used to adjust the system's inertial attitude so as to approach or attain a desired target attitude. A control algorithm designed to generate the maneuver commands that cause the necessary relative motions is tested with several cases representing a variety of dynamic conditions. The control can accommodate many different system configurations and dynamic conditions such as nonzero system momentum, a problem that historically has proved difficult to solve in a generalized, three-dimensional mode. Additionally, the control can return the system's geometric configuration to its initial state by the conclusion of the reorientation. The results indicate that the control can accomplish nearly complete reorientations in all cases tested while meeting the system constraints.

关键词： Attitude Control System Control algorithm Actuators Quaternions Numerical optimization Multibody Simulation Propellant Spacecraft Attitude Control optimization algorithm Spacecraft System

来源：评论

学校读者我要写书评

暂无评论

Using the two-branch tournament genetic algorithm for multiobjective design

引用

AIAA JOURNAL 1999年第2期37卷 261-267页

作者： Crossley, WA Cook, AM Fanjoy, DW Venkayya, VB Purdue Univ Sch Aeronaut & Astronaut W Lafayette IN 47907 USA USAF Res Lab Struct Div Wright Patterson AFB OH 45433 USA

The two-branch tournament genetic algorithm is presented as an approach to determine a set of Pareto-optimal solutions to multiobjective design problems. Because the genetic algorithm searches using a population of points rather than using a point-to-point search, it is possible to generate a large number of solutions to multiobjective problems in a single run of the algorithm. The two-branch tournament and its implementation in a genetic algorithm (GA) to provide these solutions are discussed. This approach differs from most traditional methods for GA-based multiobjective design;it does not require the nondominated ranking approach nor does it require additional fitness manipulations. A multiobjective mathematical benchmark problem and a 10-bar truss problem were solved to illustrate how this approach works for typical multiobjective problems. These problems also allowed comparison to published solutions. The two-branch GA was also applied to a problem combining discrete and continuous variables to illustrate an additional advantage of this approach for multiobjective design problems. Results of all three problems were compared to those of single-objective approaches providing a measure of how closely the Pareto-optimal set is estimated by the two-branch GA. Finally, conclusions were made about the benefits and potential for improvement of this approach.

关键词： Genetic algorithm Trusses Young's Modulus Multidisciplinary Design optimization Structural optimization optimization algorithm Material Properties Composite Structures Axial Stress

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：