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Optimal design of process parameters of rotary-draw bending process for thin-walled rectangular tube of aluminum alloy

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART B-JOURNAL OF ENGINEERING MANUFACTURE 2014年第11期228卷 1442-1448页

作者： Zhao, Gangyao Liu, Yuli Zhang, Ranyang Yang, He Northwestern Polytech Univ Sch Mat Sci & Engn Xian 710072 Peoples R China Nanchang Hangkong Univ Sch Aeronaut Mfg Engn Nanchang 330063 Jiangxi Peoples R China

The rotary-draw bending process of thin-walled rectangular tube is a complex process with the interaction of many factors. The wrinkling may be produced if the process parameters are inappropriate. So, here, based on finite element numerical simulation, and taking the clearances and the frictions between tube and dies as the optimal design variables and the wrinkling height as the optimal objective, the optimization design for rotary-draw bending process of thin-walled rectangular 3A21 aluminum alloy tube has been carried out by using sequential quadratic programming method. Then, the recommended values of the clearances between mandrel, wiper die and bending die and tube, and the friction coefficients between pressure die, mandrel and wiper die and tube are obtained. The achievements of this study are significant to reduce the manufacturing cost and increase efficiency and bending quality.

关键词： Aluminum alloy thin-walled rectangular tube rotary-draw bending process parameters optimization design sequential quadratic programming

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Vibration suppression of curved beam-type structures using optimal multiple tuned mass dampers

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JOURNAL OF VIBRATION AND CONTROL 2014年第6期20卷 859-875页

作者： Yang, F. Sedaghati, R. Esmailzadeh, E. S China Univ Technol Coll Automat Sci & Engn Guangzhou Guangdong Peoples R China Concordia Univ Dept Mech & Ind Engn Montreal PQ Canada Univ Ontario Inst Technol Fac Engn & Appl Sci Oshawa ON L1H 7K4 Canada

This paper established a thorough optimization procedure of the multiple tuned-mass-damper system to suppress the vibration levels of the curved beam-type structures with multiple vibration dominant modes. A hybrid optimization methodology, which combines the global optimization method based on the Genetic Algorithm and the local optimization method based on sequential quadratic programming, has been developed. The established hybrid optimization procedure is then utilized to find the optimum values of the design parameters, namely, the spring stiffness, damping factor and the position of the attached tuned-mass-damper systems, in order to suppress the vibration amplitude either at a particular mode or at several modes simultaneously.

关键词： sequential quadratic programming Genetic Algorithm tuned-mass-dampers random loading hybrid optimization Curved beam

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Optimal Control Framework for a Centralized Approach to Separation Management

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2014年第3期37卷 1033-1038页

作者： Walter, Leif Kostina, Ekaterina French German Inst St Louis F-68301 St Louis France Univ Marburg Fac Math & Comp Sci D-52425 Marburg Germany

I. Introduction With the increase in demand and capacity, Air Traffic Management (ATM) will face further challenges to keep delay considerably low while increasing safety standards at a cheaper cost. When addressing these challenges imposed by future ATM programs (SESAR, NextGen), controllers will need sophisticated decision support tools to deal with upcoming traffic flows in an efficient way. As it was pointed out in the Performance Review Report 2010 , [12], 5 % of all flights in Europe are held on the ground to manage en-route congestion, resulting in more than 50 % of all delay minutes within the system. In the future, air navigation service providers (ANSPs) will need to deliver more capacity, in a cheaper, safer, and environmental-friendlier way. This goal will not be achieved without the aid of sophisticated and automated tools that will assist the human air traffic controller (ATCO). One of the air traffic management fields that can contribute to provide to future capacity is separation management . In the context of this paper, separation management is the task of separating aircraft in an allocated airspace volume as efficiently as possible. The aim of this paper is to present the application of optimal control theory in a central- ized approach to separation management, where we use information of the current traffic situation in a sector to derive an optimal control problem. The solution of this control problem consecutively provide conflict-free trajectories for all users within the regarded airspace. Solutions are obtained by using a direct method that is composed of multiple shooting discretization and a sequential quadratic programming (SQP) method to solve the resulting nonlinear optimization problem.

关键词： Optimal Control Airspace Bank Angle Flight Tracking ATM sequential quadratic programming Air Traffic Controller Predictive Control Method Knots Indicated Airspeed Base of Aircraft Data

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Optimal control for far-distance rapid cooperative rendezvous

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING 2014年第14期228卷 2662-2673页

作者： Feng, Wei-ming Ren, Fei Shi, Lei Shandong Univ Dept Engn Mech Jinan 250062 Peoples R China

This study investigated the far-distance cooperative rendezvous problem for two spacecrafts. The orbital dynamics equations were represented based on the orbital elements with an improved vernal equinox and were normalized. Pontryagin's extremum principle was introduced into the dynamics equations and the co-state equations were obtained. A performance evaluation function was created by particle swarm optimization algorithm based on simulated annealing. The convergent co-state initial vector was obtained using an improved particle swarm optimization algorithm. The initial vector was set as the initial value for optimization and a rapid small-population genetic algorithm was applied, before the approximate global optimum was obtained rapidly. The fine adjustment of the search process was performed based on sequential quadratic programming and the results were sufficiently precise. The process of optimization was simulated for problems that involved far-distance coplanar cooperative rendezvous and active-passive rendezvous, which showed that cooperative rendezvous had more advantages than active-passive rendezvous in terms of fuel saving and time.

关键词： Far-distance cooperative rendezvous genetic algorithm optimal control particle swam optimization sequential quadratic programming

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Constrained Diffusion Kurtosis Imaging Using Ternary Quartics & MLE

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MAGNETIC RESONANCE IN MEDICINE 2014年第4期71卷 1581-1591页

作者： Ghosh, Aurobrata Milne, Tristan Deriche, Rachid INRIA Sophia Antipolis Athena Project Team Mediterranee France

PurposeDiffusion kurtosis imaging (DKI) is a recent improvement over diffusion tensor imaging that characterizes tissue by quantifying non-gaussian diffusion using a 3D fourth-order kurtosis tensor. DKI needs to consider three constraints to be physically relevant. Further, it can be improved by considering the Rician signal noise model. A DKI estimation method is proposed that considers all three constraints correctly, accounts for the signal noise and incorporates efficient gradient-based optimization to improve over existing methods. MethodsThe ternary quartic parameterization is utilized to elegantly impose the positivity of the kurtosis tensor implicitly. sequential quadratic programming with analytical gradients is employed to solve nonlinear constrained optimization efficiently. Finally, a maximum likelihood estimator based on Rician distribution is considered to account for signal noise. ResultsExtensive experiments conducted on synthetic data verify a MATLAB implementation by showing dramatically improved performance in terms of estimation time and quality. Experiments on in vivo cerebral data confirm that in practice the proposed method can obtain improved results. ConclusionThe proposed ternary quartic-based approach with a gradient-based optimization scheme and maximum likelihood estimator for constrained DKI estimation improves considerably on existing DKI methods. Magn Reson Med 71:1581-1591, 2014. (c) 2013 Wiley Periodicals, Inc.

关键词： diffusion kurtosis imaging ternary quartics constrained optimization sequential quadratic programming maximum likelihood estimator

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Shape optimization of revolute-jointed single link flexible manipulator for vibration suppression

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MECHANISM AND MACHINE THEORY 2014年 75卷 150-160页

作者： Mahto, Sachindra NERIST Dept Mech Engn Itanagar 791109 Arunachal Prade India

In this work, the shape optimization of a single link revolute-jointed flexible manipulator is carried out. Manipulator link is considered as a Euler-Bernoulli beam and finite element based on Lagrange approach is employed for dynamic analysis. sequential quadratic programming (SQP) method is applied to extremize the objective functions. Four different optimization problems are solved for comparative study of the model for vibration suppression. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Flexible revolute manipulator Euler-Bernoulli beam Shape optimization Finite element method sequential quadratic programming

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Trim Calculation of the CH-53 Helicopter Using Numerical Continuation Method

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2014年第4期37卷 1343-+页

作者： Cao, Yihua Cao, Long Wan, Shaofeng Beihang Univ Sch Aeronaut Sci & Engn Beijing 100191 Peoples R China

Trim analysis is a basic and important routine in flight mechanics. It is not always easy, especially for rotorcraft. Trim of the hover case is first calculated. In this case, the main rotor shaft tilt angle is chosen to be the continuation parameter, which leads to a new embedding method that is different from most existing approaches. The forward-flight case is then calculated, and the result of the hover case is used as the starting point. To improve the accuracy of ODE solutions, smaller step size and a higher-order solver are needed, both of which make the computation time consuming. In the trim calculation of CH-53, the N-R iteration converges in seven steps. The whole set of the helicopter trim states, including hover, forward flight, sideslip, steady climb, descent, even coordinated turns, etc., forms a multidimensional manifold in the state space. The continuation method is capable of tracing out all these trim states and providing a global analysis, even if the helicopter model has a high degree of nonlinearity and complex coupling.

关键词： Helicopter Rotor Flight Testing Aerodynamic Torque Fuselages Mathematical Models Fixed Wing Aircraft Rotorcrafts sequential quadratic programming Unmanned Aerial Vehicle Helicopter Flight Dynamics

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Reliability-Based Design Optimization for the Structures with Fuzzy Variables and Uncertain-but-Bounded Variables

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JOURNAL OF AEROSPACE INFORMATION SYSTEMS 2014年第6期11卷 412-422页

作者： Tang Zhangchun Lu Zhenzhou Northwestern Polytech Univ Xian 710072 Peoples R China

A study was conducted to demonstrate direct reliability-based design optimization (DRBDO) for the structures with fuzzy variables and uncertain-but-bounded variables. An approach called target performance-based approach (TPBA) was developed to address the problems associated with DRBDO. The proposed TPBA was obtained by a numbered of equations that were motivated by the performance measure approach (PMA) for probabilistic RBDO and the concerned performance-based approach (CPA) for nonprobabilistic RBDO. The similarities were that they were based on the equivalence between reliability index constraints and target performance constraints. TPBA was applied to the situation with fuzzy variables and uncertain-but-bounded variables, whereas PMA and CPA were applied to random variables and nonprobabilistic framework.

关键词： Trusses sequential quadratic programming Finite Element Modeling Compressive Stress Material Properties Elastic Modulus Structural Design Aspect Ratio Numerical Analysis MATLAB

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A novel 3D model retrieval approach using combined shape distribution

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MULTIMEDIA TOOLS AND APPLICATIONS 2014年第3期69卷 799-818页

作者： Zou, Kuan-Sheng Ip, Wai-Hung Wu, Chun-Ho Chen, Zeng-Qiang Yung, Kai-Leung Chan, Ching-Yuen Hong Kong Polytech Univ Dept Ind & Syst Engn Kln Hong Kong Peoples R China Nankai Univ Dept Automat Tianjin 300071 Peoples R China

With the rapid development of 3D digital shape information, content-based 3D model retrieval has become an important research field. 3D models are likely to be as prevalent as other multimedia data types in the future. There is a pressing need for effective content-based 3D model retrieval methods. In this paper, a novel combined shape distribution (CSD) descriptor is proposed for 3D model retrieval based on principal plane analysis and group integration. Firstly, based on principal plane analysis, the second principal plane is obtained by using sequential quadratic programming. Secondly, two novel 3D shape descriptors are proposed by introducing the plane normal vectors to other shape distributions. Thirdly, since the histogram of the proposed descriptors can be classified as belonging to one of three types: positive, negative, or crossed with each principal plane, further improvements to the descriptors are presented by integrating these three types of histograms. Finally, a CSD descriptor based on the synthesis of the above descriptors is proposed. Several retrieval performance measures and visual experimental results show that the new methods achieved good retrieval performance.

关键词： 3D model retrieval Shape distribution Principal plane analysis Combined shape distribution sequential quadratic programming

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Application of Different Algorithms to Optimal Design of Canal Sections

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JOURNAL OF APPLIED RESEARCH AND TECHNOLOGY 2014年第4期12卷 762-768页

作者： Kentli, A. Mercan, O. Marmara Univ Fac Engn Dept Mech Engn Istanbul Turkey

Today the increased world population and therefore the growth demand has forced the researchers to investigate better water canal networks distributing much more water while at least keeping its quality. Canal design formulas are explicitly obtained for different cross-sections considering minimum area but optimal design of canal sections considering seepage and evaporation losses are still an open area to study. In this study, two different algorithms are applied to this problem and results are compared with the one in literature. Genetic algorithm and sequential quadratic programming technique are used in optimization. Triangular, rectangular and trapezoidal cross-sections are optimized. It is seen that both algorithms are giving more accurate results than in literature.

关键词： Design of canal section genetic algorithm sequential quadratic programming seepage loss

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