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8th International Conference on Structural Dynamics (EURODYN)

作者： Ikago, Kohju Sugimura, Yoshifumi Saito, Kenji Inoue, Norio Tohoku Univ Grad Sch Engn Aoba Ku Sendai Miyagi 980 Japan NTT Facil Inc Res & Dev Headquarters Toshima Ku Tokyo Japan NTT Facil Inc Bldg Engn Headquarters Minato Ku Tokyo Japan

ISBN: (纸本)9789076019314

The authors have presented a new seismic control device the tuned viscous mass damper (TVMD). The TVMD consists of a viscous mass damper with an apparent mass amplifier and a soft spring which connects the damper to the primary system. The mass amplifier has allowed us to make the additional mass and device itself smaller compared with a conventional tuned mass damper (TMD). The design method to determine an optimum set of damper parameters has not yet been presented for the vibration control system of a damped MDOF structure, while that of an undamped SDOF structure is obtained by the fixed point method. In this paper, we present a design method to obtain a set of optimum damper parameters for the seismic control system of a damped MDOF structure using sequential quadratic programming (SQP).

关键词： Tuned viscous mass damper Dynamic vibration absorber Optimum vibration control Fixed point method sequential quadratic programming Seismic control

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Parametric Surfaces with Volume of Solid Control for Optimisation of Three Dimensional Aerodynamic Topologies

Parametric Surfaces with Volume of Solid Control for Optimis...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Payot, A. D. J. Rendall, T. C. S. Allen, C. B. Univ Bristol Dept Aerosp Engn Bristol Avon England

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

This paper presents a topologically flexible parameterisation method suitable for the optimisation of 3 dimensional aerodynamics using traditional boundary fitted meshes. This parameterisation extends the restricted-snake volume of solid (RSVS) parameterisation previously developed by the authors. This is achieved by extending restricted snakes, a parametric active contour method, into a restricted surface capable of efficiently evolving arbitrary complex topologies handling collisions with no floating point arithmetic. This is integrated with a surface generation rule which allows smooth shapes with intuitive parameterisation of topology. The 3D-RSVS is presented along with results displaying its smooth behaviour, it's ability to produce shapes of aerodynamic interest and it's topological flexibility. A hierarchical approach to the volume of solid design variables is presented for the RSVS, allowing automatic design of the grids on which VOS are specified. An optimisation framework is proposed and some example 2 dimensional optimisation results are presented.

关键词： Aerodynamic Shape Optimization sequential quadratic programming Computational Fluid Dynamics Numerical Optimization Reynolds Averaged Navier Stokes Image Segmentation Structural Optimization Airbus A380 Aircraft Configurations Singular Value Decomposition

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Nonlinear system identification tools applied to the modelling of submarine dynamics 1

Nonlinear system identification tools applied to the modelli...

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1st IFAC Workshop on Guidance and Control of Underwater Vehicles

作者： Furlong, ME Hearn, GE Veres, SM Rogers, E Univ Southampton Sch Engn Sci Southampton SO9 5NH Hants England

ISBN: (纸本)0080442021

This paper presents initial results on the use of nonlinear systems identification algorithms to estimate the hydrodynamic coefficients in fully coupled, nonlinear submarine motion equations. Parameter identification algorithms rely on the sequential quadratic programming technique. The paper briefly describes the form of the non-linear equations used in the submarine simulation, describes the system identification algorithms developed and then illustrates their application to three test cases of interest. These are based on horizontal motion only and aim to identify the model coefficients in the cases when these are completely unknown, partially known, and partially known but with an error on the known values respectively. Copyright (C) 2003 IFAC.

关键词： system identification sequential quadratic programming submarine/AUV hydrodynamic coefficients motion simulation

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Computational Design and Optimization of Wind Farms using Analytical Derivatives

Computational Design and Optimization of Wind Farms using An...

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AIAA Aviation Forum and Exposition

作者： Ashuri, T. Bista, S. Hosseini, S. E. Khan, M. S. Hamidi, R. Jalilzadeh Arkansas Tech Univ Dept Mech Engn Coll Engn & Appl Sci Russellville AR 72801 USA Arkansas Tech Univ Dept Elect Engn Coll Engn & Appl Sci Russellville AR 72801 USA

ISBN: (数字)9781624105890

ISBN: (纸本)9781624105890

This paper presents a multidisciplinary framework for computational design and optimization of coupled offshore wind farm layout and support structure using analytical derivatives. Gradient-based optimization with exact analytical derivatives scales well with large design problems, and it is the preferred approach over gradient-free techniques. We used the second order Larsen model to simulate the wake in the wind farm. Combined with an energy production model and Weibull wind distribution function, the annual energy production of the wind farm is computed. Timoshenko beam elements model the support structure including the soil-structure interaction. Airy's wave theory with Wheeler stretching is utilized for modeling the wave kinematics and to obtain the hydrodynamic loads using Morison's equation. Cost models are used to evaluate the levelized cost of energy as the objective function. The design constraints are the support structure buckling, modal-frequency, and stresses. To evaluate the effectiveness of the proposed approach, we performed an optimization of a feasible baseline design consisting of 6 Vestas V80 wind turbines. Compared to the baseline design, our results show that the coupled layout and support structure approach reduces the levelized cost of energy by 1.4%. This efficient computational framework allows the concurrent design of the wind farm layout and support structure with thousands design variables, and it suitable for detailed design of offshore wind farms.

关键词： Blade Element Momentum Theory Energy Generation Aerodynamic Loads Morison Equation sequential quadratic programming Turbulent Boundary Layer Multidisciplinary Design Optimization Sensitivity Analysis Electrical Systems Stiffness Matrices

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Market Applications in the Electricity Market of the Russian Federation

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INTERNATIONAL JOURNAL OF PUBLIC ADMINISTRATION 2019年第15-16期42卷 1363-1369页

作者： Davidson, Mikhail R. Labutin, Gleb, V Moscow MV Lomonosov State Univ Fac Computat Math & Cybernet Moscow Russia Consultnext LLC Moscow Russia JSC Syst Operator United Power Syst Markets Dev Dept Moscow Russia

A unique specificity of Russian wholesale electricity market is the economic dispatch model based on explicit nonlinear power flow equations underlying the market applications. This paper presents the solution method used for the market applications that is presently employed by the commercial operator and the system operator of the Russian energy system. It is proved to be an adequate and reliable scheduling market technology. Empirical observations on the model properties that impact the rate of convergence and review of the convergence results are presented.

关键词： Day ahead market balancing market optimal power flow sequential quadratic programming

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An Interactive Evolutionary Multi-objective Optimization Method Based on Polyhedral Cones

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4th Conference on Learning and Intelligent Optimization

作者： Sinha, Ankur Korhonen, Pekka Wallenius, Jyrki Deb, Kalyanmoy Aalto Univ Sch Econ Dept Business Technol Helsinki 00076 Finland

ISBN: (纸本)9783642137990

This paper suggests a preference based methodology, where the information provided by the decision maker in the intermediate runs of an evolutionary multi-objective optimization algorithm is used to construct a polyhedral cone. This polyhedral cone is used to eliminate a part of the search space and conduct a more focussed search. The domination principle is modified, to look for better solutions lying in the region of interest. The search is terminated by using a local search based termination criterion. Results have been presented on two to five objective problems and the efficacy of the procedure has been tested.

关键词： Evolutionary multi-objective optimization multiple criteria decision-making interactive multi-objective optimization sequential quadratic programming preference based multi-objective optimization

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Design Optimization of Metallic Alloy Microstructures under Epistemic Uncertainty

Design Optimization of Metallic Alloy Microstructures under ...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Acar, Pinar Virginia Tech Dept Mech Engn Blacksburg VA 24061 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

The present work addresses the optimization of the mechanical performance of the metallic alloy microstructures under epistemic uncertainty. The single crystal material properties are necessary to compute the volume-averaged properties of polycrystals in order to analyze the mechanical behavior under large deformations. In the case of the polycrystalline Ti-7Al, which is a candidate material for future aerospace applications, the reported mechanical property values differ in the literature because of the relative immaturity of the material. Therefore, we consider these variations as epistemic uncertainty, and solve for the statistical features of the single crystal parameters given the range of values for the volume-averaged properties. Next, the volume-averaged linear and non-linear material properties, including compliance, bending and torsional natural frequencies, are optimized by considering the epistemic uncertainty in the system. The findings indicate that the epistemic uncertainty significantly affects the optimum microstructure designs in different problems.

关键词： Microstructure Alloys Mechanical Properties Material Properties sequential quadratic programming Cantilever Beam Probability Distribution Stiffness Matrices Inverse Problems Monte Carlo Simulation

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The impact of stack allocation on the performance of a hybrid multi-stack fuel cell system

The impact of stack allocation on the performance of a hybri...

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2024 Vehicle Power and Propulsion Conference

作者： Yamchi, Hamid Bakhshi Kandidayeni, Mohsen Kelouwani, Sousso Houton, Loic Univ Quebec Trois Rivieres Dept Elect & Comp Engn Quebec City PQ Canada Univ Quebec Trois Rivieres Dept Mech Engn Quebec City PQ Canada

ISBN: (纸本)9798331541613;9798331541606

Multi-stack fuel cell systems (MFCSs), composed of multiple low-power fuel cells operating independently, offer increased power range, reliability, space flexibility, and modularity, making them ideal for heavy-duty applications. The performance of MFCSs is influenced by both the number and combinations of stacks that are used to construct the system. This paper examines the impact of these factors on the operational costs of fuel cell systems (FCS), encompassing hydrogen consumption and stack degradation costs. Three case studies are investigated, and in each case, the best allocation scheme is introduced based on the value of the objective function. sequential quadratic programming (SQP) is selected to perform energy management among power sources. Also, the results demonstrate that increasing the number of stacks from two to three resulted in a 6.33% reduction in operational costs, while further augmenting the number of stacks from three to four notably decreased expenses by approximately 14.87%.

关键词： Multi-stack fuel cell stack allocation sequential quadratic programming fuel cell degradation

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Optimization of Turbine Tilt in a Wind Farm

Optimization of Turbine Tilt in a Wind Farm

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AIAA Science and Technology Forum and Exposition (AIAA SciTech Forum)

作者： Cutler, James Stanley, Andrew P. J. Thomas, Jared J. Ning, Andrew Brigham Young Univ Dept Mech Engn Provo UT 84602 USA

ISBN: (数字)9781624106095

ISBN: (纸本)9781624106095

Wind farm power production is significantly affected by upstream turbines creating wakes of slower wind speeds that overlap the rotor swept areas of downstream turbines. By optimizing the tilt angle of the turbines in a farm, wakes may be deflected away from downstream turbines, increasing the overall energy production. In this study, we optimized the tilt angle of turbines in a wind farm to maximize energy production. We used an analytic wake model modified for gradient-based optimization to consider wake deflection from tilt. We considered optimizing the tilt angle of each turbine assuming that it remained fixed for the lifetime of the farm. We also considered active tilt control. In a test case using the Princess Amalia 60-turbine wind farm, optimizing fixed tilt angles resulted in a 2.77% increase in the annual energy production(AEP) while using active tilt control resulted in an 13.64% increase in AEP.

关键词： Turbines Energy Production Yaw Control Power Coefficient Velocity Profiles sequential quadratic programming Large Eddy Simulation Free Stream Velocity Control Optimization Turbulence Intensity

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On the Performance of SQP Methods for Nonlinear Optimization

On the Performance of SQP Methods for Nonlinear Optimization

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Conference on Modeling and Optimization - Theory and Applications (MOPTA)

作者： Gill, Philip E. Saunders, Michael A. Wong, Elizabeth Univ Calif San Diego Dept Math La Jolla CA 92093 USA Stanford Univ Dept Management Sci & Engn Syst Optimizat Lab Stanford CA 94305 USA

ISBN: (纸本)9783319236995;9783319236988

This paper concerns some practical issues associated with the formulation of sequential quadratic programming (SQP) methods for large-scale nonlinear optimization. SQP methods find approximate solutions of a sequence of quadratic programming (QP) subproblems in which a quadratic model of the Lagrangian is minimized subject to the linearized constraints. Numerical results are given for 1153 problems from the CUTEst test collection. The results indicate that SQP methods based on maintaining a quasi-Newton approximation to the Hessian of the Lagrangian function are both reliable and efficient for general large-scale optimization problems. In particular, the results show that in some situations, quasi-Newton SQP methods are more efficient than interior methods that utilize the exact Hessian of the Lagrangian. The paper concludes with discussion of an SQP method that employs both approximate and exact Hessian information. In this approach the quadratic programming subproblem is either the conventional subproblem defined in terms of a positive-definite quasi-Newton approximate Hessian or a convexified subproblem based on the exact Hessian.

关键词： Nonlinear programming sequential quadratic programming SQP methods Interior methods Convexification Active-set methods quadratic programming

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