The Experts below are selected from a list of 1179 Experts worldwide ranked by ideXlab platform
A M Savill - One of the best experts on this subject based on the ideXlab platform.
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multi objective optimisation of horizontal axis wind turbine structure and energy production using aerofoil and blade properties as Design variables
Renewable Energy, 2014Co-Authors: Gunter Reinald Fischer, Timoleon Kipouros, A M SavillAbstract:The Design of wind turbine blades is a true multi-objective engineering task. The aerodynamic effectiveness of the turbine needs to be balanced with the system loads introduced by the rotor. Moreover the problem is not dependent on a single geometric property, but besides other parameters on a combination of aerofoil family and various blade functions. The aim of this paper is therefore to present a tool which can help Designers to get a deeper insight into the complexity of the Design space and to find a blade Design which is likely to have a low cost of energy. For the research we use a Computational Blade Optimisation and Load Deflation Tool (CoBOLDT) to investigate the three extreme point Designs obtained from a multi-objective optimisation of turbine thrust, annual energy production as well as mass for a horizontal axis wind turbine blade. The optimisation algorithm utilised is based on Multi-Objective Tabu Search which constitutes the core of CoBOLDT. The methodology is capable to parametrise the spanning aerofoils with two-dimensional Free Form Deformation and blade functions with two tangentially connected cubic splines. After geometry generation we use a panel code to create aerofoil polars and a stationary Blade Element Momentum code to evaluate turbine performance. Finally, the obtained loads are fed into a structural layout module to estimate the mass and stiffness of the current blade by means of a Fully Stressed Design. For the presented test case we chose post optimisation analysis with parallel coordinates to reveal geometrical features of the extreme point Designs and to select a compromise Design from the Pareto set. The research revealed that a blade with a feasible laminate layout can be obtained, that can increase the energy capture and lower steady state systems loads. The reduced aerofoil camber and an increased L/D-ratio could be identified as the main drivers. This statement could not be made with other tools of the research community before.
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Multi-objective optimisation of horizontal axis wind turbine structure and energy production using aerofoil and blade properties as Design variables
2014Co-Authors: Gr Fischer, Kipouros T, A M SavillAbstract:The Design of wind turbine blades is a true multi-objective engineering task. The aerodynamic effectiveness of the turbine needs to be balanced with the system loads introduced by the rotor. Moreover the problem is not dependent on a single geometric property, but besides other parameters on a combination of aerofoil family and various blade functions. The aim of this paper is therefore to present a tool which can help Designers to get a deeper insight into the complexity of the Design space and to find a blade Design which is likely to have a low cost of energy. For the research we use a Computational Blade Optimisation and Load Deflation Tool (CoBOLDT) to investigate the three extreme point Designs obtained from a multi-objective optimisation of turbine thrust, annual energy production as well as mass for a horizontal axis wind turbine blade. The optimisation algorithm utilised is based on Multi-Objective Tabu Search which constitutes the core of CoBOLDT. The methodology is capable to parametrise the spanning aerofoils with two-dimensional Free Form Deformation and blade functions with two tangentially connected cubic splines. After geometry generation we use a panel code to create aerofoil polars and a stationary Blade Element Momentum code to evaluate turbine performance. Finally, the obtained loads are fed into a structural layout module to estimate the mass and stiffness of the current blade by means of a Fully Stressed Design. For the presented test case we chose post optimisation analysis with parallel coordinates to reveal geometrical features of the extreme point Designs and to select a compromise Design from the Pareto set. The research revealed that a blade with a feasible laminate layout can be obtained, that can increase the energy capture and lower steady state systems loads. The reduced aerofoil camber and an increased L/. D-ratio could be identified as the main drivers. This statement could not be made with other tools of the research community before. © 2013 Elsevier Ltd
Gunter Reinald Fischer - One of the best experts on this subject based on the ideXlab platform.
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multi objective optimisation of horizontal axis wind turbine structure and energy production using aerofoil and blade properties as Design variables
Renewable Energy, 2014Co-Authors: Gunter Reinald Fischer, Timoleon Kipouros, A M SavillAbstract:The Design of wind turbine blades is a true multi-objective engineering task. The aerodynamic effectiveness of the turbine needs to be balanced with the system loads introduced by the rotor. Moreover the problem is not dependent on a single geometric property, but besides other parameters on a combination of aerofoil family and various blade functions. The aim of this paper is therefore to present a tool which can help Designers to get a deeper insight into the complexity of the Design space and to find a blade Design which is likely to have a low cost of energy. For the research we use a Computational Blade Optimisation and Load Deflation Tool (CoBOLDT) to investigate the three extreme point Designs obtained from a multi-objective optimisation of turbine thrust, annual energy production as well as mass for a horizontal axis wind turbine blade. The optimisation algorithm utilised is based on Multi-Objective Tabu Search which constitutes the core of CoBOLDT. The methodology is capable to parametrise the spanning aerofoils with two-dimensional Free Form Deformation and blade functions with two tangentially connected cubic splines. After geometry generation we use a panel code to create aerofoil polars and a stationary Blade Element Momentum code to evaluate turbine performance. Finally, the obtained loads are fed into a structural layout module to estimate the mass and stiffness of the current blade by means of a Fully Stressed Design. For the presented test case we chose post optimisation analysis with parallel coordinates to reveal geometrical features of the extreme point Designs and to select a compromise Design from the Pareto set. The research revealed that a blade with a feasible laminate layout can be obtained, that can increase the energy capture and lower steady state systems loads. The reduced aerofoil camber and an increased L/D-ratio could be identified as the main drivers. This statement could not be made with other tools of the research community before.
Kalyanmoy Deb - One of the best experts on this subject based on the ideXlab platform.
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an improved Fully Stressed Design evolution strategy for layout optimization of truss structures
Computers & Structures, 2016Co-Authors: Ali Ahrari, Kalyanmoy DebAbstract:FSD-ES is improved to handle the displacement constraints more efficiently.The improved version follows the principles of contemporary evolution strategies.Evaluation of a kinematically unstable Design is revised.Complicated truss optimization test problems are developed.The improved FSD-ES is demonstrated to outperform the best available peer methods. During the recent decade, truss optimization by meta-heuristics has gradually replaced deterministic and optimality criteria-based methods. While they may provide some advantages regarding their robustness and ability to avoid local minima, the required evaluation budget grows fast when the number of Design variables is increased. This practically limits the size of the problems to which they can be applied. Furthermore, many recent stochastic optimization methods handle the size optimization only, the potential saving from which is highly limited, when compared to the most sophisticated, and obviously the most challenging scenario, simultaneous topology, shape and size (TSS) optimization. In a recent study by the authors, a method based on combination of optimality criteria and evolution strategies, called Fully Stressed Design based on evolution strategies (FSD-ES), was proposed for TSS optimization of truss structures. FSD-ES outperformed available truss optimizers in the literature, both in efficiency and robustness. The contribution of this study is twofold. First, an improved version of FSD-ES method, called FSD-ES-II, is proposed. In comparison with the earlier version, it takes the displacement constraints in the resizing step into account and can handle constraints governed by practically used specifications. Update of strategy parameters is also revised following contemporary and new developments in evolution strategies. Second, a test suite involving a number of complicated TSS optimization problems is chosen to overcome usual shortcomings in the available benchmark problems. For each problem, performance of FSD-ES-II is compared with the best results available in the literature, often showing a significant superiority of the proposed approach.
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simultaneous topology shape and size optimization of truss structures by Fully Stressed Design based on evolution strategy
Engineering Optimization, 2015Co-Authors: Ali Ahrari, Ali Asghar Atai, Kalyanmoy DebAbstract:The most effective scheme of truss optimization considers the combined effect of topology, shape and size (TSS); however, most available studies on truss optimization by metaheuristics concentrated on one or two of the above aspects. The presence of diverse Design variables and constraints in TSS optimization may account for such limited applicability of metaheuristics to this field. In this article, a recently proposed algorithm for simultaneous shape and size optimization, Fully Stressed Design based on evolution strategy (FSD-ES), is enhanced to handle TSS optimization problems. FSD-ES combines advantages of the well-known deterministic approach of Fully Stressed Design with potential global search of the state-of-the-art evolution strategy. A comparison of results demonstrates that the proposed optimizer reaches the same or similar solutions faster and/or is able to find lighter Designs than those previously reported in the literature. Moreover, the proposed variant of FSD-ES requires no user-based tu...
Timoleon Kipouros - One of the best experts on this subject based on the ideXlab platform.
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multi objective optimisation of horizontal axis wind turbine structure and energy production using aerofoil and blade properties as Design variables
Renewable Energy, 2014Co-Authors: Gunter Reinald Fischer, Timoleon Kipouros, A M SavillAbstract:The Design of wind turbine blades is a true multi-objective engineering task. The aerodynamic effectiveness of the turbine needs to be balanced with the system loads introduced by the rotor. Moreover the problem is not dependent on a single geometric property, but besides other parameters on a combination of aerofoil family and various blade functions. The aim of this paper is therefore to present a tool which can help Designers to get a deeper insight into the complexity of the Design space and to find a blade Design which is likely to have a low cost of energy. For the research we use a Computational Blade Optimisation and Load Deflation Tool (CoBOLDT) to investigate the three extreme point Designs obtained from a multi-objective optimisation of turbine thrust, annual energy production as well as mass for a horizontal axis wind turbine blade. The optimisation algorithm utilised is based on Multi-Objective Tabu Search which constitutes the core of CoBOLDT. The methodology is capable to parametrise the spanning aerofoils with two-dimensional Free Form Deformation and blade functions with two tangentially connected cubic splines. After geometry generation we use a panel code to create aerofoil polars and a stationary Blade Element Momentum code to evaluate turbine performance. Finally, the obtained loads are fed into a structural layout module to estimate the mass and stiffness of the current blade by means of a Fully Stressed Design. For the presented test case we chose post optimisation analysis with parallel coordinates to reveal geometrical features of the extreme point Designs and to select a compromise Design from the Pareto set. The research revealed that a blade with a feasible laminate layout can be obtained, that can increase the energy capture and lower steady state systems loads. The reduced aerofoil camber and an increased L/D-ratio could be identified as the main drivers. This statement could not be made with other tools of the research community before.
Ali Ahrari - One of the best experts on this subject based on the ideXlab platform.
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an improved Fully Stressed Design evolution strategy for layout optimization of truss structures
Computers & Structures, 2016Co-Authors: Ali Ahrari, Kalyanmoy DebAbstract:FSD-ES is improved to handle the displacement constraints more efficiently.The improved version follows the principles of contemporary evolution strategies.Evaluation of a kinematically unstable Design is revised.Complicated truss optimization test problems are developed.The improved FSD-ES is demonstrated to outperform the best available peer methods. During the recent decade, truss optimization by meta-heuristics has gradually replaced deterministic and optimality criteria-based methods. While they may provide some advantages regarding their robustness and ability to avoid local minima, the required evaluation budget grows fast when the number of Design variables is increased. This practically limits the size of the problems to which they can be applied. Furthermore, many recent stochastic optimization methods handle the size optimization only, the potential saving from which is highly limited, when compared to the most sophisticated, and obviously the most challenging scenario, simultaneous topology, shape and size (TSS) optimization. In a recent study by the authors, a method based on combination of optimality criteria and evolution strategies, called Fully Stressed Design based on evolution strategies (FSD-ES), was proposed for TSS optimization of truss structures. FSD-ES outperformed available truss optimizers in the literature, both in efficiency and robustness. The contribution of this study is twofold. First, an improved version of FSD-ES method, called FSD-ES-II, is proposed. In comparison with the earlier version, it takes the displacement constraints in the resizing step into account and can handle constraints governed by practically used specifications. Update of strategy parameters is also revised following contemporary and new developments in evolution strategies. Second, a test suite involving a number of complicated TSS optimization problems is chosen to overcome usual shortcomings in the available benchmark problems. For each problem, performance of FSD-ES-II is compared with the best results available in the literature, often showing a significant superiority of the proposed approach.
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simultaneous topology shape and size optimization of truss structures by Fully Stressed Design based on evolution strategy
Engineering Optimization, 2015Co-Authors: Ali Ahrari, Ali Asghar Atai, Kalyanmoy DebAbstract:The most effective scheme of truss optimization considers the combined effect of topology, shape and size (TSS); however, most available studies on truss optimization by metaheuristics concentrated on one or two of the above aspects. The presence of diverse Design variables and constraints in TSS optimization may account for such limited applicability of metaheuristics to this field. In this article, a recently proposed algorithm for simultaneous shape and size optimization, Fully Stressed Design based on evolution strategy (FSD-ES), is enhanced to handle TSS optimization problems. FSD-ES combines advantages of the well-known deterministic approach of Fully Stressed Design with potential global search of the state-of-the-art evolution strategy. A comparison of results demonstrates that the proposed optimizer reaches the same or similar solutions faster and/or is able to find lighter Designs than those previously reported in the literature. Moreover, the proposed variant of FSD-ES requires no user-based tu...
