A Preference-Based Robust Design Metric

1998 ◽  
Author(s):  
Harikumar V. Iyer ◽  
Sundar Krishnamurty
Keyword(s):  
Decision Making ◽  
Optimal Design ◽  
Design Method ◽  
A Priori ◽  
Design Procedure ◽  
Design Criterion ◽  
Design Metrics ◽  
Overall Design ◽  
Space Reduction ◽  
Robust Optimal Design

Abstract Robust optimal design can be studied as a problem in decision-making requiring tradeoffs between mean and variance attributes. In this context, this paper views Taguchi’s philosophy based design metrics using signal-to-noise (SN) ratios as empirical applications of decision-making under uncertainty with a priori sets of attribute tradeoff values. Alternatively, this paper presents a more rigorous preference-based design metric using concepts from utility theory to accurately capture designer’s intent and preferences. The use of this design metric as the robust optimal design criterion in a modified TRED (Tradeoffs in Robust Engineering Design) method with an innovative response-surface based iterative design space reduction strategy is presented. The effectiveness of the overall design procedure and the performance of the preference-based design metric are tested with the aid of demonstrative case studies and the results are discussed.

scholarly journals A Two-Round Optimization Design Method for Aerostatic Spindles Considering the Fluid–Structure Interaction Effect

2021 ◽  
Vol 11 (7) ◽  
pp. 3017
Author(s):  
Qiang Gao ◽  
Siyu Gao ◽  
Lihua Lu ◽  
Min Zhu ◽  
Feihu Zhang
Keyword(s):  
Optimal Design ◽  
Optimization Design ◽  
Design Method ◽  
Fluid Structure Interaction ◽  
Design Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aerostatic Spindle

The fluid–structure interaction (FSI) effect has a significant impact on the static and dynamic performance of aerostatic spindles, which should be fully considered when developing a new product. To enhance the overall performance of aerostatic spindles, a two-round optimization design method for aerostatic spindles considering the FSI effect is proposed in this article. An aerostatic spindle is optimized to elaborate the design procedure of the proposed method. In the first-round design, the geometrical parameters of the aerostatic bearing were optimized to improve its stiffness. Then, the key structural dimension of the aerostatic spindle is optimized in the second-round design to improve the natural frequency of the spindle. Finally, optimal design parameters are acquired and experimentally verified. This research guides the optimal design of aerostatic spindles considering the FSI effect.

Robust Optimal Design of a Gas Turbine Cogeneration Plant Under Uncertain Energy Demands and Costs

2015 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Masashi Ohkura ◽  
Tetsuya Wakui
Keyword(s):  
Optimal Design ◽  
Gas Turbine ◽  
Energy Supply ◽  
Design Method ◽  
Performance Comparison ◽  
Energy Demands ◽  
Robust Optimal Design ◽  
Optimal Design Method ◽  
Supply Systems ◽  
Energy Supply Systems

In designing energy supply systems, designers should consider that energy demands and costs as parameters have some uncertainties, evaluate the robustness in system performances against the uncertainties, and design the systems rationally to heighten the robustness. A robust optimal design method of energy supply systems under only uncertain energy demands was revised so that it can be applied to systems with complex configurations and large numbers of periods for variations in energy demands. In addition, a method of comparing performances of two energy supply systems under only uncertain energy demands was proposed by utilizing a part of the revised robust optimal design method. In this paper, the revised robust optimal design method as well as the proposed performance comparison method are extended so that they can be applied to the robust optimal design and the performance comparison of energy supply systems under not only uncertain energy demands but also uncertain energy costs. Through a case study on a gas turbine cogeneration system for district energy supply, the validity and effectiveness of the extended optimal design method and features of the robust optimal design are clarified. In addition, the gas turbine cogeneration system is compared with a conventional energy supply system using the extended performance comparison method.

Multiobjective Robust Optimal Design of a Gas Turbine Cogeneration Plant Under Uncertain Energy Demands

2001 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Koichi Ito
Keyword(s):  
Optimal Design ◽  
Energy Saving ◽  
Gas Turbine ◽  
Energy Supply ◽  
Design Method ◽  
Primary Energy ◽  
Weighted Sum ◽  
Cogeneration Plant ◽  
Energy Demands ◽  
Robust Optimal Design

A multiobjective robust optimal design method based on the minimax regret criterion is proposed for sizing equipment of energy supply plants so that they are robust in economic and energy saving characteristics under uncertain energy demands. Equipment capacities and utility contract demands as well as energy flow rates are determined to minimize a weighted sum of the maximum regrets in the annual total cost and primary energy consumption, and satisfy all the possible energy demands. This optimization problem is formulated as a kind of multilevel linear programming one, and its solution is derived by repeatedly evaluating lower and upper bounds for the optimal value of the weighted sum of the maximum regrets. Through a case study on a gas turbine cogeneration plant for district energy supply, the trade-off relationship between the robustness in economic and energy saving characteristics is clarified.

Strength Optimization of Infant Pop-Up Seat Frame Using Discrete Material and Thickness Optimization

2021 ◽  
Vol 11 (3) ◽  
pp. 1-20
Author(s):  
YeongJo Ju ◽  
Euysik Jeon
Keyword(s):  
Optimal Design ◽  
High Strength Steel ◽  
Design Method ◽  
High Strength ◽  
Optimization Method ◽  
Design Criterion ◽  
Thickness Optimization ◽  
Element Analysis ◽  
Strength Design ◽  
Seat Frame

In this paper, the authors proposed an optimal design method for the strength design of infant pop-up seat frame combined with rear seats for infants, children, and adults, not removable booster seats or car seats. Frame strength design was performed using discrete material and thickness optimization (DMTO) method considering high strength steel (HSS) and advanced high strength steel (AHSS). Structural design using the Section 4 link mechanism was performed, and the weakness of the seat frame due to static load was confirmed through finite element analysis. An optimal design criterion was established by carrying out a case study to derive the limiting conditions according to static and dynamic loads. In consideration of these criteria, the optimal design according to d-optimal and discrete Latin-hypercube (DLH) was performed among the design of experiments (DOE). And the strength of the pop-up seat frame for infants according to each DOE was checked, and the strength optimization method was suggested by comparing the lightweight ratio.

Robust Optimal Design in Multistage Expansion of a Gas Turbine Cogeneration Plant Under Uncertain Energy Demands

2003 ◽  
Author(s):  
Ryohei Yokoyama ◽  
Koichi Ito ◽  
Tatsuhiro Murata
Keyword(s):  
Optimal Design ◽  
Gas Turbine ◽  
Energy Supply ◽  
Design Method ◽  
Design Stage ◽  
Cogeneration Plant ◽  
District Energy ◽  
Expansion Planning ◽  
Energy Demands ◽  
Robust Optimal Design

In designing cogeneration plants, the estimation of energy demands is an important work. However, many conditions under which energy demands are estimated have some uncertainty at the design stage. Therefore, designers should consider that energy demands have some uncertainty, evaluate the robustness in the performance under uncertain energy demands, and design plants rationally in consideration of the robustness. The authors have developed a robust optimal design method based on the minimax regret criterion for the single-stage planning of energy supply plants. In this paper, the method is extended for the multistage expansion planning. Under uncertain energy demands increasing stepwise, equipment capacities and utility contract demands as well as energy flow rates for each expansion period are determined in consideration of their sequential relationships to minimize the maximum regret in the annual total cost and satisfy all the possible energy demands for all the expansion periods. Through a case study on a gas turbine cogeneration plant for district energy supply, features of the economic robustness and the robust optimal design are clarified in relation to the uncertainty in energy demands and the numbers of years for the expansion periods.

Study on Overall Design of a Vertical Take-Off and Landing Unmanned Aerial Vehicle Powered by Electric Ducted Fans

2021 ◽  
Author(s):  
Tawei Chou ◽  
Qiyu Ying ◽  
Yuping Qian ◽  
Weilin Zhuge ◽  
Yangjun Zhang
Keyword(s):  
Power Unit ◽  
Unmanned Aerial Vehicle ◽  
Cfd Simulation ◽  
Design Method ◽  
Load Capacity ◽  
Design Procedure ◽  
Low Noise ◽  
Overall Design ◽  
Ducted Fan ◽  
Aerial Vehicle

Abstract Facing the growing traffic fleet in the cities nowadays, it is believed that three-dimensional urban transportation could be a solution and will be introduced in the near future. Vertical take-off and landing flying platforms powered by ducted fans will attract increasingly attention because it has advantages on high propulsion efficiency, low noise, and better safety. However, unlike traditional open-blade multi-rotor drones, ducted fan drones lack a systematic design approach that comprehensively considers the overall system performance and the power unit efficiency. Current design procedure leads to insufficient load capacity and low efficiency systems. This paper proposes an overall design method for a ducted fan-type vertical take-off and landing flight platform. The ducted fan and motor of the core power unit are designed and selected aiming at improving aerodynamic efficiency and structural utilization of the system. A heavy-load vertical take-off and landing Unmanned Aerial Vehicle (UAV) powered by ducted fans with a take-off weight of 450kg is designed based on this method. CFD simulation is utilized to calculate the performance of the designed Unmanned Aerial Vehicle, and finite element analysis is carried out to examine the overall strength safety. The final design results show that the overall design method plays a great role in the development of ducted fan UAV.

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