scholarly journals Risk-Based Multiobjective Optimal Seismic Design for RC Piers Using the Response Surface Method and NSGA-II

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Sicong Hu ◽  
Yixuan Zou ◽  
Yufeng Gai ◽  
Zheng Huang ◽  
Guquan Song
Keyword(s):  
Response Surface ◽  
Seismic Design ◽  
Seismic Risk ◽  
Design Method ◽  
Design Parameters ◽  
Surface Model ◽  
Pareto Optimal ◽  
Pareto Optimal Solutions ◽  
Optimal Solutions ◽  
Seismic Design Method

In this paper, a risk-based multiobjective optimal seismic design method for reinforced concrete (RC) piers is proposed. This method is used to determine the size and reinforcement ratios of piers to minimize the seismic risk of bridge systems and the construction cost of piers. The Pacific Earthquake Engineering Research- (PEER-) based probabilistic seismic risk assessment approach and the response surface method (RSM) are adopted to develop the seismic risk response surface model, which represents the relationship between the design parameters of piers and the seismic risk of bridge systems. The Pareto optimal solutions of piers are determined by applying an improved version of the nondominated sorting genetic algorithm (NSGA-II). As a case study, the proposed optimal seismic design method is applied to a continuous concrete box girder bridge. The optimal design schemes of piers according to two strategies are determined from the Pareto optimal solutions. The results show that the seismic risk response surface model can be used to accurately describe the relationship between the design parameters of piers and the seismic risk of bridge systems. The case study demonstrates the effectiveness of the proposed optimal seismic design method. The analysis of the Pareto optimal solutions allows designers to more rationally conduct the seismic design of piers.

Multiobjective Optimization Design of a Pump–Turbine Impeller Based on an Inverse Design Using a Combination Optimization Strategy

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Wei Yang ◽  
Ruofu Xiao
Keyword(s):  
Response Surface ◽  
Optimization Design ◽  
Design Method ◽  
Inverse Design ◽  
Design Parameters ◽  
Surface Model ◽  
Optimization Strategy ◽  
Pump Turbine ◽  
Combination Optimization ◽  
Final Design

This paper presents an automatic multiobjective hydrodynamic optimization strategy for pump–turbine impellers. In the strategy, the blade shape is parameterized based on the blade loading distribution using an inverse design method. An efficient response surface model relating the design parameters and the objective functions is obtained. Then, a multiobjective evolutionary algorithm is applied to the response surface functions to find a Pareto front for the final trade-off selection. The optimization strategy was used to redesign a scaled pump–turbine. Model tests were conducted to validate the final design and confirm the validity of the design strategy.

Aerodynamic Performances and Flow Fields of Pareto Optimal Solutions in an Aerodynamic Design of a Wind-Lens Turbine

2015 ◽  
Author(s):  
Nobuhito Oka ◽  
Masato Furukawa ◽  
Kazutoyo Yamada ◽  
Akihiro Oka ◽  
Yasushi Kurokawa
Keyword(s):  
Optimal Design ◽  
Wind Tunnel ◽  
Design Method ◽  
Flow Fields ◽  
Pareto Optimal ◽  
Pareto Optimal Solutions ◽  
Optimal Solutions ◽  
Aerodynamic Design ◽  
Aerodynamic Performances ◽  
Optimal Design Method

The new type of shrouded wind turbine called “wind-lens turbine” has been developed. The wind-lens turbine has a brimmed diffuser called “wind-lens”, by which the wind concentration on the turbine blade and the significant enhancement of the turbine output can be achieved. A simultaneous optimization method for the aerodynamic design of rotor blade and wind-lens has been developed. The present optimal design method is based on a genetic algorithm (GA) which enables multi objective aerodynamic optimization. In the present study, aerodynamic performances and flow fields of the Pareto optimal solutions of wind-lens turbines designed by the present optimal design method have been investigated by wind-tunnel tests and three-dimensional Reynolds averaged Navier-Stokes (RANS) analyses. Output power coefficients obtained from the wind-tunnel tests in the optimal wind-lens turbine exceeded the Betz limit, which is the performance limitation for bare wind turbines. The numerical results and the experimental results show that the suppression of flow separations in the diffuser is important to achieve significant improvement in aerodynamic performances. As a result, it is found that the aerodynamic performance of wind-lens turbine is significantly affected by the interrelationship between the internal and external flow fields around the wind-lens.

Optimal Dimensioning for Parallel Manipulators: Workspace, Dexterity, and Energy

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Oscar Altuzarra ◽  
C. Pinto ◽  
B. Sandru ◽  
A. Hernandez
Keyword(s):  
Parallel Manipulator ◽  
Optimization Problems ◽  
Parallel Manipulators ◽  
Design Parameters ◽  
Frobenius Norm ◽  
Pareto Optimal ◽  
Pareto Optimal Solutions ◽  
Optimal Solutions ◽  
Motion Generation ◽  
Schönflies Motion

In mechanism design and in the particular case of the parallel manipulator, most optimization problems involve simultaneously optimizing more than one objective function. In this paper, a method to identify Pareto-optimal solutions for the design of low-mobility parallel manipulators is presented. A 4-degree-of-freedom symmetric parallel manipulator for Schönflies-motion generation is taken as a case study. The design goals used are workspace volume and manipulator dexterity based on a dispersion weighted Frobenius norm. In addition, an expression for energy per cycle has been defined for different types of trajectory to evaluate the power drive. Finally, the set of Pareto-optimal solutions of the design parameters are represented in the design parameter space.

On utility of inductive learning in multiobjective robust design

1999 ◽  
Vol 13 (1) ◽  
pp. 27-36 ◽  
Author(s):  
BABAK FOROURAGHI
Keyword(s):  
Robust Design ◽  
Inductive Learning ◽  
Regression Tree ◽  
Optimization Techniques ◽  
Design Parameters ◽  
Pareto Optimal ◽  
Pareto Optimal Solutions ◽  
Optimal Solutions ◽  
Engineering Design Problems ◽  
Target Values

Most engineering design problems involve optimizing a number of often conflicting performance measures in the presence of multiple constraints. Traditional vector optimization techniques approach these problems by generating a set of Pareto-optimal solutions, where any specific objective can be further improved only at the cost of degrading one or more other objectives. The solutions obtained in this manner, however, are only single points within the space of all possible Pareto-optimal solutions and generally do not indicate to designers how small deviations from predicted design parameters settings affect the performance of the product or the process under study.In this paper we introduce a new approach to robust design based on the concept of inductive learning with regression trees. Given a set of training examples relating to a multiobjective design problem, we demonstrate how a multivariate regression tree can utilize an information-theoretic measure of covariance complexity to capture optimal, tradeoff design surfaces. The novelty of generating design surfaces as opposed to traditional points in the design space is that now designers are able to easily determine how the responses of a product or process vary as design parameters change. This ability is of paramount importance in situations where design parameter settings need to be modified during the lifetime of a product/process due to various economic or operational constraints. As a result, designers will be able to select optimal ranges for design parameters such that the product's performance indices exhibit minimal or tolerable deviations from their target values. To highlight the advantages of our methodology, we present a multiobjective example that deals with optimum design of an electric discharge machining (EDM) process.

Resilience-based Seismic Design Optimization of typical Highway RC Bridges by Response Surface Method and NSGA-II Algorithm

2021 ◽  
Author(s):  
Sicong Hu ◽  
Baokui Chen ◽  
Guquan Song ◽  
Lianhua Wang
Keyword(s):  
Response Surface ◽  
Response Surface Method ◽  
Seismic Design ◽  
Nonlinear Time History Analysis ◽  
Design Parameters ◽  
Surface Model ◽  
Nsga Ii ◽  
Surface Method ◽  
Material Cost ◽  
Seismic Resilience

Abstract To maximize the seismic performance and minimize the material cost of the typical highway reinforced concrete (RC) bridges, a resilience-based multi-objective optimal seismic design method is proposed in this study. The size of elastomeric bearings and the cross-section arrangement of RC piers are chosen as the design parameters. To improve the accuracy and efficiency, the nonlinear time history analysis (NTHA) based cloud analysis approach is associated with the response surface method (RSM) to obtain the seismic resilience during the seismic optimization process. Moreover, the optimization problem is solved through an improved version of non-dominated sorting genetic algorithm (NSGA-II) algorithm. Following, the proposed method is applied to a typical highway RC bridge, and the optimal design schemes are determined from the Pareto optimal solutions. The results show that the resilience response surface model can be used to accurately predict the seismic resilience of bridges. The proposed method can adjust the damage grades of various components by considering the contribution of various components, entailing the minimization of material cost and the maximization of seismic resilience.

Seismic Design Method for Hybrid Viaduct in Japanese Railways

2000 ◽  
Vol 16 (20) ◽  
pp. 338-346
Author(s):  
Kiyomitsu MURATA ◽  
Masato YAMADA ◽  
Tomohiro TAKAYAMA ◽  
Masanori KINOSHITA
Keyword(s):  
Seismic Design ◽  
Design Method ◽  
Seismic Design Method

Research Situation on the Performance-Based Seismic Design Method for Reinforced Concrete Structure

2010 ◽  
Vol 163-167 ◽  
pp. 1757-1761
Author(s):  
Yong Le Qi ◽  
Xiao Lei Han ◽  
Xue Ping Peng ◽  
Yu Zhou ◽  
Sheng Yi Lin
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
Design Method ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Seismic Evaluation ◽  
Seismic Codes ◽  
Performance Based Seismic Design ◽  
Capacity Calculation ◽  
Seismic Design Method

Various analytical approaches to performance-based seismic design are in development. Based on the current Chinese seismic codes，elastic capacity calculation under frequent earthquake and ductile details of seismic design shall be performed for whether seismic design of new buildings or seismic evaluation of existing buildings to satisfy the seismic fortification criterion “no damage under frequent earthquake, repairable under fortification earthquake, no collapse under severe earthquake”. However, for some special buildings which dissatisfy with the requirements of current building codes, elastic capacity calculation under frequent earthquake is obviously not enough. In this paper, the advanced performance-based seismic theory is introduced to solve the problems of seismic evaluation and strengthening for existing reinforced concrete structures, in which story drift ratio and deformation of components are used as performance targets. By combining the features of Chinese seismic codes, a set of performance-based seismic design method is established for reinforced concrete structures. Different calculation methods relevant to different seismic fortification criterions are adopted in the proposed method, which solve the problems of seismic evaluation for reinforced concrete structures.

scholarly journals Optimization Of Multi-Module CrN/CrCN Coatings

2015 ◽  
Vol 60 (2) ◽  
pp. 1037-1043
Author(s):  
Ł. Szparaga ◽  
P. Bartosik ◽  
A. Gilewicz ◽  
J. Ratajski
Keyword(s):  
Optimization Procedure ◽  
Stress And Strain ◽  
Pareto Optimal ◽  
Mutual Distance ◽  
Pareto Optimal Solutions ◽  
Optimal Solutions ◽  
Decision Criteria ◽  
Decision Variables ◽  
42Crmo4 Steel ◽  
The Stability

Abstract In the paper was proposed optimization procedure supporting the prototyping of the geometry of multi-module CrN/CrCN coatings, deposited on substrates from 42CrMo4 steel, in respect of mechanical properties. Adopted decision criteria were the functions of the state of internal stress and strain in the coating and substrate, caused by external mechanical loads. Using developed optimization procedure the set of optimal solutions (Pareto-optimal solutions) of coatings geometry parameters, due to the adopted decision criteria was obtained. For the purposes of analysis of obtained Pareto-optimal solutions, their mutual distance in the space of criteria and decision variables were calculated, which allowed to group solutions in the classes. Also analyzed the number of direct neighbors of Pareto-optimal solutions for the purposes of assessing the stability of solutions.

scholarly journals Seismic Design Method for CFS Diagonal Strap-Braced Stud Walls: Experimental Validation

2016 ◽  
Vol 142 (3) ◽  
pp. 04015154 ◽  
Author(s):  
Luigi Fiorino ◽  
Ornella Iuorio ◽  
Vincenzo Macillo ◽  
Maria Teresa Terracciano ◽  
Tatiana Pali ◽  
...  
Keyword(s):  
Seismic Design ◽  
Experimental Validation ◽  
Design Method ◽  
Seismic Design Method
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