scholarly journals Survey on Design of Truss Structures by Using Fuzzy Optimization Methods

10.5772/36651 ◽  
2012 ◽  
Author(s):  
Aykut Kentli
Keyword(s):  
Fuzzy Optimization ◽  
Optimization Methods ◽  
Truss Structures

GA-Based Multi-Objective Fuzzy Matter-Element Optimization

2002 ◽  
Author(s):  
Yanwei Zhao ◽  
Ertian Hua ◽  
Guoxian Zhang ◽  
Fangshun Jin
Keyword(s):  
Genetic Algorithms ◽  
Optimization Problem ◽  
Fuzzy Optimization ◽  
Optimization Methods ◽  
Optimization Criterion ◽  
Multi Objective ◽  
Simple Genetic Algorithms ◽  
Solving Strategy ◽  
Crossover And Mutation ◽  
Better Than

The solving strategy of GA-Based Multi-objective Fuzzy Matter-Element optimization is put forward in this paper to the kind of characters of product optimization such as multi-objective, fuzzy nature, indeterminacy, etc. Firstly, the model of multi-objective fuzzy matter-element optimization is created in this paper, and then it defines the matter-element weightily and changes solving multi-objective optimization into solving dependent function K(x) of the single objective optimization according to the optimization criterion. In addition, modified adaptive macro genetic algorithms (MAMGA) are adopted to solve the optimization problem. It emphatically modifies crossover and mutation operator. By the comparing MAMGA with adaptive macro genetic algorithms (AMGA), not only the optimization is a little better than the latter, but also it reaches the extent to which the effective iteration generation is 62.2% of simple genetic algorithms (SGA). Lastly, three optimization methods, namely fuzzy matter-element optimization, linearity weighted method and fuzzy optimization, are also compared. It certifies that this method is feasible and valid.

scholarly journals A novel method of sensitivity analysis testing by applying the DRASTIC and fuzzy optimization methods to assess groundwater vulnerability to pollution: the case of the Senegal River basin in Mali

2017 ◽  
Vol 17 (8) ◽  
pp. 1375-1392 ◽  
Author(s):  
Keita Souleymane ◽  
Tang Zhonghua
Keyword(s):  
Sensitivity Analysis ◽  
River Basin ◽  
Fuzzy Optimization ◽  
Groundwater Vulnerability ◽  
Optimization Methods ◽  
Integrated Analysis ◽  
Fuzzy Method ◽  
Senegal River ◽  
Drastic Method ◽  
Senegal River Basin

Abstract. Vulnerability to groundwater pollution in the Senegal River basin was studied by two different but complementary methods: the DRASTIC method (which evaluates the intrinsic vulnerability) and the fuzzy method (which assesses the specific vulnerability by taking into account the continuity of the parameters). The validation of this application has been tested by comparing the connection in groundwater and distribution of different established classes of vulnerabilities as well as the nitrate distribution in the study area. Three vulnerability classes (low, medium and high) have been identified by both the DRASTIC method and the fuzzy method (between which the normalized model was used). An integrated analysis reveals that high classes with 14.64 % (for the DRASTIC method), 21.68 % (for the normalized DRASTIC method) and 18.92 % (for the fuzzy method) are not the most dominant. In addition, a new method for sensitivity analysis was used to identify (and confirm) the main parameters which impact the vulnerability to pollution with fuzzy membership. The results showed that the vadose zone is the main parameter which impacts groundwater vulnerability to pollution while net recharge contributes least to pollution in the study area. It was also found that the fuzzy method better assesses the vulnerability to pollution with a coincidence rate of 81.13 % versus that of 77.35 % for the DRASTIC method. These results serve as a guide for policymakers to identify areas sensitive to pollution before such sites are used for socioeconomic infrastructures.

scholarly journals Vulnerability Identification of Hajiabad Plain Aquifer: The DRASTIC Model and the GIS-Based Fuzzy Logic Method

2021 ◽  
Vol 14 ◽  
pp. 117862212110484
Author(s):  
Mehrdad Hassanzadeh ◽  
Mehdi Momeni Reghabadi ◽  
Amir Robati
Keyword(s):  
Fuzzy Logic ◽  
Water Samples ◽  
Groundwater Resources ◽  
Fuzzy Optimization ◽  
Optimization Methods ◽  
Aquifer Vulnerability ◽  
Optimal Method ◽  
Drastic Model ◽  
Vulnerability Maps ◽  
Bandar Abbas

Hajiabad plain with an area of about 158 km2 is located about 160 km north of Bandar Abbas in Iran. Due to the significance of this plain in terms of agricultural and drinking water supply in the region and the declining groundwater level in the region, the withdrawal of water resources has been prohibited in recent years. The purpose of this study is to determine the vulnerability of the aquifer using the DRASTIC model and the optimal method of fuzzy logic as well as the drastic method calibrated with nitrate. Finally, the final vulnerability maps were calibrated with EC values. In order to investigate the hydrogeochemical properties of groundwater resources of the plain, 26 water samples were collected from designated points in different periods of the water year 2018. Water samples were analyzed in Hormozgan soil and water laboratory. Also, the results of water sample data analyzed by Hormozgan Regional Water Organization were used. Assessment of aquifer vulnerability based on vulnerability models showed that the east and parts of the center of the plain were subject to the highest vulnerability, while the southern, southwestern, and northern slopes of the plain were of the lowest vulnerability. The determined coefficients between nitrate and DRASTIC vulnerability models and fuzzy optimization were estimated to be 0.41 and 0.36, respectively. Nitrate concentration validation demonstrated that the vulnerabilities of Hajiabad plain aquifer were almost similar under both drastic model and fuzzy optimization methods.

scholarly journals Enhanced Artificial Coronary Circulation System Algorithm for Truss Optimization with Multiple Natural Frequency Constraints

2019 ◽  
Author(s):  
Ali Kaveh ◽  
Mohsen Kooshkbaghi
Keyword(s):  
Structural Optimization ◽  
Coronary Circulation ◽  
Dynamic Performance ◽  
Optimization Methods ◽  
Gradient Algorithm ◽  
Truss Structures ◽  
Truss Optimization ◽  
Circulation System ◽  
Frequency Constraints ◽  
Local Optima

In this paper, an enhanced artificial coronary circulation system (EACCS) algorithm is applied to structural optimization with continuous design variables and frequency constraints. The standard algorithm, artificial coronary circulation system (ACCS), is inspired biologically as a non-gradient algorithm and mimics the growth of coronary tree of heart circulation system. Designs generated by the EACCS algorithm are compared with other popular evolutionary optimization methods, the objective function being the total weight of the structures.Truss optimization with frequency constraints has attracted substantial attention to improve the dynamic performance of structures. This kind of problems is believed to represent nonlinear and non-convex search spaces with several local optima. These problems are also suitable for examining the capabilities of the new algorithms. Here, ACCS is enhanced (EACCS) and employed for size and shape optimization of truss structures and six truss design problems are utilized for evaluating and validating of the EACCS. This algorithm uses a fitness-based weighted mean in the bifurcation phase and runner phase of the optimization process. The numerical results demonstrate successful performance, efficiency and robustness of the new method and its competitive performance to some other well-known meta-heuristics in structural optimization.

Models for Optimization of Gantry Crane Main Girder

2007 ◽  
Vol 348-349 ◽  
pp. 657-660
Author(s):  
Boris Aberšek ◽  
Samo Mikluš
Keyword(s):  
Steel Structures ◽  
Optimization Methods ◽  
Truss Structures ◽  
Gantry Crane ◽  
Mathematical Methods ◽  
Object Function ◽  
Volume Weight ◽  
Load Carrying ◽  
Definition Of ◽  
Main Girder

The optimization is the process of searching for the best results in a certain load case. Complete definition of optimization includes three conditions, which are closely connected: • optimization target, defined with object function, • subject of optimization, • optimization methods. The object functions can be different process parameters such as costs, manufacturing time, costefficiency, productivity etc. In designing of the structures such as a crane there is a tendency particularly towards reducing the weight of steel structures with the same load-carrying capacity. Thus the object function can be the volume, weight or mass of the structure. In the paper we will devote ourselves to optimization of truss structures-gantry crane mean girder by means of the FEM. This method has become indispensable in all areas of analyses of structures in combination with mathematical modeling and mathematical methods of optimization and is particularly of assistance to designers in conceiving the steel structures.

A fuzzy optimization method for octet-truss lattices

2019 ◽  
Vol 25 (9) ◽  
pp. 1525-1535
Author(s):  
Yunhui Yang ◽  
Libin Zhao ◽  
Dexuan Qi ◽  
Meijuan Shan ◽  
Jianyu Zhang
Keyword(s):  
Mechanical Properties ◽  
Lattice Structure ◽  
Fuzzy Optimization ◽  
Material Model ◽  
Optimization Methods ◽  
Optimization Method ◽  
Optimality Criteria ◽  
Content Type ◽  
Unit Cells ◽  
Octet Truss

Purpose This paper aims to present a multiscale fuzzy optimization (FO) method to optimize both the density distribution and macrotopology of a uniform octet-truss lattice structure. Design/methodology/approach The design formulae for the strut radii are presented based on the effective mechanical properties obtained from the representative volume element. The proposed basic lattice material is applied in a normalization process to determine the material model with penalization. The solid isotropic material with penalization (SIMP) method is extended to solve the minimum compliance problem using the optimality criteria. The evolutionary deletion process is proposed to delete elements corresponding to thin-strut unit cells and to obtain the optimal macrotopology. Findings Both numerical cases indicate that the FO results significantly improved in structural performance compared with the results of the conventional SIMP. The deleting threshold controls the macrotopology of the graded-density lattice structures with negligible effects on the mechanical properties. Originality/value This paper presents one of the first multiscale optimization methods to optimize both the relative density and macrotopology of uniform octet-truss lattices. The material model and corresponding optimality criteria of octet-truss lattices are proposed and implemented in the optimization.

scholarly journals A new hybrid method for size and topology optimization of truss structures using modified ALGA and QPGA

2016 ◽  
Vol 23 (2) ◽  
pp. 252-262 ◽  
Author(s):  
Nima NOII ◽  
Iman AGHAYAN ◽  
Iman HAJIRASOULIHA ◽  
Mehmet Metin KUNT
Keyword(s):  
Cross Sections ◽  
Large Scale ◽  
Convergence Rates ◽  
Design Method ◽  
Optimization Methods ◽  
Cholesky Factorization ◽  
Truss Structures ◽  
Design Solution ◽  
Design Parameters ◽  
Traditional Design

Modified Augmented Lagrangian Genetic Algorithm (ALGA) and Quadratic Penalty Function Genetic Algo­rithm (QPGA) optimization methods are proposed to obtain truss structures with minimum structural weight using both continuous and discrete design variables. To achieve robust solutions, Compressed Sparse Row (CSR) with reordering of Cholesky factorization and Moore Penrose Pseudoinverse are used in case of non-singular and singular stiffness matrix, respectively. The efficiency of the proposed nonlinear optimization methods is demonstrated on several practical exam­ples. The results obtained from the Pratt truss bridge show that the optimum design solution using discrete parameters is 21% lighter than the traditional design with uniform cross sections. Similarly, the results obtained from the 57-bar planar tower truss indicate that the proposed design method using continuous and discrete design parameters can be up to 29% and 9% lighter than traditional design solutions, respectively. Through sensitivity analysis, it is shown that the proposed methodology is robust and leads to significant improvements in convergence rates, which should prove useful in large-scale applications.

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