The Experts below are selected from a list of 11385 Experts worldwide ranked by ideXlab platform
Jasbir S Arora - One of the best experts on this subject based on the ideXlab platform.
-
optimal design of latticed towers subjected to Earthquake Loading
Journal of Structural Engineering-asce, 2002Co-Authors: Fatma Y Kocer, Jasbir S AroraAbstract:The problem of optimal design of latticed transmission towers subjected to normal operating loads and an Earthquake load is formulated. A time history analysis of the structure is performed. The constraints given in a design code are imposed. Many of the constraints are time dependent; therefore methods to treat them are incorporated in the solution process. All members are treated as equal- ~unequal-! legged angle sections. The members are selected from the sections available in a manufacturer's catalog. Two methods are presented and evaluated for such discrete variable optimization problems. The first method, called the two-phase method, uses a combi- nation of continuous and discrete optimization algorithms, and the second one, called an adaptive discrete assignment method ~ADAM!, uses only a continuous optimization algorithm. The proposed methods are applicable to any discrete variable problem that can be formulated as a continuous problem. In addition, the problem is solved using a genetic algorithm ~GA!. The efficiency and practicality of the proposed methods are compared to those of the GA. From the results, it is concluded that the GA is a very straightforward method to use for discrete problems; however, it requires a significant amount of Central Processing Unit time. On the other hand, the two-phase method and the ADAM do not require as much computational effort but the discrete designs found with them are slightly more expensive. Also, numerical implementation of the two methods requires more effort.
-
optimal design of h frame transmission poles for Earthquake Loading
Journal of Structural Engineering-asce, 1999Co-Authors: Fatma Y Kocer, Jasbir S AroraAbstract:The design of H-frame transmission poles subjected to static and dynamic loads (Earthquake load) is formulated as an optimization problem. Time history analysis, discrete design variables, and optimization algorithms are integrated to solve the problem. With time history analysis, structural nonlinearity can be incorporated in the formulation; however, stress constraints based on ASCE design force the final design to remain elastic. Two cost functions are defined: Material cost and total initial cost. A method to treat time-dependent constraints is selected for use with two discrete variable optimization methods: Simulated annealing and genetic algorithm. A simple penalty function is defined to account for constraints in the algorithms. Several solution cases are defined and solved. Results show the genetic algorithm to be superior to simulated annealing. Both algorithms are quite simple and appropriate to solve discrete variable problems. Computational times with the methods are quite large because many ...
S Gholizadeh - One of the best experts on this subject based on the ideXlab platform.
-
optimal design of arch dams subjected to Earthquake Loading by a combination of simultaneous perturbation stochastic approximation and particle swarm algorithms
Applied Soft Computing, 2011Co-Authors: S M Seyedpoor, E Salajegheh, J Salajegheh, S GholizadehAbstract:An efficient optimization procedure is introduced to find the optimal shapes of arch dams considering fluid-structure interaction subject to Earthquake Loading. The optimization is performed by a combination of simultaneous perturbation stochastic approximation (SPSA) and particle swarm optimization (PSO) algorithms. This serial integration of the two single methods is termed as SPSA-PSO. The operation of SPSA-PSO includes three phases. In the first phase, a preliminary optimization is accomplished using the SPSA. In the second phase, an optimal initial swarm is produced using the first phase results. In the last phase, the PSO is employed to find the optimum design using the optimal initial swarm. The numerical results demonstrate the high performance of the proposed strategy for optimal design of arch dams. The solutions obtained by the SPSA-PSO are compared with those of SPSA and PSO. It is revealed that the SPSA-PSO converges to a superior solution compared to the SPSA and PSO having a lower computation cost.
-
optimal design of structures for Earthquake Loading by self organizing radial basis function neural networks
Advances in Structural Engineering, 2010Co-Authors: S Gholizadeh, E SalajeghehAbstract:In order to efficiently find the optimal design of structures subjected to Earthquake Loading two strategies are adopted. In the first strategy, a neural system consisting of self organizing map (SOM) and radial basis function (RBF) neural networks is employed to predict the time history responses of structures. The neural system is termed as self organizing radial basis function (SORBF) networks. To train SORBF, the input-output samples are classified by employing SOM clustering, and then an RBF neural network is trained for each cluster by using the data located. In the second strategy, an improved genetic algorithm, the so-called virtual subpopulation (VSP), is employed to find the optimum design. To improve the performance generality of the SORBF, a VSP based optimal approach is employed. Two structures are designed for optimal weight using exact and approximate time history analyses. The numerical results demonstrate the efficiency and computational advantages of the proposed methodology.
-
optimum shape design of arch dams for Earthquake Loading using a fuzzy inference system and wavelet neural networks
Engineering Optimization, 2009Co-Authors: S M Seyedpoor, E Salajegheh, J Salajegheh, S GholizadehAbstract:An efficient methodology is proposed to find the optimum shape of arch dams considering fluid-structure interaction subject to Earthquake Loading. The Earthquake load is considered by time variant ground acceleration applied in the upstream–downstream direction of the arch dam. The optimization is carried out by particle swarm optimization, employing real values of design variables. To reduce the computational cost of the optimization process, two strategies are adopted. In the first strategy, the most influential design variables on arch-dam response from original variables are selected using an adaptive neuro-fuzzy inference system. In the second, arch-dam response is predicted by a properly trained wavelet radial basis function neural network employing the influential design variables as the inputs. In order to assess the effectiveness of the suggested methodology, a real arch dam is considered as a test example. The numerical results demonstrate the computational advantages of the proposed methodology...
Franz D Fisher - One of the best experts on this subject based on the ideXlab platform.
-
storage tanks under Earthquake Loading
Applied Mechanics Reviews, 1990Co-Authors: F G Rammerstorfer, Knut Scharf, Franz D FisherAbstract:This is a state-of-the-art review of various treatments of Earthquake loaded liquid filled shells by the methods of Earthquake engineering, fluid dynamics, structural and soil dynamics, as well as the theory of stability and computational mechanics. Different types of tanks and different possibilities of tank failure will be discussed. The authors will emphasize cylindrical above-ground liquid storage tanks with vertical axis. But many of the treatments are also valid for other tank configurations. For the calculation of the dynamically activated pressure due to an Earthquake a fluid-structure-soil interaction problem must be solved. The review will describe the methods, proposed by different authors, to solve this interaction problem. To study the dynamic behavior of liquid storage tanks, one must distinguish between anchored and unanchored tanks. In the case of an anchored tank, the tank bottom edge is fixed to the foundation. If the tank is unanchored, partial lifting of the tank's bottom may occur, and a strongly nonlinear problem has to be solved. They will compare the various analytical and numerical models applicable to this problem, in combination with experimental data. An essential aim of this review is to give a summary of methods applicable as tools for an Earthquake resistantmore » design, which can be used by an engineer engaged in the construction of liquid storage tanks.« less
Fatma Y Kocer - One of the best experts on this subject based on the ideXlab platform.
-
optimal design of latticed towers subjected to Earthquake Loading
Journal of Structural Engineering-asce, 2002Co-Authors: Fatma Y Kocer, Jasbir S AroraAbstract:The problem of optimal design of latticed transmission towers subjected to normal operating loads and an Earthquake load is formulated. A time history analysis of the structure is performed. The constraints given in a design code are imposed. Many of the constraints are time dependent; therefore methods to treat them are incorporated in the solution process. All members are treated as equal- ~unequal-! legged angle sections. The members are selected from the sections available in a manufacturer's catalog. Two methods are presented and evaluated for such discrete variable optimization problems. The first method, called the two-phase method, uses a combi- nation of continuous and discrete optimization algorithms, and the second one, called an adaptive discrete assignment method ~ADAM!, uses only a continuous optimization algorithm. The proposed methods are applicable to any discrete variable problem that can be formulated as a continuous problem. In addition, the problem is solved using a genetic algorithm ~GA!. The efficiency and practicality of the proposed methods are compared to those of the GA. From the results, it is concluded that the GA is a very straightforward method to use for discrete problems; however, it requires a significant amount of Central Processing Unit time. On the other hand, the two-phase method and the ADAM do not require as much computational effort but the discrete designs found with them are slightly more expensive. Also, numerical implementation of the two methods requires more effort.
-
optimal design of h frame transmission poles for Earthquake Loading
Journal of Structural Engineering-asce, 1999Co-Authors: Fatma Y Kocer, Jasbir S AroraAbstract:The design of H-frame transmission poles subjected to static and dynamic loads (Earthquake load) is formulated as an optimization problem. Time history analysis, discrete design variables, and optimization algorithms are integrated to solve the problem. With time history analysis, structural nonlinearity can be incorporated in the formulation; however, stress constraints based on ASCE design force the final design to remain elastic. Two cost functions are defined: Material cost and total initial cost. A method to treat time-dependent constraints is selected for use with two discrete variable optimization methods: Simulated annealing and genetic algorithm. A simple penalty function is defined to account for constraints in the algorithms. Several solution cases are defined and solved. Results show the genetic algorithm to be superior to simulated annealing. Both algorithms are quite simple and appropriate to solve discrete variable problems. Computational times with the methods are quite large because many ...
S M Seyedpoor - One of the best experts on this subject based on the ideXlab platform.
-
optimal design of arch dams subjected to Earthquake Loading by a combination of simultaneous perturbation stochastic approximation and particle swarm algorithms
Applied Soft Computing, 2011Co-Authors: S M Seyedpoor, E Salajegheh, J Salajegheh, S GholizadehAbstract:An efficient optimization procedure is introduced to find the optimal shapes of arch dams considering fluid-structure interaction subject to Earthquake Loading. The optimization is performed by a combination of simultaneous perturbation stochastic approximation (SPSA) and particle swarm optimization (PSO) algorithms. This serial integration of the two single methods is termed as SPSA-PSO. The operation of SPSA-PSO includes three phases. In the first phase, a preliminary optimization is accomplished using the SPSA. In the second phase, an optimal initial swarm is produced using the first phase results. In the last phase, the PSO is employed to find the optimum design using the optimal initial swarm. The numerical results demonstrate the high performance of the proposed strategy for optimal design of arch dams. The solutions obtained by the SPSA-PSO are compared with those of SPSA and PSO. It is revealed that the SPSA-PSO converges to a superior solution compared to the SPSA and PSO having a lower computation cost.
-
optimum shape design of arch dams for Earthquake Loading using a fuzzy inference system and wavelet neural networks
Engineering Optimization, 2009Co-Authors: S M Seyedpoor, E Salajegheh, J Salajegheh, S GholizadehAbstract:An efficient methodology is proposed to find the optimum shape of arch dams considering fluid-structure interaction subject to Earthquake Loading. The Earthquake load is considered by time variant ground acceleration applied in the upstream–downstream direction of the arch dam. The optimization is carried out by particle swarm optimization, employing real values of design variables. To reduce the computational cost of the optimization process, two strategies are adopted. In the first strategy, the most influential design variables on arch-dam response from original variables are selected using an adaptive neuro-fuzzy inference system. In the second, arch-dam response is predicted by a properly trained wavelet radial basis function neural network employing the influential design variables as the inputs. In order to assess the effectiveness of the suggested methodology, a real arch dam is considered as a test example. The numerical results demonstrate the computational advantages of the proposed methodology...
-
adaptive neuro fuzzy inference system for high speed computing in optimal shape design of arch dams subjected to Earthquake Loading
Mechanics Based Design of Structures and Machines, 2009Co-Authors: S M Seyedpoor, J SalajeghehAbstract:An efficient methodology is proposed to find optimal shapes of arch dams, including fluid-structure interaction for Earthquake Loading. The optimization is implemented using a particle swarm optimization (PSO). In order to reduce the computational cost of the optimization process, an adaptive neuro-fuzzy inference system (ANFIS) is utilized to predict the arch dam response instead of directly evaluating it by a time-consuming finite element analysis (FEA). The presented ANFIS is compared with a back-propagation neural network (BPNN) and appears to have better performance. Test example results demonstrate the computational advantages of the proposed method for the optimal design of arch dams when compared with those of obtained through FEA.
