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Topology optimization for the seismic design of truss-like structures
, Article Computers and Structures ; Volume 89, Issue 7-8 , April , 2011 , Pages 702-711 ; 00457949 (ISSN) ; Pilakoutas, K ; Moghaddam, H ; Sharif University of Technology
2011
Abstract
A practical optimization method is applied to design nonlinear truss-like structures subjected to seismic excitation. To achieve minimum weight design, inefficient material is gradually shifted from strong parts to weak parts of a structure until a state of uniform deformation prevails. By considering different truss structures, effects of seismic excitation, target ductility and buckling of the compression members on optimum topology are investigated. It is shown that the proposed method could lead to 60% less structural weight compared to optimization methods based on elastic behavior and equivalent static loads, and is efficient at controlling performance parameters under a design...
Tolerance Analysis and Dimensional Error Propagation in Truss Structures
, M.Sc. Thesis Sharif University of Technology ; Movahhedy, Mohammad Reza (Supervisor)
Abstract
An analytical method is developed for description of the assembly process and dimensional error propagation in planar truss structures using two core concepts of “triangular unit cell” and “redundant member”.In order to clarify backbone of the developed method, its connections with other studies in the fields of tolerance analysis, robust design and structural optimization are discussed.Subsequently, triangular unit cell is defined as the basic element of internally determinate trusses and a suitable formulation is derived for calculating its dimensional error propagations characteristics.It is shown that having such a model for a single unit cell is sufficient for tolerance analysis of the...
Discrete optimum design of truss structures by an improved firefly algorithm
, Article Advances in Structural Engineering ; Vol. 17, issue. 10 , 2014 , p. 1517-1530 ; Makiabadi, M ; Sarcheshmehpour, M ; Sharif University of Technology
Abstract
This paper presents an improved firefly algorithm (FA) for fast optimization of truss structures with discrete variables. The enhanced accelerated firefly algorithm (AFA) is a simple, but very effective modification of FA. In order to investigate the performance and robustness of the proposed algorithm, some benchmark (structural optimization) problems are solved and the results are compared with FA and other algorithms. The results show that in some test cases, AFA not only finds lighter structures compared to other algorithms, but also converges faster. In the rest test cases, the optimal solutions are found with very less computational effort. The study also shows that the proposed AFA...
Application and Comparison of Modern Optimization Methods for Optimal Seismic Design of Trusses under Base Excitation
, M.Sc. Thesis Sharif University of Technology ; Joghatayi, Abdolreza (Supervisor)
Abstract
Taking into consideration of optimization methods has been increased recently. Optimization methods in engineering that consumes a lot of time and cost have been developed. Optimal design of structures is a matter that grabbed the attention of civil engineers and due to the deficiency of classical methods the modern approaches are being developed. One of the most important structures that are constructed for industrial and transportation purposes are truss structures.Structural control under support excitation is constraining the structure to some structural limitations. The final target in this paper is to apply the modern methods to get the optimal weight of structure under seismic loads....
The Assessment of Irregular Mid-Rise Steel Structures with Outriggers
, M.Sc. Thesis Sharif University of Technology ; Mofid, Masood (Supervisor)
Abstract
The system considered on this structure is for the design on mid-high Buildings from 15 and 20 floors above the base level and n floors below the base level and the limitation of the number of floors is due to the computer facility and restrictions. There is going to be an irregularity in some chosen floor at lower-floor, mid-floor, or upper-floor which is assuming one floor from the structure to have a different height with respect to the others. The height of the considered floor is going to increase up to 25% with respect to the other floors and the design of outriggers with these three assumptions is going to be assessed separately. In this system, a central core of steel is constructed...
Optimal design of truss structures with frequency constraints: a comparative study of DE, IDE, LSHADE, and CMAES algorithms
, Article Engineering with Computers ; 2021 ; 01770667 (ISSN) ; Mesbahi, P ; Moosavian, N ; Daliri, H ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
The present study examines the performance of three powerful methods including the original differential evolution (DE), the improved differential evolution (IDE), and the winner of the CEC-2014 competition, LSHADE, in addition to the covariance matrix adaptation evolution strategy (CMAES) for size optimization of truss structures under natural frequency constraints. Despite the abundant researches on novel meta-heuristic algorithms in the literature, the application of CMAES, one of the most powerful and reliable optimization algorithms, on the optimal solution of the truss structures has received scant attention. For consistent comparison between these algorithms, four stopping criteria...