Comparison of four meta-heuristic algorithms for optimal design of double-layer barrel vaults

2018 ◽  
Vol 33 (3-4) ◽  
pp. 115-123
Author(s):  
Ali Kaveh ◽  
Majid Ilchi Ghazaan ◽  
Soroush Mahjoubi
Keyword(s):  
Optimal Design ◽  
Double Layer ◽  
Heuristic Algorithms ◽  
Size Optimization ◽  
Community Centers ◽  
Cross Sectional ◽  
Long Span ◽  
Design Variables ◽  
Rail Station ◽  
Barrel Vaults

Barrel vaults are effective semi-cylindrical forms of roof systems that are widespread for multipurpose facilities including warehouse, rail station, pools, sports center, airplane hungers, and community centers because of providing long-span and economical roof with significant amount of space underneath. In the present study, size optimization of double-layer barrel vaults with different configurations is studied. Four recently developed algorithms consisting of the CBO, ECBO, VPS, and MDVC-UVPS are employed and their performances are compared. The structures are subjected to stress, stability, and displacement limitations according to the provisions of AISC-ASD. The design variables are the cross-sectional areas of the bar elements which are selected from steel pipe sections. The numerical results indicate that the MDVC-UVPS outperforms the other algorithms in finding optimal design in all examples.

scholarly journals Prediction of Optimal Design and Deflection of Space Structures Using Neural Networks

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Reza Kamyab Moghadas ◽  
Kok Keong Choong ◽  
Sabarudin Bin Mohd
Keyword(s):  
Neural Networks ◽  
Optimal Design ◽  
Double Layer ◽  
Optimization Problem ◽  
Computational Cost ◽  
Space Structures ◽  
Maximum Deflection ◽  
Cross Sectional ◽  
Design Variables ◽  
Low Computational Cost

The main aim of the present work is to determine the optimal design and maximum deflection of double layer grids spending low computational cost using neural networks. The design variables of the optimization problem are cross-sectional area of the elements as well as the length of the span and height of the structures. In this paper, a number of double layer grids with various random values of length and height are selected and optimized by simultaneous perturbation stochastic approximation algorithm. Then, radial basis function (RBF) and generalized regression (GR) neural networks are trained to predict the optimal design and maximum deflection of the structures. The numerical results demonstrate the efficiency of the proposed methodology.

Optimal design of nonlinear large-scale suspendome using cascade optimization

2017 ◽  
Vol 33 (1) ◽  
pp. 3-18 ◽  
Author(s):  
Ali Kaveh ◽  
Masoud Rezaei ◽  
MR Shiravand
Keyword(s):  
Optimal Design ◽  
Large Scale ◽  
Simple Procedure ◽  
Geometry Optimization ◽  
Steel Structures ◽  
Optimization Method ◽  
Scale Space ◽  
Cross Sectional ◽  
Colliding Bodies Optimization ◽  
Design Variables

Large-scale suspendomes are elegant architectural structures which cover a vast area with no interrupting columns in the middle. These domes have attractive shapes which are also economical. Domes are built in a wide variety of forms. In this article, an algorithm is developed for optimum design of domes considering the topology, geometry, and size of member section using the cascade-enhanced colliding bodies optimization method. In large-scale space steel structures, a large number of design variables are involved. The idea of cascade optimization allows a single optimization problem to be tackled in a number of successive autonomous optimization stages. The variables are the optimum height of crown and tubular sections of these domes, the initial strain, the length of the struts, and the cross-sectional areas of the cables in the tensegrity system of domes. The number of joints in each ring and the number of rings are considered for topology optimization of ribbed and Schwedler domes. Weight of the dome is taken as the objective function for minimization. A simple procedure is defined to determine the configuration of the domes. The design constraints are considered according to the provisions of Load and Resistance Factor Design–American Institute of Steel Constitution. In order to investigate the efficiency of the presented method, a large-scale suspendome with more than 2266 members is investigated. Numerical results show that the utilized method is an efficient tool for optimal design of large-scale domes. Additionally, in this article, a topology and geometry optimization for two common ribbed and Schwedler domes are performed to find their optimum graphs considering various spans.

Optimal design of double layer barrel vaults considering nonlinear behavior

2016 ◽  
Vol 58 (6) ◽  
pp. 1109-1126 ◽  
Author(s):  
Saeed Gholizadeh ◽  
Changiz Gheyratmand ◽  
Hamed Davoudi
Keyword(s):  
Optimal Design ◽  
Double Layer ◽  
Nonlinear Behavior ◽  
Barrel Vaults

Shape Optimal Design of Elastic Planar Frames With Elastic and Skew-Sliding Supports

1997 ◽  
Author(s):  
M. M. Oblak ◽  
M. Kegl ◽  
D. Dinevski
Keyword(s):  
Optimal Design ◽  
Linear Response ◽  
Frame Structure ◽  
Design Element ◽  
Cross Sectional ◽  
Design Elements ◽  
Beam Elements ◽  
Design Variables ◽  
Planar Frames ◽  
Gradient Based

Abstract This paper describes an approach to shape optimal design of elastic, statically loaded, planar frames with kinematically non-linear response where special attention is focused on consideration of elastic and skew-sliding supports. A frame structure is treated as to be assembled from several design elements each of them being defined as a Bézier curve. The design variables may influence the position and the shape of each design element, the cross-sectional properties of beam elements, the elastic properties of the supports as well as the angles of inclination of sliding supports. Highly accurate, locking-free and initially curved beam elements are employed to ensure accurate and reliable results. The optimal design problem is defined in a general form and its solution, by employing gradient based methods of mathematical programming, is discussed briefly. The theory is illustrated with a numerical example.

Shape Optimization of a Double-Layer Space Truss Described by a Parametric Surface

1997 ◽  
Vol 12 (2) ◽  
pp. 109-119 ◽  
Author(s):  
M. Ohsaki ◽  
Tsuneyoshi Nakamura ◽  
M. Kohiyama
Keyword(s):  
Double Layer ◽  
Layer Surface ◽  
Optimal Solutions ◽  
Parametric Surface ◽  
Cross Sectional ◽  
Space Truss ◽  
Design Variables ◽  
Lattice Space ◽  
Control Net ◽  
Structural Volume

A method is presented for finding the optimal configuration of a double-layer space truss described by a parametric surface. The number of design variables is drastically reduced, without sacrificing the smoothness of the upper layer surface, by using the control net parameters as design variables. The coordinates of the lower nodes are defined by using a vertical or normal offset vectors from the upper surface. Curvatures of the curve associated with the lower polygon are calculated for evaluating feasibility and regularity of the a double-layer lattice space truss. In the examples, a feasible optimum design, which minimizes compliance under constraints on structural volume, are successfully found by using the proposed method. It is shown that the optimal solutions strongly depend on the specified ratios of the cross-sectional areas of the members.

scholarly journals Size and Shape Optimization of Space Trusses Considering Geometrical Imperfection-Sensitivity in Buckling Constraints

2018 ◽  
Vol 3 (12) ◽  
pp. 1314 ◽  
Author(s):  
Fardad Haghpanah ◽  
Hamid Foroughi
Keyword(s):  
Optimal Design ◽  
Structural Engineering ◽  
Real Life ◽  
Imperfection Sensitivity ◽  
Cross Sectional ◽  
Design Variables ◽  
Geometrical Imperfection ◽  
Discrete Design Variables ◽  
Teaching Learning ◽  
Space Trusses

Optimal design considering buckling of compressive members is an important subject in structural engineering. The strength of compressive members can be compensated by initial geometrical imperfection due to the manufacturing process; therefore, geometrical imperfection can affect the optimal design of structures. In this study, the metaheuristic teaching-learning-based-optimization (TLBO) algorithm is applied to study the geometrical imperfection-sensitivity of members’ buckling in the optimal design of space trusses. Three benchmark trusses and a real-life bridge with continuous and discrete design variables are considered, and the results of optimization are compared for different degrees of imperfection, namely 0.001, 0.002, and 0.003. The design variables are the cross-sectional areas, and the objective is to minimize the total weight of the structures under the following constraints: tensile and compressive yielding stress, Euler buckling stress considering imperfection, nodal displacement, and available cross-sectional areas. The results reveal that higher geometrical imperfection degrees significantly change the critical buckling load of compressive members, and consequently, increase the weight of the optimal design. This increase varies from 0.4 to 119% for different degrees of imperfection in the studied trusses.

scholarly journals Optimization Of Double-Layer Braced Barrel Vaults

2015 ◽  
Vol 15 (2) ◽  
Author(s):  
Maksym Grzywiński
Keyword(s):  
Double Layer ◽  
Discrete Optimization ◽  
Optimization Problem ◽  
Limit State ◽  
Discrete Optimization Problem ◽  
Cross Sectional ◽  
Optimization Constraints ◽  
Space Design ◽  
Design Variables ◽  
Structural Space

Abstract The paper deals with discussion of discrete optimization problem in civil engineering structural space design. Minimization of mass should satisfy the limit state capacity and serviceability conditions. The cross-sectional areas of truss bars are taken as design variables. Optimization constraints concern stresses, displacements and stability, as well as technological and computational requirements.

Optimal Design for Prestressed Structures Based on Continuous and Discrete Variables

2011 ◽  
Vol 243-249 ◽  
pp. 1003-1007
Author(s):  
Yong Hua Yang ◽  
Jie Wu
Keyword(s):  
Optimal Design ◽  
Search Algorithm ◽  
Relative Difference ◽  
Continuous Variable ◽  
Difference Quotient ◽  
Cross Sectional ◽  
Design Variables ◽  
Continuous And Discrete Variables ◽  
The Mathematical Model ◽  
Prestressed Structures

The mathematical model of optimal design for prestressed structures is established and a two-level algorithm based on hybrid variables is proposed. At the first level, the prestressed forces are chosen to be the design variables and the optimal design for prestressed forces based on continuous variable is carried out. At the second level, the cross-sectional areas are chosen to be the design variables and the discrete sizing optimization is carried out under fixed prestressed forces, the local constrains are satisfied with one-dimensional search algorithm, the integral constrains are satisfied with the relative difference quotient algorithm, and the efficiency of the relative difference quotient algorithm is greatly improved by introducing the assumption of statically determinant structures. The numerical example shows the correctness and effectiveness of the method.

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