scholarly journals Wind load effect in topology optimization problems

2007 ◽  
Vol 75 ◽  
pp. 012048 ◽  
Author(s):  
R Zakhama ◽  
M M Abdalla ◽  
Z Gürdal ◽  
H Smaoui
Keyword(s):  
Topology Optimization ◽  
Optimization Problems ◽  
Wind Load ◽  
Load Effect

Finding Better Local Optima in Topology Optimization via Tunneling

2018 ◽  
Author(s):  
Shanglong Zhang ◽  
Julián A. Norato
Keyword(s):  
Topology Optimization ◽  
Optimization Problems ◽  
Structural Response ◽  
Free Form ◽  
Local Optima ◽  
Design Representation ◽  
Tunneling Method ◽  
Optimization Parameters ◽  
Gradient Based ◽  
Geometric Primitives

Topology optimization problems are typically non-convex, and as such, multiple local minima exist. Depending on the initial design, the type of optimization algorithm and the optimization parameters, gradient-based optimizers converge to one of those minima. Unfortunately, these minima can be highly suboptimal, particularly when the structural response is very non-linear or when multiple constraints are present. This issue is more pronounced in the topology optimization of geometric primitives, because the design representation is more compact and restricted than in free-form topology optimization. In this paper, we investigate the use of tunneling in topology optimization to move from a poor local minimum to a better one. The tunneling method used in this work is a gradient-based deterministic method that finds a better minimum than the previous one in a sequential manner. We demonstrate this approach via numerical examples and show that the coupling of the tunneling method with topology optimization leads to better designs.

scholarly journals A stochastic approach for the wind load effect on steel structures

2016 ◽  
Vol 69 (2) ◽  
pp. 137-145 ◽  
Author(s):  
Thiago Dias dos Santos ◽  
Gustavo Henrique Siqueira ◽  
Luiz Carlos Marcos Vieira Junior
Keyword(s):  
Steel Structures ◽  
Stochastic Approach ◽  
Wind Load ◽  
Load Effect

Topology Optimization Considering Gravitational and Centrifugal Forces

2006 ◽  
Author(s):  
Bin Zheng ◽  
Hae Chang Gea
Keyword(s):  
Topology Optimization ◽  
Kinetic Energy ◽  
Structural Design ◽  
Gravitational Force ◽  
Body Force ◽  
Optimization Problems ◽  
Sensitivity Analyses ◽  
Centrifugal Forces ◽  
Gravitational Forces ◽  
Mean Compliance

In this paper, topology optimization problems with two types of body force are considered: gravitational force and centrifugal force. For structural design under both external and gravitational forces, a total mean compliance formulation is used to produce the stiffest structure. For rotational structural design with high angular velocity, one additional design criteria, kinetic energy, is included in the formulation. Sensitivity analyses of the total mean compliance and kinetic energy are derived. Finally, design examples are presented and compared to show the effects of body forces on the optimized results.

Solving Topology Optimization Problems Using Wavelet Approximations

1998 ◽  
Author(s):  
Giuseppe C. A. DeRose ◽  
Alejandro R. Díaz
Keyword(s):  
Finite Element ◽  
Topology Optimization ◽  
Finite Element Methods ◽  
Condition Number ◽  
Optimization Problems ◽  
Mesh Size ◽  
Elasticity Problem ◽  
New Method ◽  
Galerkin Scheme

Abstract A new method to solve topology optimization problems is discussed. This method is based on the use of a Wavelet-Galerkin scheme to solve the elasticity problem associated with each iteration of the topology optimization sequence. Typically, finite element methods are used for this analysis. However, as the mesh size grows, the computational requirements necessary to solve the finite element equations increase beyond the capacity of current desk top computers. This problem is inherent to finite element methods, as the condition number of finite element matrices increases with mesh size. Wavelet-Galerkin techniques are used to replace standard finite element methods in an attempt to alleviate this problem. Examples demonstrating the performance of the new methodology are presented.

Determination of Basic Wind Velocity for Wind Load-Governed Limit State

2019 ◽  
Author(s):  
Ji Hyeon Kim ◽  
Hae-Sung Lee
Keyword(s):  
Wind Velocity ◽  
Reliability Index ◽  
General Procedure ◽  
Limit State ◽  
Wind Load ◽  
Wind Pressure ◽  
Load Factor ◽  
Load Effect ◽  
Design Life ◽  
Target Reliability Index

<p>This paper proposes a general procedure for evaluating a nominal value of wind velocity for a wind load- governed limit state to secure a target reliability index during the design life of a structure. The nominal value of wind velocity, referred to as a basic wind velocity, and wind load factor should be determined so that the factored wind load effect secures a target reliability index for a wind load-governed limit state. In this study, the analytical form of the return period of the basic wind velocity is expressed as a function of the target reliability index, wind load factor, and statistical parameters of wind pressure, which are derived as linear functions of the coefficient of wind velocity. The proposed approach is applied to the Korean Highway Bridge Design Code-Cable supported Bridge, which specifies the design life of a structure as 100- and 200-year.</p>

A NEW ELEMENT-BASED METHOD FOR SOLVING STRUCTURAL TOPOLOGY OPTIMIZATION PROBLEMS WITH NON-UNIFORM MESHES

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kuang-Wu Chou ◽  
Chang-Wei Huang
Keyword(s):  
Topology Optimization ◽  
Optimization Problems ◽  
Optimization Method ◽  
Optimal Topology ◽  
Evolutionary Stage ◽  
Structural Topology Optimization ◽  
Volume Constraint ◽  
Structural Topology ◽  
Exchange Method ◽  
Python Scripting

This study proposes a new element-based method to solve structural topology optimization problems with non-uniform meshes. The objective function is to minimize the compliance of a structure, subject to a volume constraint. For a structure of a fixed volume, the method is intended to find a topology that could almost conform to the compliance minimum. The method is refined from the evolutionary switching method, whose policy of exchanging elements is improved by replacing some empirical decisions with ones according to optimization theories. The method has the evolutionary stage and the element exchange stage to conduct topology optimization. The evolutionary stage uses the evolutionary structural optimization method to remove inefficient elements until the volume constraint is satisfied. The element exchange stage performs a procedure refined from the element exchange method. Notably, the procedures of both stages are refined to conduct non-uniform finite element meshes. The proposed method was implemented to use the Abaqus Python scripting interface to call the services of Abaqus such as running analysis and retrieving the output database of an analysis. Numerical examples demonstrate that the proposed optimization method could determine the optimal topology of a structure that is subject to a volume constraint and whose mesh is non-uniform.

scholarly journals Component Combination Rules of Wind Load Effects of Building Structures

2020 ◽  
Vol 10 (24) ◽  
pp. 8775
Author(s):  
Haiwei Guan ◽  
Yuji Tian
Keyword(s):  
Extreme Values ◽  
Simulation Method ◽  
Wind Load ◽  
Combination Method ◽  
Wind Effect ◽  
Building Structures ◽  
Combination Rules ◽  
Load Effect ◽  
Mean Values ◽  
Standard Deviations

Under the action of the same wind azimuth, the extreme values of the wind load effect components of building structures are generated in the along-wind, cross-wind, vertical, and torsional directions. In designing the wind-resistant structure, the extreme values of effect components need to be combined to determine the internal force envelope values of members. Complete quadratic combination (CQC) and Turkstra combination rules are often used to determine the combination value of extreme values of wind effect components. The extreme probability distribution expressions of the CQC, and the Turkstra and approximate rules, are derived. The simplified combination Equations and combination coefficients of the CQC and Turkstra approximate rules are proposed in this paper. We use the combination Equations and Monte Carlo simulation method to analyze the accuracy of Turkstra and its approximate rules. The results show that the combination extreme is associated with the correlation coefficients, mean values, ratios of standard deviations, and fluctuating extremes of effect components. The errors between Turkstra and its approximate rules are small when load effect components show a positive correlation. The errors are largest when the standard deviations of components are equal. Our research results provide a theoretical basis for the combination method of wind load effect components of building structures.

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