Environmental considerations for structural design of flat plate buildings – Significance of and interrelation between different design variables

2021 ◽  
pp. 128123
Author(s):  
Hoang Tran Mai Kim Trinh ◽  
Sanaul Chowdhury ◽  
Jeung-Hwan Doh ◽  
Tingting Liu
Keyword(s):  
Flat Plate ◽  
Structural Design ◽  
Design Variables ◽  
Environmental Considerations

Strength Model Uncertainties of Burst, Yielding, and Excessive Bending of Piping

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Kleio Avrithi ◽  
Bilal M. Ayyub
Keyword(s):  
Structural Design ◽  
Design Method ◽  
Strength Model ◽  
Allowable Stress ◽  
Model Uncertainties ◽  
Reliability Based Design ◽  
Design Variables ◽  
Strength Models ◽  
Potential Use ◽  
Allowable Stress Design

Nuclear safety-piping is designed according to the ASME Boiler and Pressure Vessel Code, Sections III, NB-, NC-, and ND-3600 that use the allowable stress design method (ASD). The potential use instead of reliability-based design equations for nuclear piping could benefit the structural design by providing, among others, consistent reliability levels for piping. For the development of such equations, not only the probabilistic characteristics of the design variables are needed, but also the quantification of the uncertainties introduced by the strength models that are used in order to estimate the resistance of pipes subjected to different loadings. This paper evaluates strength models, and therefore provides necessary information for the reliability-based design of pipes for burst or yielding due to internal pressure and for excessive bending.

Smart Optimization of Machine Systems Using Hierarchical Genotype Representations

1999 ◽  
Author(s):  
Masataka Yoshimura ◽  
Kazuhiro Izui
Keyword(s):  
Structural Design ◽  
Hierarchical Structures ◽  
Optimization Methods ◽  
Optimization Method ◽  
Design Problems ◽  
Design Variables ◽  
The Hierarchical Structure ◽  
Machine Systems ◽  
System Designs ◽  
Crossover And Mutation

Abstract Design problems for machine products are generally hierarchically expressed. With conventional product optimization methods, it is difficult to concurrently optimize all design variables of portions within the hierarchical structure. This paper proposes a design optimization method using genetic algorithms containing hierarchical genotype representations, so that the hierarchical structures of machine system designs are exactly expressed through genotype coding, and optimization can be concurrently conducted for all of the hierarchical structures. Crossover and mutation operations for manipulating the hierarchical genotype representations are also developed. The proposed method is applied to a machine-tool structural design to demonstrate its effectiveness.

Parametric Optimization for Structural Design Problems

2019 ◽  
Author(s):  
Krupakaran Ravichandran ◽  
Nafiseh Masoudi ◽  
Georges M. Fadel ◽  
Margaret M. Wiecek
Keyword(s):  
Structural Design ◽  
Optimization Problem ◽  
Parametric Optimization ◽  
Optimization Problems ◽  
Nonlinear Constraint ◽  
Computational Performance ◽  
Design Variables ◽  
Input Parameters ◽  
Parametric Optimization Problem ◽  
Objective Function Values

Abstract Parametric Optimization is used to solve problems that have certain design variables as implicit functions of some independent input parameters. The optimal solutions and optimal objective function values are provided as functions of the input parameters for the entire parameter space of interest. Since exact solutions are available merely for parametric optimization problems that are linear or convex-quadratic, general non-convex non-linear problems require approximations. In the present work, we apply three parametric optimization algorithms to solve a case study of a benchmark structural design problem. The algorithms first approximate the nonlinear constraint(s) and then solve the optimization problem. The accuracy of their results and their computational performance are then compared to identify a suitable algorithm for structural design applications. Using the identified method, sizing optimization of a truss structure for varying load conditions such as a varying load direction is considered and solved as a parametric optimization problem to evaluate the performance of the identified algorithm. The results are also compared with non-parametric optimization to assess the accuracy of the solution and computational performance of the two methods.

Set-Based Design Method for the Early Phase Design of Structures With Uncertainties

2010 ◽  
Author(s):  
Masato Inoue ◽  
Yutaka Hattori ◽  
Haruo Ishikawa
Keyword(s):  
Structural Design ◽  
Early Phase ◽  
Design Method ◽  
Analysis Tool ◽  
Design Variables ◽  
Point Solution ◽  
Design Solutions ◽  
Set Based Design ◽  
Express Information ◽  
Analyze Structure

Since an early phase of design intrinsically contains uncertainties from various sources of variations, design performances are fluctuating or reflect uncertainty caused by uncertain design variables. Analysis tool such as finite element method (FEM) is useful for structural analysis. However, using unique point solution does not express information about uncertainties. Designers need to figure out an outline of the structural feature and have to obtain a design idea under some uncertain design information in a structural design at the early phase of design. We have proposed a preference set-based design (PSD) method that generates a ranged set of design solutions that satisfy sets of performance requirements. This study proposes a structural design method for the early phase of design based on the PSD method that is possible to analyze structure with design uncertainty by elastic FEM and obtain a ranged set of design solutions. That is, a design method for analyzing structures and obtaining a ranged set of design solutions with uncertainties of material property and dimension of structure (coordinates of geometry) under fluctuating distribution of performance characteristics of stress and displacement is proposed. In order to illustrate the availability of our approach, design problem of 3-dimensional truss structure is solved.

scholarly journals Modelling and Structural Design for Parallel Umbrella-Shaped Cable-Strut Structures Based on Stationary Potential Energy Principles

2019 ◽  
Vol 2019 ◽  
pp. 1-24 ◽  
Author(s):  
Mingmin Ding ◽  
Bin Luo ◽  
Lifeng Han ◽  
Qianhao Shi
Keyword(s):  
Potential Energy ◽  
Structural Design ◽  
Local Deformation ◽  
Calculation Model ◽  
Total Weight ◽  
Stationary Potential ◽  
Design Variables ◽  
Static Responses ◽  
Height Increase ◽  
Simplified Calculation

A method for the modelling and structural design of a parallel umbrella-shaped cable-strut structure (PUSC) is presented. First, simplified calculation models of a PUSC are built. Next, based on the principle of stationary potential energy, the relationships among the cable sectional areas, prestress forces, vector height, sag height, overall displacement, and local deformation are proposed. Then, the static responses of the PUSC under vertical loads and wind loads are put forward. Finally, a calculation model of a 100 m-span PUSC is developed and optimized to verify the feasibility of the proposed method. The results show that when the combinations of the loading, variation ranges of the vector height and sag height, and material properties of the components are given, the sectional areas of the cables, dimensions of the inner strut, and prestress forces of these components can be obtained. A greater external load requires a corresponding increase in vector height and sag height to increase the overall stiffness, leading to larger sectional dimensions of the components and a greater prestress of the entire structure. Therefore, the total weight of the cables and inner struts are determined. Moreover, because the weight of the cables decreases and the weight of the inner struts increases as the vector height and sag height increase, the total weight of the cables and struts decreases sharply during the initial stage, decreases gradually during the second stage, and increases slowly during the last stage after reaching the minimum value. For the optimal design of the calculation model, using the vector height and sag height as design variables provides an adequate geometric stiffness and a suitable prestress for the PUSC to fulfill the requirements of all the loading combinations.

Optimum Structural Design of Naval Vessels

2003 ◽  
Vol 40 (03) ◽  
pp. 149-157
Author(s):  
Seo Seung II ◽  
Son Keon Ho ◽  
Park Myung Kyu
Keyword(s):  
Structural Analysis ◽  
Structural Design ◽  
Design Method ◽  
Design Standards ◽  
Naval Vessel ◽  
Main Design ◽  
Optimum Structural Design ◽  
Design Variables ◽  
Analysis Theory ◽  
The U.S

Naval vessels are not regulated by class rules, but by special regulations. This study introduces the concept and characteristics of the regulations of the U.S. Navy, which has been the most reliable in setting design standards of naval vessels and helps designers comprehend the effect of each regulation on design results. Also, an optimum structural design method combined with structural analysis theory is proposed for an actual naval vessel to be designed according to U.S. Navy regulations. The validity of the proposed method is shown by the optimum design results for the midship section. The optimum spacings of longitudinal and transverse web frames are found, and the effect of the main design variables is investigated.

scholarly journals Dividing-Wall Column Design: Analysis of Methodologies Tailored to Process Simulators

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1189
Author(s):  
Gloria A. Buitimea-Cerón ◽  
Juergen Hahn ◽  
Nancy Medina-Herrera ◽  
Arturo Jiménez-Gutiérrez ◽  
José A. Loredo-Medrano ◽  
...  
Keyword(s):  
Case Studies ◽  
Structural Design ◽  
Design Procedure ◽  
The Other ◽  
Preliminary Design ◽  
Dividing Wall Column ◽  
Operating Variables ◽  
Design Variables ◽  
Column Design ◽  
Proposed Modification

Dividing-wall columns (DWCs) are intensified processes that have attracted industrial and academic attention due to the reduction in operating and installation costs compared to traditional distillation systems. Several methodologies are available for the design of DWCs. Most of them consist of three parts: an analysis of operating variables; an analysis of the structural design (topology); and an optimization of the resulting preliminary design. This paper aims to study three widely used design methodologies reported in the literature for DWCs, i.e., Triantafyllou and Smith (T&S), minimum vapor (Vmin), and Sotudeh and Shahraki (S&S) methods, along with their implementation on process simulators. A proposed modification to the S&S methodology is also presented. A comparison of the methods is carried out and rated against designs with minimum total annual costs. The analysis considers the effect of different structural design variables to initialize the design procedure with each methodology. Five case studies involving mixtures with different ease of separation index were evaluated. The results show that the most efficient techniques were obtained with a modified Sotudeh and Shahraki’s methodology. It was also found that the T&S approach stands out from the other methods, as it provided excellent initial designs for the case studies tested in this work.

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