Reliability-based optimization considering design variables of discrete size

2010 ◽  
Vol 32 (9) ◽  
pp. 2919-2930 ◽  
Author(s):  
M.A. Valdebenito ◽  
G.I. Schuëller
Keyword(s):  
Design Variables ◽  
Reliability Based Optimization

Reliability Based Optimization of Submarine Pressure Hulls With Inelastic Interstiffener Buckling Failure

2006 ◽  
Author(s):  
P. Radha ◽  
K. Rajagopalan
Keyword(s):  
Unconstrained Minimization ◽  
Computer Code ◽  
Correction Method ◽  
Penalty Function Method ◽  
Simulation Design ◽  
Design Variables ◽  
Minimization Technique ◽  
Buckling Failure ◽  
Optimal Values ◽  
Reliability Based Optimization

Uncertainties that exist in modelling and simulation, design variables and parameters, manufacturing processes etc., may lead to large variations in the performance characteristics of the system. Optimized deterministic designs determined without considering uncertainties can be unreliable and may lead to catastrophic failure of the structure being designed. Reliability based optimization (RBO) is a methodology that addresses these problems. In this paper the reliability based optimization of submarine pressure hulls in which the failure gets governed by inelastic interstiffener buckling has been described. The problem has been formulated to minimize the ratio of weight of shell-stiffener geometry to the weight of liquid displaced, subjected to reliability based inelastic interstiffener buckling constraint. Since the methods of analysis of inelastic buckling failure of submarine pressure hulls are inadequate, in the present study the Johnson-Ostenfeld inelastic correction method has been adopted for formulating the constraint. By considering spacing of the stiffener, thickness of the plating and depth of the stiffener as the design variables, Sequential Unconstrained Minimization Technique (SUMT) has been used to solve the design problem. RBO has been carried out to get the optimal values of these design variables for a target reliability index using Interior Penalty Function Method for which an efficient computer code in C++ has been developed.

Reliability Based Optimization of Steel Monopod Offshore-Towers

2008 ◽  
Author(s):  
H. Karadeniz ◽  
V. Togan ◽  
T. Vrouwenvelder
Keyword(s):  
Natural Frequency ◽  
Cross Section ◽  
Sequential Quadratic Programming ◽  
Limit State ◽  
State Function ◽  
Wave Loading ◽  
Extreme Wave ◽  
Design Variables ◽  
Reliability Based Optimization ◽  
Numerical Strategy

In this work, the implementation of reliability-based optimization (RBO) of a circular steel monopod-offshore-tower with constant and variable diameters (represented by segmentations) and thicknesses is presented. The tower is subjected to the extreme wave loading. For this purpose, the deterministic optimization of the tower is performed with constraints including stress, buckling, and the lowest natural frequency firstly. Then, a reliability-based optimization of the tower is performed. The reliability index is calculated from FORM using a limit state function based on the lowest natural frequency. The mass of the tower is considered as being the objective function; the thickness and diameter of the cross-section of the tower are taken as being design variables of the optimization. The numerical strategy employed for performing the optimization uses the IMSL-Libraries routine that is based on the Sequential Quadratic Programming (SQP). In addition, to check the results obtained from aforementioned procedure, the RBO of the tower is also performed using the genetic algorithms (GA) tool of the MATLAB. Finally, a demonstration of an example monopod tower is presented.

scholarly journals Improved Artificial Bee Algorithm for Reliability-based Optimization of Truss Structures

2017 ◽  
Vol 11 (1) ◽  
pp. 235-243
Author(s):  
Li Yancang ◽  
Wang Jie ◽  
Liu Libo ◽  
Zhao Jie
Keyword(s):  
Truss Structure ◽  
Truss Structures ◽  
Engineering Practice ◽  
Discrete Variable ◽  
Small Interval ◽  
Bee Colony ◽  
Design Variables ◽  
Reliability Based Optimization ◽  
Set Up ◽  
Discrete Variable Optimization

Introduction: In order to optimize the reliability of the truss structure more effectively, an improved artificial bee colony algorithm based on small interval was proposed and employed to the engineering practice. Method: First, the optimization model based on the reliability was set up. In the model, the bars were treated as design variables, and the total weight was the object function. Then, the comparisons with other methods in solving the truss structure discrete variable optimization demonstrate the feasibility and effectiveness of the improved algorithm. Conclusion: This work provides a new method for the reliability-based optimization of truss structures.

Reliability-Based Optimization of the Stacking Sequence Layup in Post-Buckled Composite Stiffened Panels

2016 ◽  
Vol 713 ◽  
pp. 22-25
Author(s):  
Carlos López ◽  
Omar Bacarreza ◽  
Aitor Baldomir ◽  
Santiago Hernández ◽  
M.H. Ferri Aliabadi
Keyword(s):  
Progressive Failure ◽  
Reaction Force ◽  
Stacking Sequence ◽  
Random Parameters ◽  
Reliability Based Design Optimization ◽  
Stiffened Panels ◽  
Reliability Based Design ◽  
Design Variables ◽  
Post Buckling ◽  
Reliability Based Optimization

This paper presents a methodology to carry out Reliability-Based Design Optimization (RBDO) in composite stiffened panels. The target is to maximize the reaction force that the panel can withstand before collapse, setting the shortening of failure as the probabilistic constraint. The design variables are the stacking sequence orientations of the composite plies while the random parameters are the elastic properties of the material. In order to predict the collapse load properly, post-buckling and progressive failure analyses are considered within the FE solver employed.

THE EFFECTS OF MAP DESIGN VARIABLES ON MAP USER PERFORMANCE.

1967 ◽  
Author(s):  
GEORGE R. WHEATON ◽  
ALBERT ZAVALA ◽  
HAROLD P. VAN COTT
Keyword(s):  
User Performance ◽  
Design Variables ◽  
Map Design
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