scholarly journals Cutting the double loop: Theory and algorithms for reliability‐based design optimization with parametric uncertainty

2019 ◽  
Vol 118 (12) ◽  
pp. 718-740 ◽  
Author(s):  
Zachary Rosario ◽  
Richard W. Fenrich ◽  
Gianluca Iaccarino
Keyword(s):  
Design Optimization ◽  
Parametric Uncertainty ◽  
Double Loop ◽  
Reliability Based Design Optimization ◽  
Reliability Based Design ◽  
Loop Theory

scholarly journals Multi-Objective, Reliability-Based Design Optimization of a Steering Linkage

2020 ◽  
Vol 10 (17) ◽  
pp. 5748
Author(s):  
Suwin Sleesongsom ◽  
Sujin Bureerat
Keyword(s):  
Design Optimization ◽  
Double Loop ◽  
Reliability Based Design Optimization ◽  
Case Scenario ◽  
Worst Case ◽  
Multi Objective ◽  
Reliability Based Design ◽  
Linkage Design ◽  
A New Technique ◽  
Optimization Loop

Reliability-based design optimization (RBDO) of a mechanism is normally based on the non-probabilistic model, which is viewed as failure possibility constraints in each optimization loop. It leads to a double-loop nested problem that causes a computationally expensive evaluation. Several methods have been developed to solve the problem, which are expected to increase the realization of optimum results and computational efficiency. The purpose of this paper was to develop a new technique of RBDO that can reduce the complexity of the double-loop nested problem to a single-loop. This involves using a multi-objective evolutionary technique combined with the worst-case scenario and fuzzy sets, known as a multi-objective, reliability-based design optimization (MORBDO). The optimization test problem and a steering linkage design were used to validate the performance of the proposed technique. The proposed technique can reduce the complexity of the design problem, producing results that are more conservative and realizable.

A Single-Loop Method for Reliability-Based Design Optimization

2004 ◽  
Author(s):  
Jinghong Liang ◽  
Zissimos P. Mourelatos ◽  
Jian Tu
Keyword(s):  
Design Optimization ◽  
Optimization Problem ◽  
Computational Effort ◽  
Side Impact ◽  
Double Loop ◽  
Reliability Based Design Optimization ◽  
Deterministic Optimization ◽  
Single Loop ◽  
Reliability Based Design ◽  
Reliability Assessments

Reliability-Based Design Optimization (RBDO) can provide optimum designs in the presence of uncertainty. It can therefore, be a powerful tool for design under uncertainty. The traditional, double-loop RBDO algorithm requires nested optimization loops, where the design optimization (outer) loop, repeatedly calls a series of reliability (inner) loops. Due to the nested optimization loops, the computational effort can be prohibitive for practical problems. A single-loop RBDO algorithm is proposed in this paper for both normal and non-normal random variables. Its accuracy is the same with the double-loop approach and its efficiency is almost equivalent to deterministic optimization. It collapses the nested optimization loops into an equivalent single-loop optimization process by imposing the Karush-Kuhn-Tucker optimality conditions of the reliability loops as equivalent deterministic equality constraints of the design optimization loop. It therefore, converts the probabilistic optimization problem into an equivalent deterministic optimization problem, eliminating the need for calculating the Most Probable Point (MPP) in repeated reliability assessments. Several numerical applications including an automotive vehicle side impact example, demonstrate the accuracy and superior efficiency of the proposed single-loop RBDO algorithm.

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