of Section II Section II, "A Comparative Study of Heuristic Reliability Optimization Methods" investigates the effectiveness of a mixed-integer programming method. This method is a combination of the heuristic redundancy method and the sequential search method. The heuristic method determines the integer variables (number of redundancies) by assuming that the real variables (reliability level) ...

In this paper we develop a search procedure for redundancy optimization of reliability models. We consider those systems where the reliability cannot be evaluated exactly but must be estimated through Monte Carlo simulation. At each iteration, two neighboring configurations are compared and the one that appears to be better is passed on to the next iteration. The search procedure uses an incre...

In this study, an effective method for reliabilitybased design optimization is proposed enhancing sequential optimization and reliability assessment (SORA) method by a family of methods of moving asymptotes (MMA) approximations. In SORA, reliability estimation and deterministic optimization are performed sequentially. And the sensitivity and function value of probabilistic constraint at the mos...

Injuries to the lower extremities are one of the major issues in vehicle to pedestrian collisions. To minimize injury risks of pedestrian lower extremity, this paper presents the design optimization of a typical vehicle front-end structure subjected to two different impact cases of TRL-PLI and Flex-PLI. Several approaches involving sampling techniques, surrogate model, multiobjective optimizati...

The failure probability of the structures is one of the challenging problems in structural engineering. To obtain the reliability index introduced by Hasofer and Lind, one needs to solve a nonlinear equality constrained optimization problem. In this study, four of the most recent metaheuristic algorithms are utilized for finding the design point and the failure probability of problems with cont...

Topology optimization often incorporates a reliability analysis to take the randomness in the design parameters into account. This strategy is inherently a double-loop procedure due to the probabilistic constraints in optimization. To simplify the calculation procedure, an equivalent-deterministic constraint, which is constructed by adding a penalty on the right hand side (RHS) of a limit state...

Reliability based optimization (RBO) is one of the most appropriate methods for structural design under uncertainties. It searches for the best compromise between cost and safety while considering system uncertainties by incorporating reliability measures within the optimization. Despite the advantages of RBO, its application to practical engineering problem is still quite challenging. In this ...

Slope stability analysis has received increased attention recently. Slope stability problems may be solved using both deterministic and probabilistic approaches and can be characterized as optimization problems. In the deterministic approach, the factor of safety is the function to be minimized, and for probabilistic analysis, the reliability index is considered the objective function. The sear...

Various uncertainties are inevitable in complex engineered systems and must be carefully treated in design activities. Reliability-Based Multidisciplinary Design Optimization (RBMDO) has been receiving increasing attention in the past decades to facilitate designing fully coupled systems but also achieving a desired reliability considering uncertainty. In this paper, a new formulation of multid...

In this study, the direct method including evaluation criteria of handling qualities as optimization method’s constraints are carried out to complement problems of the indirect method that assesses whether a flight control system designed by existing optimization techniques satisfies handling qualities or not. For the direct method, co-evolutionary augmented Lagrangian method is used. F-16 long...