Reliability-based optimal structural design by the decoupling approach

A decoupling approach for solving optimal structural design problems involv ing reliability terms in the objective function, the constraint set or both is discussed and extended. The approach employs a reformulation of each pr oblem, in which reliability terms are replaced by deterministic functions. The reformulated problems can be solved by existing semi-infinite optimizat ion algorithms and computational reliability methods. It is shown that the reformulated problems produce solutions that are identical to those of the original problems when the limit-state functions defining the reliability p roblem are affine. For nonaffine limit-state functions, approximate solutio ns are obtained by solving series of reformulated problems. An important ad vantage of the approach is that the required reliability and optimization c alculations are completely decoupled, thus allowing flexibility in the choi ce of the optimization algorithm and the reliability computation method. (C ) 2001 Elsevier Science Ltd. All rights reserved.