A directional surrogate model tailored for efficient reliability based design optimization

• Reliability based design optimization (RBDO) aims at minimizing an objective while constraining the failure probability of structural components. Due to the iterative nature of both the minimization and the failure probability validation, there is considerable computational effort associated with it. In this paper, a computationally inexpensive approach for RBDO is presented. The key contribution is the directional surrogate model and its associated advantages; a sound balance between accuracy and computational cost, including the possibility to fit model coefficients based on an optimal experiment design, high fidelity modeling of representative structural responses, treatment of multiple constraints without added computational cost, and straightforward sequential linear programming implementation. The directional surrogate model is of power type with nonlinear behaviour only in the gradient direction, thus balancing accuracy and computational cost. Moreover, information from prior iterations are used in every iteration in a weighted least squares optimization. When benchmarked against existing approaches from the literature using a well known reference problem, it is shown to be highly efficient. It also shows promising stability and convergence rate for additional challenging problems to which it has been applied.

Nyckelord

FORM

Surrogate Model

Design of Experiments

Multiple Constraints

Publikations- och innehållstyp

vet (ämneskategori)

rap (ämneskategori)