Active learning for structural reliability analysis with multiple limit state functions through variance-enhanced PC-Kriging surrogate models
This work addresses the need for probabilistic characterization of multiple damage conditions in engineering applications, offering an incremental improvement over existing active learning methods.
The paper tackled the problem of efficiently estimating multiple limit state functions for structural reliability analysis under limited computational budgets, using active learning with variance-enhanced PC-Kriging surrogate models, and demonstrated effectiveness in a nonlinear structural setting and a practical ship collision scenario.
Existing active strategies for training surrogate models yield accurate structural reliability estimates by aiming at design space regions in the vicinity of a specified limit state function. In many practical engineering applications, various damage conditions, e.g. repair, failure, should be probabilistically characterized, thus demanding the estimation of multiple performance functions. In this work, we investigate the capability of active learning approaches for efficiently selecting training samples under a limited computational budget while still preserving the accuracy associated with multiple surrogated limit states. Specifically, PC-Kriging-based surrogate models are actively trained considering a variance correction derived from leave-one-out cross-validation error information, whereas the sequential learning scheme relies on U-function-derived metrics. The proposed active learning approaches are tested in a highly nonlinear structural reliability setting, whereas in a more practical application, failure and repair events are stochastically predicted in the aftermath of a ship collision against an offshore wind substructure. The results show that a balanced computational budget administration can be effectively achieved by successively targeting the specified multiple limit state functions within a unified active learning scheme.