An Efficient Safety Life Analysis Method Under Required Failure Possibility Constraint by SK-FS-Based Dichotomy

Safety life analysis can provide guidance for safety service and maintenance plan of structure. To efficiently analyze the structural safety life under required failure possibility in the presence of fuzzy uncertainty, this paper proposes a sequential Kriging (SK)-based fuzzy simulation (FS) combined with dichotomy (SK-FS-D) method. Firstly, based on monotonic relationship of time-dependent failure possibility (TDFP) and service time, the SK-FS-D uses dichotomy method to search the safety life. Secondly, the SK-FS-D proposes a strategy of sequentially updating Kriging surrogate model in the candidate sample pool (CSP) of fuzzy simulation (FS) to estimate the TDFP corresponding to each possible life searched by dichotomy, and the next dichotomy interval is determined by TDFP estimated by the convergent Kriging model. This strategy can improve the efficiency of SK-FS-D by avoiding training Kriging model at the life not visited by dichotomy and extend the engineering applicability of SK-FS-D by inheriting the advantages of FS method. Moreover, the CSP reduction strategy is further adopted to improve the computational efficiency of TDFP according to some correct information provided by the convergent Kriging model and the property of fuzzy design point. Finally, one numerical example and three engineering examples are introduced to verify the superior performance of the proposed SK-FS-D over the existing methods.