Applying integration order descending method (IODM) to reliability sensitivity analysis (RSA)

To our knowledge, no paper in the open literature has applied the IODM to the RSA. We now apply it and obtain its two versions applicable to the RSA of the two structural systems: (1) single failure mode; (2) multiple failure mode. Taking into account two-dimensional, three-dimensional and any number of dimensions of random variables, section 1 of the full paper discusses the two IODM versions, each of which is applicable to both single failure mode and multiple failure mode. Section 2 derives the formulas for calculating the numerical values of RSA with the two IODM versions. Eqs. (28), (33) and (34) are applicable to the RSA of any number of dimensions of random variables. Section 3 gives four numerical RSA examples. The RSA calculation results, given in Tables 1, 2, 3 and 5, show preliminarily that; (1) the two IODM versions can obtain highly precise estimates; (2) the two versions are independent of the explicit expression of limit state equation; (3) the calculation precision obtainable with version 1 is somewhat higher than that obtainable with version 2.