time-dependent reliability analysis of rotor-blade systems with floquet-moment-evd interval approximation

We study the time-dependent reliability problem of the linear time-periodic rotor-blade model under stochastic forcing, encompassing a broad class of mechanical systems (wind and tidal turbines, helicopter rotors). the periodic modes from floquet theory are used to implement efficient moment-propagation convolution expressions for the response of the system, thus characterizing the limit state function. we then propose an interval-based decomposition strategy to estimate the probability of failure using results from extreme value theory. the approach is compared with raw monte carlo simulation for a simplified rotor-blade structure subjected to gaussian and non-gaussian non-stationary loads, showing substantial gains in computation time and excellent accuracy. the approach is original and stands in contrast to instant-based discretization approaches popular in the time-dependent reliability literature.