Stochastic analysis of combined dynamic responses and their effects

Gaussian response processes which are the stochastic combinations of narrow-banded component processes in two highly different frequency domains are analysed using their spectral functions and stochastic envelopes. Structural failure modes under such response processes are considered as overload, fatigue and fracture. Fatigue damage is estimated using stress ranges consistent with those counted by the rainflow counting method. Risk of overload and fracture is assessed by estimating the frequency of the response process upcrossing the constant or time-varying strength threshold. The probabilistic models presented enable a theoretical approach to estimating the failure probabilities of the considered failure modes.