Output-only fatigue prediction of uncertain steel structures

Abstract

A fatigue estimation framework for steel structures is proposed in this study, under realistic assump-tions on the sensor network capacity and under the premise of uncertainty in the structural information available throughout the life-cycle of the monitored structure. To this purpose, in a first step, a joint input-state-parameter estimation problem is formulated, which integrates the dual Kalman filter and the unscented Kalman filter. The former aims at estimating the unknown structural excitations, while the latter solves the state and parameter estimation problem that is closely related to the estimation of stresses in critical areas. Accordingly, in a second step, a fatigue estimator is developed using material fatigue data and damage accumulation rules, which evaluates the stresses at all unmeasured hotspot locations of the structure to the fatigue damage accumulation and prognosis of the remaining fatigue life. Numerical simulations under different measurement setups and available structural properties are presented, in order to demonstrate the method's effectiveness.