A streamline approach to multiaxial fatigue monitoring using virtual sensing

Abstract

This paper presents a framework for fatigue monitoring on linear components of a structure subjected to unknown loads using a limited number of outputonly vibration measurements. It exploits virtual sensing techniques to estimate the dynamical responses, including virtual multiaxial strain/stress time histories. It applies joint input-state estimation algorithms to predict the dynamical response of the structural components. The resulting virtual multiaxial stress histories are used to compute the fatigue load cycles and corresponding fatigue damage. The proposed streamline approach allows the use of different available methodologies for virtual sensing and multiaxial fatigue analysis. A numerical validation example is provided using the tower of a reference wind turbine model subject to realistic wind loads. The proposed procedure can be adopted over a monitoring period to produce a global fatigue damage accumulation map from limited vibration data. It thus provides realistic fatigue damage accumulation information for a component based on the actual operational conditions of a structure.