Ceramic coatings are widely used in Thermal Barrier coating systems to protect the substrates from high operating temperatures. Over the last decade there has been significant research into the potential use of such coatings as damping treatments that has shown that they could provide significant amount of added damping to be of practical value in aero-engine components. This paper covers the methods developed to (a) evaluate their effectiveness, (b) estimate their material loss factor and modulus of elasticity and (c) predict the added damping when applied to an aero-engine component. Earlier research has demonstrated that the behaviour of ceramic coatings to be amplitude-dependent (non-linear) and as such, traditional characterisation techniques is rendered unsuitable. A new mixed experimental-numerical approach was developed for such materials: it combines vibration testing and iterative Finite Element modelling that allows one to estimate their material loss factor and modulus of elasticity. For a new damping treatment to be of practical value one has to demonstrate that by adding extra mass on a component, significant benefits in reducing vibration levels are obtained. This was achieved by predicting the effect of adding a damping coating on a component and by validating the predictions by carrying our experiments of the actual component under static and rotating conditions. A Rolls-Royce plc propriety software was developed that allows one to add on the finite element model of a component a coating patch of certain thickness at a desired location. This software loads the material properties obtained by the mixed experimental-numerical technique developed earlier and predicts the behaviour of the component. The experimental validation was carried out with custom made components on a Rolls-Royce plc test rig. Good agreement between experiments" and predictions was found and thus validating the predictive capability and proving that ceramic coatings can be of practical application for aero-engine components.
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