Study of the amplitude-dependent mechanical behaviour of yttria-stabilised zirconia thermal barrier coatings

Micromechanical theoretical and computational modeling of energy dissipation due to nonlinear vibration of hard ceramic coatings with microstructural recursive faults

“…nonlinear) damping and stiffness behavior. This dependency has been reported first by Cross et al (1973) about four decades ago and rediscovered by Patsias and co-workers (Shipton and Patsias, 2003;Patsias et al, 2004;Tassini et al, 2006Tassini et al, , 2007 and Palazotto and co-workers (Ivancic, 2003;Ivancic and Palazotto, 2005;Blackwell et al, 2007;Reed, 2007;Reed et al, 2007;Pearson, 2008), where plasma sprayed ceramic coatings on metal substrates were investigated for damping capacity. This nonlinear behavior has resulted in numerous problems with regard to accurately characterizing and modeling these materials.…”

“…doi:10.1016/j.ijsolstr.2010.04.016 thermal barrier coatings (TBCs) to protect engine components from high temperatures and corrosion. In fact, recent research have indicated that ceramic TBCs can also provide some degree of vibration damping (Shipton and Patsias, 2003;Patsias et al, 2004;Tassini et al, 2006Tassini et al, , 2007Blackwell et al, 2007;Reed, 2007;Reed et al, 2007;Lauwagie et al, 2008;Pearson, 2008). However, constitutive modeling of this damping has been very limited in the literature due to the complex nonlinear damping behavior of these TBCs and due to the absence of a microstructural understanding of the origin of such nonlinear damping behavior.…”

“…The main difference between these two methods, in terms of the coating's microstructure they produce, is that APS form splat or lamellae microstructure whereas EBPVD form columnar microstructure (see Tassini et al (2007) for microscopic images). Although the current micromechanical modeling approach is intended for predicting the nonlinear damping response of TBCs produced by APS or EBPVD techniques, the focus of this study is on TBCs produced by the APS method.…”

“…To the authors' best knowledge, there have been only two attempts to model the nonlinear damping behavior of plasma sprayed TBCs. One by Reed (2007) and the other by Tassini et al (2007), where both have used the Iwan (1966) spring-slider-mass analytical model in which energy dissipation is attributed only to internal friction. The Iwan (1966) model is based on the idea that as the material is loaded to greater and greater levels, more and more sliders begin to slip and the stiffness of the material continues to decrease until the point at which all the sliders have slipped.…”

Determination of mechanical properties of non-linear coatings from measurements with coated beams

“…Tests conducted for the purpose of determining material properties have also been performed with beams coated only over a short segment in a region of high strain (Patsias et al, 2004a;Tassini et al, 2006;Reed, 2007) In such cases, the mode shape changes markedly when the coating is applied, and the ratio of kinetic energies does not take the simple form as in Eq. (1), nor does the strain energy ratio take the simple form of Eq.…”