Numerical simulation of EBPVD thermal barrier coatings spallation

An elastoviscoplastic finite element model is proposed to assess the bond-coat/oxide interface critical energy release rate in an EBPVD thermal barrier coating (TBC). The local stress fields responsible for the crack initiations are analyzed at the interfacial roughness scale. The TBC bond strength is identified from experimental results of spallation tests. The local spallation of the topcoat is modeled by the insertion of cohesive zone models, based on the continuum damage mechanics framework. The bond-coat/oxide interface strength evolution shows a continuous decline as a function of the oxidation time. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.