Modelling the fracture behaviour of thermal barrier coatings containing healing particles

Journal article (2018)

Authors

J. Krishnasamy Aerospace Structures & Computational Mechanics - Aerospace Engineering
Sathiskumar A. Ponnusami University of Oxford
S.R. Turteltaub Aerospace Structures & Computational Mechanics - Aerospace Engineering
S. van der Zwaag Novel Aerospace Materials - Aerospace Engineering
Research Group
Aerospace Structures & Computational Mechanics (Aerospace Engineering) (TU Delft)
Copyright: © 2018 J. Krishnasamy, Sathiskumar A. Ponnusami, S.R. Turteltaub, S. van der Zwaag
DOI
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https://doi.org/10.1016/j.matdes.2018.07.026
Fracture mechanics Thermal barrier coatings Cohesive elements Healing particles Thermal mismatch
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Published Date

05-11-2018

Language

English

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Faculty

Aerospace Engineering

Department

Aerospace Structures & Materials

Research Group

Aerospace Structures & Computational Mechanics

Abstract

The performance of a self-healing Thermal Barrier Coating (TBC) containing dispersed healing particles depends crucially on the mismatch in thermomechanical properties between the healing particles and the TBC matrix. The present work systematically investigates this phenomenon based on numerical simulations using cohesive element-based finite element analysis. The effect of the mismatch in Coefficient of Thermal Expansion (CTE) and fracture strength between the healing particles and the matrix on the fracture characteristics is quantified in detail. Unit cell-based analyses are conducted on a representative self-healing TBC system under a thermal loading step typically experienced by TBC systems in jet turbines. Two different simulation setups are considered within the TBC unit cell namely (i) a single pair of healing particles and (ii) a randomly distributed array of healing particles. The results of the simulations are reported in terms of the fracture pattern, crack initiation temperature and crack length for various CTE mismatch ratios. Correlations are established between the results obtained from the two simulation setups essentially revealing the effect of spatial distribution and proximity of healing particles on the fracture pattern. The results obtained from the analyses can be utilised to achieve a robust design of a self-healing TBC system.