PSI - Issue 68

Elena Fedorova et al. / Procedia Structural Integrity 68 (2025) 908–914 Elena Fedorova et al./ Structural Integrity Procedia 00 (2025) 000–000

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Fig.5. Finite element model of the TBC.

The thermal loading history consists of heating to 1100 °C followed by dwelling for 23 h, and finally cooling down to room temperature at 30 °C/min. The oxide grow stresses are assumed to be negligible compared with the thermally induced stresses. Materials of all TBC layers are considered to be homogeneous and isotropic. The substrate, TC and TGO are treated as viscous-elastic materials, while the BC material exhibits the elastic-ideal plastic behavior. Thermomechanical as well as and interface failure properties of the TBC components have been extracted from Burov and Fedorova (2021). The bilinear cohesive zone material model implemented in ANSYS was used to simulate the crack development along the TC/TGO and TGO/BC interfaces. The interfacial debonding is delineated by the contact gap and tangential slip values. In mixed-mode debonding, the interface separation is governed by both normal and tangential components of contact stress:

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Damage is initiated when the corresponding stress in the cohesive element reaches its critical value s max or t max . No damage is assumed under pure compression. The non-dimensional effective separation parameter is defined as:

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A power law energy criterion defines the debonding completion:

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The normal and tangential fracture energies are computed as:

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