PSI - Issue 23

Vera Petrova et al. / Procedia Structural Integrity 23 (2019) 407–412 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

412

6

This modeling of thermal fracture of a FGC/H structure was performed for the case of one cycle of thermo mechanical loading (cooling) and can be used as part of a study of the fracture process in FGM coatings under cyclic heating-cooling thermal loading. It was obtained that for a positive εa , the case, where magnitudes of the thermal expansion coefficient have larger values in the upper part of the FGM layer, the SIF k I is much larger than the values for negative εa and for a homogeneous material. The magnitude of the SIF k II is also larger, but not as much as for the SIF k I . A general theoretical formulation of the model for the thermal fracture analysis of functionally graded coatings on a homogeneous substrate (FGCs/H) has been performed by means of integral equations. Illustrative examples are presented to show the influence of the parameters of the problem on the interaction of edge cracks with an internal crack. Optimal crack configurations can be determined at which the stress intensity factors at crack tips possess minimum values or at which the critical loads are maximal and, accordingly, the fracture resistance of FGC/H structures can be improved. 5. Conclusions

Acknowledgements

The authors would like to acknowledge the financial support of the German Research Foundation under Grant Schm 746/209-1.

References

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