PSI - Issue 28

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Nikolay Dolgov et al. / Procedia Structural Integrity 28 (2020) 1010–1017 Nikolay Dolgov & Tsanka Dikova / Structural Integrity Procedia 00 (2019) 000 – 000

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The results of the calculations in accordance with the model of Dolgov et al. (1995), Dolgov et al. (1996) and Dolgov et al. (1997) are shown in Fig. 5 and Fig. 6. In that case, the same elastic characteristics are used as for the calculation according to the model of Frank et al. (2009). Additionally, it was considered that the coating length l is 10 mm, the coating width b is 7 mm, and the coating thickness h is 150 μ m.

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Fig. 5. Stress  x (  ,  ) as a function of the parameters  = x / l and  = y / b ((a) isometric view and (b) side view).

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Fig. 6. Stress  y (  ,  ) as a function of the parameters  = x / l and  = y / b ((a) isometric view and (b) side view).

3. Discussion Analysis of the stresses fields in the porcelain coating, generating during tension of flat coated specimens in the direction of the z -axis (Fig. 1), has shown that except the basic normal stresses  z , additional normal stresses  x also appear in the coating, which are perpendicular to the direction of the tensile load. These additional stresses can cause both cross-link cracks by Liu et al. (2019), and buckling of the coatings by Frank et al. (2009), Andersons et al. (2009), Cordill and Taylor (2015), Zhang et al. (2017), and Wu (2019). The character of these fractures depends on the mismatch between the Poisson’s ratios of the substrate and the coating. The following advantages and limitations of the proposed model can be revealed: