PSI - Issue 47

Alexander Ilyin et al. / Procedia Structural Integrity 47 (2023) 290–295 A. Ilyin and Y. Pronina / Structural Integrity Procedia 00 (2019) 000–000

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remains constant and equal 5 mm. Constants of the corrosion kinetics are a = 0.1 mm/year and m = 0.0005 mm/(year·MPa); t c = 1year. Figure 2 shows the growth of the relative stress σ 1 / σ* at different nodes (marked by points with numbers) on the inner surface of the toroidal shell cross-section with time. Here, r i = 4.75 mm, R = 10 mm, and p = 4 MPa. As one can see, the greater the value of angle φ , the higher is stress σ 1 . The smallest stress is observed at φ = 0° and the largest at φ =180°; for other values of R > r o this conclusion holds true. It can be concluded that the service life of the toroidal shell is to be determined by the thickness and the stress value at this point (node 61 in Figures 1 and 2).

Fig. 2. The stress growth at different nodes on the inner surface of the toroidal shell cross-section.

Figure 3 shows the growth of the relative stress σ 1 / σ* at the node 61 for different distance parameters R with time, where r = 4.5 mm, and p = 4 MPa. It can be noticed that the lower the distance parameter R is , the higher is the rate of the stress growth. For sufficiently large distance parameters (for example, R = 10 r o in Figure 3), the results tend to the solution for a cylindrical pipe (perfect tube).

Fig. 3. The growth of the stress at node 61 for different distance parameters R .