PSI - Issue 33

D.D. Okulova et al. / Procedia Structural Integrity 33 (2021) 1055–1064 Author name / Structural Integrity Procedia 00 (2019) 000–000

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3.2. Linearly elastic model In the case of linearly elastic model, structural steel with Young’s modulus E = 200 GPa and Poisson’s ratio ν = 0.3 was used. The internal pressure is p = 1 MPa. The material and the pressure value were chosen due to the purpose of complementing the results obtained in the work of Sedova et al. (2021). Multiple simulations with different element sizes were performed for each CAD-model to ensure convergence. 4. Results and discussion 4.1. Effect of the number of the defects (Elastic-plastic model) Five different geometries (models) with random distribution of defects along the equator of the sphere were built for each considered number n . The distribution of maximum principal stress in the notched shell was analysed for each geometry. The maximum value, max  , of maximum principal stress, observed for a certain geometry, was normalised by pressure p and denoted by K :

max p   ,

K

(1)

where max  is a maximum (among all the points of the corroded shell) of maximum principal stress for a certain geometrical model. Figure 3 shows the values of K for five different geometries for each number of defects n (points of different colours correspond to different geometries). Overlaps between neighbouring notches took place for all the considered numbers n (Fig. 4).

Fig. 3. The maximum relative stress K for various numbers n of defects. Random distribution of defects. Elastic-plastic model