PSI - Issue 40

3

N.A. Makhutov et al. / Procedia Structural Integrity 40 (2022) 283–295 N.A. Makhutov at al. / Structural Integrity Procedia 00 (2022) 000 – 000

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M z

Q z

M y

N x

Q y

M x

b)

a)

Fig. 2. Design diagrams for pipelines: a) basic regulatory calculation for design stage; b) checking calculation for design and operation stage

Components of the main nominal tension in verification check calculations for design and operation stages (Fig. 2, b)) are determined for all forces in cross section by Mazur et al. (2004) and Lisin et al. (2018) using formulas for thin-walled shells.         1 2 3 , , , , , , , , , x y Z x y Z F p N Q Q M M M     (2) where – longitudinal force from pressure р and temperatures t; у , – shearing forces from action of supports, soils, wind, snow; у , – torsion and bending torques from displacement of soil supports and distortion of longitudinal axis х with radius . During actual operation, force factors, corrosion that reduces wall thickness and cracks l , initial process and operation defects, concentration of stresses α σ from welds and distortion of cross-section form (with diameters ≤ d ≤ ) , make the components of local maximum stresses { σ 1 , σ 2 , σ 3 } max higher than the nominal ones from (2).         1 2 3 max 1 2 3 min max , , , , , , , , F l d d          (3)