DOI: 10.24412/2076-6785-2021-3-50-55
Abstract
At the stage of assessing the technical condition of main pipelines, the stress concentration factor for stresses occurring in the pipe wall in the area of the identified corrosion defect is taken as a deterministic value. The models used to calculate this factor contain such a parameter as the pipe wall thickness, which is a random variable and has individual distributions even for pipes of the same range. Due to the presence of a functional relationship with the thickness of the pipe wall, the values of the stress concentration factor also obey distributions, the type of which depends on the statistical spread of the values of the pipe wall thickness. The necessity of taking into account the stress concentration factor in the calculation models as a random variable is justified by the example of assessing the strength reliability and the level of risk of linear sections of the main oil pipeline complicated by a corrosion defect.
Material and methods
The pipe wall thickness was measured using an ultrasonic thickness gauge of the DM2 model manufactured by “Krautkrämer GmbH & CO” (Germany). The processing of the measurement results and the calculation of the values of the reliability indicators are based on the methods of nonparametric statistics and the theory of reliability. The stress concentration coefficient is calculated on the basis of the
B31G standard.
Keywords
main oil pipeline, linear part, corrosion defect, stress concentration factor, strength reliability, failure probability
