PSI - Issue 20

Yakov Mikhailovich Andreev et al. / Procedia Structural Integrity 20 (2019) 167–173 Yakov Mikhailovich Andreev et al. / Structural Integrity Procedia 00 (2019) 000–000

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Fig. 2. Horizontal curvature of the axis of the gas pipeline

Fig. 3. Vertical curvature of the axis of the gas pipeline

Additionally, a control method based on the magnetic memory of the metal was used to search for stress concentrations in the considered section of the gas pipeline. The control was carried out by a scanning device of the Russian design Type 11-6KB paired with the TSC-6M-8 device in the zone, including bare and underground sections of the gas pipeline, the length of which was 470 m (Fig. 4). Calculations and analysis of the data obtained were carried out in the program “MPM-System 4”, designed to process data on the stress-strain state of equipment and structures according to the method of magnetic memory of metal (http://www.mmmsystem.ru/Products/MMM System-4.html). Based on the results of processing the control data, useful signals were found that indicate the stress-strain state of sections A and B of the gas pipeline with bends and are characterized by a coincidence of the distance between the conditional extrema Hy1 and Hy2 (see Fig. 4) for more information about the documents (http://meganorm.ru/Data2/l/4293794/4293794977.pdf) and RD 102-008-2002 (2003) in the magnetogram with the diameter (0.72 m) and the distance between the welds (11 m). As shown in fig. 4, in section A, magnetic anomalies of class A1 are observed, which manifest themselves in the form of sharp changes in the magnetic field with high values of the gradient dH (A / m2) and with a frequent change of sign. An anomaly of class A1 indicates the possible presence of hazardous zones of stress concentration, the location of which coincides with the point of exit of the gas pipeline from the ground. In section B, magnetic anomalies of class A2 were detected, which indicates the presence of less dangerous stress concentrations exceeding the stresses in the remaining sections of the gas pipeline. The location of section B coincides with the entry point of the gas pipeline into the ground.