PSI - Issue 16

Borys Paton et al. / Procedia Structural Integrity 16 (2019) 176–183 Borys Paton et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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As we can see, AE activity of the material at its deformation has different values in different pipeline points. Monitoring system selects the weakest locations and automatically, in real time, calculates the predicted breaking load. The highest AE activity corresponds to a section between transducers 8 and 12 . The first and second antennas show coordinates of 63 and 51 m with the highest AE activity. At the same time, predicted breaking loads are several times higher than the working loads, that is indicative of the possibility of further operation of these pipeline runs (yellow color). Antenna 3 controls the pipeline section, located in worse conditions compared to sections 1 and 2. In this case in pipe section at the distance of approximately 10 m from its start the predicted breaking load is approximately 2 times higher than the working load, whereas sections 1 and 2 show that the breaking load exceeds the working one by approximately 4 times (color of zone3 is orange). Safety factors for the predicted breaking load were established to improve the reliability of taking the decision on the need to stop and take the structure out of service based on monitoring data. Here, the greater the difference between the predicted and working load, the smaller the safety factor set by the system. With reduction of P work. / P prev. ratio, the safety factor is automatically increased. a b

Fig. 5. AE activity level in two pipeline runs in operation 13 h 13 min (antenna 1) (a) and 6 h 22 min (antenna 2) (b) after the start of monitoring (top table gives magnitudes of predicted limit load).

Fig. 6. Schematic of HIO pipeline with locations of higher AE activity (numbers show quantity of AE transducers; crosses are technological marks).