PSI - Issue 42

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Chmelko,V. at all: / Structural Integrity Procedia 00 (2022) 000–000

Chmelko et al. / Procedia Structural Integrity 42 (2022) 315–320

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Fig. 8. Degree of safety against pipeline failure as a function of axial buckling (DN500, t=10 mm, buckling length 4.25 m, defect size 30x30 mm). 4. Conclusions The occurrence of small corrosion defects in pipeline casings is a frequent phenomenon with relatively little impact on their integrity. Other factors that reduce the safety of pipeline operation - shape deviations and additional bending - have been discussed. On the basis of the analysis and computational simulations carried out, it can be concluded that: • Existing standards for assessing the safety of operation of pipelines with corrosion defects are not sensitive enough to small defect sizes, which corresponds to reality • The influence of inaccuracies in the shape of pipelines is significant, especially in the elastic region • The impact of additional bending is highly dangerous depending on the size of the pipe axis deflection and the length of such a section; for a DN=500, t=10 mm pipe, an axis deflection of 1 m on a 6 m pipe section already threatens the integrity of a pipe with a corrosion defect size of 30x30 mm depth over 50% of the wall thickness; for larger pipe diameters, this impact is much more significant • Using experimentally verified simulations, it is possible to assess the safety of pipeline operation under the synergy of these effects using the diagrams documented in Figure 8 Acknowledgements This contribution has been elaborated under supporting of the Slovak Research and Development Agency under the contract No. APVV-17-0666. References [1] Nanney, S., 2012. Pipeline Safety Update. NAPCA Workshop, Texas [2] Abdelkader Guillal et all., 2019. Sensitivity of reliability-based fatigue analysis to crack shape development in cracked pipeline. Procedia Struct. Integr. 22, 201–210 [6]Kastner W, Rohrich E, Schmitt W, Steinbuch R. Critical crack sizes in ductile piping. Int J Pressure Vessels Piping 1981;9:197–219. [7]Schulze HD, Togler G, Bodman E. Fracture mechanics analysis on the initiation and propagation of circumferential and longitudinal defects in straight pipes and pipe bends. Nucl Eng Des 1980;58:19–31. [8] Iľkaev R., Seleznev V., Aleshin V., Klishin G., 2005. Numeri cal simulation of gas pipeline networks, URSS Moscow [9] Chmelko, V., Garan, M., Berta, I., 2020,.Calculation of burst pressure of pipeline with local defect. Procedia Struct. Integr. 26, 417 - 421 [10] Chmelko,V., Biro,D., 2019. Safety of pressure pipe operation with corrosive defect. Procedia Struct. Integr. 17, 520–525, [3] Cosham, Hopkins, 2003. The Pipeline Defect Assessment Manual (PDAM); Penspen Ltd. [4] ASME B31.G: Manual for Determining the Remaining Strength of Corroded Pipelines, 2009. [5] Det Norske Veritas, Corroded Pipelines, Resommended Pratice DNV-RP-F101, © Det Norske Veritas , 2010. 42s