Vol.22, No.1, 2022, pp. 63–68
UDC:

STRUCTURAL INTEGRITY AND LIFE ASSESSMENT OF OIL DRILLING RIG PIPES USING ANALYTICAL METHOD

Radzeya Zaidi1, Aleksandar Sedmak1*, Snežana Kirin2, Igor Martić2, Živče Šarkočević3

1) University of Belgrade, Faculty of Mechanical Engineering, SERBIA

email: asedmak@mas.bg.ac.rs

2) University of Belgrade, Innovation Centre of the Faculty of Mechanical Engineering, Belgrade, SERBIA

3) University of Priština, Faculty of Technical Sciences, Kosovska Mitrovica, SERBIA

 

Abstract

Structural integrity and life assessment of oil rig pipes using analytical method is presented and applied to an oil drilling rig pipe. The new concept based on risk evaluation according to probability and consequence of failure is used. Analytical expressions for surface cracks, provided by Raju and Newman, are used to calculate stress intensity factors for different crack geometries. Furthermore, the rig welded pipe failure probability is estimated by simple application of the Failure Assessment Diagram (FAD) and used together with potential consequences to evaluate the risk level by application of risk matrix. The same logic is employed in the case of cyclic loading, i.e. fatigue crack growth, by using Paris law to calculate crack length depending on the number of cycles. Simple numerical integration is applied to take into account the change of the geometry parameter Y due to increasing depth of a surface crack.

Keywords: oil rig pipe, analytical methods, failure assessment diagram, Paris law

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