Numerical Simulations of Full-Scale Corroded Pipe Tests With Combined Loading

Abstract

The ANSI/ASME B31G guideline has been useful to pipeline operators in assessing the integrity of corroded line pipe. Because large safety margins have had to be incorporated, the guidelines can be excessively conservative, which in turn can force costly repairs and replacements that may not actually be necessary. On the other hand, because the current guidelines consider only pressure loading and neglect bending and axial compression, they could give nonconservative failure predictions when combined loading exists. Therefore, a study was initiated to develop a theoretically sound methodology for assessing the integrity of corroded line pipe subjected to combined loading. A key step in the successful application of this methodology is the development of a sophisticated three-dimensional finite element procedure that can accurately simulate full-scale pipe tests under conditions of combined loading. This paper describes thirteen full-scale failure tests on artificially corroded pipes subjected to simultaneous internal pressure, bending, and longitudinal compression and presents a detailed account of the finite element analysis procedure that was developed to simulate these tests numerically. Additional finite element analyses that were conducted to investigate the effect of key parameters on failure, and to expand the corroded pipe failure database, are also discussed.