Finite Element Modeling and Quantification of Mechanical Damage Severity in Pipelines

Abstract

Mechanical damage is one of the major threats to oil and gas transmission pipeline integrity, which has been the case now for decades. Although much work has been done in that context, due to the complexity of its effects mechanical damage severity remains difficult to quantify. Thus, work continues to better understand the failure mechanism and develop the means to screen damage severity. The present paper adopts a validated elastic-plastic finite element analysis (FEA) model to simulate mechanical dents in pipelines and to quantify the effects of damage through a broad parametric study. This considers the need for three-dimensional FEA models and the effects of FEA element type, soil constraint condition, indenter type, pipeline grade and initial pipe pressure on dent response. The FEA model is also used to assess the minimum wall thickness for which a dent has the minimal effect on pipeline integrity. Finally, application of the proposed FEA model is illustrated by successfully predicting the failure behavior of a dent in a full-scale fatigue test involving a modern pipeline steel.