Stress and Strain Analysis of Sealing Cup With Internal Groove of Pipeline Inner Inspection Tool in Dented Oil and Gas Pipeline

Abstract As an important mode of oil and gas transportation, pipelines will produce different forms of defects with the increase of service life and the change of external environment. Regular inspection in pipeline is an important way to ensure the safe operation of pipeline. As an important driving component of the pipeline inner inspection tool, the reducing ability of the sealing cup determines whether it can have stable passability when the inner diameter of the pipeline changes or when defects such as dents occur in the pipeline. This article designed a conical sealing cup with an internal groove structure, and the kinematic simulation model of the pipeline inner inspection tool in the non-destructive straight pipe was established based on the finite element method. A push experimental platform was established for the study, and strain data of the sealing cup before and after entering the pipeline were collected. The trend of change was in good agreement with the simulation curve. In order to avoid the stuck of pipeline inner inspection tool in the pipeline dents, the simulation study was conducted on a 6%OD dent defect pipeline using a 19mm thick sealing cup as an example. The study showed that the groove morphology of the cup in contact with the defect pipeline stretched towards both sides, and the surrounding area of internal groove contracted inward to promote the overall diameter change of the cup. Compared to the cup without groove, the maximum contact stress was significantly reduced, which proves that it has better diameter reducing ability and higher passability. According to the model introduced in this article, it can provide guidance for the application of sealing cup with internal groove.