Multifactor Coupling Wear Behaviors of Pipeline Inspection Gauge Cups: Experimental Tests and Simulation Analyses

Abstract

In long-distance inspection operations of oil and gas pipelines, the severe wear of the pipeline inspection gauge (PIG) cups will cause derivation of the mandrel from the pipe axis, which is detrimental to the detection results and pipeline safety. The essential of the cup wear belongs to eccentric wear of polyurethane rubber (PUR) under the interference contact. Distinctly from the traditional wear, there is a multiple coupling relationship between contact stress, wear rate, and wear loss. This paper first obtains a correlation model between wear rate and contact stress through a self-designed PUR specimen wear test and on this basis modifies the Archard model. Subsequently, the modified Archard model was written into a subroutine, and the secondary development of the Abaqus Umeshmotion module was used to establish a three-dimensional finite-element model verified by a full-size wear experiment, for simulating the wear process of the cup. According to the wear loss curve, the wear process of the driving cup can be divided into four stages: severe wear, heavy wear, moderate wear, and mild wear. For cups with different interferences and structures, the initial contact position and contact stress distribution are distinct, which in turn affects their wear rate and wear loss. A reasonable increase in interference and selection of cups with a smaller interface ratio and hardness can effectively improve their wear resistance and service life. The gravity will lead to eccentric wear, which causes nonuniform wear loss around the circumferential even exceeding the maximum interference and thus affects the service life. The conclusion of this paper provides certain guiding significance for the design of the PIG cup structure and benefits the improvement of detection operation security.