Identification of coating defects in cathodically protected underground pipelines

Abstract

SUMMARYCoating defects may occur, for many di erent reasons, at some points on the surface of a cathodically protected structure. These defects behave anodically and may cause strong localized corrosion. It is possible to identify the position of coating defects by using measured values of the electrochemical potential at some points in the electrolyte or on its surface. To achieve this, an inverse BEM-based genetic algorithm is developed to identify the position of defects in cathodically protected underground pipelines. The formulation is validated through its application to practical problems involving strongly non-linear polarization curves, inÿnite electrolytes, unknown number of defects and measurement noise.

Application of solar photovoltaic electricity in unravelling the effects of coating defects on cathodic protection parameters of buried pipeline

“…Resistance plotted against the size of the defect on a buried pipe when cathodic protection is applied for 25 minutesThe resistance increased at the initial stage when the defect was initiated and decreased drastically between 0.3 and 0.4 cm 2 before beginning to drop slightly and then increased with an increase in the number of defects. This is as a result of the adhesive strength of the coating observed at the substrate as a result of more defects and in consonant with Miltiadou & Wrobel[28]. At this point,…”

“…The resistance increased at the initial stage when the defect was initiated and decreased drastically between 0.3 and 0.4 cm 2 before beginning to drop slightly and then increased with an increase in the number of defects. This is as a result of the adhesive strength of the coating observed at the substrate as a result of more defects and in consonant with Miltiadou & Wrobel [28]. At this point, IOP Publishing doi:10.1088/1755-1315/1178/1/012002 10 the protective barrier is broken due to the time spent by the substrate in the electrolyte leading to a decrease in resistance [13,29].…”

“…In their views, current will accumulate at the region where the pipe is experiencing a single defect [17]. Relatedly, current flow over the coating experiences a non-uniform flow as the number of defects size increases on the pipeline [13,28]. This can lead to hydrogen embrittlement and cathodic disbondment.…”

An accelerated boundary element method via cross approximation of integral kernels for large‐scale cathodic protection problems

“…This feature makes the BEM an ideal tool for modeling problems involving infinite and semi‐infinite domains. The BEM has been successfully utilized to analyze CP systems in ships (DeGiorgi & Wimmer, 2005; Iwata et al., 1992; Kalovelonis et al., 2019; Zamani, 1988), offshore structures (Amaya & Aoki, 2003), buried pipelines (Lan et al., 2002; Cicognani et al., 1990; Rodopoulos et al., 2019; Tang et al., 2009), underground structures (Abootalebi et al., 2010; Aoki et al., 2004; Miltiadou & Wrobel, 2003), and steel‐reinforced concrete (Ridha et al., 2001; Santos et al., 2018).…”