corrosion protection and composite repair of steel components and fatigue life prediction of pipeline

• DOI: 10.7282/t3-ymxm-6w09
• Publication Date: 2020-01-01
• Authors: Milad Salemi

Pipeline is one of most important transportation infrastructures in the U.S. Many of pipe structures are old and have been in service in for decades. Effective maintenance is needed to keep pipeline infrastructure in serviceable condition and prevent catastrophic failure against corrosion and fatigue. This research investigates application of inorganic coating for corrosion protection and composite repair of steel pipeline. First, a customized accelerated corrosion procedure was developed to induce rapid degradation in coated steel specimens with organic and inorganic coatings. Bonding strengths of the coatings with steel substrate were examined using the modified lap shear test. Inorganic coating matrix was fabricated with various nano-materials to investigate the effectiveness of nano-modification. Furthermore, Carbon fiber reinforced polymer (CFRP) laminates were tested on coated and uncoated steel specimens to evaluate their repair capabilities. Laboratory test results from shear and tension coupons were then used as baseline inputs for finite element modeling (FEM) of pipeline structure. The FE models were used to calculate stress intensity factor (SIF) of pipeline with crack defects and composite repair. Finally, the fatigue life of pipeline was calculated using a backward-forward Bayesian inference methodology based on the observed crack growth measurements and cycle data that predicts the probability density of failure after initially estimating the equivalent initial flaw size (EIFS). The study results show that composite repair with inorganic coating can be an effective method for steel pipeline repair and service life extension.