Profile Matching for Performance Assessment of Dented Pipe

Abstract In the finite element analysis of dented pipes, an indenter is numerically pushed against the pipe wall to produce a dent profile measured from in-line inspection (ILI). The analysis is repeated until the differences between the calculated and measured profiles (i.e., depths) are less than a tolerance limit. If the differences between the depths are less than the typical ILI measurement tolerance, then the FE profile is assumed to represent the actual profile. ILI tools were reported to measure dent depths with a tolerance of 0.5% and 0.77% of the pipe’s outer diameter. However, many different dent profiles can be developed with depths within the tolerance limit, resulting in different stress and strain levels, that can affect the assessment results. This paper presents an investigation of the effects of different profile shapes on the results of performance assessment of dented pipes. Three-dimensional FE analysis was conducted to simulate the dent on a pipe using the different sizes and shapes of the indenter. The stresses and strains on the pipes with the dent depths within the tolerance are compared. The study reveals that the dent profile created using the depth tolerance criteria may lead to misleading information of the pipe performance.