Limit Analysis of Shells With Random Pattern of Spread Pits Available to Purchase

Limit analysis is used to determine the strength of the shells weakened by the material loss due to pitting corrosion. The wall is modeled as a multi-layer structure. The outer layers include penetrations due to the pitting attack. The layers with pits are analyzed as the plane perforated sheets with the equivalent, uniform pattern of circular holes, subjected to the arbitrarily oriented biaxial loading. The results of these analyses have been used for the evaluation of the pitting corrosion in the American Petroleum Institute Recommended Practice for Fitness-For-Service API-579. Examples of evaluations are provided for the pressure vessel and storage tank walls.