Optimal maintenance planning in pipelines with corrosion defects considering different types of steel.

Resumo

Recent studies indicate that most of the world's fuel is composed of oil and gas, being transported by
pipelines. In this scenario, corrosion is considered one of the main problems that affect the integrity of these
elements, in which the risks associated with failures can have human, environmental and financial repercussions.
Thus, planning its maintenance is essential to control the risk of failures and prevent accidents. In this context, the
present work aims to evaluate the influence of the types of steel, considering different expressions for the
calculation of the pressure of failure, in the cost and probability of failure of the optimal timeline for different
numbers of inspections, not being restricted to the approach of fixed intervals. More than one failure mode is
considered, the 'interior-point' algorithm is used in the optimization and the reliability analysis is performed with
Monte Carlo simulations, commonly used in the literature. To determine the starting point of the optimization, the
objective function is calculated on a sample constructed using the Latin Hypercube - LHS technique. Preliminary
results shows that different types of steel have a significant effect on optimal costs and probability of failure for
different numbers of inspections.