Método de avaliação da vida à fadiga de risers flexíveis através do monitoramento das deformações dos arames da armadura de tração

Abstract

Flexible risers are critical elements in a subsea production system. Due to the complexity of these structures, a number of factors influence the evaluation of their integrity, so the application of monitoring systems is essential to ensure operational safety and reduce design conservatism. The objective of this study was to develop a method for continuous and real-time monitoring of the top end fitting and the first intermediate connection fatigue life. The method is based on measuring the strains of outer tensile wires on the top riser structure. In order to evaluate the method, a full-scale dynamic test of a 8 inch flexible pipe structure data and monitoring system data of two flexible risers, connected at a floating unit anchored into a water depth of 2200 m, are used. The fatigue damage calculated considering the stresses obtained through the model was similar to the predicted damage to the dynamic test. For the field data, the tension obtained by the model was compared to the tension calculated using numerical simulation and floating unit monitoring data. The results showed a good correlation of the tension amplitudes with numerical model, indicating the applicability of the model to monitoring the flexible riser end fitting fatigue life.