Critérios de falha e modelos analíticos para análise local em dutos flexíveis com armaduras de tração em material compósito

Abstract

This research investigates, in the first moment, analytical models to calculate the stresses in tensile armors of unbonded flexible pipe under axisymmetric and flexure loading considering material changes from carbon steel to unidirectional carbon-fiber composite. Although considering same geometric characteristic of helical armours, the material changes generate modifications in analytical equations for stresses calculation. Second aspects investigated are different failures criteria present on literature for damage detection in composite material. Composites, due its constitutive form, develop complex failure mechanisms and the several criteria try to identify damage considering some mechanisms, disregarding others. Considering a flexible pipe application in 3000 m of deep-water, the loading estimated for riser section are used to calculate stress on composite material (present on tensile armour) and verify failure detection for each criteria.