The Finite Elenment Analysis Of The Collision In Deep Water Risers

The riser is one of the most important parts of the structure structural system of the offshore engineering and is weak and is easy to damage. Because of the complexity of the environment, the risers are sensitive to many factors. The risers are damaged and fatigue due to impact between the risers that result from the internal and external fluids, which causes not only project loss but also the environment pollution. Therefore it is necessary to do the structure mechanic analysis of risers.This paper will study the collision between the deep-water risers by the finite element software ABAQUS. At present, when dynamic response to the collision between the risers is obtained on the assumption that the risers are the rigid body and normal when impacting in the most of the researches. However it is more reasonable that we view the risers as the transformative body and they are not normal when impacting when obtain the dynamic response to the collision between the risers. The oblique impact mentioned in this study includes oblique impact in view of geometry and velocity. The former means that the risers are at angle geometrically in the case of the same impact velocity and the latter means that the orientation of the riser velocity is different and is at angle in case that the geometry angle between the risers is invariable—they are at the angle of 90 in this study. Explicit dynamics method is used to analyze the structural behavior of the collision of adjacent risers in Spar platform. In this study, a 3D finite element analysis based on explicit dynamics was carried out to investigate the dynamic response to the collision between the adjacent risers in the different condition and the behavior established during the impact event.