The rigid finite element and segment methods in dynamic analysis of risers

摘要

Dynamic analysis of risers used for transporting hydrocarbons from the bottom of the sea to tanks placed on vessels or platforms requires consideration of the influence of the water environment. Risers are long pipes (as long as 3000 m) with diameters of 0.3-0.6 m and with dominant bending flexibility; thus the deflections may be large. Appropriate discretisation, and consideration of the influence of the sea floor, waves, currents, drag and buoyancy forces, are essential for numerical static and dynamic analysis of risers. The paper presents riser models obtained by means of the segment method with joint (JSM) and absolute (ASM) coordinates as well as by means of the rigid finite element method (RFEM), together with the applications of the models. Aspects concerned with numerical effectiveness of these methods in dynamic analysis of risers are discussed.