Study on lateral vibration analysis of marine riser in installation-via variational approach

In this paper, a dynamic analysis model has been established to analyze lateral vibration of marine riser in installation. The governing differential equation has been deduced by variation method. The general formula of riser lateral dynamical response has also been obtained through analyzing the analysis model and the boundary conditions. In this model, the riser is regarded as a beam suspended in the floating drilling platform (ship) and subjected to the axial force and the lateral forces changes with time and water depth (WD). Finally, the expression of the lateral vibration has been obtained and the maximum lateral vibration displacement variations with WD, riser size, weight of Blow out preventers and Lower Marine Risers Package (BOPS/LMRP), wave height and wave period have also been discussed.