Free spans or suspended spans normally occur in subsea pipelines due to the irregularity of seabed and/or the scouring action of sea water. A problem of significance to the free spans of subsea pipeline is that currents or waves flowing across pipelines can shed vortices and induce vibration which may cause fatigue damage to the pipelines. Natural frequencies of free spans are required when solving vibration amplitude and cyclic stresses in the free span. The natural frequency is usually calculated with simplified equations, where factors such as boundary conditions and axial forces are not accurately taken into account. In this study, the influence of boundary conditions, mass of hydrocarbon products, axial force, and multiple spans on the natural frequencies of pipeline are investigated and corresponding suggestions are provided for frequency calculation.
|Pages (from-to)||81 - 89|
|Number of pages||9|
|Journal||International Journal of Steel Structures|
|Publication status||Published - 2010|