| The construction of submarine pipelines during collection and delivery of gas and oil is increasing with the exploration and utilization on the offshore oil/gas resource in China.Seismic loading ought to be taken into account while constructing submarine pipelines in the seismic active zones, especially in offshore area of China. State of the art of dynamic characteristics study on submarine pipeline from domestic and foreign specialists is discussed in the paper. Considering the effects of terrestrial and submarine pipeline, input direction of seismic wave, water depth, span, proximity from the seabed, support conditions at pipeline ends and different transmitting materials in the pipe on dynamic response, 120 groups of dynamic model experiments simulating free spanning submarine pipeline were achieved on an underwater shaking table.Meanwhile, the natural frequency of experimental model for each case is compared and in good agreement with that of theoretical analysis basing on the dynamic governing equation of free spanning submarine pipeline derived from Morison equation. According to the equation, numerical analysis was carried out by finite element method. The results display that the computation may correspond with the experiment very well.The other model is founded for the response of free spanning submarine pipelines due to the lift forces, and a fatigue assessment process is expounded in detail. The response of the suspended span and the elements affecting the response are discussed, and the accumulated fatigue damage is computed. The Rayleigh damping that is introduced in solving the above two equations is greatly simplified the solving process. |
