Study On Impact Damage Mechanism Of Subsea Pipeline Based On Plastic Foundation String Model

Subsea pipelines are the lifelines for transporting ocean oil and gas during the production of offshore oil and gas fields.When the subsea pipeline is in operation,there are a large number of accidental loads caused by third-party activities that impact the subsea pipeline and cause subsea pipeline depression.Due to the special nature of its operating environment,once a subsea pipeline is leaked or damaged due to deformation after impact,it will have a huge harm on the production of offshore oil and gas fields and the marine environment.Therefore,accurately predicting the damage mechanism of the subsea pipeline after being impacted is of great significance for improving the safety of the subsea pipeline.In view of the theoretical analysis of the impact damage of subsea pipelines that are currently under researched,this paper divides the deformation of the subsea pipeline into the cross-sectional deformation and the generator deformation based on the plastic foundation string model.Through the virtual displacement principle,the energy balance equation is obtained and the pressure is taken into account.I established a dented model under the influence of internal and external pressure differences in subsea pipeline,and the relationship between the impact force and the depth of the dented has been solved under the fixed end and capped end.The results obtained were verified with the two empirical formulas and the finite element model calculation results.Finally,this paper analyzes the parameters of the pressure level and the ratio of diameter to thickness,which provides a good reference for manufacture and the safety of the subsea pipeline.