Failure Analysis Of Deepwater Oil And Gas Transportation Sandwich Pipes

Oil and gas resources are currently the world's major energy supply.With the rapid development of society and economy,people have shifted their exploration of oil and gas resources from shallow seas to deep seas.Performance analysis of deepwater underwater structures is an important direction for China's current development of offshore oil.As the "lifeline" in marine oil and gas production systems,it has practical significance and necessity to work on the characterization of marine pipeline structure.Due to the high hydrostatic pressure in deep water environment,this paper will focus on the study of the buckling failure of marine pipeline structures under hydrostatic pressure.In this paper,firstly,through theoretical derivation,the critical pressure calculation formula for thick-walled pipes is proposed and extended to calculate the critical buckling pressure of sandwich pipes.Then,based on the constant defect modal method,the finite element numerical model containing the initial defect pipeline was established using ABAQUS finite element software,and the buckling characteristics of the pipeline with defects were numerically simulated.This article is mainly divided into 4 chapters,the main content is as follows:(1)The deep-water underwater sandwich tube structure was introduced,and the buckling failure problem of the sandwich tube structure was introduced.Based on the previous research on the buckling of the pipe was clarified,and the necessity of the study was explained.(2)By introducing the plastic yielding layer and cracking layer in a thick-walled circular tube,the formula for the critical buckling pressure of a thick-walled tube under external pressure is derived theoretically,and based on the assumption that there is no bonding between layers,the The method was applied to the calculation of the critical buckling pressure of a non-bonded sandwich tube structure.The critical buckling pressures of the single-layer tube and the sandwich tube were calculated using the calculation method of this paper,and by compared with the existing research results,the rationality of the method was verified.(3)This paper described the specific flow of structural analysis by finite element numerical method,and summarized the method of buckling analysis of the structure in ABAQUS.The theoretical basis for the buckling stability analysis of the pipe structure using the finite element method is described in detail.(4)A numerical calculation model of sandwich pipe under external pressure was established by the finite element method,of which the interlayer pipe filled with strain-hardening cement-based material.In addition the nonlinear buckling analysis andeigenvalue buckling analysis were performed by a case study.By a wide range of parameters,the effect of geometric parameters and material parameters on the buckling performance of the sandwich pipe structure was studied.