Research On Finite Element Application Of Submarine Pipeline Design

Submarine pipeline is an important part of offshore oil production system, whichconnects offshore oil production system, transportation system and storage system,even the offshore oil field and onshore oil field. With the development of offshore oilengineering, submarine pipelines are more and more necessary for that. Andsubmarine pipeline design work is also a vital part of submarine pipeline engineering.There is no meaning of sequent construction and operation without excellent designwork being as the basis of the whole submarine pipeline project. During thecollaboration with oversea companys since 1985, ours has learnt and mastered thetechnology of submarine pipeline design and ours design level are advancinggradually. However, there is still lay-behind by others nations compared with overseaadvanced level.Excel calculation sheet made according to the design standards and finiteelements analysis (FEA) are commonly tools used in design of submarine pipeline incivil and oversea. SUSPEND, OFFPIPE and AUTOPIPE are finite elements analysisprogram in common use. However, these programs are produced a long time ago andmake use of general input data and the characteristic of individual model is not in thecentral to analysis and calculation. Therefore accuracy has been influenced upon.The subject of dissertation is aiming to apply FEA theory and FEA software todesign of submarine pipeline. The dissertation does research on the subject by twopractical projects, and puts forward creatively FEA model on riser lifting and FEAmodel on pipeline cross. ANSYS is a general FEA tool in industry and three steps ofPREPROCESSOR, SOLUTION and POST are applied to submarine pipeline analysis.Compared ANSYS' analysis result and SUSPEND's that, the maximum stress comesforth in the same place however ANSYS' analysis result is more conservative thanSUSPEND's that.The other FEA model is about the crossing pipeline that one new builded pipelinewill pass through three old pipelines and the aim is to ensure the new pipeline security,which is very important. The dissertation builds up FE model for cross pipeline andmakes finite elements analysis. The analysis result indicates pipeline is safe andpipeline stress is in the control by modifing the concrete mat thickness to adjust thebend curvature of pipeline.Another subject is on boundary conditions of laying pipeline which is regarded ascontinuous beam and whose boundary conditions are stimulated by spring-contactelements.