| As is known to all, the ocean is one of earth’s most valuable natural resources in the21stcentury. It covers around70percent of the earth surface. Such a vast ocean explores abundantbiological resources, natural resources and mineral resources. However, with the continuouslyexploitation of oil on land and the gradual reduction of resource reserves, offshore oil and gasextraction has caused wide international concerns over the recent years. Subsea pipeline hasbeen used and developed in the marine oil and gas area for several decades. The steelpipelines have been widely used in most of the subsea pipelines, but there are many problemsin their cases, such as poor corrosion resistance, environmental pollution and high pipelinelaying cost. When composite pipeline came out, it well remedied for the steel pipeline’sdefect. Nowadays, in some foreign countries, lots of companies have already chosencomposite pipelines as the submarine pipelines. With the continuous development ofcomposite pipelines, it will be first choice for the subsea pipeline to displace the steel ones.Currently, the design of subsea pipelines’ laying specific to steel pipelines and thepipe-laying ship method, especially S-lay method has been widely used. Whereas, for thethermoplastic composite pipelines, due to the continuous manufacturing and bending, thereels stored around, the reel method would be the best choice. This paper mainly explores themechanics problem of thermoplastic composite reinforced pipe-laying.Firstly, because of the material property of thermoplastic composite reinforced pipelinesis very complex, there are no mature researches results can be referenced, it needs to useexperimental methods to conduct researches on pipeline mechanical property of thermoplasticcomposite material intensified ones and application of pipe-laying. The tests including:tension test, bent test and pipe-laying model test. It could be the judgment criteria for thepipelines destroy from the mechanical property tests. The pipe-laying model test would verifythe results of the nonlinear finite element method.Secondly, this paper introduces general finite element software (ABAQUS) to analysisthe thermoplastic composite pipe-laying condition in different water depth, to build pipeline’smodel, load steps, applied loads and boundary conditions. The wave flow load would be usedon the ABAQUS/AQUA module. After analysis the model, it could be taken out the pipeline configuration, tension of topside and bottom, bending moment distribution and so onfrom the computation structure. Through the experiments to verify the validity of finiteelement method and the analysis result of finite element method would further verify theanalysis result of pipe-laying from numeric iteration.Thirdly, this paper provides a new numerical computation method, through a largenumber of achievement researches from laying theory, combined with natural catenariestheory and foundation beam theory, and considered material tensile and bending properties.Specifically, using finite element divisions for suspension parts and natural catenaries ascalculation; considering the contact area of soil elastic and the foundation beam theory tocalculate, these methods’ calculation results are very close to the nonlinear finite elementcalculation results, especially on the key points. Finally, it shows the correctness on thenumerical calculation.Last but not least, this paper examines the thermoplastic composite pipeline installationstability problems through the tests and finite element numerical method, summarizes thefactors influencing the pipeline installation stability by loading different velocities andcontrolling pipeline weight analysis. All of them will give many significant conclusions onsome practical engineering and lead a further research direction on thermoplastic compositematerial reinforced pipeline. |
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