Composite Materials Marine Riser Buckling And Arrestor Research

With the development of society,energy is becoming more and more important.People begin to turn their eyes to the rich resources of the vast ocean.Marine riser is an important component of offshore oil and gas transportation,with respect to the metal riser,the composite material has the advantages of good flexibility,corrosion resistance,convenient transportation and installation,become a new choice for offshore oil and gas pipeline.However,it is easier to buckling than the traditional steel tube in the ocean environment due to the bad ocean conditions.Therefore,the study of buckling and buckling of composite risers are beneficial to theoretical and practical significance for the production,erection,service and maintenance of composite risers.In this paper,in order to investigate the factors that affect the buckling resistance of composite risers,first of all,based on the nonlinear ring theory and the virtual work principle,a model for buckling analysis of composite risers is established.Explored the influence of the geometry(length,diameter,thickness),layer angle and the number of layers on composite pipe anti buckling capacity by using ANSYS and ABAQUS software,and optimization of the composite riser model size.Then,in order to accord with the actual condition of the composite riser,the original pipe model are respectively applied three kinds of initial defect: initial displacement imperfection and initial ellipticity and delamination defects.Whereafter,exploring the effect of three kinds of initial defects on the composite riser ability to resist buckling,and analyze the mechanism that how initial defects make effect on composite riser ability to resist buckling.Finally,based on the above research results,this paper design a grouted slip-on arrestor that conforms to the composite riser,Explore the effect and action principle of buckle arrestor,and explore buckle arrestor effect with initial defects.Thus,it can be used as a basis theoretical about the design and installation of the buckle arrestor.Meanwhile,it also provides some guidance for the design,installation and mai ntenance of composite riser.From the above research results,found that the longer the riser is,the thinner the riser is,the weaker the ability to resist buckling is.The higher the number of risers,the stronger the ability to resist buckling is.The two kinds bility to resist buckling of the composite riser are opposite.The two ability to resist buckling of the riser is quite balanced,when the layer angle is about 50 degrees.According to the research found that initial defect have a huge effection on the composite riser ability to resist buckling.And the mechanism of the initial defect affects ability to resist buckling of the riser is that: The initial defect causes the riser more easily local buckling due to external pressure,then propagating buckles to the entire riser,causing the riser to collapsed.In addition It is helpful to improve the ability to resist buckling of the buckle arrestor,and the mechanism of buckle arrestor affects ability to resist buckling is that: the buckle arrestor can impede the propagating of buckle,the higher order buckling mode is presented,thus enhancing the resistance to buckling of the riser.Moreover,the initial defects has a certain inhibitory on the effect of the buckle arrestor.