The Numerical Simulation And Optimal Design Of The Composite Catenary Riser

The development of human society dependents on the energy.As a non-renewable energy,oil is inseparable with our life.Offshore oil resource accounts for 34% of total global oil resource.Since oil and gas resource reduces rapidly on land and offshore area,it is urgent to exploit oil and gas resource in deep-sea area,which leading to lots of technical problems to the existing mining facilities.One of the most serious problem is that the traditional steel riser is too heavy because of its high density,and then the economic costs will increase sharply.In addition,poor corrosion resistance of steel in sea leads to a shorter life of the riser.Therefore,it is necessary to find a suitable material to replace traditional steel to exploit deep-sea oil and gas resources.Composite materials have many advantages such as small density,high strength,high stiffness,corrosion resistance,low thermal conductivity and strong ability to resist fatigue.Thus,it is a good choice to use composite riser instead of steel pipe to exploit deep-sea oil and gas resources.Although composite is not a kind of new material,the corresponding design is not mature as metal material.At the same time,the anisotropic characteristics of the composite material increase the difficulty of the riser design,so it is still necessary to carry out lots of research on deep-sea composite riser.In this paper,the integral model and partial model of composite riser is established in ANSYS based on the theory of compound material mechanics,then the mechanical properties of the composite riser can be obtained.Then,the riser's dangerous section and the design weaknesses are identified by analyzing the strength and stability of the composite riser.Finally,the composites layer and the joint of the composite riser have been optimized by the improved PSO algorithm based on ANSYS and MATLAB.The improved PSO algorithm is more advanced since it overcomes the shortcoming of easily falling into local extremum within traditional PSO algorithm.The results demonstrated that the ability to resist buckling has been improved,and the weight of the composite riser and the economic cost has been reduced by optimization.The conclusions obtained in this paper provide a certain theoretical reference basis for practical production.