| The riser is one of the important equipment of development of the offshore oil and gas. More than shallow sea, marine environment of deep sea riser is more bad. So, the requirement of deep sea oil drilling riser about the material selection, structure and manufacturing installation process is very high, generally single riser is very difficult to achieve this standard. At present, the composite riser is widely applied in deep sea oil field because of its rich structure, good mechanical properties. Because the force of the riser under the sea is complex when working, the response of the riser under various loading conditions needs to be considered.In this paper, the research content is as follows:(1) A kind of deep sea oil drilling riser with a high tensile performance was designed. The riser uses high tensile strength of steel strip as the outer layer material wrapped in strength level was relatively low can be welded pipe outer wall, including the riser tube, axial steel belt layer and layer 2 different Angle of spiral steel band. The design adopted the mechanical connection of two kinds of welding of high strength steel, the structures of the riser were abundant. Not only high strength, light weight and no weld, greatly improving the riser in the strength of the joint.(2) Structural response analysis model of the proposed composite riser under bending load was proposed and the relationship between the strip layer strain and laid of spiral angle was deduced in polar coordinates, through the principle of equal strain energy with the moment to do work outside, it was concluded that the composite pipe spiral steel belt layer and calculation formula of bending stiffness of composite bending of the stand pipe at the mechanism of response characteristics.(3) The response of the riser under axisymmetric load was analyzed. First of all, unknown variables of response of each layer under the axisymmetric load was given; Then, equations corresponding to unknown variables was deduce according to the balance equation, constitutive equation and the deformation coordination equation; Finally, the response of the pipe under the action of axisymmetric load equation is obtained, and relationship between the spiral steel strip layer laying angle and complex of the overall response was discussed.(4) Numerical simulation of the compound riser model was conducted the structural response of the composite riser under bending load, axial force and axial torque was respectively analysed. Parameterized modeling of pipe spiral steel belt layer was conducted using ANSYS APDL language script, then model was imported into finite element software ABAQUS. The longitudinal changes along the riser of Composite pipe spiral axial stress of the steel strip layer was obtained by calculating and the overall response of the riser was obtained, and the stiffness calculation results with the theoretical calculation results were compared. |
