Fiber reinforced polymeric laminated materials are suitable for risers in deep-sea applications due to their superior strength, corrosion and fatigue resistance, light weight, low maintenance cost, low transportation cost, and ability for continuous manufacturing. However, due to their anisotropic material properties, the modeling of the dynamic response due to interaction with the internal flow and the sea water is more complicated. In the present work a model for flow induced instability analysis of long, multi-layered, fiber reinforced risers is performed. The motion equations take into account the elastic flexural restoring force of the anisotropic material, the centrifugal force of the fluid flowing in curved portions of the pipe, the Corriolis force, the inertia force of the mass of pump, pipe, and fluid, and the effect of the surrounding water. Combination of the motion equations yields a fourth order partial differential equation in terms of flexural displacements. The transfer matrix method is implemented to the above equation for the critical flow velocities calculation. The “global stiffness matrix” of the pipe-pump system containing the boundary conditions, the anisotropic material properties and the flow parameters, is derived. The condition for non-trivial solution is solved numerically yielding the values of the critical flow velocity, i.e. the internal flow velocity causing flow induced pipeline instability. The results are affected by the anisotropic properties of the material, the mass of the hanged pump, the drag coefficient, and the flow parameters. The results are commented and discussed.

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